11September 2006 /
33September 2006 /
1.1. FastFast tuning of beam. tuning of beam.
2.2. DetectionDetection of high energy of high energy electronselectrons (from 2 photon (from 2 photon processes).processes).
3.3. ShieldShield inner detector from inner detector from backscattered backscattered electronselectrons & & synchrotronsynchrotron radiation. radiation.
BeamCal
44September 2006 /
1.1. LinearLinear response. response.2.2. Fast responseFast response & short dead & short dead
time.time.3.3. Confined showerConfined shower within. within.4.4. Compactness.Compactness.5.5. High granularity.High granularity.6.6. Handle Handle high radiationhigh radiation doses doses
(up to 10MGy/year) without (up to 10MGy/year) without significant degradation.significant degradation.
Detector requirements
SemiconductorsSemiconductors
55September 2006 /
1.1. Impurities / traps Impurities / traps dark dark currentcurrent at room temp’ + at room temp’ + hysteresishysteresis..
2.2. Charge Collection Distance Charge Collection Distance (CCD).(CCD).
Energy Energy depositeddeposited energy energy measuredmeasured..
Need-to-know facts about GaAs
66September 2006 /
IV - Measurements
77September 2006 /
The Need for IT Measurements
88September 2006 /
IT – both sensors in the air
99September 2006 /
IT – both sensors in the air
1010September 2006 /
10exp expBG
B
E T PI P
K T T
IT – both sensors in the air
1111September 2006 /
Sensor positions
basebase
samplesample
sensorssensors
1212September 2006 /
Both sensors in the airBoth sensors in the air
IT – one sensor on base
1313September 2006 /
IT – one sensors on base
1414September 2006 /
IT – one sensors on base
311,333 , 327,349 K
1515September 2006 /
IT – Analysis
Varshni 305, 1.4355 eV1 0.02BGE T
GaAs2: 0.667 0.005 eV
: 0.780 0.001 eVGaAs3:
: 0.823 0.001 eV
BG
BG
E
E
10exp expBG
B
E T PI P
K T T
1616September 2006 /
Average distance “traveled” Average distance “traveled” before recombination or before recombination or trapping.trapping.
9090Sr - sourceSr - source
Charge Collection Distance
/
/
560 , 4.2
245 130 245 31850
MPV e h
MPV
e h
eVMIP E eV
m
MIPm e
E
1717September 2006 /
Minimum Ionizing Particle
MPV MPVCCD L -G
1818September 2006 /
Charge Collection Distance
Sample thickness 245 m
208202196192
183175 450V
1919September 2006 /
