From - Fri Jan 5 22:59:11 2001 Path: dscomsa.desy.de!axdsya.desy.de!vaxnews!CRITTENDEN From: CRITTENDEN@axdsya.desy.de Newsgroups: desy.zeus.calor Subject: === F/RCAL PMT High Voltage History 1992 - 1996 === Date: 26 Jun 1996 18:03:04 +0200 Organization: DESY Lines: 118 Sender: daemon@dscomsa.desy.de Distribution: local Expires: 11 Jul 96 18:02:50 Message-ID: <00022884_VAXNEWS@axdsya.desy.de> NNTP-Posting-Host: dscomsa.desy.de =========================== F/RCAL High Voltage History =========================== Jim C. 26 June 1996 The nominal HV settings for the forward and rear calorimeters have been saved since 1992 in ascii files on the aritra/caldev disk directory /data/calhv/hvnominal/frcal_old. I have analysed those files and put the data into ntuples to facilitate plotting the data. In order to estimate the variation in gain of the tubes I employed the algorithm we use for setting the voltages via UNO measurements: dG/G = 7.5 * dV/V. However, it should be borne in mind that these measurements cannot distinguish between a change in the calorimeter light yield and a change in the phototube performance. ---------------------------------------------------------------------- Conclusions ----------- The gain changes of the FHAC, REMC, and RHAC phototubes (R580) during the time period covered by the study (July, 1992 until now) differ from those of the FEMC tubes (XP1911). The most likely gain change for the FHAC, REMC, and RHAC tubes is -20% and that for the FEMC tubes is +6%. A gain-change-region defined to include 80% of the FHAC, REMC, and RHAC tubes extends from -30% to -10%. The corresponding region for FEMC tubes extends from -10% to +20%. The high voltage values for the FHAC, REMC, and RHAC tubes show a distinct rising trend, increasing by about ten volts per year. Such a distinct trend for the FEMC tubes is not observed. ---------------------------------------------------------------------- The rest of this message consists of technical details for people wishing to look at the plots and learn how to make their own. There is a lot of interesting data here and a variety of studies would be useful: 1) Are the beam pipe regions surviving? 2) How many tubes/year will be reaching their hv upper limit in 1996,7,8,...? are examples which occur to me offhand. Technical Details ----------------- I have created a new directory /data/calhv/hvnominal/hvhistory which contain the files: hv.f A FORTRAN program which reads the HV files and creates two ntuple files. The executable hv is made via the Makefile. Whenever it is executed it will include all the latest HV files. It excludes some uninteresting files from 1992 to 1996, using a total of 28 files at present. hv.log A log file produced when running hv via: hv >& hv.log & hvhistory.ntu A big ntuple (~10 MB = 28 files x 6652 tubes x 12 variables) which has all the HV in it. See below for a description of the variables. hvsummary.ntu An ntuple with one entry for each F/RCAL tube. One of the variables is the gain change from the first to last HV file. hv1.kumac An example kumac using hvsummary.ntu showing the gain changes leading to the conclusions above. hv2.kumac A kumac showing the HV trends for four sets of six tubes in the beam pipe regions of F/RCAL as examples. It takes about five minutes to run, since the ntuple is big and the kumac is written in a stupid way. hv1.ps These contain the postscript plots made by these kumacs. hv2.ps index.dat Just some numbers that hv.f needs. ------------------------------------------------------------------------------- I also made a macro which you can run from caw called pmgainchange. It might make some vaguely interesting plots, but it probably needs some more work. ------------------------------------------------------------------------------- Here is a description of the variables in the ntuples: hvsummary.ntu ------------- ******************************************************** * NTUPLE ID= 9000 ENTRIES= 6652 High Volts ******************************************************** * Var numb * Name * Lower * Upper * ******************************************************** * 1 * cell_no * 0.106000E+03 * 0.443010E+05 * Poser number * 2 * index * 0.100000E+01 * 0.665200E+04 * CAW index * 3 * age * 0.142600E+04 * 0.142600E+04 * Time since 1.1.92 in days * 4 * firsthv * 0.000000E+00 * 0.160000E+04 * HV on 23.7.92 * 5 * lasthv * 0.000000E+00 * 0.160000E+04 * HV on 18.6.96 * 6 * delgain * -.450673E+01 * 0.750000E+01 * Gain change via dG/G~dV/V * 7 * cal * 0.100000E+01 * 0.300000E+01 * FCAL: 1 RCAL: 3 * 8 * module * 0.100000E+01 * 0.230000E+02 * * 9 * tower * 0.100000E+01 * 0.230000E+02 * * 10 * side * 0.000000E+00 * 0.100000E+01 * Side 0: -x Side 1: +x * 11 * type * 0.100000E+01 * 0.700000E+01 * 1-4:EMC 5:HAC0 6,7:HAC1,2 ******************************************************** hvhistory.ntu ------------- ******************************************************** * NTUPLE ID= 9000 ENTRIES= 186256 High Volts ******************************************************** * Var numb * Name * Lower * Upper * ******************************************************** * 1 * cell_no * 0.106000E+03 * 0.443010E+05 * * 2 * index * 0.100000E+01 * 0.665200E+04 * * 3 * hv * 0.000000E+00 * 0.192000E+04 * * 4 * year * 0.920000E+02 * 0.960000E+02 * * 5 * month * 0.500000E+01 * 0.110000E+02 * * 6 * day * 0.100000E+01 * 0.310000E+02 * * 7 * age * 0.204000E+03 * 0.163000E+04 * * 8 * cal * 0.100000E+01 * 0.300000E+01 * * 9 * module * 0.100000E+01 * 0.230000E+02 * * 10 * tower * 0.100000E+01 * 0.230000E+02 * * 11 * side * 0.000000E+00 * 0.100000E+01 * * 12 * type * 0.100000E+01 * 0.700000E+01 * ********************************************************