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Irradiation Goals Confirm that the breakdown performance improves with dose-Done Check that breakdown does not appear after inversion on n-type sensors-Done Confirm I bias, V dep changes as expected for proton/neutron irradiation Test CCE, resolution, etc. performance after proton irradiation with pixel telescope
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Proton Irradiation Irradiated 2 sets (n-type,p-type) of phi sensors and R sensors –Phi sensor: 1.47x10 15 p/cm 2 → 9x10 14 niel/cm 2 (7 years @ 8mm) –R sensor: 1.4x10 15 p/cm 2 → 8.5x10 14 niel/cm 2 (6.6 years @ 8mm) Built 1 set into double-R and double-Phi modules for FNAL test beam and laser test Other set used for CV measurements Phi Sensors R Sensors
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N-type R Sensor CV After 30 min@60 C equiv. 11 day@20 C Dep V:~560 V With no annealing, it is difficult to say if part depletes. The three clear kinks in the CV correspond to unirradiated left, partly irradiated middle, and fully irradiated right of sensor. So annealed to lower depletion point.
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P-type R Sensor CV After 30 min@60 C equiv. 11 day@20 C Dep V:~530 V With no annealing, it is difficult to say if part depletes. The three clear kinks in the CV correspond to unirradiated left, partly irradiated middle, and fully irradiated right of sensor. So annealed to lower depletion point.
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Laser Test-Proton Irradiation N-type Irr N-type non-Irr P-type Irr P-type non-Irr Laser tested double-R and double-phi modules while cooled (~-7 C at sensor) –Stability of laser focus, intensity difficult to control See similar fraction (Irr/Non- Irr) of charge in both p-type and n-type –Somewhere between 50-70% 8.5x10 14 niel/cm 2 –From previous proton irradiaton on minis expect 40% (1.8x10 15 niel/cm 2 ) 68% (6.6x10 14 niel/cm 2 ) With annealing to minima, expect 10-15% more charge collected –Will try to anneal during FNAL test-beam
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Proton Irradiation Conclusions From RD48 damage constants, expect ~480 V depletion voltages after annealing for measured dose of proton for n-type and p-type silicon –We measured somewhere between 530-560 V for the n-type and p-type From previous proton irradiations of n-in-p minis, we expect to collect ~60% of the max charge –From laser, get 50-70% pre-annealing –Will confirm with test beam Thus, I would expect modules to be fully efficient after this dose (6.6 years @ 8 mm)
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Irradiation Results-IV P-type N-type 5x10 13 /cm 2 1.5x10 14 /cm 2
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Low dose (~4-5x10 -13 neq/cm 2, expected 5x10 -13 neq/cm 2 ) High dose (~1.3-1.6x10 -14 neq/cm 2, expected 1.5x10 -14 neq/cm 2 ) Error dominated by uncertainty in annealing time
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Neutron Irradiation Results-CV P-type N-type V dep Pre =81V V dep Post =167 V V dep =86 V 5x10 13 /cm 2 1.5x10 14 /cm 2 V dep Pre =81V V dep Post =393 V V dep =312 V V dep Pre =21V V dep Post =299 V V dep =320 VV dep Pre =25V V dep Post =277 V V dep =302 V
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Irradiation Results Irradiation of ~136 kRads with 6 MeV photons –Hard breakdown behaviour improved greatly due to radiation Charge in oxide –Soft breakdown behaviour (semi-ohmic) improved only in 1 of 3 sensors (2 unchanged) Should improve with neutron/proton irradiation which causes more bulk damage Irradiation with neutrons at Ljubljaba –Breakdown behaviour gone –P-type and n-type IV similar after doses –For neutron irradiation, p-type sensors have higher V dep 390 vs. 280-300 after 1.5x10 14 neq/cm 2 –Expect V dep to be similar for n and p- type sensors with ~10 14 neq/cm 2 proton irradiations –Changes in depletion voltages close to expected: From TDR, 1.3x10 14 neq/cm 2 in 5 month LHC dose: V dep =250 V Scaling for 5x10 13 neq/cm 2, measured V dep =86 V, expected V dep =96 V Scaling for 1.5x10 14 neq/cm 2, measured V dep =302-320 V, expected V dep =288 V –Differences between measured and expected may be due to annealing
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