[d2n-analysis-talk] S1 and S2m Raw TDC Times

[David Flay]

Hi Brad,

To follow up on your comment about the large peak in the S1 and S2m TDC
times at large values (~200ns), I plotted the <raw> S1 and S2m TDC times
(in ns) over the range [-100,300] with a binning of 300.  See the attached
plots.

The blue peaks are the left times, the red are the right times.

For both S1 and S2m, the large peak does indeed show up at large times. 
Also of concern is a double peak structure in the S1 times.  I've done
this for the usual run 20676 (p = 0.60 GeV, 4-pass), and also I've done it
for a different run 20240 (p = 1.60 GeV, 5-pass).  Both runs yield similar
results.

I was hoping that these large peaks (at ~200ns) were possibly due to the
process of going from raw to corrected times, but this seems to not be the
case...

The first four plots show the S1 and S2m raw times for runs 20676 and
20240 with what I call trigger cuts:

    //one track from the target
    cut0 = Form("(L.tr.n==1)");
    //trigger cuts
    cut0 += Form("&&(DL.edtpl==0)&&((DL.evtypebits&(1<<3))==(1<<3))");
    //VDC cuts -- requirement of one track reconstruction
    cut0 += Form("&&(L.vdc.u1.nclust==1)&&(L.vdc.v1.nclust==1)");
    cut0 += Form("&&(L.vdc.u2.nclust==1)&&(L.vdc.v2.nclust==1)");

The last four plots show the same times, but now also including a GC cut:

    //GC ADC cut
    cut0 += Form("&&(L.cer.asum_c>300)");


So, for the most part, the behavior is roughly the same for both runs. 
However, run 20676 starts with 1.4M events, while 20240 starts out with
~800k events.


Dave

-------------------------------------------------
David Flay
Physics Department
Temple University
Philadelphia, PA 19122

office: Barton Hall, BA319
phone: (215) 204-1331

e-mail: flay at jlab.org
            flay at temple.edu

website: http://www.jlab.org/~flay
              http://quarks.temple.edu
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