n_tof-ph2 the physics case and the related proposal for measurements at n_tof for the period...
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nn_TOF-Ph_TOF-Ph22The Physics case and the related proposal The Physics case and the related proposal for measurements at n_TOF for the period for measurements at n_TOF for the period 2006-20102006-2010
A MengoniA MengoniCERN , GenevaCERN , GenevaENEA, BolognaENEA, Bologna
The CERN The CERN nn_TOF Facility_TOF Facility n_TOF 1-2-3: the physics casesn_TOF 1-2-3: the physics cases Capture studies, fission studies and othersCapture studies, fission studies and others Opportunities with a new, shorter flight-path & EAR-2Opportunities with a new, shorter flight-path & EAR-2 Phase-2 implementationPhase-2 implementation
www.cern.ch/n_TOF
The The nn_TOF facility at CERN_TOF facility at CERN
www.cern.ch/n_TOF
TThe real worldhe real world nn_TOF commissioned_TOF commissioned
in 2002in 2002
www.cern.ch/n_TOF
nn_TOF basic parameters_TOF basic parametersproton beam momentumproton beam momentum 20 GeV/c20 GeV/c
intensity intensity (dedicated mode)(dedicated mode) 7 x 107 x 1012 12 protons/pulseprotons/pulse
repetition frequencyrepetition frequency 1 pulse/2.4s1 pulse/2.4s
pulse widthpulse width 6 ns (rms)6 ns (rms)
n/pn/p 300300
lead target dimensionslead target dimensions 80x80x60 cm80x80x60 cm33
cooling & moderation materialcooling & moderation material HH22OO
moderator thickness in the exit moderator thickness in the exit faceface
5 cm5 cm
neutron beam dimension in EAR-1neutron beam dimension in EAR-1
(capture mode)(capture mode)2 cm (FWHM)2 cm (FWHM)
TThe real worldhe real world nn_TOF beam _TOF beam
characteristics: characteristics: Neutron intensity Neutron intensity and resolutionand resolutionin the full energy in the full energy rangerange
2nd collimator =1.8 cm
nn_TOF _TOF TTAC for (n,AC for (n,) ) measurementsmeasurements
• High detection efficiency: ≈100% (to be compared with 5% of C6D6 or 0.1% of Moxon-Rae)
• Good energy resolution (direct background suppression mechanisms based on combined multiplicity and energy deposition analysis)
n
• 40 BaF2 crystals 12 pentagons & 28 hexagons 15 cm crystal thickness Carbon-fiber 10B-enriched capsules
• Full Monte Carlo simulations all EM cascades capture events for BG determination
The n_TOF Collaboration
The n_TOF Collaboration
• Structure mounted in April-04• 4 geometry: end of May-04• 1.5 month commissioning• Au(n,) & other standards
First measurement with a radioactivesample started in August 2004
237Np(n,)
www.cern.ch/n_TOF
sample
nn_TOF _TOF TTAC for (n,AC for (n,) ) measurementsmeasurements
WWhy we do all thishy we do all this??
Objectives of the activity at Objectives of the activity at nn_TOF_TOF
1.1. CCross sections relevant for Nuclear Astrophysicsross sections relevant for Nuclear Astrophysics
2.2. MMeasurements of neutron cross sections relevant for easurements of neutron cross sections relevant for Nuclear Waste Transmutation and related Nuclear Nuclear Waste Transmutation and related Nuclear Technologies (*)Technologies (*)
3.3. NNeutrons as probes for fundamental Nuclear Physicseutrons as probes for fundamental Nuclear Physics
The n_TOF Collaboration
(*) contract with the EC (FP5) ended on December 2004www.cern.ch/n_TOF
www.cern.ch/n_TOF
neutrons
56Fe 91.72
57Fe 2.2
58Fe 0.28
Fe
Co
60Ni 26.223
59Co100
59Fe 44.503 d
60Fe 1.5 106 a
60Co5.272 a
61Co1.65 h
61Ni 1.140
62Ni 3.634
Ni 63Ni 100 a
64Ni 0.926
58Co70.86 d
62Cu9.74 m
63Cu69.17
64Cu 12.7 h
61Fe 6 m
Cu
56Fe 91.72
57Fe 2.2
58Fe 0.28
Fe
Co
60Ni 26.223
59Co100
59Fe 44.503 d
60Fe 1.5 106 a
60Co5.272 a
61Co1.65 h
61Ni 1.140
62Ni 3.634
Ni 63Ni 100 a
64Ni 0.926
58Co70.86 d
62Cu9.74 m
63Cu69.17
64Cu 12.7 h
61Fe 6 m
Cu
The canonical s-process
½ of the elements above Fe are produced by the s-process½ of the elements above Fe are produced by the s-process The astrophysical sites of the s-process are:The astrophysical sites of the s-process are:
He burning in intermediate/massive starsHe burning in intermediate/massive stars Low-mass AGB’sLow-mass AGB’s
There exists a direct correlation There exists a direct correlation between the neutron capture cross section between the neutron capture cross section and the abundance (and the abundance ((n,(n,) ) ·· N = const. N = const.))
The neutron capture cross sections The neutron capture cross sections are key ingredients for s-process nucleosynthesisare key ingredients for s-process nucleosynthesis
NNucleosynthesis: the ucleosynthesis: the ss--process process
NNucleosynthesis: ucleosynthesis: the s-process &the s-process &the r-process residualsthe r-process residuals
NNrr = N= Nsolarsolar - N - NssNNrr = N= Nsolarsolar - N - Nss
20 40 60 80 100 120NEUTRON NUMBER
1
10
100
1000
MA
XW
EL
LIA
N A
VE
RA
GE
D C
RO
SS S
EC
TIO
N
(mb)
BaBa
CdCd
CeCe
CrCr
DyDy ErEr
FeFe
GdGd
GeGe
HfHf
HgHgKrKr
MoMo NdNdNiNi
OsOs
PbPb
PdPd
PtPt
RuRuSeSe
SmSm
SnSn
SrSr
TeTe
WW
XeXe
YbYbZnZn
ZrZr
even-even nuclei
Neutron capture cross Neutron capture cross sections:sections:available dataavailable data
Objectives of the activity at Objectives of the activity at nn_TOF_TOF
1.1. CCross sections relevant for Nuclear Astrophysicsross sections relevant for Nuclear Astrophysics
2.2. MMeasurements of neutron cross sections relevant for easurements of neutron cross sections relevant for Nuclear Waste Transmutation and related Nuclear Nuclear Waste Transmutation and related Nuclear Technologies (*)Technologies (*)
3.3. NNeutrons as probes for fundamental Nuclear Physicseutrons as probes for fundamental Nuclear Physics
The n_TOF Collaboration
(*) contract with the EC (FP5) ended on December 2004www.cern.ch/n_TOF
NNuclear waste: TRU uclear waste: TRU (1000 MW (1000 MW LWR)LWR)
239Pu: 132 Kg/yr
237Np: 10.1 Kg/yr
241Am: 0.5 Kg/yr 243Am: 2.4 Kg/yr
244Cm 0.6 Kg/yr
LLFP
LLFP 52.2 Kg/yr
LWR 52 Units
Spent fuel800 t/y
Recovered U, Pu760 t/y
REPROCESSINGHLWHLW
MA: 1t FP: 39tP&T TECHNOLOGIESP&T TECHNOLOGIES
FINAL DISPOSAL(100 times reduced)
PPartitioning and artitioning and TTransmutationransmutation
Yucca Mountain repository would last for 500 Yucca Mountain repository would last for 500 yr !yr !
Nuclear Data needs for Nuclear Data needs for AADSDS Subcritical reactor coreSubcritical reactor core Spallation neutrons: high Spallation neutrons: high
energiesenergies Trasmutation of TRU: exotic fuelTrasmutation of TRU: exotic fuel
Zen-ADS
AcceleratorAcceleratorprotons
Reactor neutrons
www.cern.ch/n_TOF
nn_TOF experiments _TOF experiments 2002-42002-4
The n_TOF Collaboration
TTargetarget Motivations & NotesMotivations & Notes24,25,2624,25,26MgMg Isotopic abundance ratios in stellar grains. Isotopic abundance ratios in stellar grains.
Importance of Importance of 2222Ne(Ne(,n),n)2525Mg for the s-process Mg for the s-process neutron balance. neutron balance.
Light nuclei, small cross sections. Light nuclei, small cross sections.
90,91,92,93,94,9690,91,92,93,94,96ZrZr s-process branching at A=95 & observed abundance s-process branching at A=95 & observed abundance patterns in stellar grains. Sensitivity to neutron flux patterns in stellar grains. Sensitivity to neutron flux during the s-process.during the s-process.9393Zr(Zr(1/21/2 = 1.5 Myr) = 1.5 Myr)
139139LaLa Bottleneck in the s-process flow. N=82 neutron shell Bottleneck in the s-process flow. N=82 neutron shell closureclosure
151151SmSm s-process branching at A s-process branching at A ≈ 150. ≈ 150. 151151Sm is radioactive Sm is radioactive
((1/21/2 = 93 yr) = 93 yr)
186,187,188186,187,188OsOs Nuclear cosmochronology (Re/Os clock)Nuclear cosmochronology (Re/Os clock)
s-process branching at A s-process branching at A ≈ 185≈ 185
204,206,207,208204,206,207,208PbPb209209BiBi
Termination of the s-process. Small Termination of the s-process. Small //elel
CCaptureapture151151SmSm204,206,207,208204,206,207,208Pb, Pb, 209209BiBi232232ThTh24,25,2624,25,26MgMg90,91,92,94,9690,91,92,94,96Zr, Zr, 9393ZrZr139139LaLa186,187,188186,187,188OsOs233,234233,234UU237237Np,Np,240240Pu,Pu,243243AmAm
FFissionission233,234,235,236,238233,234,235,236,238UU232232ThTh209209BiBi237237NpNp241,243241,243Am, Am, 245245CmCm
nn_TOF-Ph_TOF-Ph22 objectives objectives
1.1. CCross sections relevant for Nuclear Astrophysicsross sections relevant for Nuclear Astrophysics
2.2. MMeasurements of neutron cross sections relevant for easurements of neutron cross sections relevant for Nuclear Waste Transmutation and related Nuclear Nuclear Waste Transmutation and related Nuclear TechnologiesTechnologies
3.3. NNeutrons as probes for fundamental Nuclear Physicseutrons as probes for fundamental Nuclear Physics
The n_TOF Collaborationwww.cern.ch/n_TOF
The The nn_TOF-Ph_TOF-Ph22 experiments experiments
Capture measurementsCapture measurementsMo, Ru, Pd stable isotopes
Fe, Ni, Zn, and Se (stable isotopes)79Se
A≈150 (isotopes varii)
234,236U, 231,233Pa
235,238U
239,240,242Pu, 241,243Am, 245Cm
r-process residuals calculationisotopic patterns in SiC grains
s-process nucleosynthesis in massive starsaccurate nuclear data needs for structural materials
s-process branching pointslong-lived fission products
Th/U nuclear fuel cycle
standards, conventional U/Pu fuel cycle
incineration of minor actinides
n_TOF-Ph2
Fission measurementsFission measurementsMA
235U(n,f) with p(n,p’)
234U(n,f)
ADS, high-burnup, GEN-IV reactors
new 235U(n,f) cross section standard
study of vibrational resonances at the fission barrier
Other measurementsOther measurements147Sm(n,), 67Zn(n,), 99Ru(n,)58Ni(n,p), other (n,lcp)
Al, V, Cr, Zr, Th, 238U(n,lcp)
He, Ne, Ar, Xe
n+D2
p-process studiesgas production in structural materials
structural and fuel material for ADS and other advanced nuclear reactors
low-energy nuclear recoils (development of gas detectors)
neutron-neutron scattering length
n_TOF-Ph2
The The nn_TOF-Ph_TOF-Ph22 experiments experiments
n_TOF-Ph2
n_TOF targetn_TOF target
NewExperimentalArea (EAR-2)
The second n_TOF beam line & The second n_TOF beam line & EAR-2EAR-2
EAR-1 (at 185 m)
~ 20 m~ 20 m
Flight-path length : Flight-path length : ~~20 m20 mat 90at 90° respect to p-beam direction° respect to p-beam directionexpected neutron flux enhancement: ~ 100expected neutron flux enhancement: ~ 100drastic reduction of the tdrastic reduction of the t00 flash flash
Flight-path length : Flight-path length : ~~20 m20 mat 90at 90° respect to p-beam direction° respect to p-beam directionexpected neutron flux enhancement: ~ 100expected neutron flux enhancement: ~ 100drastic reduction of the tdrastic reduction of the t00 flash flash
Improvements (ex: Improvements (ex: 151151Sm case)Sm case)
sample mass / 3 sample mass / 3 s/bkgd=1s/bkgd=1 use BaFuse BaF22 TAC TAC x 10 x 10 use Duse D22OO 3030 x 5 x 5 use 20 m flight pathuse 20 m flight path 3030 x 100 x 100
consequences for consequences for sample masssample mass
50 mg50 mg
5 mg 5 mg 1 mg1 mg 10 10 gg
boosts sensitivity by a factor of 5000 !
problems of sample production and safety issues relaxed
EAR-EAR-22: Optimized sensitivity: Optimized sensitivity
Letter of IntentLetter of Intent signed by signed by 2424 research labs of the n_TOF Collaboration + research labs of the n_TOF Collaboration + 44
newcomersnewcomers(January 2005)(January 2005)
n_TOF-Phn_TOF-Ph22 scientific proposal scientific proposal the n_TOF 1-2-3 document (September 2004)the n_TOF 1-2-3 document (September 2004) CB meeting of February 10-11, 2005CB meeting of February 10-11, 2005 the the nn_BANT Symposium (March 2005)_BANT Symposium (March 2005) INTC meeting (May 2005) INTC meeting (May 2005) Joint n_TOF/ISOLDE initiative: NuPAC (Nuclear Physics and Joint n_TOF/ISOLDE initiative: NuPAC (Nuclear Physics and
Astrophysics at CERN)- “Villars meeting” @ CERN promoted by Astrophysics at CERN)- “Villars meeting” @ CERN promoted by the INTC (October 10-12, 2005)the INTC (October 10-12, 2005)
The n_TOF-Ph2 MoU – end of 2005/beginning of 2006The n_TOF-Ph2 MoU – end of 2005/beginning of 2006
Road-map towards n_TOF-PhRoad-map towards n_TOF-Ph22
www.cern.ch/n_TOF n_TOF-Ph2
: endorsement of the scientific case : endorsement of the scientific case for Ph2for Ph2
The The nn_TOF Collaboration_TOF Collaboration
40 Research Institutions40 Research Institutions120 researchers 120 researchers www.cern.ch/n_TOF
The The EEndnd
www.cern.ch/n_TOF n_TOF-Ph2
n_TOF-Ph2
Capture studiesCapture studies
n_TOF-Ph2
Capture studies: Mo, Ru, and Pd Capture studies: Mo, Ru, and Pd
Motivations:Motivations:
• Accurate determination of the r-process Accurate determination of the r-process abundances (r-process residuals) from abundances (r-process residuals) from observationsobservations
• SiC grains carry direct information on s-process SiC grains carry direct information on s-process efficiencies in individual AGB stars. Abundance efficiencies in individual AGB stars. Abundance ratios in SiC grains strongly depend on available ratios in SiC grains strongly depend on available capture cross sections data.capture cross sections data.
Motivations:Motivations:
• Accurate determination of the r-process Accurate determination of the r-process abundances (r-process residuals) from abundances (r-process residuals) from observationsobservations
• SiC grains carry direct information on s-process SiC grains carry direct information on s-process efficiencies in individual AGB stars. Abundance efficiencies in individual AGB stars. Abundance ratios in SiC grains strongly depend on available ratios in SiC grains strongly depend on available capture cross sections data.capture cross sections data.
NNrr = N= Nsolarsolar - N - NssNNrr = N= Nsolarsolar - N - Nss
n_TOF-Ph2
• Setup: The n_TOF TACn_TOF TAC in EAR-1 (a few cases with C6D6 if larger neutron scattering)• All samples are stable and non-hazardous• Metal samples preferable (oxides acceptable)
Estimated # of protons 20 x 5x1016 = 10101818
sample
Capture studies: Mo, Ru, and Pd Capture studies: Mo, Ru, and Pd
n_TOF-Ph2
Capture studies: Fe, Ni, Zn & Capture studies: Fe, Ni, Zn & Se Se
Motivations: Motivations:
• Study of the weak s-process component (nucleosynthesis up to A ~ 90) • Contribution of massive stars (core He-burning Contribution of massive stars (core He-burning phase) to the s-process nucleosynthesis.phase) to the s-process nucleosynthesis.
• s-process efficiency due to bottleneck cross s-process efficiency due to bottleneck cross sections (Example: sections (Example: 6262Ni) Ni)
Motivations: Motivations:
• Study of the weak s-process component (nucleosynthesis up to A ~ 90) • Contribution of massive stars (core He-burning Contribution of massive stars (core He-burning phase) to the s-process nucleosynthesis.phase) to the s-process nucleosynthesis.
• s-process efficiency due to bottleneck cross s-process efficiency due to bottleneck cross sections (Example: sections (Example: 6262Ni) Ni)
In addition:In addition:
Fe and Ni are the most important structural materials for nuclear technologies. Fe and Ni are the most important structural materials for nuclear technologies. Results of previous measurements at n_TOF show that capture rates for light Results of previous measurements at n_TOF show that capture rates for light and intermediate-mass isotopes need to be revised.and intermediate-mass isotopes need to be revised.
In addition:In addition:
Fe and Ni are the most important structural materials for nuclear technologies. Fe and Ni are the most important structural materials for nuclear technologies. Results of previous measurements at n_TOF show that capture rates for light Results of previous measurements at n_TOF show that capture rates for light and intermediate-mass isotopes need to be revised.and intermediate-mass isotopes need to be revised.
n_TOF-Ph2
32
30
34
38 40 42 44 46 48 50
Capture studies: Fe, Ni, Zn & Capture studies: Fe, Ni, Zn & Se Se
The The 7979Se caseSe case
• s-process branching: neutron density & temperature s-process branching: neutron density & temperature conditions for the weak component.conditions for the weak component.• tt1/21/2 < 6.5 x 10 < 6.5 x 104 4 yryr
The The 7979Se caseSe case
• s-process branching: neutron density & temperature s-process branching: neutron density & temperature conditions for the weak component.conditions for the weak component.• tt1/21/2 < 6.5 x 10 < 6.5 x 104 4 yryr
• Setup: CC66DD66 in EAR-1• All samples are stable(*) and non-hazardous• Metal samples preferable (oxides acceptable)
Capture studies: Fe, Ni, Zn & Capture studies: Fe, Ni, Zn & SeSe
(*) except 79Se
n_TOF-Ph2
n_TOF-Ph2
Capture studies: A Capture studies: A ≈ 150≈ 150
• branching isotope in the Sm-Eu-Gd region: test for low-mass TP-AGB
• branching ratio (capture/-decay) provides infos on the thermodynamical conditions of the s-processing (if accurateaccurate capture rates are known!)
Sm
Eu
Gd
150Sm
151Sm 93 a
152Sm
153Sm 42.27 h
154Sm
151Eu
152Eu 9 h
153Eu
154Eu 8.8 a
155Eu 4.761 a
156Eu 15.2 d
152Gd
153Gd
239.47 d
154Gd
155Gd
156Gd
157Gd
• EAR-2 requiredEAR-2 required• Sample from ISOLDE?Sample from ISOLDE?• EAR-2 requiredEAR-2 required• Sample from ISOLDE?Sample from ISOLDE?
Capture studies: actinidesCapture studies: actinides
Neutron cross section measurements for nuclear waste Neutron cross section measurements for nuclear waste transmutation and advanced nuclear technologiestransmutation and advanced nuclear technologies
241,243241,243AmAm The most important neutron poison in the fuels proposed for transmutation scenarios. Build up of Cm isotopes.
239,240,242239,240,242PuPu (n,) and (n,f) with active canning. Build up of Am and Cm isotopes.
245245CmCm No data available.
235,238235,238UU Improvement of standard cross sections.
232232Th,Th,233,234233,234UU231,233231,233PaPa
Th/U advanced nuclear fuels. 233U fission with active canning.
All measurements can be done in EAR-1 (except All measurements can be done in EAR-1 (except 241241Am and Am and 233233Pa)Pa)All measurements can be done in EAR-1 (except All measurements can be done in EAR-1 (except 241241Am and Am and 233233Pa)Pa)
50m Kapton windows
400m ISO 2919 Ti canning (400 mg!) +
actinide sampleair
vacuum
Neutron absorber
Calorimeter
rays
Actual setup with thick sample cannings
Capture studies: actual TAC setupCapture studies: actual TAC setup
n_TOF-Ph2
C12H20O4(6Li)2
Neutron Absorber
10B loaded Carbon Fibre
Capsules
Neutron Beam
n_TOF-Ph2
Effect of the Ti canning (neutron sensitivity)
Capture studies: actual TAC setupCapture studies: actual TAC setup
Window surrounded by neutron absorber
(10B or 6Li doped polyethylene)
Thin Al backing +
actinide sample
vacuum
Neutron absorber
Calorimeter
Capture studies: Capture studies: Low neutron Low neutron sensitivity setupsensitivity setup
n_TOF-Ph2
Neutron beam
Mini Ionisation chamber
Stack of with 200 g/cm2
samples on thin backings
Fission Fragments
rays
Measurement of capture cross sections of fissile materials (veto) and measurement of the (n,)/(n,f) ratio.
Capture studies: Capture studies: active canning for active canning for simultaneous (n,simultaneous (n,) & (n,f) measurements) & (n,f) measurements
n_TOF-Ph2
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n_TOF-Ph2
Fission studiesFission studies
n_TOF-Ph2
45 degrees
p’
n
"Thin" E detector
E detector
235U
proton containing target (polyethylene)
fission fragmentsdetector
"Thick" E/Low E detector
104 105 106 107 108
1E-3
0.01
0.1
Count rate protons
235
U
Counts
En, eV
BeamBeam capture mode (2 mm capture mode (2 mm ØØ))
Scattering angleScattering angle 3030°°
Target thicknessTarget thickness 250 250 g/cmg/cm22
Detector radiusDetector radius 20 mm20 mm
Target-to-detector distanceTarget-to-detector distance 250 mm250 mm
Fission studies Fission studies absolute absolute 235235U(n,f) cross section from (n,p) U(n,f) cross section from (n,p) scatteringscattering
(n,p) larger or comparable up to 100 MeV
H235U 0.01 1 100 Neutron energy [MeV]
n_TOF-Ph2
Fission studies Fission studies FF distributions in vibrational resonancesFF distributions in vibrational resonances
Neutron beam
Position-sensitivedetector
Time-tag detector
Sample
Vacuum chamber
Principles:Principles:
• Time-tag detector for the “start” signal• Masses (kinetic energies) of FF from position-sensitive detectors (MICROMEGAS or semiconductors)
Principles:Principles:
• Time-tag detector for the “start” signal• Masses (kinetic energies) of FF from position-sensitive detectors (MICROMEGAS or semiconductors)
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n_TOF-Ph2
Fission studies Fission studies cross sections with PPAC detectors: present cross sections with PPAC detectors: present setup setup
Measurements:Measurements:
• 231231Pa(n,f) Pa(n,f) • Fission fragments angular distributions (45Fission fragments angular distributions (45°° tilted targets) tilted targets) for for 232232Th, Th, 238238U and other low-activity actinidesU and other low-activity actinides
EAR-EAR-22 boost: boost:• measurements of measurements of 241,243241,243Am (in class-A lab)Am (in class-A lab)• measurements of measurements of 241241Pu and Pu and 244244Cm (in class-A lab)Cm (in class-A lab)
Measurements:Measurements:
• 231231Pa(n,f) Pa(n,f) • Fission fragments angular distributions (45Fission fragments angular distributions (45°° tilted targets) tilted targets) for for 232232Th, Th, 238238U and other low-activity actinidesU and other low-activity actinides
EAR-EAR-22 boost: boost:• measurements of measurements of 241,243241,243Am (in class-A lab)Am (in class-A lab)• measurements of measurements of 241241Pu and Pu and 244244Cm (in class-A lab)Cm (in class-A lab)
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n_TOF-Ph2
Fission studies Fission studies with twin ionization chamber with twin ionization chamber
Measurements:Measurements:
• FF yields: mass & charge FF yields: mass & charge • Test measurement with Test measurement with 235235U then measurements of other MAU then measurements of other MA
Measurements:Measurements:
• FF yields: mass & charge FF yields: mass & charge • Test measurement with Test measurement with 235235U then measurements of other MAU then measurements of other MA
Twin ionization detector with measurement ofboth FF (PPAC principle)
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n_TOF-Ph2
1.1. CIC: compensated ion chamber CIC: compensated ion chamber already tested at n_TOFalready tested at n_TOF
For n_TOF-Ph2:
• four chambers in the same volume for multi-sample measurements
Measurements:Measurements:
• 147147Sm(n,Sm(n,) (tune up experiment)) (tune up experiment)• 66LiF target for calibrationLiF target for calibration
EAR-EAR-22 boost: boost:• approx 100 times the ORELA count rate approx 100 times the ORELA count rate expectedexpected• 6767Zn and Zn and 9999Ru (n,Ru (n,) measurements) measurements
Measurements:Measurements:
• 147147Sm(n,Sm(n,) (tune up experiment)) (tune up experiment)• 66LiF target for calibrationLiF target for calibration
EAR-EAR-22 boost: boost:• approx 100 times the ORELA count rate approx 100 times the ORELA count rate expectedexpected• 6767Zn and Zn and 9999Ru (n,Ru (n,) measurements) measurements
(n,p), (n,(n,p), (n,) & (n,lcp) ) & (n,lcp) measurementsmeasurements
n_TOF-Ph2
2.2. MICROMEGAS MICROMEGAS already used for measurements of nuclear recoils at n_TOFalready used for measurements of nuclear recoils at n_TOF
For n_TOF-Ph2:
• converter replaced by sample
• expected count rate: 1 reaction/pulse (=200 mb, Ø=5cm, 1m thick)
(n,p), (n,(n,p), (n,) & (n,lcp) ) & (n,lcp) measurementsmeasurements
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n_TOF-Ph2
(n,p), (n,(n,p), (n,) & (n,lcp) ) & (n,lcp) measurementsmeasurements
3.3. Scattering chambers with Scattering chambers with E-E or E-E or E-E-E-E telescopes E-E telescopes
Measurements:Measurements:
• 5656Fe and Fe and 208208Pb (tune up experiment)Pb (tune up experiment)• Al, V, Cr, Zr, Th, and Al, V, Cr, Zr, Th, and 238238UU• a few x 10a few x 1018 18 protons/sample in fission modeprotons/sample in fission mode
Measurements:Measurements:
• 5656Fe and Fe and 208208Pb (tune up experiment)Pb (tune up experiment)• Al, V, Cr, Zr, Th, and Al, V, Cr, Zr, Th, and 238238UU• a few x 10a few x 1018 18 protons/sample in fission modeprotons/sample in fission mode
Setup: in parallel with fission detectors
production cross sections (En) for (n,xc)
c = p, , d
differential cross sections d/d, d/dE<< back<< back
n_TOF-Ph2
Neutron scattering reactionsNeutron scattering reactions
N e u tro n b e a m
D ta rg e t2
P ro to n d e te c to r
N e u tro n d e te c to r
5 m
3 4 º
8 0 º
4 6 c
m
D 3
D 4
Neutron incident energy 30 – 75 MeV in 2.5 MeV bins
Kiematic locus of the n + 2H n + p + n reaction for:En = 50 MeVΘn = 20º, Φn = 0ºΘp = 50º, Φp = 180º
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Direct n + n scattering experiment not feasible! Direct n + n scattering experiment not feasible!
Alternatively, interaction of two neutrons in the final Alternatively, interaction of two neutrons in the final state of a nuclear reaction. Examples of such state of a nuclear reaction. Examples of such reactions are:reactions are:
++ + + 22H H n + n + n + n +
n + n + 22H H n + n + p n + n + p
n_TOF-Ph2
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