[d2n-analysis-talk] DL.bit3 Analysis

[David Flay]

Hi Brad,

So, I've been looking at the DL.bit3 histogram a bit closer.

In trying to understand if hits in the broader peak at ~700 channels, I
considered the individual hits.  DL.bit3 has 3 hits (according to the
MakeSelector.h file I generated from the ROOTfile).

Looking at hits 0 and 1, I plotted their TDC histograms (see attached).  A
plot of hit 0 shows a self-timing peak at ~1000 channels.   We see a broad
peak at ~700 channels featured in hit 1, in addition to a large peak <=20
channels. I'm not quite sure why this is...

My thinking was that the number of entries in the histogram for hit[0]
(12097) + hit[1] (177) should add to give the total number of events
(12275) seen in the histogram at the top left (DL.bit3, no specification
of hit number).  This is the case if I ignore that large peak <=20
channels in the histo for hit[1].   Am I plotting these variables
incorrectly?

To see of these two respective histograms have any correlation, I then
plotted DL.bit3[0] against DL.bit3[1] , which shows that the events in
DL.bit3[0] are correlated to those in the broad peak at 700 channels
(horizontal band in the 2D histo).  To me, this tells me that there are a
small number of events in the main self-timing peak of DL.bit3 correlated
to those events in the broader peak.  This amounts to ~1.4% of the total
selected events (12275) in the study.

The tag 'Good Electron Cuts' in the first attachment corresponds to:

one-track, VDC, Deadtime pulser, GC sum > 300, E/p>0.54, and GC TDC cuts.

Also -- If I make a cut (DL.evtypebits&(1<<3))==(1<<3) on the DL.bit3
histogram, events still show up outside the cut range specified in the
source (THaDecD (see attached -- red line [dead time pulse + evtypebits
cut] overlaps exactly with black line [dead time pulse cut]).  Wouldn't
the evtypebits pick out only those events that are within the (200,1500)
cut window?



-------------------------------------------------
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
-------------------------------------------------
-------------- next part --------------
A non-text attachment was scrubbed...
Name: DL-bit3_study_20676_8_26_10.png
Type: image/png
Size: 33460 bytes
Desc: not available
Url : https://mailman.jlab.org/pipermail/d2n-analysis-talk/attachments/20100826/41ecb40f/attachment-0002.png 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: DL-bit3_evtypebits-cut_20676_8_26_10.png
Type: image/png
Size: 9696 bytes
Desc: not available
Url : https://mailman.jlab.org/pipermail/d2n-analysis-talk/attachments/20100826/41ecb40f/attachment-0003.png