From: Kris Hagel (hagel@comp.tamu.edu)
Date: Wed Feb 12 2003 - 14:05:52 EST
Djamel, As far as I understand, TOF1 and TOF2 are not calibrated. I started trying to do that last week at BNL in my spare time while I was not on shift. I ran into problems calibrating because the matching between T1 and TD1 is not in order. At first I thought it was because TD1 was not calibrated, but it turns out that it has at least a nominal calibration. On the other hand, it was moved and the matching code has the x and y positions of TD1 "kind of" hardcoded in and the numbers now would be different. So I am examining how to resolve that in the easiest way without making it so it doesn't work for last years p+p data (which for sure has to be gone through again) Kris Djamel Ouerdane wrote: >Hi all, > >Inspired by some TOF stuff picked up from a PHENIX PhD thesis, I checked >if the BRAHMS TOF PID was as optimal as it should be. If you follow this >link, you will see that it's obvisouly not true : > >http://www.nbi.dk/~ouerdane/cal/weirdtof.html > >The FS data correspond to 4 deg. B 1/5 (run 5362) >I have a comment and a question. > >Comment : > The TOFW signal looks reasonable. For H1 and H2, hum... > I suspect the slewing correction is the "sinner". > The TOF resolution would be improved if the visible stripes seen for H1 > and H2 converged... > >Question : > why do we have the large dE particles at beta ~ 1 in H1 and H2? > Do they correspond in fact to fast multicharged particles ? > Or is there something really screwy ? or a physical effect I ignore ? > (The track-tof matching made sure that a single matched a single hit) > Have in mind that TOFW, H2 and H1 are calibrated with the same BRAT > modules, using the same algorithms. > > >As far as I can tell, a lot of data sets are affected in this way (but I >haven't checked yet all possible settings). > >In my opinion, this should be fixed ASAP. > >Djam > > > >
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