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Home » Analysis and Reconstruction » Tracking & Vertexing » [MarlinTPC] PulseFinder questions and issues
[MarlinTPC] PulseFinder questions and issues [message #1861] Fri, 25 September 2009 08:13 Go to previous message
rosemann
Messages: 41
Registered: March 2009
Location: hamburg.de
Hi,

I reworked the PulseFinderProcessor of MarlinTPC/reconstruction. While encouraging testing to report any trouble, there are several issues.

1) Flagging pulses as "overflow".
When the electronics saturate (max value of bit resolution reached), then this needs to be tagged. Unfortunately the pulse finder is the wrong place to do this. Especially with /pedestal subtracted/ data the maximum adc value can only be reached, if the pedestal value (for this pad, in this run) is zero. We might need to flag this /overflow/ at a different stage. It is possible to compute the unsubtracted value (by adding the pedestal value, unelegant) or if the unsubtracted data is available to find this value (also very unelegant). But where? One place might be the RawDataToTrackerDataConverter. Or is it a processor on its own? Unfortunately only the TrackerPulses have the quality bit, which makes the producer of the TrackerPulse objects the only good place.

Any suggestions?

2) Pulse splitting
Currently the splitting of pulses is implemented, and executed regardless. I could make this optional, to allow for later splitting; maybe in a different processor.
While I strongly believe in modularisation, I'm not sure if this a good case. Somehow I would rather implement different algorithms within the existing processor. But I'm open to both suggestions as well as discussion.

3) Negative adc counts
This is only a minor issue, please assume here a positive electronics polarity. With my test cases it is actually wanted, that when the pulse "charge" (actually: summed ADC counts) is computed, negative values are actually subtracted from the total charge. But this might not be true for other, common cases. Also the pulse time calculation by using the center of gravity is affected by this.


Cheers,
Christoph


When you have eliminated the impossible, whatever remains, however improbable, must be the truth. (Sir A.C. Doyle in Sign of Four)
 
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