DB table for TPC Anode HVs

 The TPC group has decided it is interested in having the anode high voltages stored in the Offline database. To this end, we propose to add a table at Calibrations_tpc / tpcAnodeHV which will need columns for:

   unsigned short  sector;   /*  sector 1-24 */
   unsigned short  socket;   /*  MWC socket/card (ISOR=17,OSIR=18,OSOR=19)  */
   float  voltage;           /*   HV setting  */

I have placed this declaration into an idl file at StDb/idl/tpcAnodeHV.idl in CVS, which should appear in DEV in tonight's AutoBuild. Since this is rather small amount of data, maintenance of the table would be simplified by creating 456 elementIDs for the table (perhaps using an index seed called tpcSectSock or any other appropriate name) for the 24 sectors * 19 sockets.

A map of which anode wires correspond to which HV socket is available from TPC hardware documentation here, and the padrows influenced by each socket are listed here (where sockets are labeled as "cards" under Anode-wire termination).

Our plan is to use this information in offline reconstruction to know when:

  • HV sections have been turned off and padrows near such sections should be masked out because of questionable cluster shape/reconstruction
  • HV sections have tripped and the data from padrows under and near it (or perhaps the whole TPC) should be ignored/discarded
  • HV sections are being run at reduced voltage and a different gain and/or dE/dx calibration needs to be utilitized




p.s. I later learned that the Anode HV channels operate the sockets in pairs and triplets. For each sector, the map is as follows:

HV channelsockets