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Hall C

Hall C supports two spectrometers as standard equipment, the High Momentum Spectrometer (HMS) and the Short Orbit Spectrometer (SOS). Most experiments run in the Hall are coincidence between these or with a User supplied ``third arm'' detector. There are typically 4 FASTBUS crates and 2 VME crates that make up the front-end for the DAQ system. As with the other experimental halls the limitation to the DAQ is with the conversion and readout of the digitzing modules (primarily the Lecroy 1872 TDC).

Requirements in the energy upgrade proposal include the building of a new Super HMS spectometer for 12 GeV electrons. This will add several thousand detector channels. At the higher electron energies and more forward angles, larger backgrounds may require the implementation of a fast hardware Level 2 trigger. Hence, they would like to upgrade all the DAQ electronics to support pipelined readout (1-2 $\mu$s after the event) and maximum event rates in excess of 10 $\,$kHz . Going to a full pipelined readout scheme would also allow the elimination of a large amount of cable delay currently used for all detector signals.





David Abbott
1/5/2000