gaas:cr detector testing for fcal calorimeter at planned linear accelerator ilc
DESCRIPTION
GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC . V. Elkin, U.Kruchonak. XVI научная конференция молодых учёных и специалистов ОМУС 20 12. The International Linear Collider ILC. ~ 30 km. Parameters of the ILC: - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/1.jpg)
GaAs:Cr detector testing for FCAL calorimeter at planned linear
accelerator ILC
V. Elkin, U.Kruchonak
XVI научная конференция молодых учёных и специалистов ОМУС 2012
![Page 2: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/2.jpg)
The International Linear Collider ILC
Parameters of the ILC:•e+e- accelerator, sc cavities, gradient 31.5 MV/m => 30km long•CMS energy: 200 to 500 GeV (possible upgrade to 1 TeV)•One interaction region, beam crossing angle of 14mrad and two detectors („push-pull“ scenario) •Peak luminosity: 2 x 1034 cm-2s-1
•typical beam size: (h x v) 650 nm x 5.7nm & beam intensity 2 x 1010 e+e-
~ 30 km
![Page 3: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/3.jpg)
10.10.2007 C.Grah: Radhard Sensors for BeamCal 3
Very Forward Region of the ILC Detectors
• R&D of the detectors in the forward region is done by the FCAL Collaboration.• Precise (LumiCal) and fast (BeamCal) luminosity measurement • Hermeticity (electron detection at low polar angles)• Mask for the inner detectors• Not shown here: GamCal, a beamstrahlung photon detector at about 180m post-IP.
LumiCal
TPC
ECAL
HCAL
BeamCal
![Page 4: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/4.jpg)
10.10.2007 C.Grah: Radhard Sensors for BeamCal 4
The Beam Calorimeter - BeamCal
Interaction point
Compact EM calorimeter with sandwich structure: 30 layers of 1 X0
o 3.5mm W absorber and 0.3mm radiation hard sensor Angular coverage from 5mrad to 28 mrad
(6.0 > |η| > 4.3) Moliére radius RM ≈ 1cm Segmentation between 0.5 and 0.8 x RM
BeamCalLDC
~10cm
~12cm
Space for electronics
![Page 5: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/5.jpg)
The Challenges for BeamCal
e+e- pairs from beamstrahlung are deflected into the BeamCal
15000 e+e- per BX
=> 10 – 20 TeV total energy dep. ~ 10 MGy per year strongly dependent on the beam and magnetic field configuration
=> radiation hard sensors Detect the signature of single high energetic particles on top of the background.
=> high dynamic range/linearity
e- e+e-
e-
γ
e-
γ
e+e.g. Breit-Wheeler process
![Page 6: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/6.jpg)
![Page 7: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/7.jpg)
GaAs:Cr Sensor Plane
Produced by the Siberian Institute of Technology, Tomsk semi-insulating GaAs doped by Sn (shallow donor) compensated by Cr (deep acceptor): to compensate electron trapping centers EL2+ and provide i-type conductivity.
![Page 8: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/8.jpg)
8
Advantages of Cr impurity as compared to the EL2 centers for detector material production
Deep acceptor
Deep donor
-
+
• small value of the electron capture cross section and absence of the field increase of the capture cross section on the electric field intensity
• absence of current oscillations
• possibility to reach uniform high electric field distribution through whole the detector with the thickness up to 1 mm
![Page 9: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/9.jpg)
9
Electrophysical characteristics of high resistivity GaAs
Material о
(10 -9/*cм)
no
(10 5 cm –3)
po
(10 5 cm –3)
Ln
(cm)
GaAsEL2
6-9 70-100 4-6 0.03 - 0.05
GaAsCr
0.6-1.1 2-3 120-200 0.07 – 0.2
The hole concentration in GaAs:Cr exceeds the concentration of electrons. The difference changes from 10 to 100 times depending on conditions of the diffusion process and the initial material characteristics.
![Page 10: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/10.jpg)
• 11 sector size GaAs sensors• Thickness - 500 μm • Metallization -1 μm Ni• 12 rings• 64 pads from 18 to 42 mm2
• Surrounded by 120 μm width guard ring
GaAs:Cr Sensor Plane
![Page 11: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/11.jpg)
№ Detector thickness,um
collected charge,
e
metallization,Type of metallization
pixels Guard ring
1 AG-84 №13 498 38450 Ni Ni
2 AG 84 № 26 502 36490 Ni Ni
3 AG 84 № 7 490 39750 Ni Ni
4 AG 84 № 19 495 38520 Ni Ni
5 AG 84 № 21 492 36560 Ni Ni
6 AG 84 № 32 502 38720 Ni Ni
7 AG 84 № 39 495 36450 Ni Ni
8 AG 84 № 41 487 37700 Ni Ni
9 AG 84 № 29 487 38420 Ni Ni
10 AG 84 № 28 500 38590 Ni Ni
11 AG 221 №25 492 41570 Ni Ni
GaAs:Cr Sensor producer data
![Page 12: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/12.jpg)
Circuit of capacitance measurement
Bias
Adap
ter
BP
Guar
d Ri
ng
L
H
Bias
Rin
g
LCR
Met
er
![Page 13: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/13.jpg)
Typical C-V , measured between pad and backplane for different rates 100Hz -100 kHz
•Capacitance decrease with frequency
•Chosen frequency 10kHz
![Page 14: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/14.jpg)
Pads capacitance distribution for 8 sensors
![Page 15: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/15.jpg)
Pads capacitance distribution
![Page 16: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/16.jpg)
A
DC-P
ADs
BP
Guar
d Ri
ngCircuit for I/V pad measurement
Typical IV measurement for single pad is symmetric and linear in the range +/-500V
![Page 17: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/17.jpg)
Temperature dependence of the resistance
Measured from -10 C to 50 CThe range from 65 GΩ*cm to 0.12 G Ω*cm
![Page 18: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/18.jpg)
Measurement of the barrier height on border of metal−semiinsulating gallium arsenide
total current through the device
Reff - effective resistance of the entire device
In or Isat - Saturation current - Limiting current from metal to semiconductor
[1]
S- Cross-sectional area, A*n = 8.16 A*cm-2 *K-2 - Richardson constant for GaAs
T - Temperature of device, q - electron charge, k - Boltzmann constant
- barrier height on border of metal−semiinsulating gallium arsenide
![Page 19: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/19.jpg)
I-V in range +/-10VParameterization of the IV curve by 4 parameters:
• Isaturation-• Isaturation+• Resestivity-• Resestivity+
![Page 20: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/20.jpg)
Average resistivity and barrier height of AG84N19
![Page 21: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/21.jpg)
Average resistivity and barrier height of 11 sensors № Detector thickness,
umResistivity, Ohm*cm Darrier height, volts
ρ+ ρ- φ+ φ-
1 AG-84 №13 498 Not processed Not processed Not processed Not processed
2 AG 84 № 26 502 1.20E9 1.10E9 0.75 0.74
3AG 84 № 7
490 2.25E9 2.18E9 0.78 0.79
4 AG 84 № 19 495 3.00E9 2.79E9 0.78 0.78
5 AG 84 № 21 492 2.42E9 2.37E9 0.76 0.76
6 AG 84 № 32 502 3.20E9 3.04E9 0.78 0.77
7 AG 84 № 39 495 3.71E9 3.48E9 0.79 0.76
8 AG 84 № 41 487 4.07E9 3.84E9 0.76 0.75
9 AG 84 № 29 487 3.67E9 3.23E9 0.78 0.81
10 AG 84 № 28 500 2.09E9 1.92E9 0.76 0.77
11AG 221 №25
492 2.49E9 2.42E9 0.79 0.81
![Page 22: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/22.jpg)
Unusual padsSome pads or guard rings have untypical behavior.For now we’ve found 6 sensors with guard ring and one pad: that
may be related to metallization defects or internal structure injury. It appears on the crystal boundary in all cases.
![Page 23: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/23.jpg)
Unusual pad, unusual guardring and normal pad C-V
Growth up to 110pF at 100 V
Similar behavior with guard ring
Break through while measuring with guard ring
Typical C < 12pF at 10kHz
![Page 24: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/24.jpg)
Unusual pad I-V
Growth up for positive Vbias
Normal behavior in negative area
Similar behavior with guard ring
![Page 25: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/25.jpg)
Unusual padsNo Pad No Breakdown voltage, V
AsGa84N7 Guard ring -330AsGa84N7 Ring12-Pad1 -310AsGa84N13 Guard ring -160; +200AsGa84N13 Ring12-Pad6 -280AsGa84N21 Guard ring +30AsGa84N21 Ring1-Pad4 +50AsGa84N26 Guard ring -110; +230AsGa84N26 Ring12-Pad1 -210AsGa84N28 Guard ring -300AsGa84N28 Ring12-Pad6 +330AsGa84N41 Guard ring +110AsGa84N41 Ring12-Pad6 +110
![Page 26: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/26.jpg)
Thank youfor attention!
![Page 27: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/27.jpg)
Forward region of the ILC
Beam calorimeter (BeamCal) - monitor the beam parameters at the interaction point; adjacent to the beampipe.
Luminosity detector (LumiCal) – covers larger polar angles; luminometer of the detector.
The gamma detector (GamCal) – together with BeamCal, measures beamstrahlung photons, which are very collinear to the beam.
![Page 28: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/28.jpg)
Изучение характеристик детекторов на основе GaAs компенсированного
хромом для будущего калориметра FCAL линейного ускорителя ILC
V. Elkin, U.Kruchonak
![Page 29: GaAs:Cr detector testing for FCAL calorimeter at planned linear accelerator ILC](https://reader035.vdocuments.net/reader035/viewer/2022062411/56816938550346895de09fbf/html5/thumbnails/29.jpg)
Gallium arsenide (GaAs) Compound semiconductor, direct bandgapTwo sublattices of face centered cubic lattice(zinc-blende type)
GaAs grown by Liquid EncapsulatedCzochralski (LEC).doped by Te or Sn (shallow donor)to fill EL2+ trapping centers.Compensated by Cr (deep acceptor) tohigh-ohmic intrinsic material.Compensation is temperature controlled
Semi-insulating - no p-n junction
Signal charge transport mainly by electrons
Structure provided by metallisation (similar to diamond)
Density 5.32 g/cm3 Pair creation E 4.3 eV/pair Band gap 1.42 eV Electron mobility 8500 cm2/Vs Hole mobility 400 cm2/Vs Dielectric const. 12.85 Radiation length 2.3 cm Ave. Edep/100 μm 69.7 keV (by 10 MeV e-) Ave. pairs/100 μm 13000 Structure p-n or insul