september 2006 / 1. / 2 1) gaas, who needs it anyway ? 2) iv - measurments 3) it - measurments 4)...

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 /