From: Ian Bearden (bearden@nbi.dk)
Date: Wed Feb 12 2003 - 14:42:58 EST
I have a couple of questions about this... 1) is this true of any other settings? In particular, what about higher p and larger angles? 2) If this were what you call 'fast multicharge particles' why is this a continuos band, and not a blob at deltaE=4,9,etc? 3)What fraction of the data around beta~1 has deltaE>2? 4)What does this plot look like slat by slat? i.e. which slats have the line which has beta>1 and which slats have beta<1? Is it split in odd and even slats (and thus related to the path length?). -Ian On onsdag, feb 12, 2003, at 19:23 Europe/Copenhagen, 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 > > > -- > 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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