DØ Silicon Radiation Damage So Far
Sergey Burdin (FNAL) for the DØ Collaboration
All Experimenters’ Meeting
8/8/2005
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 2
DØ Silicon Detector
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 3
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 4
DØ Silicon Detector Failure Modes Components Failures
Radiation Damage
Fra
cti
on
of
dis
ab
led
S
ilic
on
Mod
ule
s
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 5
Radiation Monitoring Instantaneous beam losses are measured by
BLMs and FINGERS Radiation damages to the Silicon Detector
are studied using Bias Current Measurements Depletion Voltage Measurements
Charge Collection Efficiency Noise at n-side
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 6
Dependence of Bias Current on Delivered Luminosity
Layer 1 Layer 3
Warm-up during shutdown
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 7
Estimate of the Radiation Dose
Description of annealing processes could be tuned using this data
John Omotani
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 8
Dependence of Depletion Voltage from Dose Measured at Booster
7/1/05
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 9
Depletion Voltage: Noise at n-side
Noise at n-side in Double Sided Double Metal sensors has abnormal behavior To be cross-checked at the test-stand
Sara Lager
0.3 fb-10.5 fb-1
1.0 fb-1 1.0 fb-1
beam beam
no beam beam
beam beam
no beam beam
0.3 fb-1 0.5 fb-1
1.0 fb-1 1.0 fb-1
Voltage (V) Voltage (V)
Noi
se (
AD
C c
oun
ts)
Noi
se (
AD
C c
oun
ts)
Layer 1 (DSDM) Layer 4 (DS)
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 10
L1 DSDM
L2 DS
L3 DSDM
L4 DS
Change in Depletion Voltage for Different Layers
Sara Lager
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 11
Depletion Voltage: Charge Collection Efficiency
HV Scan with tracks
Vdepletion
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 12
Comparison of different methods
Depletion voltages measured using different methods agree
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 13
There are indications that the depletion voltage for the DSDM sensors decreases with radiation dose
Dependence of Depletion Voltage from Delivered Luminosity
DSDM
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 14
Prospects for Depletion Voltage
Behavior of depletion voltage for DSDM sensors agrees with the booster measurements of the DS ladders
Assuming this agreement in future Vdepletion ~ Vmax = 150V at delivered luminosity 5—7 fb-1
D0SMT Depletion Voltage
0
50
100
150
200
250
0.00E+00 5.00E+12 1.00E+13 1.50E+13 2.00E+13 2.50E+13 3.00E+13 3.50E+13 4.00E+13 4.50E+13
Fluence (1 MeV n)
De
ple
tio
n V
olt
ag
e
DS ladder IDS Ladder IIDS wedgeSS Ladder ISS Ladder IIDSDM LadderFluence 8/1/05Calculated VdLayer 1 (inner) DSDMLayer 1 (outer) DSDM
Booster/D0 disagreementfor double metal detectors
8/8/2005 D0 Radiation Damage / S. Burdin (FNAL) @ AEM 15
Summary We study the radiation damage using several
methods DSDM sensors have abnormal noise behavior
Within assumptions made at previous slide We should be able to deplete the DØ silicon Layer 1 up
to 5—7 fb-1
Other silicon layers should survive longer Lower depletions limits would reduce this range