CVD Diamond Sensor Studies

for the Beam Calorimeter of the ILC Detector

K. Afanaciev2, I.Emelianchik2, Ch. Grah1, E. Kouznetsova1,

W. Lange1, W. Lohmann1

1 DESY, Zeuthen2 NCPHEP, Minsk

Beam Calorimeter

BeamCal: (4-28) mrad

• fast beam diagnostics

• detection and measurement of high energetic electrons and photons at very small angles

-

e+

e-

Z0

μ-

~

χ0

μ+

~ +

χ0

e+

e-

e+

e-

+-

σ ~ 102 fb (SPS1a)

σ ~ 106 fb

Beam Calorimeter Requirements:

Diamond/Tungsten sandwich

~15000 e+e- per BX (30 – 60 TeV)

~10 MGy / year for some area

=>

• radiation hard material

• with small Moliere radius

ILC bunch:small sizehigh charge

-> beamstrahlung :

-> high energy deposition in the Beam Cal:

pCVD Sensor Measurements

Requirements:

- stability under irradiation

- linearity of response

Measurements:

Current-Voltage characteristics

Charge Collection EfficiencyQmeas/Qcreated = CCD/L

Qcreated(MIP) = 36 eh/mm

Irradiation tests (up to 100 Gy)

Linearity measurements

Samples:

Fraunhofer IAF, Element Six

12x12 mm2, 300-900 m

&

Gate

PA

discr

discr

delayADC

Sr90

PM1

PM2

diamond

scint.

pCVD SensorsIrradiation Measurements:

~ 0.15 Gy/h

~ 0.60 Gy/h

~50%

Hadronic beam, 3 & 5 GeV

(CERN PS)

Fast extraction mode

~104-108 / ~10 ns

ADC

Diamond (+ PA) Scint.+PMT&

signal gate

pCVD Sensorslinearity test:

10 ns

17 s

Linearity testwide intensity range:

+ absolute intensity measurement (Thermoluminescence dosimetry)

relative intensities estimated from PMT’s: ~(1- 600)

HV(PMT)

intensity

L

R

),(),(),(

),(),(

)tan(,

1)(

202

0

2200

2/12

HVQdHVQdd

dHVQ

ddHVQddHVQ

Rd

Dd

ddI

PMT

LED

PMT calibration

Back to the testbeam data…HV(PMT)

intensity

LR

+ absolute calibration for one of the runs

1 RI = (27.3+/-2.9) 103 MIP/cm2

Linearity of diamond response

E64 FAP2

•The covered range : the particle fluence up to 107 MIPs per bunch

•The obtained deviation from a linear response: ~30% - at the level of systematic errors of the fluence calibration

Conclusions