| Study of energy loss of GEM! [message #8654] |
Tue, 26 May 2009 11:48  |
donghee
Messages: 385
Registered: January 2009
Location: Germnay
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first-grade participant |
From: *dip.t-dialin.net
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Dear Gem experts,
When I study gem stuff, I have seen a energy loss information
in gem class, namely PndGemTrack::GetELoss().
How do you know Energy Loss for GEM?
If I correctly understand, GEM is a tracking device for most forward angle. There is no ADC front-end-electronics.
I would like to know how can access energy loss conceptionally?
Thank you!
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| Re: Study of energy loss of GEM! [message #8655 is a reply to message #8654] |
Tue, 26 May 2009 11:54  |
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Anonymous Poster
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From: *natpool.mwn.de
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Hi,
I am just guessing here, but do we have an idea yet about the amp/shaper/ADC (or even TDC) combination that should be used for reading out these detectors? Probably not.... But why do you need an amplitude info? It should be enough for this tracker to give a point which is smeared with a realistic resolution (in my mind something like 80mum or so).
Cheers, Christian
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| Re: Study of energy loss of GEM! [message #8665 is a reply to message #8662] |
Tue, 26 May 2009 13:32 |
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Anonymous Poster
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From: *natpool.mwn.de
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No worries 
Well then my question would be: Why do you want the Eloss signal from a GEM. It has huge Landau fluctuations (I guess around primary 30 e- in average or so), so you cant use it for PID. The only thing you can use the amplitude for is for looking for amplitude correlation in a double strip readout for pattern recognition and I assume that will be done. And of course we will need either ADC or TDC for the readout at the end of the day. And you can guess the amplitude of a charge pulse if you measure time over threshold in a TDC.
But maybe there is something I didnt think of?
Cheers, Christian
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| Re: Study of energy loss of GEM! [message #8666 is a reply to message #8665] |
Tue, 26 May 2009 13:50 |
Radoslaw Karabowicz
Messages: 108
Registered: June 2004
Location: GSI
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continuous participant |
From: *gsi.de
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Dear guys,
there is a plan to have at least 4-5 bit ADC information taken from the GEM detectors.
This information will be used only to get better point resolution and is not suitable for any PID considerations.
In the central region a particle flying perpendiculary to the plane will be firing at least 3 to 4 strips, and the ADC will be used to calculate the center of gravity.
yours,
radek
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