Djam observed and reported a problem in the acceptance calculation using brag for 30 deg. That hits in T2 looked strange. I checked it this morning and observed that geant gave an error message when being run ***** GSAHIT OVERFLOW WHEN IUSET= T2 IUDET= T2PR HITS( 1)=-0.4113410E+03 ORIG= 0.4000000E+03 FACT= 0.1000000E+04 ***** GSAHIT OVERFLOW WHEN IUSET= T2 IUDET= T2PR HITS( 4)=-0.4129992E+03 ORIG= 0.4000000E+03 FACT= 0.1000000E+04 This is the clue - the global xhits are more negative than the orgin for the hit in that variable. Since hits are stored (global) inside geant as hitval= (x + origin)*fact as integer the wrong global value is stored. See the cern geant web pages fro more on hits (and nearby pages) http://wwwinfo.cern.ch/asdoc/geant_html3/node148.html The origins for t2,tof2, c1 as well for t3,t4 t5 were changed and commited (FFS up to 30 deg BFS to~20deg - which it cannot do physically) The version is now 1.1.14 and has been installed in opt/brahms/new. Lesson to be learned a) Though much of BRAG has been extensively tested there can still be problems b) In case of problems check log-output for possible errors that might be a clue. c) As was done- communicate problems Thanks to Pawel for posting tracking effeciencies for the FS. This bring up a point- I would think that part of the effeciencies say determined for T1 (and T1) is due to bad and non-instrumented pads. If this is the case I think it is --incorrect -- in the geometric acceptance to take into account dead and non instrumented pads as I believe it is done in the BrGeanToTpcTrackCandidate. If so we should either change the geometric acceptance-calculation, or take the effect of of the 'experimental tracking eff' which seems at best difficult. Comments to this? regards from a hot and steamy Long Island Flemming ------------------------------------------------------ Flemming Videbaek Physics Department Brookhaven National Laboratory tlf: 631-344-4106 fax 631-344-1334 e-mail: videbaek@bnl.gov
This archive was generated by hypermail 2b30 : Thu Jul 04 2002 - 09:40:16 EDT