[d2n-analysis-talk] d2n BB replay

[posik at jlab.org]

Hi Brad,

  I have been looking in to the odd TDC signal produced from PMT4
(attached below BBDecData_tdc4.ps). Here is a copy of the last email
between Brad and I:

   >  However I am now looking at some Cerenkov TDCs and I am noticing
that PMT4
> is showing an odd TDC (see below I attached TDC of PMT 2 and PMT4 for run
> 1386 ) and it seems as though the good electron timing peak is missing, I
> would expect it to be around 200-300 TDC chans. The rest of the TDCs look
> good. I checked the db_DBB.dat file and did not see anything obvious there.
> I think we even kept the TDC modual stable through the experiment crate 8,
> slot 16. This problem is also showing up on several other runs I looked at
> as well, 1466, 2064.

DBB.BBcerT02 looks 'OK'.  The signal:noise is pretty low (short peak),
but the structure is at least reasonable.  If the signal:noise on that
peak is close to PMT01 and 03, then I would think it is fine.

DBB.BBcerT04 is crazy...  That looks more like a screwed up ADC spectrum
than a TDC histogram.  See if you can find any run(s) where it looks OK,
then work back to find where it transitions from good to bad..


Today, I have found the cause of this problem. It has to do with the
replay script and not a DB issue. The replay script that I was using was
"replay_det_BB.C" and it called the class "BBDetData" to decode the DBB
class. This caused TDC 4 to look odd (chan 0-400 seemed to be missing).
However, when I use the class "THaDecData" class, everything looks good
(see THaDecData_tdc4.ps below).

I am currently looking into what may be causing the problem in
"BBDecData", if anyone has any suggestions or hunches please tell.


-Matt
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