Hi, <br> Sorry to bother those who is not interested.<br> I found something strange when I tried to calibrate the CC TDC. <br>I am not sure if this is a bug. I have even set the calibration database<br>constants CC_CALIB->TDC->T1=0.01 and CC_CALIB->TDC->T0=0,<br>
I found in the cooking result that 'cc_t' in h10 ntuple is very closed to 0.05*TDC, <br>not 0.01*TDC.<br>------------------------------------------------------------------------------------<br>Here is the original code in the latest cc and seb from cvs.<br>
("cvs co cc" and "cvs co seb" :)<br clear="all">jixie@ifarml5> grep -i ch2nsec *<br>
cc_evnt.F: real thet_cc(18), ch2nsec, ch_time<br>
cc_evnt.F: data NWRITE,NWARN /0,0/, ch2nsec /0.05/ <b> !this line set ch2nsec to 0.05</b><br>
cc_evnt.F: ch2nsec = abs(xcct2ch(n_SECT_CC(i),n_CC_hit(i))) <b> ! xcct2ch is T1 in calibration database<br>! ch2nsec is updated to T1</b>
<br>
cc_evnt.F: tdc(nhits) = ch2nsec*I_TDC_CC(i) + ch_time <b>! I_TDC_CC is TDC in raw bos file</b><br>
cc_evnt.F: tclust(nrclust) = tdc(nhits) ! cluster time (nsec)<br>
cc_evnt.F: <b> nrtime(nrclust) = tclust(nrclust) / ch2nsec + 0.5</b> <b>! this line could be wrong </b><br>
<br>
jixie@ifarml5> grep nrtime seb/*<br>
seb/trk_2_cc.F: cctime(npart_cc) = nrtime(cchit)*0.05<br>
------------------------------------------------------------------------------------<br><br>cc/cc_evnt.F is trying to fill ccrc bank. nrtime, one variable of this bank,<br>is calculated as <br>"nrtime(nrclust) = tclust(nrclust) / ch2nsec + 0.5 ", where <br>
1) ch2nsec is the calbration constant CC_CALIB->TDC->T1, <br>2) tclust(nrclust) = tdc(nhits) = ch2nsec*I_TDC_CC(i) + ch_time , <br>3)ch_time here is the calbration constant CC_CALIB->TDC->T0, <br>4)I_TDC_CC is the RAW CC TDC in bos file<br>
<br>in seb/trk_2_cc.F, I found this line<br>" cctime(npart_cc) = nrtime(cchit)*0.05".<br><br>From the above we can see that<br><b> --> nrtime = TDC+ T0/T1 +0.5<br> --> cctime = 0.05 *TDC + 0.05* T0/T1 + 0.025<br>
</b><br>I think this should not be the correct way for calibration. It made no sence to provide both T1 and T0 <br>to calibrate the CC time. I think the correct way should be <br>"cc_evnt.F: nrtime(nrclust) = tclust(nrclust)/<b>0.05</b> + 0.5"<br>
<br>If we change this line like the following, we can see that <br><b>--> nrtime = T1/0.05 *TDC + T0/0.05 + 0.5<br>
--> cctime = T1 *TDC + T0 + 0.025</b><br>
<br>Am I right?<br><br>Thank you for your time.<br><br>-- <br>Best Regards,<br>Jixie Zhang<br><br>