Revision as of 17:53, 15 September 2011

Objectives

The possibility to carry out a BCAL beam test in the spring of 2012 has been discussed within the Calorimetry Working Group (CWG). Below, information is being gathered to agree upon the goals for this test before proceeding further and requesting parasitic time in Hall-B.

The central objective is to fully instrument a BCAL module with SiPMs, complete with their board electronics, cooling and mechanical assembly, coupled to Flash ADCs and readout by the planned Hall-D DAQ system. This would afford a comprehensive tryout of all aspects connected with the BCAL readout in a realistic beam environment and expose any issues that would require corrections or adjustments, before instrumenting the BCAL modules in the solenoid.

In no particular order, below are possible goals, for discussion.

1. Instrument a module with 80 SiPMs, 40 per side. If possible, these should be instrumented as planned for the physics runs, with
   1. final lightguides
   2. pre-amplifier boards
   3. full cooling
   4. mechanical assemblies
   5. cabling,
   6. Flash ADCs and F1 TDCs
   7. the Hall-D DAQ system
   8. Data runs will be converted for analysis by ROOT.
2. Such a test will allow verification of operation in a beam environment, and would give us valuable information in validating our MC studies on SiPM noise, thresholds, etc.
3. If possible, a broad energy range should be used, from at least 500 MeV to 2 GeV. This would extend the range acquired during the 2006 beam tests, and would allow us to get a better handle on the floor term in the energy resolution, by going to higher energies.
4. The module should be oriented to allow both 90 degree and shallow angle (>20 degrees) measurements. These would then be compared to the 2006 data and show the difference in behaviour between SiPMs and PMTs.
5. To achieve a large energy range, the module may have to be placed at a location behind the tagger, where a full-length module would not fit. If this is the case, a shorter module can be used out of an existing prototype piece, or especially constructed in Regina following the completion of the 49 modules (48 plus the spare). Calculations would have to be carried out to determine the appropriate length so as not to clip the showers for the shallow angle measurements.
6. If available by that time, Athens LEDs should be installed at least on two opposing BCAL cells, located centrally and surrounded by other cells so as to investigate operation as well as optical cross talk.

Calculations

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