[d2n-analysis-talk] BB cer TDCs

[posik at jlab.org]

Hi All,

 So I was playing around with the Big bite TDCs today and forming a cut
that incorporates all the multi-hits for each TDC, so that I can apply it
to the cerenkov ADC signals.

  The multihit TDC cut loops over all tdc-hits and accepts only a certain
timing peak. ie

    for(Int_t nhit=0;nhit<6;nhit++){ //loop over multihit TDC
               if(nhit==0){
                   tdc_ct=Form("(DBB.BBcerT%02d[Ndata.DBB.BBcerT%02d]<%f&&DBB.BBcerT%02d[Ndata.DBB.BBcerT%02d]>%f)",pmt,pmt,tdc_hi,pmt,pmt,tdc_low);
                }else{
                   tdc_ct+=
Form("||(DBB.BBcerT%02d[Ndata.DBB.BBcerT%02d-%d]<%f&&DBB.BBcerT%02d[Ndata.DBB.BBcerT%02d-%d]>%f)",pmt,pmt,nhit,tdc_hi,pmt,pmt,nhit,tdc_low);
                }
            }
 where pmt is the pmt that you are looking at and tdc_hi and tdc_lo are
the high and low ranges of the timing peak.This is shown below in the
plot multi_tdc.png. The blue histo is the raw TDC and the red is the
multi-hit cut TDC, there seems to be some background/noise in some of the
higher chans (>400), this can be removed by using an extra cut

  ("DBB.BBcerT%02d<400",pmt) where pmt is the pmt you are looking at.

Next I wanted to look at the cerenkov ADC sum, so I plot this and start to
apply multi-hit TDC cuts defined above to the sum by "OR" ing the TDC cuts
for each TDC, something like:

 tdc_cut1 || tdc_cut2 || tdc_cut3 || ect

However when I begin to "OR" the TDCs and apply them to the ADC sum, the
sum goes to zero. And yet applying the individual TDC cuts to the
individual ADCs, they seem ok.

What I think may be happening is that I am using THaCherenkov class to
produce the ADCs (each individual ADC, ped subtracted ADC, gain corrected
ADC and the ADC sum) and I am using the DBB class for the TDCs. I was
wondering if it is possible that the two classes are some how conflicting
when I try to "OR" the DBB TDCs. As a curiosity I tried to use the
THaCherenkov TDCs(only single hit) and they leave me with a signal when
"OR" ing them together. You can see the cerenkov ADC sum using the
THCherenkov TDCs below(bb_cer_sum.png).

I was wondering if anyone had any input on this issue?

Thanks
Matt
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