From: Djamel Ouerdane (ouerdane@nbi.dk)
Date: Wed Feb 12 2003 - 13:23:27 EST
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 -- Djamel Ouerdane ------------------------------------------o | Niels Bohr Institute | Home: | | Blegdamsvej 17, DK-2100 Ø | Jagtvej 141 2D, | | Fax: +45 35 32 50 16 | DK-2200 Copenhagen N | | Tel: +45 35 32 52 69 | +45 35 86 19 74 | | http://www.nbi.dk/~ouerdane | | ouerdane@nbi.dk | o---------------------------------------------------------o
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