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BaBar Drift Chamber Gas System

Calculation of the gas leak of the drift chamber

(updated 08 Sept 2004, V. Poireau)

Method (pdf) (doc) to calculate the DCH gas leak.


There is a semi-automatic script which allows you to compute the leak for a particular date. You give the date in input to this script, then it uses the method described in the above document and gives you the leak rate as well as a ps and a gif file of the fit.
You need to have these 3 files:
- leak.csh
- leak.inp
- leak.kumac
(You could also find/run them under ~babardch/gasLeak/).

How to use this script: type |leak.csh -h| for details.
You can run it interactively: |leak.csh|.
or with arguments: |leak.csh 20Aug2004 14:25:00 15:25:00|
In any case, don't forget, as instructed, to type |exec leak| in PAW!

Some example of leak tests done previously:
- |leak.csh 20Aug2004 14:25:00 15:25:00|
- |leak.csh 11Aug2004 13:00:00 13:20:00|
- |leak.csh 30Jan2002 16:00:00 17:00:00|

Be careful: there is some issue with daylight saving time and OdcNtupleMaker! It could be necessary to subtract 1 hour to the local time (during the summer)!

Some results:
Using this method (which helps for coherence of the results), we obtain:
- 30 Jan 2002: leak rate at 4 mbar = 0.181 l/min
- 11 Aug 2004 (an anormal leak was observed at this time): leak rate at 4 mbar = 1.07 l/min
- 20 Aug 2004 (the previous anormal leak was fixed) : leak rate at 4 mbar = 0.158 l/min

Page maintained by Vincent.Poireau@lapp.in2p3.fr.