From: Ian Bearden (bearden@nbi.dk)
Date: Wed Feb 12 2003 - 17:06:53 EST
On onsdag, feb 12, 2003, at 21:27 Europe/Copenhagen, Djamel Ouerdane wrote: > >> 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? > > yes, same behaviour (all settings I could check are affected). > > >> 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? > > it was a question. I don't know yet. For what I know, there is some non > linearity that I could deduce from the multiple matchings (more than > one > track matched with a TOF hit), the dE peak is positioned at 1.7 > instead of > 2. But this is maybe not so reliable > >> 3)What fraction of the data around beta~1 has deltaE>2? > > around 5% at 4 deg (might be setting dependent). > > >> 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? > > there's no slat dependence, all of them shows this stuff individually > That's why I suspect it's the slewing correction. This calibration > provides a set of parameters for each top and bottom tubes. If they're > not > good, you can get this behaviour. What I will do to make sure is to > make > the same plots but with dE_top OR dE_bot and NOT the geometrical > average. > This does sound really weird. How can a single slat give different times for the same energy if it is the slewing? Also, what cuts have you put on the tracks? It bothers me a bit that the tail goes to such high dE, I guess it cannot be due to z>1 particles (5% is way too high). At 4 degrees for low field settings, maybe 5% is not crazy for double hits. If, however, you say you see the same behavior at 12 degrees, then I guess it is not due to multiple hits... One thing that might be interesting to check is to make a pion cut in the RICH and see how this plot looks for those tracks. -Ian PS: Kris, I am working on the calibrations for d+Au, and they are 'almost' ready to go. If you are also looking into this it might be a reasonable idea for us to pool our resources. > > >> Is it split in odd and even slats (and thus related to the path >> length?). >> > > no > > more later. > > Djam > >
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