From: Peter H. L. Christiansen (pchristi@nbi.dk)
Date: Thu Feb 13 2003 - 07:57:07 EST
Hi I will make another comment now that we are talking about the TOF. I looked at the FFS to get a better y=2 point for my thesis and I find that the TOF efficiency of H1 calculated in my simple way (pointed&&good hit)/pointed have 2 strange problems, see http://www.nbi.dk/~pchristi/BRAHMS/TOF/ The first problem is that the efficiency is very significantly lower for the the first slats. The second problem is that there seems to be a strong even-uneven slat dependence with as high as 10% difference between neighboring slats. This must have something to do with the pointing and likely have to do with two effects. 1) In the current dsts deltaSlat==0 (pointed and found slat has to agree) have been enforced (by accident). 2) The low momentum tracks have large angles and the pointing is done always to a fixed plane while the actual slats alternate like this x x x x x x x x x x x x x x What the exact effect is I have no idea.... I am writing this to make the point that when we redo the datareduction we should also try to fix/understand these things.... Cheers Peter On Thu, 13 Feb 2003, Djamel Ouerdane wrote: > hi Flemming, > > As I said in my last emails, I suspect tubes to be non linear and I did > not remove the ADC gaps, which gives the impression that large ADC > particles popylate the spectra. > > The setting was 4 deg, B 1/5 > > 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 > > -- :-) --------------------------- )-: Peter H L Christiansen @ NBI EMAIL : pchristi@nbi.dk OFFICE : Tb1@NBI (353 25269) HOME : Frimestervej 22, 1. tv PHONE : 35824930/40840492 :-D --------------------------- \-:
This archive was generated by hypermail 2.1.5 : Thu Feb 13 2003 - 07:57:39 EST