Radiation Characteristics of L2 Prototypes for D0 Run2b Upgrade

Transcription

1 D0 RunIIb Silicon Radiation Characteristics of L2 Prototypes for D0 Run2b Upgrade Sergey Korjenevski Tim Bolton Regina Demina Kansas State University March 6, 2003 D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

2 Expected Dose in Run 2b Setup Results Step 1: irradiation JRM Annealing Clean room IV CV measurements Cold chuck Outline Dose received Depletion and leakage current, Rate of deterioration Conclusions They serve the purpose D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

3 Expected Dose of Radiation Dose expected for L2 is about 0.3E+14 1MeV n per cm 2 Doses comparable to LHC use their R&D 10 years of CMS at inner radius Flux, in 1.0E14 1MeV n equivalent per cm L0 L1 L Int L, fb-1 D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

4 Setup - Irradiation Irradiation Vacuum 10 MeV protons Faraday cup to register flux D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

5 Setup - Annealing After irradiation handling After each irradiation session the sensors were held in oven at 60ºC for 80 minutes (as recommended by ROSE collaboration). Than they were transferred to the freezer and kept at around -25ºC taken out only for quick IV CV tests which would take approximately 30 minutes. D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

6 Clean room Keithley 237 HP 4284A LCR meter LabView interface Cold Chuck operated at 1ºC Dry environment ~ 20% Freezer to store irradiated samples Setup - Testing D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

7 Dose Received Dose delivered is significantly higher than expected 20 fb -1 equivalent to 0.3E14 n/cm 2 for layer 2 D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

8 L2-HPK-052 Depletion Voltage Results L2HPK-052 1\C^2 vs Voltage, L2-HPK Vdep=101V 1/C^2 (1/pF)^ Vdep = 68V Vdep = 63 V 0.00E E E Voltage (V) D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

9 Results L2HPK-062 L2-HPK-062 Depletion Voltage 1\C^2 vs Voltage Vfd=96V Vfd=90V Vfd=58V Vfd=28V Vfd=48V 1/C^2 (1/pF)^ E E E E E Voltage (V) D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

10 Type Inversion FDV, V HPK 52 HPK 54 hpk 59 HPK E E E E E+14 Dose, 1MeV n/cm2 D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

11 Results L2HPK-052 L2-HPK-052 Current Current HPK 052, January 2003 Signal/Noise > E+06 Current (na) 1.00E E E E+02 Breakdown at 550V 0.00E E E E+01 Limit on Vbrkdn < 350V 1.00E Voltage (V) D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

12 Results L2HPK-054 L2-HPK-054 Current L22-HPK-054 Signal/Noise > E E+06 Current (na) 1.00E E E E E E E E E E Voltage (V) D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

13 Results L2HPK-059 L2-HPK-059 Current Current (na) E E E E E Voltage (V) D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

14 Results L2HPK-062 L2-HPK-062 Current Signal/Noise > E E+05 Current (na) 1.00E E E E E Voltage (V) 0.00E E E E E+14 s/n>10 D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

15 Strip Measurements Out of 1278 channels (2 sensors) one new pinhole was detected Current through dielectric L2-HPK-052 After Before D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

16 Strip Measurement Coupling Capacitance. Bias voltage was setup through 4.75 Mohm resistance which prevents detector from being fully depleted. PinHole Test After Irradiation Cac, pf Before Irr Cac, pf Capacitance (pf) BEFORE Strip # AFTER D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

17 R poly Typical value before irradiation is 0.8Mohm Some degradation of material would cause resistivity to drop Rpoly from 0.8Mohm to 0.58Mohm Implant from 1.5Mohm to 1.0 Remains within specs Rpoly + Implant 1.5MOhm Rpoly 0.58MOhm Strip # D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

18 Interstrip capacitance Before Irradiation Total Load Capacitance, Sensor #88 CL (pf) V 10 V 20 V 30 V 40 V 50 V 60 V 70 V 80 V 90 V 100 V E E E E E+06 Frequency (Hz) D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

19 Interstrip capacitance After Irradiation E E E E E E E+07 D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

20 Last Slide After irradiation all four sensors have depletion voltage less than 200V and breakdown higher than 400V. Though delivered dose is significantly higher than expected, about 10 times in December run and about 3 times in January, detectors are still fully operational and within specifications. D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

21 Silicon Detectors: bulk damage Non Ionising Energy Loss chart Damage constants for various particles and energies are all calculated relative to 1Mev neutrons Caused primarily by displacing a PKA out of the Si lattice. It creates a pair V-I Binding energy is 25eV If kinetic energy is sufficient the PKA will travel creating more point defects and finally will come to rest in a highly disordered area (cluster). Energy loss via ionisation does not play a role: bulk damage depends exclusively on NIEL D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

22 Results L2HPK-054 L2-HPK-054 Depletion Voltage L2-HPK Vdep=104V 1/C^2 (1/pF)^ Vdep=62V Vdep=130V E E E Voltage (V) D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

23 Results L2HPK-059 L2-HPK-059 Depletion Voltage 1\C^2 vs Voltage Vdep: 96V Vdep: 86V Vdep: 68V Vdep: 27V Vdep: 57V 1/C^2 (1/pF)^ E E E E E Voltage (V) D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20

24 α = 1.0 ± 0.2 x Damage Rate α D0 RunIIb Silicon PRR L2-5, Mar 6, out of 20