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Study of energy loss of GEM! [message #8654] Tue, 26 May 2009 11:48 Go to next message
donghee is currently offline  donghee
Messages: 385
Registered: January 2009
Location: Germnay
first-grade participant
From: *dip.t-dialin.net
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!
Re: Study of energy loss of GEM! [message #8655 is a reply to message #8654] Tue, 26 May 2009 11:54 Go to previous messageGo to next message
Anonymous Poster From: *natpool.mwn.de
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
Re: Study of energy loss of GEM! [message #8662 is a reply to message #8655] Tue, 26 May 2009 12:42 Go to previous messageGo to next message
donghee is currently offline  donghee
Messages: 385
Registered: January 2009
Location: Germnay
first-grade participant
From: *dip.t-dialin.net
Dear Christian,

I wonder that how one can estimate energy loss in certain detector without ADC.
This is very simple academical question (at least in my side) Smile
I assume that GEM has only TDC info. then I would like to knnow how energy loss can define from TDC info?

I know this question is not so professional, if I finished PhD already. Smile

Best wishes,
Donghee
Re: Study of energy loss of GEM! [message #8665 is a reply to message #8662] Tue, 26 May 2009 13:32 Go to previous messageGo to next message
Anonymous Poster From: *natpool.mwn.de
No worries Wink

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
Re: Study of energy loss of GEM! [message #8666 is a reply to message #8665] Tue, 26 May 2009 13:50 Go to previous message
Radoslaw Karabowicz is currently offline  Radoslaw Karabowicz
Messages: 108
Registered: June 2004
Location: GSI
continuous participant
From: *gsi.de
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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