Post on 14-Jan-2016
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