On Mon, Jul 12, 2010 at 1:28 PM, Brad Sawatzky <<a href="mailto:brads@jlab.org">brads@jlab.org</a>> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote">
The idea is that T4 should catch the good triggers that T3 misses, thus<br>
measuring the inefficiency of T3. So, what you do is this:<br>
- Get a sample of good electrons by applying cuts similar to when you<br>
did the cerenkov efficiency analysis (but allow the trigger type to<br>
be T3 .or. T4.<br>
For the case where we have a prescale of 1 for T3, then each T4 (after<br>
'good electron' cuts) means that we have something that looks like an<br>
electron, but it only fired one paddle plane when both should have<br>
fired. So, this expression:<br>
<br>
eff_3 = bit3/(bit3 + bit4)<br>
<br>
bitN = trigger N latch bit, after prescaling. This is set<br>
if and only if:<br>
- a TN trigger is seen at the TS within 10ns of whatever<br>
generated the L1A, .AND.<br>
- it passes the prescale condition for trigger N<br>
<br>
will give you the effieciency of the T3 trigger. That is, it will<br>
answer the question: for good electrons, what fraction of the time will<br>
T3 fire? As defined above, it should be independent of other triggers,<br>
prescaling, etc.<br></blockquote><div><br>Using this equation, I have (for run 20676):<br> <br>efficiencies:<br></div></div>Trigger 3: 99.9280 +/- 0.0228%<br>Trigger 4: 0.0720 +/- 0.0228%<br><br>with the statistical error given as:<br>
<br>de = sqrt((bit4)/(bit3)*1.0/((bit3)+(bit4))); (for trigger 3)<br><br>for trigger 4, let bit3 <-> bit4 in the above equation.<br><br>The cuts used:<br> <br> //one track from the target<br> cut0 = Form("(L.tr.n==1)");<br>
//cut out the pulser, T8 trigger<br> cut0 += Form("&&(DL.edtpl==0)&&(((DL.evtypebits&(1<<8))!=(1<<8)))");<br><br> cut1 = cut0;<br> //VDC cuts -- requirement of one track reconstruction<br>
cut1 += Form("&&(L.vdc.u1.nclust==1)&&(L.vdc.v1.nclust==1)");<br> cut1 += Form("&&(L.vdc.u2.nclust==1)&&(L.vdc.v2.nclust==1)");<br><br> cut2 = cut1;<br> //PID cuts<br>
cut2 += Form("&&(L.cer.asum_c>300)&&(prl_E_P>0.54)&&(L.prl1.e>200)");<br><br>I wanted to show you these numbers before I do this for all the kinematics. <br><br>-- <br>-----------------------------------------------------------<br>
David Flay<br>Physics Department<br>Temple University<br>Philadelphia, PA 19122 <br><br>office: Barton Hall, BA319<br>phone: (215) 204-1331<br><br>e-mail: <a href="mailto:flay@jlab.org">flay@jlab.org</a> <br> <a href="mailto:flay@temple.edu">flay@temple.edu</a><br>
<br>website: <a href="http://www.jlab.org/~flay">http://www.jlab.org/~flay</a><br> <a href="http://quarks.temple.edu">http://quarks.temple.edu</a><br>-----------------------------------------------------------<br>
<br><br>