Acceptance test at Duke

Seog Oh/ Duke University/June, 2003 TRT/ ATLAS week at CERN

Acceptance test at Duke


After completion of stringing (still in the stringing station) HV testing of each straw at 1700 volts in air

No arcing Current <10 A About 5-10% wires fail Replace them.

Tension measurement. Acceptance criteria 128 Hz < Tension < 170 Hz Tfront – Tback < 3 Hz About ~1% wires fail the test Replace them

Seal the tension plate and purging volume Straw volume <1 mb/bar/min Purging volume < 10 mb/bar/min


Front/back tension



Leak Rate –straw volume

Module leak Rate

0

1

2

3

4

5

6

7

8

9

1 2 3 4 5 6 7 8 9 10

(mbar/bar/minute)x10

Nu

mb

er o

f m

od

ule

s


Signal Test Use X-ray scanner Ar-CO2(70-30) but no CO2 in the purging volume

Current is recorded at 1600 Volts.– No attempt to reduce the current below ~100 nA but the current

draw is typically less than a few hundred nA after fixing noisy channels.

Wires with HV problem are removed and re-strung if necessary. Usually there are one or two wires per module with the problem.

No problem for a few days ADC spectrum is recorded from the front and back.

Check the signal shape and counting rate.– Reverse voltage is applied to the noisy straws– There are a couple of channels per module fail the signal test.

These wires are removed and re-strung if necessary.• Bad wire-joint: front and back are connected• No signal: a wire is not connected to a socket• Very noisy channel


Signal test output


When modules leave Duke, no more than 1% of straws are dead. The passport has a list of bad wires with reasons for failure. ~1/2 of the wires can be saved with re-stringing.

Dimension check Use the fixture from IU to make sure module dimensions are

within the specification.

Ready for gain mapping.

Documents

Acceptance test at Duke