Results from Proton-Irradiation+ “short“ QTC status

Sensor Meeting Tracker-Week 12.07.2001

Frank Hartmann, Christian Piasecki

Optical inspection of all 78 sensors is finished

All Sensors are fine!and compatible to the former results, shown at the last meetings.

Results can be regarded at http:\\www-ekp.uni-karlsruhe.physik.de/~cms/

Electrical-Tests of 32 Sensors finished

• Still problems with „residual“ passivation-layer on the DC-Pads at the „long side“.

• But no problems when we measure the DC-Pads at the „short side“.

Breakdown of the 6054848-Sensor

During first IV-Measurement

ca. 400µA

IV after Breakdown

Did we lost contact to Bias-Ring ?Problem happened during IV curve:

NO movementsNO relais changes

at the simplest and earliest test;with 7 m tip

Solve: as Vienna we started tomeasure with 2 probes

Materials

• Hamamatsu Full Sensor (W6b 4919-39)Thickness: 500 mResistivity: 4.6 kcm

• Hamamatsu teststructures (same batch no. 35-41)

• ST Full Sensor (04439218)Thickness: 500 mResistivity: 5.1 kcm

Irrad. Assembly

Improvements to our IQC-Probestation for measurements at –10°C

Cold bath to fight humidity

The Cooling-Jig

Place for several probes to travel withthe jig, plus a „lid“ to avoid condensation!

Air-Cooler with dry iceSintered copper to havea maximum of surface to transfer minus temperaturefrom dry ice to air

Inlet

Outlet

Proton-Irradiation-Resultsnew dose calculations (p n)

all in 10^14 n(1MeV)/cm^2

Ham. Diode39: Ileak 2,56

Ni 2.6

Ham. FSensor: Ileak 3,8 (difficult-not reliable)

Ni 3,0

ST FSensor: Ileak 0,85

Ni 0,70

Ham. Diode41: Ileak 0,94

Ni 0,72

Ham. Mini41: Ileak 0,95

Ni 0,72

Wanted:

2.5

1.5

(less irrad from cyclotron as calculated)

0.9

31MeV p

33MeV p

Multi-CV Babysensor41 after Irrad

157pF

134Pf

Low dose

Multi-CV Babysensor39 after Irrad

185pF

146pF

High dose

Depletion Voltage and Fluence OLD (shown in Catania)

0 50 100 150 200 250 300

0,0

2,0x1019

4,0x1019

6,0x1019

8,0x1019

1,0x10200 50 100 150 200 250 300

0,0

2,0x1019

4,0x1019

6,0x1019

8,0x1019

1,0x10200 50 100 150 200 250 300

0

1x1017

2x1017

3x1017

4x1017

5x1017

150V

No Fluence

Bias Voltage [V]

CV on Ham. TS - Minisensor

180V

Low Fluence

Ca

pa

cita

nce

-2

220V

High Fluence

Depletion Voltage and FluenceNEW (on HPK minisensors)

CV for HPK 39 (FS+Baby+Diode)

Interstrip capacitance of HPK sensor (1 neighbour)

100 fF 3.2 pF

Interstrip Capacitance (one neighbour) vs. Bias Voltage

after Irradiation

0 200 400 600 800 1000

3,5

4,0

4,5

5,0

5,5

6,0Hamamatsu FS - C

int on strip 335

Cin

t [p

F]

Bias Voltage [V]

0 10 20 30 40 50 60

1,0

1,2

1,4

1,6

1,8

2,0

Interstrip Capacitance on TS H39

Before After irrad. and annealing

Inte

rstr

ip C

ap

aci

tan

ce [p

F]

Interstrip Capacitance on TS 39 after Irradiation (2 neighbours)

Some bad contacts due to residuals of conductive rubber!?!?!

Vbias = 400V

Interstrip Capacitance Baby41(2 neighbours)

600V 900V

Interstrip Resistance vs. Biasvoltage

HPK TS-Baby39 (full dose)

Strip 80-81 at –7°C Strip 88-89 at –5,5°C

Voltage[V] Rint[Mohm] ^2 Voltage[V] Rint[Mohm] ^2

0 26,4 2,72 E-4 0 20,6 2,44 E-4 50 119 7,19 E-4 50 232 2,27 E-3 100 675 5,66 E-4 100 to high ~ E-2 150 to high ~ E-2 200 to high ~ E-2

Conclusion

• Evaluation on minisensor, diode and FS only

• Irradiation with protons is feasible with small bias voltage near to final LHC condition

• The IQC in Karlsuhe is ready with some possible improvements, learned at this system test level

• Many improvements already implemented since Catania

Proposal for the ingot pre-qualification!!

Strip-Values after Breakdown

ca. 0.5nA

Nominal behavior