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Chiho Wang ATLAS TRT Duke University Hampton, May. 2002 1 Xe-CO 2 Stability Chiho Wang Duke University.

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Presentation on theme: "Chiho Wang ATLAS TRT Duke University Hampton, May. 2002 1 Xe-CO 2 Stability Chiho Wang Duke University."— Presentation transcript:

1 Chiho Wang ATLAS TRT Duke University Hampton, May Xe-CO 2 Stability Chiho Wang Duke University

2 Chiho Wang ATLAS TRT Duke University Hampton, May Setup  X-ray aperture limits active region ~ 6-7cm on straw.  0.002” Cu foil reduced X-ray intensity to ~0.1uA/cm  Only 1 pair of ASD sockets are active to draw current.  Scan along straw at 8cm intervals.  At each location, raise HV from 1550V to 1750V at 25V step, 20 sec interval.  Record current & # of Trips.

3 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09 ASD #1

4 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09 ASD #2

5 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #3

6 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #4

7 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #5

8 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #6

9 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #10

10 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #11

11 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #15

12 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #16

13 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #21

14 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #22

15 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #27

16 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #28

17 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #30

18 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #31

19 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #32

20 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD #33

21 Chiho Wang ATLAS TRT Duke University Hampton, May Observation  Most ASD HV trip at mid wire support location.  Some ASD HV trip at end wire support.  After several hours of “burning” at the wire support, it gets more stable and less likely to trip u ASD were scanned many times with Ar-CO2 before taking Xe data. They are obviously more stable. u In the case of Ar-CO2, X-ray also triggers a self-sustained current draw that lasts for several hours even after X-ray is turned off. This contributes to an increase of current draw when X-ray passes through mid wire support. This current, however, also dies out after burning.

22 Chiho Wang ATLAS TRT Duke University Hampton, May Module 2.09, ASD 30, Ar-CO2

23 Chiho Wang ATLAS TRT Duke University Hampton, May Summary  Xe-CO2 is stable at 1750V with 0.3uA/cm local rate  Mid wire support tends to be unstable in the beginning of the chamber operation, but can be improved with “burning”.  Some end wire supports also show the same instability but not as often as mid wire support.


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