gamma rays detectors 1) comparative characteristics of detectors 2) scintillation detectors 3)...
TRANSCRIPT
Gamma rays detectors
1) Comparative characteristics of detectors
2) Scintillation detectors
3) Semiconductor detectors
4) Crystal diffraction spectrometers
HPGE detectors of satellite INTEGRAL
Energie [keV]
Poč
et HPGe
Plastic
NaI(Tl)
CZT
Comparison of natural background spectra detected by different types of detectors (taken from presentation of ORTEC company)
BGO crystals from Novosibirsk
NaI(Tl) detectorfor satelliteFermi
Comparative characteristics of detectors
Sensitivity ndash capability to produce measurable signal for given type of particle and energy Depends on 1) cross-section of ionization reactions photon reactions 2) detector mass its construction 3) detector noise 4) thickness and type of material surrounding sensitive detector volume
Response ndash relation between particle energy and detector output (total charge or current amplitude of pulse)
Response function F(EEacute) - spectrum S(Eacute) of monoenergetic beam is observed by detector as complicated function Usually near to Gauss function with tail to lower energies Measured distribution of pulse amplitude P(E)
E ndash energy at measured spectrum Eacute- initial energy
Time response ndash time of detector signal creation
Pulse form ndash detector signal shape leading edge declining (even more components) fast component slow component
EdEEFESEP )()()(
1) detector is not sensitive2) Detector is always sensitive ndash bdquopile-upldquo is created ndash amplitude superposition
Death time ndash time needed for creation and analysis of detector signal
Real number of particles NS = mT = k + mkτ
m ndash real count rate T ndash time of measurementk ndash number of registered cases
Case 1 (death time is not extended)
Real count rate
TkTk
m1
Case 2 (death time is extended)
Assumption death time τ is constant
Distribution of intervals t between signal arrivalmtemtP )(
then probability that t gt τ
mmt edtemtP )(
and relation between registration number k and real count rate m is mmTek
Dead time and its influence
Detection efficiency ndash ratio between number of detected particles and number of particles emitted by source ndash absolute efficiency It consists of intrinsic efficiency εVNI and geometrical efficiency (acceptance) εGEO ε = εVNIεGEO Standard ndash line 1332 keV of 60Co It is determined also relatively ndash detector comparably to standard (NaI(Tl) with sizes 762762 cm) in given geometry ( - distance 25 cm) εNaI = 012
Ratio between peak and Compton background ndash for gamma ray detectors ndash ratio between maximal amplitude in peak 1332 keV and mean value in the region 1040 ndash 1096 keV Energy resolution ndash the smallest distinguishable energy difference ΔE between two near energies Monoenergetic beam rarr ideally δ-function ndash practically peak with finite width (mostly Gauss shape) Resolution is presented in the form of full width at half maximum ndash FWHM) Relative resolution ΔEE in [] is also used differences from Gauss shape are given by FWTM ndash width in 110 of high FWFM ndash width 150 of high Gauss FWTMFWHM = 182 FWFMFWHM = 238 Also other distributions asymmetries electrostatic spectrometer ndash Lorentz shape
Detector absorbing only part of energy
Detector absorbing total energy (photon detectors)
Ionization and deexcitation ndash Poisson distribution rarr standard deviation
Number of created charge carriers photons hellip
(It is valid for scintillation semiconductor gas detectors)
Se
EN
N
where eS is mean energy needed for creation of charge carrier or photon
Relation between FWHM and σ for Gauss shape FWHM = 235 σ
FWHM ndash energy resolution
Deposited energy E freely fluctuate rarr Poisson distribution is valid
Deposited energy is fixed finite value rarr Poisson is not valid correction introduces Fano
where F ndash Fano correction
SsS
S eEee
EeNFWHME 352352352
NF SeEFFWHME 352
Relative energy resolution EE
eF
E
ER S 1
~352
Time resolution ndash the smallest resolvable time difference ndash definition similar to energy resolution
Space resolution ndash the smallest resolvable space difference ndash definition similar to previous
FWHM value is influenced by another factors absorption of charge carriers photons properties of electronic hellipIn the case of independent contributions (ΔE)2 = (ΔETN)2 + (ΔEPN)2 + (ΔEELEK)2 + hellip
Comparison of absolute and relative resolution for scintillation and semiconductor detectors
Illustration of downgrade of HPGE detector of INTEGRAL satellite after irradiation (AThevenina report)
Tolerance to radiation damages ndash irradiation rarr damages crystal lattice defects bugs less sensitive ndash liquid and gas detectors more sensitive ndash scintillation and mainly semiconductor detectors
Shape after irradiation
Gauss shape before irradiation
Detectors work in strong radiation field During experiments on accelerators
Sometime gradual regeneration is possible HPGe detector is possible to regenerate after warming
Scintillation detectors
Scintillation detector 1) Scintillator 2) Photomultiplier + magnetic shielding (or photodiode) 3) Base
Ionization radiation passage rarr excitation of atoms a moleculesdeexcitation rarr energy rarr light production - luminescence
Information 1) Energy 2) Time ndash they are fast 3) Particle identification from pulse shape
Fluorescency ndash fast energy conversion to light 10-8sPhosphorescency - delayed energy conversion to light μs ndash days ndash longer λ
Properties of photomultipliers photodiodesavalanche photodiodes ndash see literature
Discharge has exponential behavior
R
t
eNN
0
PR
tt
eBeAN
One-component
Binary
τR ndash fast component τP ndash slow component
Požadavky na scintilator
1) High efficiency of excitation energy conversion to fluorescent light2) Conversion should be linear3) Transparency for fluorescence light (light emission should be in different range than light absorption4) Fluorescent spectrum should be compatible with photomultipliers5) Short decay constant 6) It should have good optical properties and easily machinable7) Index of refraction should be near to n = 15 (glass) ndash good crossing passage of light to photomultiplier
Example of signal shape of binary scintillator
ρ [gcm3] eS [eV] τ [ns]Anthracene ~08 60 30Plastic (NE111) ~12 100 17NaI 367 25 230BGO 713 300 300BaF2 489 125 06 (fast c) 600 (slow k)
Organic scintillators 1) Organic crystals ndash anthracene stilbene 2) Liquid organic scintillators very resistive against radiation damage measured radioactive substance can be part of detector 3) Plastic scintillators ndash very fast τ ~ 2 ns NE111 τleading edge = 02 ns and τ = 17 ns lower Z rarr small σ for photoeffect Compton scattering dominates addition of heavy element admixture (Pb) rarr increasing of photopeak decreasing of light output
Inorganic scintillators are slower higher Z rarr more suitable for gamma radiation CsI(Tl) NaI(Tl) (is hygroscopic) BGO (Bi4Ge3O12) BaF2PbWO4
BGO BaF2 PbWO4 very useful for high energy gamma BaF2 very fast (fast component) two components
Fano coefficient is for scintillators F ~ 1Limiting theoretical resolution without inclusion of influence of electronic and charge carrier trapping
Crystal PbWO4 of high energy photon spectrometer of project ALICEblue λ= 420 nm and green λ= 480-520 nm
BaF2 crystals of photon spectrometer TAPS
ultraviolet components λ=220nm and λ=310 nm
TA
PS
an
d A
LIC
E p
hot
o m
ater
ials
Semiconductor detectors
Very common HPGe (earlier Ge(Li)) ndash need liquid nitrogen cooling Si ndash for low energy range
Newer and up to now more special CdTe HgI2 CdZnTe (CZT) ndash up to now for lower energies cooling is not necessary eS ~ 44 eV
Ge Si ndash four valence electrons ndash electron release (its transposition from valence to conduction band) rarr creation of hole and free electron
Impurity with 3 valence electrons ndash electron recipient rarr rarr hole predominance rarr semiconductor of p typeImpurity with 5 valence electrons ndash electron donor rarr rarr predominance of electrons rarr semiconductor of n type
Ge(Li) detector ndash 1012 impurity atoms per cm3
HPGe ndash 109 impurity atoms per cm3
Prevention of thermal production of electron-hole pairs rarr temperature 77 K
Capture and recombination on dislocations and impuritiesHPGe detector placed inside Shielding lead box
WW
W p
ages
of
W W
estm
aier
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
Comparative characteristics of detectors
Sensitivity ndash capability to produce measurable signal for given type of particle and energy Depends on 1) cross-section of ionization reactions photon reactions 2) detector mass its construction 3) detector noise 4) thickness and type of material surrounding sensitive detector volume
Response ndash relation between particle energy and detector output (total charge or current amplitude of pulse)
Response function F(EEacute) - spectrum S(Eacute) of monoenergetic beam is observed by detector as complicated function Usually near to Gauss function with tail to lower energies Measured distribution of pulse amplitude P(E)
E ndash energy at measured spectrum Eacute- initial energy
Time response ndash time of detector signal creation
Pulse form ndash detector signal shape leading edge declining (even more components) fast component slow component
EdEEFESEP )()()(
1) detector is not sensitive2) Detector is always sensitive ndash bdquopile-upldquo is created ndash amplitude superposition
Death time ndash time needed for creation and analysis of detector signal
Real number of particles NS = mT = k + mkτ
m ndash real count rate T ndash time of measurementk ndash number of registered cases
Case 1 (death time is not extended)
Real count rate
TkTk
m1
Case 2 (death time is extended)
Assumption death time τ is constant
Distribution of intervals t between signal arrivalmtemtP )(
then probability that t gt τ
mmt edtemtP )(
and relation between registration number k and real count rate m is mmTek
Dead time and its influence
Detection efficiency ndash ratio between number of detected particles and number of particles emitted by source ndash absolute efficiency It consists of intrinsic efficiency εVNI and geometrical efficiency (acceptance) εGEO ε = εVNIεGEO Standard ndash line 1332 keV of 60Co It is determined also relatively ndash detector comparably to standard (NaI(Tl) with sizes 762762 cm) in given geometry ( - distance 25 cm) εNaI = 012
Ratio between peak and Compton background ndash for gamma ray detectors ndash ratio between maximal amplitude in peak 1332 keV and mean value in the region 1040 ndash 1096 keV Energy resolution ndash the smallest distinguishable energy difference ΔE between two near energies Monoenergetic beam rarr ideally δ-function ndash practically peak with finite width (mostly Gauss shape) Resolution is presented in the form of full width at half maximum ndash FWHM) Relative resolution ΔEE in [] is also used differences from Gauss shape are given by FWTM ndash width in 110 of high FWFM ndash width 150 of high Gauss FWTMFWHM = 182 FWFMFWHM = 238 Also other distributions asymmetries electrostatic spectrometer ndash Lorentz shape
Detector absorbing only part of energy
Detector absorbing total energy (photon detectors)
Ionization and deexcitation ndash Poisson distribution rarr standard deviation
Number of created charge carriers photons hellip
(It is valid for scintillation semiconductor gas detectors)
Se
EN
N
where eS is mean energy needed for creation of charge carrier or photon
Relation between FWHM and σ for Gauss shape FWHM = 235 σ
FWHM ndash energy resolution
Deposited energy E freely fluctuate rarr Poisson distribution is valid
Deposited energy is fixed finite value rarr Poisson is not valid correction introduces Fano
where F ndash Fano correction
SsS
S eEee
EeNFWHME 352352352
NF SeEFFWHME 352
Relative energy resolution EE
eF
E
ER S 1
~352
Time resolution ndash the smallest resolvable time difference ndash definition similar to energy resolution
Space resolution ndash the smallest resolvable space difference ndash definition similar to previous
FWHM value is influenced by another factors absorption of charge carriers photons properties of electronic hellipIn the case of independent contributions (ΔE)2 = (ΔETN)2 + (ΔEPN)2 + (ΔEELEK)2 + hellip
Comparison of absolute and relative resolution for scintillation and semiconductor detectors
Illustration of downgrade of HPGE detector of INTEGRAL satellite after irradiation (AThevenina report)
Tolerance to radiation damages ndash irradiation rarr damages crystal lattice defects bugs less sensitive ndash liquid and gas detectors more sensitive ndash scintillation and mainly semiconductor detectors
Shape after irradiation
Gauss shape before irradiation
Detectors work in strong radiation field During experiments on accelerators
Sometime gradual regeneration is possible HPGe detector is possible to regenerate after warming
Scintillation detectors
Scintillation detector 1) Scintillator 2) Photomultiplier + magnetic shielding (or photodiode) 3) Base
Ionization radiation passage rarr excitation of atoms a moleculesdeexcitation rarr energy rarr light production - luminescence
Information 1) Energy 2) Time ndash they are fast 3) Particle identification from pulse shape
Fluorescency ndash fast energy conversion to light 10-8sPhosphorescency - delayed energy conversion to light μs ndash days ndash longer λ
Properties of photomultipliers photodiodesavalanche photodiodes ndash see literature
Discharge has exponential behavior
R
t
eNN
0
PR
tt
eBeAN
One-component
Binary
τR ndash fast component τP ndash slow component
Požadavky na scintilator
1) High efficiency of excitation energy conversion to fluorescent light2) Conversion should be linear3) Transparency for fluorescence light (light emission should be in different range than light absorption4) Fluorescent spectrum should be compatible with photomultipliers5) Short decay constant 6) It should have good optical properties and easily machinable7) Index of refraction should be near to n = 15 (glass) ndash good crossing passage of light to photomultiplier
Example of signal shape of binary scintillator
ρ [gcm3] eS [eV] τ [ns]Anthracene ~08 60 30Plastic (NE111) ~12 100 17NaI 367 25 230BGO 713 300 300BaF2 489 125 06 (fast c) 600 (slow k)
Organic scintillators 1) Organic crystals ndash anthracene stilbene 2) Liquid organic scintillators very resistive against radiation damage measured radioactive substance can be part of detector 3) Plastic scintillators ndash very fast τ ~ 2 ns NE111 τleading edge = 02 ns and τ = 17 ns lower Z rarr small σ for photoeffect Compton scattering dominates addition of heavy element admixture (Pb) rarr increasing of photopeak decreasing of light output
Inorganic scintillators are slower higher Z rarr more suitable for gamma radiation CsI(Tl) NaI(Tl) (is hygroscopic) BGO (Bi4Ge3O12) BaF2PbWO4
BGO BaF2 PbWO4 very useful for high energy gamma BaF2 very fast (fast component) two components
Fano coefficient is for scintillators F ~ 1Limiting theoretical resolution without inclusion of influence of electronic and charge carrier trapping
Crystal PbWO4 of high energy photon spectrometer of project ALICEblue λ= 420 nm and green λ= 480-520 nm
BaF2 crystals of photon spectrometer TAPS
ultraviolet components λ=220nm and λ=310 nm
TA
PS
an
d A
LIC
E p
hot
o m
ater
ials
Semiconductor detectors
Very common HPGe (earlier Ge(Li)) ndash need liquid nitrogen cooling Si ndash for low energy range
Newer and up to now more special CdTe HgI2 CdZnTe (CZT) ndash up to now for lower energies cooling is not necessary eS ~ 44 eV
Ge Si ndash four valence electrons ndash electron release (its transposition from valence to conduction band) rarr creation of hole and free electron
Impurity with 3 valence electrons ndash electron recipient rarr rarr hole predominance rarr semiconductor of p typeImpurity with 5 valence electrons ndash electron donor rarr rarr predominance of electrons rarr semiconductor of n type
Ge(Li) detector ndash 1012 impurity atoms per cm3
HPGe ndash 109 impurity atoms per cm3
Prevention of thermal production of electron-hole pairs rarr temperature 77 K
Capture and recombination on dislocations and impuritiesHPGe detector placed inside Shielding lead box
WW
W p
ages
of
W W
estm
aier
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
1) detector is not sensitive2) Detector is always sensitive ndash bdquopile-upldquo is created ndash amplitude superposition
Death time ndash time needed for creation and analysis of detector signal
Real number of particles NS = mT = k + mkτ
m ndash real count rate T ndash time of measurementk ndash number of registered cases
Case 1 (death time is not extended)
Real count rate
TkTk
m1
Case 2 (death time is extended)
Assumption death time τ is constant
Distribution of intervals t between signal arrivalmtemtP )(
then probability that t gt τ
mmt edtemtP )(
and relation between registration number k and real count rate m is mmTek
Dead time and its influence
Detection efficiency ndash ratio between number of detected particles and number of particles emitted by source ndash absolute efficiency It consists of intrinsic efficiency εVNI and geometrical efficiency (acceptance) εGEO ε = εVNIεGEO Standard ndash line 1332 keV of 60Co It is determined also relatively ndash detector comparably to standard (NaI(Tl) with sizes 762762 cm) in given geometry ( - distance 25 cm) εNaI = 012
Ratio between peak and Compton background ndash for gamma ray detectors ndash ratio between maximal amplitude in peak 1332 keV and mean value in the region 1040 ndash 1096 keV Energy resolution ndash the smallest distinguishable energy difference ΔE between two near energies Monoenergetic beam rarr ideally δ-function ndash practically peak with finite width (mostly Gauss shape) Resolution is presented in the form of full width at half maximum ndash FWHM) Relative resolution ΔEE in [] is also used differences from Gauss shape are given by FWTM ndash width in 110 of high FWFM ndash width 150 of high Gauss FWTMFWHM = 182 FWFMFWHM = 238 Also other distributions asymmetries electrostatic spectrometer ndash Lorentz shape
Detector absorbing only part of energy
Detector absorbing total energy (photon detectors)
Ionization and deexcitation ndash Poisson distribution rarr standard deviation
Number of created charge carriers photons hellip
(It is valid for scintillation semiconductor gas detectors)
Se
EN
N
where eS is mean energy needed for creation of charge carrier or photon
Relation between FWHM and σ for Gauss shape FWHM = 235 σ
FWHM ndash energy resolution
Deposited energy E freely fluctuate rarr Poisson distribution is valid
Deposited energy is fixed finite value rarr Poisson is not valid correction introduces Fano
where F ndash Fano correction
SsS
S eEee
EeNFWHME 352352352
NF SeEFFWHME 352
Relative energy resolution EE
eF
E
ER S 1
~352
Time resolution ndash the smallest resolvable time difference ndash definition similar to energy resolution
Space resolution ndash the smallest resolvable space difference ndash definition similar to previous
FWHM value is influenced by another factors absorption of charge carriers photons properties of electronic hellipIn the case of independent contributions (ΔE)2 = (ΔETN)2 + (ΔEPN)2 + (ΔEELEK)2 + hellip
Comparison of absolute and relative resolution for scintillation and semiconductor detectors
Illustration of downgrade of HPGE detector of INTEGRAL satellite after irradiation (AThevenina report)
Tolerance to radiation damages ndash irradiation rarr damages crystal lattice defects bugs less sensitive ndash liquid and gas detectors more sensitive ndash scintillation and mainly semiconductor detectors
Shape after irradiation
Gauss shape before irradiation
Detectors work in strong radiation field During experiments on accelerators
Sometime gradual regeneration is possible HPGe detector is possible to regenerate after warming
Scintillation detectors
Scintillation detector 1) Scintillator 2) Photomultiplier + magnetic shielding (or photodiode) 3) Base
Ionization radiation passage rarr excitation of atoms a moleculesdeexcitation rarr energy rarr light production - luminescence
Information 1) Energy 2) Time ndash they are fast 3) Particle identification from pulse shape
Fluorescency ndash fast energy conversion to light 10-8sPhosphorescency - delayed energy conversion to light μs ndash days ndash longer λ
Properties of photomultipliers photodiodesavalanche photodiodes ndash see literature
Discharge has exponential behavior
R
t
eNN
0
PR
tt
eBeAN
One-component
Binary
τR ndash fast component τP ndash slow component
Požadavky na scintilator
1) High efficiency of excitation energy conversion to fluorescent light2) Conversion should be linear3) Transparency for fluorescence light (light emission should be in different range than light absorption4) Fluorescent spectrum should be compatible with photomultipliers5) Short decay constant 6) It should have good optical properties and easily machinable7) Index of refraction should be near to n = 15 (glass) ndash good crossing passage of light to photomultiplier
Example of signal shape of binary scintillator
ρ [gcm3] eS [eV] τ [ns]Anthracene ~08 60 30Plastic (NE111) ~12 100 17NaI 367 25 230BGO 713 300 300BaF2 489 125 06 (fast c) 600 (slow k)
Organic scintillators 1) Organic crystals ndash anthracene stilbene 2) Liquid organic scintillators very resistive against radiation damage measured radioactive substance can be part of detector 3) Plastic scintillators ndash very fast τ ~ 2 ns NE111 τleading edge = 02 ns and τ = 17 ns lower Z rarr small σ for photoeffect Compton scattering dominates addition of heavy element admixture (Pb) rarr increasing of photopeak decreasing of light output
Inorganic scintillators are slower higher Z rarr more suitable for gamma radiation CsI(Tl) NaI(Tl) (is hygroscopic) BGO (Bi4Ge3O12) BaF2PbWO4
BGO BaF2 PbWO4 very useful for high energy gamma BaF2 very fast (fast component) two components
Fano coefficient is for scintillators F ~ 1Limiting theoretical resolution without inclusion of influence of electronic and charge carrier trapping
Crystal PbWO4 of high energy photon spectrometer of project ALICEblue λ= 420 nm and green λ= 480-520 nm
BaF2 crystals of photon spectrometer TAPS
ultraviolet components λ=220nm and λ=310 nm
TA
PS
an
d A
LIC
E p
hot
o m
ater
ials
Semiconductor detectors
Very common HPGe (earlier Ge(Li)) ndash need liquid nitrogen cooling Si ndash for low energy range
Newer and up to now more special CdTe HgI2 CdZnTe (CZT) ndash up to now for lower energies cooling is not necessary eS ~ 44 eV
Ge Si ndash four valence electrons ndash electron release (its transposition from valence to conduction band) rarr creation of hole and free electron
Impurity with 3 valence electrons ndash electron recipient rarr rarr hole predominance rarr semiconductor of p typeImpurity with 5 valence electrons ndash electron donor rarr rarr predominance of electrons rarr semiconductor of n type
Ge(Li) detector ndash 1012 impurity atoms per cm3
HPGe ndash 109 impurity atoms per cm3
Prevention of thermal production of electron-hole pairs rarr temperature 77 K
Capture and recombination on dislocations and impuritiesHPGe detector placed inside Shielding lead box
WW
W p
ages
of
W W
estm
aier
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
Detection efficiency ndash ratio between number of detected particles and number of particles emitted by source ndash absolute efficiency It consists of intrinsic efficiency εVNI and geometrical efficiency (acceptance) εGEO ε = εVNIεGEO Standard ndash line 1332 keV of 60Co It is determined also relatively ndash detector comparably to standard (NaI(Tl) with sizes 762762 cm) in given geometry ( - distance 25 cm) εNaI = 012
Ratio between peak and Compton background ndash for gamma ray detectors ndash ratio between maximal amplitude in peak 1332 keV and mean value in the region 1040 ndash 1096 keV Energy resolution ndash the smallest distinguishable energy difference ΔE between two near energies Monoenergetic beam rarr ideally δ-function ndash practically peak with finite width (mostly Gauss shape) Resolution is presented in the form of full width at half maximum ndash FWHM) Relative resolution ΔEE in [] is also used differences from Gauss shape are given by FWTM ndash width in 110 of high FWFM ndash width 150 of high Gauss FWTMFWHM = 182 FWFMFWHM = 238 Also other distributions asymmetries electrostatic spectrometer ndash Lorentz shape
Detector absorbing only part of energy
Detector absorbing total energy (photon detectors)
Ionization and deexcitation ndash Poisson distribution rarr standard deviation
Number of created charge carriers photons hellip
(It is valid for scintillation semiconductor gas detectors)
Se
EN
N
where eS is mean energy needed for creation of charge carrier or photon
Relation between FWHM and σ for Gauss shape FWHM = 235 σ
FWHM ndash energy resolution
Deposited energy E freely fluctuate rarr Poisson distribution is valid
Deposited energy is fixed finite value rarr Poisson is not valid correction introduces Fano
where F ndash Fano correction
SsS
S eEee
EeNFWHME 352352352
NF SeEFFWHME 352
Relative energy resolution EE
eF
E
ER S 1
~352
Time resolution ndash the smallest resolvable time difference ndash definition similar to energy resolution
Space resolution ndash the smallest resolvable space difference ndash definition similar to previous
FWHM value is influenced by another factors absorption of charge carriers photons properties of electronic hellipIn the case of independent contributions (ΔE)2 = (ΔETN)2 + (ΔEPN)2 + (ΔEELEK)2 + hellip
Comparison of absolute and relative resolution for scintillation and semiconductor detectors
Illustration of downgrade of HPGE detector of INTEGRAL satellite after irradiation (AThevenina report)
Tolerance to radiation damages ndash irradiation rarr damages crystal lattice defects bugs less sensitive ndash liquid and gas detectors more sensitive ndash scintillation and mainly semiconductor detectors
Shape after irradiation
Gauss shape before irradiation
Detectors work in strong radiation field During experiments on accelerators
Sometime gradual regeneration is possible HPGe detector is possible to regenerate after warming
Scintillation detectors
Scintillation detector 1) Scintillator 2) Photomultiplier + magnetic shielding (or photodiode) 3) Base
Ionization radiation passage rarr excitation of atoms a moleculesdeexcitation rarr energy rarr light production - luminescence
Information 1) Energy 2) Time ndash they are fast 3) Particle identification from pulse shape
Fluorescency ndash fast energy conversion to light 10-8sPhosphorescency - delayed energy conversion to light μs ndash days ndash longer λ
Properties of photomultipliers photodiodesavalanche photodiodes ndash see literature
Discharge has exponential behavior
R
t
eNN
0
PR
tt
eBeAN
One-component
Binary
τR ndash fast component τP ndash slow component
Požadavky na scintilator
1) High efficiency of excitation energy conversion to fluorescent light2) Conversion should be linear3) Transparency for fluorescence light (light emission should be in different range than light absorption4) Fluorescent spectrum should be compatible with photomultipliers5) Short decay constant 6) It should have good optical properties and easily machinable7) Index of refraction should be near to n = 15 (glass) ndash good crossing passage of light to photomultiplier
Example of signal shape of binary scintillator
ρ [gcm3] eS [eV] τ [ns]Anthracene ~08 60 30Plastic (NE111) ~12 100 17NaI 367 25 230BGO 713 300 300BaF2 489 125 06 (fast c) 600 (slow k)
Organic scintillators 1) Organic crystals ndash anthracene stilbene 2) Liquid organic scintillators very resistive against radiation damage measured radioactive substance can be part of detector 3) Plastic scintillators ndash very fast τ ~ 2 ns NE111 τleading edge = 02 ns and τ = 17 ns lower Z rarr small σ for photoeffect Compton scattering dominates addition of heavy element admixture (Pb) rarr increasing of photopeak decreasing of light output
Inorganic scintillators are slower higher Z rarr more suitable for gamma radiation CsI(Tl) NaI(Tl) (is hygroscopic) BGO (Bi4Ge3O12) BaF2PbWO4
BGO BaF2 PbWO4 very useful for high energy gamma BaF2 very fast (fast component) two components
Fano coefficient is for scintillators F ~ 1Limiting theoretical resolution without inclusion of influence of electronic and charge carrier trapping
Crystal PbWO4 of high energy photon spectrometer of project ALICEblue λ= 420 nm and green λ= 480-520 nm
BaF2 crystals of photon spectrometer TAPS
ultraviolet components λ=220nm and λ=310 nm
TA
PS
an
d A
LIC
E p
hot
o m
ater
ials
Semiconductor detectors
Very common HPGe (earlier Ge(Li)) ndash need liquid nitrogen cooling Si ndash for low energy range
Newer and up to now more special CdTe HgI2 CdZnTe (CZT) ndash up to now for lower energies cooling is not necessary eS ~ 44 eV
Ge Si ndash four valence electrons ndash electron release (its transposition from valence to conduction band) rarr creation of hole and free electron
Impurity with 3 valence electrons ndash electron recipient rarr rarr hole predominance rarr semiconductor of p typeImpurity with 5 valence electrons ndash electron donor rarr rarr predominance of electrons rarr semiconductor of n type
Ge(Li) detector ndash 1012 impurity atoms per cm3
HPGe ndash 109 impurity atoms per cm3
Prevention of thermal production of electron-hole pairs rarr temperature 77 K
Capture and recombination on dislocations and impuritiesHPGe detector placed inside Shielding lead box
WW
W p
ages
of
W W
estm
aier
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
Detector absorbing only part of energy
Detector absorbing total energy (photon detectors)
Ionization and deexcitation ndash Poisson distribution rarr standard deviation
Number of created charge carriers photons hellip
(It is valid for scintillation semiconductor gas detectors)
Se
EN
N
where eS is mean energy needed for creation of charge carrier or photon
Relation between FWHM and σ for Gauss shape FWHM = 235 σ
FWHM ndash energy resolution
Deposited energy E freely fluctuate rarr Poisson distribution is valid
Deposited energy is fixed finite value rarr Poisson is not valid correction introduces Fano
where F ndash Fano correction
SsS
S eEee
EeNFWHME 352352352
NF SeEFFWHME 352
Relative energy resolution EE
eF
E
ER S 1
~352
Time resolution ndash the smallest resolvable time difference ndash definition similar to energy resolution
Space resolution ndash the smallest resolvable space difference ndash definition similar to previous
FWHM value is influenced by another factors absorption of charge carriers photons properties of electronic hellipIn the case of independent contributions (ΔE)2 = (ΔETN)2 + (ΔEPN)2 + (ΔEELEK)2 + hellip
Comparison of absolute and relative resolution for scintillation and semiconductor detectors
Illustration of downgrade of HPGE detector of INTEGRAL satellite after irradiation (AThevenina report)
Tolerance to radiation damages ndash irradiation rarr damages crystal lattice defects bugs less sensitive ndash liquid and gas detectors more sensitive ndash scintillation and mainly semiconductor detectors
Shape after irradiation
Gauss shape before irradiation
Detectors work in strong radiation field During experiments on accelerators
Sometime gradual regeneration is possible HPGe detector is possible to regenerate after warming
Scintillation detectors
Scintillation detector 1) Scintillator 2) Photomultiplier + magnetic shielding (or photodiode) 3) Base
Ionization radiation passage rarr excitation of atoms a moleculesdeexcitation rarr energy rarr light production - luminescence
Information 1) Energy 2) Time ndash they are fast 3) Particle identification from pulse shape
Fluorescency ndash fast energy conversion to light 10-8sPhosphorescency - delayed energy conversion to light μs ndash days ndash longer λ
Properties of photomultipliers photodiodesavalanche photodiodes ndash see literature
Discharge has exponential behavior
R
t
eNN
0
PR
tt
eBeAN
One-component
Binary
τR ndash fast component τP ndash slow component
Požadavky na scintilator
1) High efficiency of excitation energy conversion to fluorescent light2) Conversion should be linear3) Transparency for fluorescence light (light emission should be in different range than light absorption4) Fluorescent spectrum should be compatible with photomultipliers5) Short decay constant 6) It should have good optical properties and easily machinable7) Index of refraction should be near to n = 15 (glass) ndash good crossing passage of light to photomultiplier
Example of signal shape of binary scintillator
ρ [gcm3] eS [eV] τ [ns]Anthracene ~08 60 30Plastic (NE111) ~12 100 17NaI 367 25 230BGO 713 300 300BaF2 489 125 06 (fast c) 600 (slow k)
Organic scintillators 1) Organic crystals ndash anthracene stilbene 2) Liquid organic scintillators very resistive against radiation damage measured radioactive substance can be part of detector 3) Plastic scintillators ndash very fast τ ~ 2 ns NE111 τleading edge = 02 ns and τ = 17 ns lower Z rarr small σ for photoeffect Compton scattering dominates addition of heavy element admixture (Pb) rarr increasing of photopeak decreasing of light output
Inorganic scintillators are slower higher Z rarr more suitable for gamma radiation CsI(Tl) NaI(Tl) (is hygroscopic) BGO (Bi4Ge3O12) BaF2PbWO4
BGO BaF2 PbWO4 very useful for high energy gamma BaF2 very fast (fast component) two components
Fano coefficient is for scintillators F ~ 1Limiting theoretical resolution without inclusion of influence of electronic and charge carrier trapping
Crystal PbWO4 of high energy photon spectrometer of project ALICEblue λ= 420 nm and green λ= 480-520 nm
BaF2 crystals of photon spectrometer TAPS
ultraviolet components λ=220nm and λ=310 nm
TA
PS
an
d A
LIC
E p
hot
o m
ater
ials
Semiconductor detectors
Very common HPGe (earlier Ge(Li)) ndash need liquid nitrogen cooling Si ndash for low energy range
Newer and up to now more special CdTe HgI2 CdZnTe (CZT) ndash up to now for lower energies cooling is not necessary eS ~ 44 eV
Ge Si ndash four valence electrons ndash electron release (its transposition from valence to conduction band) rarr creation of hole and free electron
Impurity with 3 valence electrons ndash electron recipient rarr rarr hole predominance rarr semiconductor of p typeImpurity with 5 valence electrons ndash electron donor rarr rarr predominance of electrons rarr semiconductor of n type
Ge(Li) detector ndash 1012 impurity atoms per cm3
HPGe ndash 109 impurity atoms per cm3
Prevention of thermal production of electron-hole pairs rarr temperature 77 K
Capture and recombination on dislocations and impuritiesHPGe detector placed inside Shielding lead box
WW
W p
ages
of
W W
estm
aier
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
Time resolution ndash the smallest resolvable time difference ndash definition similar to energy resolution
Space resolution ndash the smallest resolvable space difference ndash definition similar to previous
FWHM value is influenced by another factors absorption of charge carriers photons properties of electronic hellipIn the case of independent contributions (ΔE)2 = (ΔETN)2 + (ΔEPN)2 + (ΔEELEK)2 + hellip
Comparison of absolute and relative resolution for scintillation and semiconductor detectors
Illustration of downgrade of HPGE detector of INTEGRAL satellite after irradiation (AThevenina report)
Tolerance to radiation damages ndash irradiation rarr damages crystal lattice defects bugs less sensitive ndash liquid and gas detectors more sensitive ndash scintillation and mainly semiconductor detectors
Shape after irradiation
Gauss shape before irradiation
Detectors work in strong radiation field During experiments on accelerators
Sometime gradual regeneration is possible HPGe detector is possible to regenerate after warming
Scintillation detectors
Scintillation detector 1) Scintillator 2) Photomultiplier + magnetic shielding (or photodiode) 3) Base
Ionization radiation passage rarr excitation of atoms a moleculesdeexcitation rarr energy rarr light production - luminescence
Information 1) Energy 2) Time ndash they are fast 3) Particle identification from pulse shape
Fluorescency ndash fast energy conversion to light 10-8sPhosphorescency - delayed energy conversion to light μs ndash days ndash longer λ
Properties of photomultipliers photodiodesavalanche photodiodes ndash see literature
Discharge has exponential behavior
R
t
eNN
0
PR
tt
eBeAN
One-component
Binary
τR ndash fast component τP ndash slow component
Požadavky na scintilator
1) High efficiency of excitation energy conversion to fluorescent light2) Conversion should be linear3) Transparency for fluorescence light (light emission should be in different range than light absorption4) Fluorescent spectrum should be compatible with photomultipliers5) Short decay constant 6) It should have good optical properties and easily machinable7) Index of refraction should be near to n = 15 (glass) ndash good crossing passage of light to photomultiplier
Example of signal shape of binary scintillator
ρ [gcm3] eS [eV] τ [ns]Anthracene ~08 60 30Plastic (NE111) ~12 100 17NaI 367 25 230BGO 713 300 300BaF2 489 125 06 (fast c) 600 (slow k)
Organic scintillators 1) Organic crystals ndash anthracene stilbene 2) Liquid organic scintillators very resistive against radiation damage measured radioactive substance can be part of detector 3) Plastic scintillators ndash very fast τ ~ 2 ns NE111 τleading edge = 02 ns and τ = 17 ns lower Z rarr small σ for photoeffect Compton scattering dominates addition of heavy element admixture (Pb) rarr increasing of photopeak decreasing of light output
Inorganic scintillators are slower higher Z rarr more suitable for gamma radiation CsI(Tl) NaI(Tl) (is hygroscopic) BGO (Bi4Ge3O12) BaF2PbWO4
BGO BaF2 PbWO4 very useful for high energy gamma BaF2 very fast (fast component) two components
Fano coefficient is for scintillators F ~ 1Limiting theoretical resolution without inclusion of influence of electronic and charge carrier trapping
Crystal PbWO4 of high energy photon spectrometer of project ALICEblue λ= 420 nm and green λ= 480-520 nm
BaF2 crystals of photon spectrometer TAPS
ultraviolet components λ=220nm and λ=310 nm
TA
PS
an
d A
LIC
E p
hot
o m
ater
ials
Semiconductor detectors
Very common HPGe (earlier Ge(Li)) ndash need liquid nitrogen cooling Si ndash for low energy range
Newer and up to now more special CdTe HgI2 CdZnTe (CZT) ndash up to now for lower energies cooling is not necessary eS ~ 44 eV
Ge Si ndash four valence electrons ndash electron release (its transposition from valence to conduction band) rarr creation of hole and free electron
Impurity with 3 valence electrons ndash electron recipient rarr rarr hole predominance rarr semiconductor of p typeImpurity with 5 valence electrons ndash electron donor rarr rarr predominance of electrons rarr semiconductor of n type
Ge(Li) detector ndash 1012 impurity atoms per cm3
HPGe ndash 109 impurity atoms per cm3
Prevention of thermal production of electron-hole pairs rarr temperature 77 K
Capture and recombination on dislocations and impuritiesHPGe detector placed inside Shielding lead box
WW
W p
ages
of
W W
estm
aier
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
Illustration of downgrade of HPGE detector of INTEGRAL satellite after irradiation (AThevenina report)
Tolerance to radiation damages ndash irradiation rarr damages crystal lattice defects bugs less sensitive ndash liquid and gas detectors more sensitive ndash scintillation and mainly semiconductor detectors
Shape after irradiation
Gauss shape before irradiation
Detectors work in strong radiation field During experiments on accelerators
Sometime gradual regeneration is possible HPGe detector is possible to regenerate after warming
Scintillation detectors
Scintillation detector 1) Scintillator 2) Photomultiplier + magnetic shielding (or photodiode) 3) Base
Ionization radiation passage rarr excitation of atoms a moleculesdeexcitation rarr energy rarr light production - luminescence
Information 1) Energy 2) Time ndash they are fast 3) Particle identification from pulse shape
Fluorescency ndash fast energy conversion to light 10-8sPhosphorescency - delayed energy conversion to light μs ndash days ndash longer λ
Properties of photomultipliers photodiodesavalanche photodiodes ndash see literature
Discharge has exponential behavior
R
t
eNN
0
PR
tt
eBeAN
One-component
Binary
τR ndash fast component τP ndash slow component
Požadavky na scintilator
1) High efficiency of excitation energy conversion to fluorescent light2) Conversion should be linear3) Transparency for fluorescence light (light emission should be in different range than light absorption4) Fluorescent spectrum should be compatible with photomultipliers5) Short decay constant 6) It should have good optical properties and easily machinable7) Index of refraction should be near to n = 15 (glass) ndash good crossing passage of light to photomultiplier
Example of signal shape of binary scintillator
ρ [gcm3] eS [eV] τ [ns]Anthracene ~08 60 30Plastic (NE111) ~12 100 17NaI 367 25 230BGO 713 300 300BaF2 489 125 06 (fast c) 600 (slow k)
Organic scintillators 1) Organic crystals ndash anthracene stilbene 2) Liquid organic scintillators very resistive against radiation damage measured radioactive substance can be part of detector 3) Plastic scintillators ndash very fast τ ~ 2 ns NE111 τleading edge = 02 ns and τ = 17 ns lower Z rarr small σ for photoeffect Compton scattering dominates addition of heavy element admixture (Pb) rarr increasing of photopeak decreasing of light output
Inorganic scintillators are slower higher Z rarr more suitable for gamma radiation CsI(Tl) NaI(Tl) (is hygroscopic) BGO (Bi4Ge3O12) BaF2PbWO4
BGO BaF2 PbWO4 very useful for high energy gamma BaF2 very fast (fast component) two components
Fano coefficient is for scintillators F ~ 1Limiting theoretical resolution without inclusion of influence of electronic and charge carrier trapping
Crystal PbWO4 of high energy photon spectrometer of project ALICEblue λ= 420 nm and green λ= 480-520 nm
BaF2 crystals of photon spectrometer TAPS
ultraviolet components λ=220nm and λ=310 nm
TA
PS
an
d A
LIC
E p
hot
o m
ater
ials
Semiconductor detectors
Very common HPGe (earlier Ge(Li)) ndash need liquid nitrogen cooling Si ndash for low energy range
Newer and up to now more special CdTe HgI2 CdZnTe (CZT) ndash up to now for lower energies cooling is not necessary eS ~ 44 eV
Ge Si ndash four valence electrons ndash electron release (its transposition from valence to conduction band) rarr creation of hole and free electron
Impurity with 3 valence electrons ndash electron recipient rarr rarr hole predominance rarr semiconductor of p typeImpurity with 5 valence electrons ndash electron donor rarr rarr predominance of electrons rarr semiconductor of n type
Ge(Li) detector ndash 1012 impurity atoms per cm3
HPGe ndash 109 impurity atoms per cm3
Prevention of thermal production of electron-hole pairs rarr temperature 77 K
Capture and recombination on dislocations and impuritiesHPGe detector placed inside Shielding lead box
WW
W p
ages
of
W W
estm
aier
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
Scintillation detectors
Scintillation detector 1) Scintillator 2) Photomultiplier + magnetic shielding (or photodiode) 3) Base
Ionization radiation passage rarr excitation of atoms a moleculesdeexcitation rarr energy rarr light production - luminescence
Information 1) Energy 2) Time ndash they are fast 3) Particle identification from pulse shape
Fluorescency ndash fast energy conversion to light 10-8sPhosphorescency - delayed energy conversion to light μs ndash days ndash longer λ
Properties of photomultipliers photodiodesavalanche photodiodes ndash see literature
Discharge has exponential behavior
R
t
eNN
0
PR
tt
eBeAN
One-component
Binary
τR ndash fast component τP ndash slow component
Požadavky na scintilator
1) High efficiency of excitation energy conversion to fluorescent light2) Conversion should be linear3) Transparency for fluorescence light (light emission should be in different range than light absorption4) Fluorescent spectrum should be compatible with photomultipliers5) Short decay constant 6) It should have good optical properties and easily machinable7) Index of refraction should be near to n = 15 (glass) ndash good crossing passage of light to photomultiplier
Example of signal shape of binary scintillator
ρ [gcm3] eS [eV] τ [ns]Anthracene ~08 60 30Plastic (NE111) ~12 100 17NaI 367 25 230BGO 713 300 300BaF2 489 125 06 (fast c) 600 (slow k)
Organic scintillators 1) Organic crystals ndash anthracene stilbene 2) Liquid organic scintillators very resistive against radiation damage measured radioactive substance can be part of detector 3) Plastic scintillators ndash very fast τ ~ 2 ns NE111 τleading edge = 02 ns and τ = 17 ns lower Z rarr small σ for photoeffect Compton scattering dominates addition of heavy element admixture (Pb) rarr increasing of photopeak decreasing of light output
Inorganic scintillators are slower higher Z rarr more suitable for gamma radiation CsI(Tl) NaI(Tl) (is hygroscopic) BGO (Bi4Ge3O12) BaF2PbWO4
BGO BaF2 PbWO4 very useful for high energy gamma BaF2 very fast (fast component) two components
Fano coefficient is for scintillators F ~ 1Limiting theoretical resolution without inclusion of influence of electronic and charge carrier trapping
Crystal PbWO4 of high energy photon spectrometer of project ALICEblue λ= 420 nm and green λ= 480-520 nm
BaF2 crystals of photon spectrometer TAPS
ultraviolet components λ=220nm and λ=310 nm
TA
PS
an
d A
LIC
E p
hot
o m
ater
ials
Semiconductor detectors
Very common HPGe (earlier Ge(Li)) ndash need liquid nitrogen cooling Si ndash for low energy range
Newer and up to now more special CdTe HgI2 CdZnTe (CZT) ndash up to now for lower energies cooling is not necessary eS ~ 44 eV
Ge Si ndash four valence electrons ndash electron release (its transposition from valence to conduction band) rarr creation of hole and free electron
Impurity with 3 valence electrons ndash electron recipient rarr rarr hole predominance rarr semiconductor of p typeImpurity with 5 valence electrons ndash electron donor rarr rarr predominance of electrons rarr semiconductor of n type
Ge(Li) detector ndash 1012 impurity atoms per cm3
HPGe ndash 109 impurity atoms per cm3
Prevention of thermal production of electron-hole pairs rarr temperature 77 K
Capture and recombination on dislocations and impuritiesHPGe detector placed inside Shielding lead box
WW
W p
ages
of
W W
estm
aier
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
Discharge has exponential behavior
R
t
eNN
0
PR
tt
eBeAN
One-component
Binary
τR ndash fast component τP ndash slow component
Požadavky na scintilator
1) High efficiency of excitation energy conversion to fluorescent light2) Conversion should be linear3) Transparency for fluorescence light (light emission should be in different range than light absorption4) Fluorescent spectrum should be compatible with photomultipliers5) Short decay constant 6) It should have good optical properties and easily machinable7) Index of refraction should be near to n = 15 (glass) ndash good crossing passage of light to photomultiplier
Example of signal shape of binary scintillator
ρ [gcm3] eS [eV] τ [ns]Anthracene ~08 60 30Plastic (NE111) ~12 100 17NaI 367 25 230BGO 713 300 300BaF2 489 125 06 (fast c) 600 (slow k)
Organic scintillators 1) Organic crystals ndash anthracene stilbene 2) Liquid organic scintillators very resistive against radiation damage measured radioactive substance can be part of detector 3) Plastic scintillators ndash very fast τ ~ 2 ns NE111 τleading edge = 02 ns and τ = 17 ns lower Z rarr small σ for photoeffect Compton scattering dominates addition of heavy element admixture (Pb) rarr increasing of photopeak decreasing of light output
Inorganic scintillators are slower higher Z rarr more suitable for gamma radiation CsI(Tl) NaI(Tl) (is hygroscopic) BGO (Bi4Ge3O12) BaF2PbWO4
BGO BaF2 PbWO4 very useful for high energy gamma BaF2 very fast (fast component) two components
Fano coefficient is for scintillators F ~ 1Limiting theoretical resolution without inclusion of influence of electronic and charge carrier trapping
Crystal PbWO4 of high energy photon spectrometer of project ALICEblue λ= 420 nm and green λ= 480-520 nm
BaF2 crystals of photon spectrometer TAPS
ultraviolet components λ=220nm and λ=310 nm
TA
PS
an
d A
LIC
E p
hot
o m
ater
ials
Semiconductor detectors
Very common HPGe (earlier Ge(Li)) ndash need liquid nitrogen cooling Si ndash for low energy range
Newer and up to now more special CdTe HgI2 CdZnTe (CZT) ndash up to now for lower energies cooling is not necessary eS ~ 44 eV
Ge Si ndash four valence electrons ndash electron release (its transposition from valence to conduction band) rarr creation of hole and free electron
Impurity with 3 valence electrons ndash electron recipient rarr rarr hole predominance rarr semiconductor of p typeImpurity with 5 valence electrons ndash electron donor rarr rarr predominance of electrons rarr semiconductor of n type
Ge(Li) detector ndash 1012 impurity atoms per cm3
HPGe ndash 109 impurity atoms per cm3
Prevention of thermal production of electron-hole pairs rarr temperature 77 K
Capture and recombination on dislocations and impuritiesHPGe detector placed inside Shielding lead box
WW
W p
ages
of
W W
estm
aier
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
ρ [gcm3] eS [eV] τ [ns]Anthracene ~08 60 30Plastic (NE111) ~12 100 17NaI 367 25 230BGO 713 300 300BaF2 489 125 06 (fast c) 600 (slow k)
Organic scintillators 1) Organic crystals ndash anthracene stilbene 2) Liquid organic scintillators very resistive against radiation damage measured radioactive substance can be part of detector 3) Plastic scintillators ndash very fast τ ~ 2 ns NE111 τleading edge = 02 ns and τ = 17 ns lower Z rarr small σ for photoeffect Compton scattering dominates addition of heavy element admixture (Pb) rarr increasing of photopeak decreasing of light output
Inorganic scintillators are slower higher Z rarr more suitable for gamma radiation CsI(Tl) NaI(Tl) (is hygroscopic) BGO (Bi4Ge3O12) BaF2PbWO4
BGO BaF2 PbWO4 very useful for high energy gamma BaF2 very fast (fast component) two components
Fano coefficient is for scintillators F ~ 1Limiting theoretical resolution without inclusion of influence of electronic and charge carrier trapping
Crystal PbWO4 of high energy photon spectrometer of project ALICEblue λ= 420 nm and green λ= 480-520 nm
BaF2 crystals of photon spectrometer TAPS
ultraviolet components λ=220nm and λ=310 nm
TA
PS
an
d A
LIC
E p
hot
o m
ater
ials
Semiconductor detectors
Very common HPGe (earlier Ge(Li)) ndash need liquid nitrogen cooling Si ndash for low energy range
Newer and up to now more special CdTe HgI2 CdZnTe (CZT) ndash up to now for lower energies cooling is not necessary eS ~ 44 eV
Ge Si ndash four valence electrons ndash electron release (its transposition from valence to conduction band) rarr creation of hole and free electron
Impurity with 3 valence electrons ndash electron recipient rarr rarr hole predominance rarr semiconductor of p typeImpurity with 5 valence electrons ndash electron donor rarr rarr predominance of electrons rarr semiconductor of n type
Ge(Li) detector ndash 1012 impurity atoms per cm3
HPGe ndash 109 impurity atoms per cm3
Prevention of thermal production of electron-hole pairs rarr temperature 77 K
Capture and recombination on dislocations and impuritiesHPGe detector placed inside Shielding lead box
WW
W p
ages
of
W W
estm
aier
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
Crystal PbWO4 of high energy photon spectrometer of project ALICEblue λ= 420 nm and green λ= 480-520 nm
BaF2 crystals of photon spectrometer TAPS
ultraviolet components λ=220nm and λ=310 nm
TA
PS
an
d A
LIC
E p
hot
o m
ater
ials
Semiconductor detectors
Very common HPGe (earlier Ge(Li)) ndash need liquid nitrogen cooling Si ndash for low energy range
Newer and up to now more special CdTe HgI2 CdZnTe (CZT) ndash up to now for lower energies cooling is not necessary eS ~ 44 eV
Ge Si ndash four valence electrons ndash electron release (its transposition from valence to conduction band) rarr creation of hole and free electron
Impurity with 3 valence electrons ndash electron recipient rarr rarr hole predominance rarr semiconductor of p typeImpurity with 5 valence electrons ndash electron donor rarr rarr predominance of electrons rarr semiconductor of n type
Ge(Li) detector ndash 1012 impurity atoms per cm3
HPGe ndash 109 impurity atoms per cm3
Prevention of thermal production of electron-hole pairs rarr temperature 77 K
Capture and recombination on dislocations and impuritiesHPGe detector placed inside Shielding lead box
WW
W p
ages
of
W W
estm
aier
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
Semiconductor detectors
Very common HPGe (earlier Ge(Li)) ndash need liquid nitrogen cooling Si ndash for low energy range
Newer and up to now more special CdTe HgI2 CdZnTe (CZT) ndash up to now for lower energies cooling is not necessary eS ~ 44 eV
Ge Si ndash four valence electrons ndash electron release (its transposition from valence to conduction band) rarr creation of hole and free electron
Impurity with 3 valence electrons ndash electron recipient rarr rarr hole predominance rarr semiconductor of p typeImpurity with 5 valence electrons ndash electron donor rarr rarr predominance of electrons rarr semiconductor of n type
Ge(Li) detector ndash 1012 impurity atoms per cm3
HPGe ndash 109 impurity atoms per cm3
Prevention of thermal production of electron-hole pairs rarr temperature 77 K
Capture and recombination on dislocations and impuritiesHPGe detector placed inside Shielding lead box
WW
W p
ages
of
W W
estm
aier
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
for T=77 K Si GeZ 14 32Atomic mass 2809 7260Density ρ [gcm3] 233 533Energy gap [eV] 11 07Electron mobility μe[ 104cm2Vs] 21 36Hole mobility μd [104cm2Vs] 11 42eS [eV] 376 296Fano coefficient F ~ 009 ~ 006
Basic semiconductor properties
Position sensitive HPGe segmenteddetectors are developed by LLNL (Californian University) its WWW
ve = μeE vd = μdE
Voltage on detector more than 1000 V
Small pulses rarr necessity of preamplifier
detector rarr premaplifier rarr amplifier rarr ADC rarr analyzer computer
Technical details ndash see recommended literature
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
- Slide 15
-
Parameters for 60Co line with energy 1332 keV
Relative efficiency To the standard (NaI(Tl)) 10 ndash 70 (εNaI = 012 εGEO ~ 058 εVNI ~ 20 )
peakcompton 130 až 160
Resolution FWHM 17 ndash 23
Peak shape FWTMFWHM ~20 (Gauss 182) FWFMFWHM 265 ndash 300 (Gauss 238)
Energy measurement accuracy up to order eV
ΔEΣ2 = ΔETN
2 + ΔEELEK2 + ΔEPN
2
Low energies ndash Si and thin HPGe detectors beryllium windowHigh energies - HPGe with large volume aluminum window
longer (6 μs) or shorter (2 - 4 μs) time constantof amplifier
ΔETN ndash intrinsic uncertainty (carrier creation)ΔEELEK ndash uncertainty given by electronicΔEPN ndash uncertainty given by electron and hole recombination and capture
Massive practical usage rarr many commercially produced types and models STN eEFFWHME 352
Limiting theoretical resolution without inclusion of influence of electronic
Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
- Slide 1
- Slide 2
- Slide 3
- Slide 4
- Slide 5
- Slide 6
- Slide 7
- Slide 8
- Slide 9
- Slide 10
- Slide 11
- Slide 12
- Slide 13
- Slide 14
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Crystal diffraction spectrometersConsist of 1) crystal lamina (quartz crystal calcite) 2) detector of X- and gamma rays
Different crystal geometries Plane crystals Curved crystals
Different configuration with one crystal Θ = ΘB
with two crystals Θ = 2ΘB
Characteristic angles influenced on line width
φZ ndash angle of source visibility from crystalφK ndash angle of collimator visibility from sourceφC ndash angle of diffraction line FWHM
ΘB ndash Bragg angleAngular FWHM φ of intensity afterwards is(for small values of all angles in radians)
φ2 asymp φZ2 + φK
2 + φC2
Example of measurement accuracy 169Yb rarr 169Tm line 63 keV ndash E = 6312080(16) keVNecessity to include influence of nucleus reflection during photon emission and accuracy
of energy standard determination
Detector
Crystallattice
Source Collimator
φK
φZ φC
ΘB
RE
E
EconstE
Econst
~
R ndash angular resolution
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