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