BRAHMS Beam-Beam Counters: Operation Manual


  1. Turn on the High Voltage:
    • Beam-beam High Voltage is operated by 3 LeCroy 4032A Mainframes.
    • High Voltage can be set by the program BRAHVO from the "pii?" "operator" account
    • One mainframe (BLT4032) is used as a power supply for Big Tubes in both arrays. All channels of BLT4032 has to be set at 2800V.
    • Other 2 mainframes (BBL4032 and BBR4032) are operating Small Tubes in respectively Right and Left Arrays. All channels in BBL4032 and BBR4032 has to be set at 1700V.
    • Detailde description of BRAHVO operations can be found at http://pii3.brahms.bnl.gov/~operator/user_guide/BrahmsUserGuide.html
      NOTE: High Voltage has to be turned on slowly, in steps of 500V or less.


  2. BrSuperMonitor is used for the on-line monitoring (assuming, that you are in "ROOT" with loaded BRAT libraries. Link above provide all neseccary information on that). BrMonitorBB has to be added as follows:
     root [0] MyBBMon = new BrSuperMonitor("name", "title", "", "EVB");
    root [1] MyBBMon->AddMonitor("BrMonitorBB");


  3. Main things to look at:
    The only thing one can get by using Beam-Beam Monitor is the status of the tubes and ADC and TDC channels. Thus, we would recommend to look at the "Monitor Pictures" of the ADC and TDC spectra ring by ring in both arrays.
    • Histograms: Individual pictures of ADC and TDC spectrum for every module.
    • Pictures:
      • Hits - Number of Modules hit in each array and Hits per individual Module Numbers.
      • Pedestals - Mean values and RMS's of the pedestals for every module.
      • AllTogether - ADC's and TDC's spectra for the whole array added up together.
      • ADC and TDC spectra of the individual modules, grouped by the Rings of the detectors in the array.
    So, the only thing one can note during the regular monitoring is the failure of the individual module in a form of an empty ADC or/and TDC spectrum. It should be documented in the Log Book. Also, E-mail to one of the addresses below would be grately appreciated :-)))).


  4. Here is a PDF picture of the Beam-Beam Cabling scheme listing all devises, cable numbers and Module Numbers.
to the Beam-Beam Counters Page
Prof. Burton Budick, Yury Blyakhman.
Last modified: Wed Apr 25 17:44:34 EDT 2001