1. Acceptance test at Duke

2. After completion of stringing (still in the stringing station)
HV testing of each straw at 1700 volts in air
No arcing
Current <10 mA
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

3. Front/back tension

5. Leak Rate –straw volume

6. 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

7. Signal test output

8. When modules leave Duke, no more than 1% of straws are dead
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.