1

Status of End-cap Modules

● Irradiated modules● Tracking with irradiated modules● K5.1 modules

1

Status of Irradiated Modules

● 5 modules (K5.0) irradiated modules✔ Some at different doses (accidental)

● 2 modules (K5.1) being irradiated

1

IV curves

● IV curves✔ Confirm that

May/June irradiation dose was half of the expected value

1

Irradiation data

● Data corrected for calibration factors and temperature

0.00 1.50 3.000.005.00

10.0015.0020.0025.0030.0035.0040.0045.0050.00

Gain

K5-312

K5-308

K5-303

K5-310

Fluence

Gain

0.00 1.50 3.001000.00

1200.00

1400.00

1600.00

1800.00

2000.00

2200.00e- ENC

K5-312

K5-303

K5-308

K5-310

Fluence

e- E

NC

0.00 1.50 3.000.00

100.00

200.00

300.00

400.00

500.00

600.00Threshold Spread

K5-312

K5-303

K5-308

K5-310

Fluence

Th

rs.

Spr

ead

(e-

EN

C)

Back to FDR (k5-308) situation with fully irradiated modules

K5- 308 K5- 312Occup @ 1f C 2.30E-03 1.40E-03Min Thrs. (f C) 1.20 1.10

Source meass. needed for max. threshold for efficiency

1

K5-312 .vs. K5-308

● K5-312, K5-308after full irradiation

● K5-312 shows some “timing” problems

1

Test beam – Eff. vs Occup.

● K5-308, can operate within specs in a narrow threshold window.● K5-310,K5-312: received half of the dose. In specs.

K5-310 K5-312 K5-308

1

Test Beam – Signal/noise

● K5-308, s/n is slightly higher than 8 at 500V● K5-310,K5-312: s/n flattens at ~350V with a value of ~11.

K5-310 K5-312 K5-308

1

Tracking

● Tracking studies made with 3 irradiated end-cap modules:✔ 2 of them were not fully irradiated.✔ Efficiency is product of individual efficiencies✔ Det. Bias only affects efficiency✔ Number of planes decreases fake rate.

⇨ With 4 planes (barrel) fake rate is <10-4 for occupancies up to 5x10-3.

1

K5.1 modules

● 4 modules have been built (2 with perfect chips,2 with 1ch dead chips)✔ K5-501,K5-503: Valencia✔ K5-502,K5-504: Geneva

● All off them showed “features” when tested in the boxes after construction.

1

K5.1 Modules

● Plug & play in the system sector disk (all)✔ Decision is made to irradiate the modules with perfect chips.

● First suspicion: electrical versus optical readout✔ Optical readout works in the box✔ Redundant (electrical) readout works on the disk

● “Undo” any grounding “improvement” in the ST trying to make the modules fail (no way)

● Suddenly the modules start working properly in the box...✔ 2 more modules are being built to understand the problem

● Other issues:✔ A drop of an oil-like substance is found on top of a chip in one of the

modules. Could be removed✔ Oil-based, “micrometric” contamination found in 2 of the modules.

1

K5.1 contamination

1

Conclusions

● Need to “source” irradiated modules:✔ Noise figures comparable to 308 in July/August.✔ Charge and S/N ???

● Tracking...✔ Up to 5x10-3 noise occupancy can be tolerated in terms of fake rate

with 4 planes of modules....● K5.1

✔ 2 modules being irradiated✔ 2 more modules being built.✔ Total of 4 modules could soon be used in the ST