I have looked a little bit on the Halog and found some stuff refering to the timing of the T2 and BB cer TDCs:<br><br> <a href="http://www.jlab.org/~adaq/halog/html/0902_archive/090216153021.html">http://www.jlab.org/~adaq/halog/html/0902_archive/090216153021.html</a><br>
<br> <a href="http://www.jlab.org/~adaq/halog/html/0902_archive/090217053534.html">http://www.jlab.org/~adaq/halog/html/0902_archive/090217053534.html</a><br><br>I checked the DBB.t2[0]:DBB.BBcerT04[0] for my 2063 run and I do see the same behaviour. So is this just a TDC/T2 walk effect? If so I am assuming that it needs to be fixed?<br>
<br>Also I have a Cerenkov sum that is built by using the multi-hit TDCs and mirror cuts, here is a plot of the cerenkov sum <a href="http://adc_mir_sum_2064.ps">adc_mir_sum_2064.ps</a>. It is for runs 2063,2064 and 2065. So I am now going to go ahead and look at the shower with various Cerenkov cuts applied to it. Before applying the Cerenkov sum cuts I took a look at what the preshower looks like (ps_2063.png). I was expecting there to be more of a seperation of the pion peak (0-500 chan) and the electron peak (500 and up chan) I seen this sort of sepeartion in some of our earlier runs (ps_1385.png), there were some BB trigger re-timings between these runs.<br>
<br>-matt<br><br><br><br><div class="gmail_quote">On Fri, Mar 12, 2010 at 4:04 PM, Brad Sawatzky <<a href="mailto:brads@jlab.org">brads@jlab.org</a>> wrote:<br><blockquote class="gmail_quote">
<div class="im">On Fri, 12 Mar 2010, MATTHEW R POSIK wrote:<br>
<br>
</div><div class="im">> Yes the red region is defined by my cut bounds. I looked at the 20<br>
> TDCs associated with the PMTs and fit the TDC signal with a Gaussian.<br>
> I then too the width to be 2*sigma for the Gaussian fit. So I have two<br>
> arrays of length 20 corresponding to the TDC peak and sigma for each<br>
> PMT. The difference in the TDC cuts is due to how well the fit fits<br>
> the TDC signal on each PMT. Some are TDC signals are not as sharp as<br>
> others. Should I fix them to all have the same width about the TDC<br>
> peak?<br>
<br>
</div>It should be a single fixed cut on all TDCs for now.<br>
<br>
I am 99% sure that the hits on the prominent 'shoulder' to the right of<br>
the peaks are real Cherenkov signals too. I think we had pretty good<br>
idea of what was going on there and how to make a correction that would<br>
put those hits back in the peak... Can't remeber the details at the<br>
moment though -- I think it had to do with how the coincidence between<br>
the Shower and Cerenkov was made. It might save you some time if you<br>
look through the halog during the d2n and transversity period.<br>
<div><div></div><div class="h5"><br>
-- Brad<br>
<br>
--<br>
Brad Sawatzky, PhD <<a href="mailto:brads@jlab.org">brads@jlab.org</a>> -<>- Jefferson Lab / Hall C / C111<br>
Ph: 757-269-5947 -<>- Pager: 757-584-5947 -<>- Fax: 757-269-5235<br>
The most exciting phrase to hear in science, the one that heralds new<br>
discoveries, is not "Eureka!" but "That's funny..." -- Isaac Asimov<br>
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</div></div></blockquote></div><br><br clear="all"><br>-- <br>Matthew Posik<br>Email: <a href="mailto:posik@temple.edu">posik@temple.edu</a><br>Temple University Physics Dept.<br>Office: BA-319<br>Office #: 215-204-1331 <br>
WebSites:<br>Temple:<br><a href="http://quarks.temple.edu/">http://quarks.temple.edu/</a><br>d2n:<br><a href="http://hallaweb.jlab.org/experiment/E06-014/">http://hallaweb.jlab.org/experiment/E06-014/</a><br><br>