AN ELECTROMAGNETIC CALORIMETER CALIBRATION SOURCE FOR THE SUPERCONDUCTING SUPER COLLIDER

THE PRODIGIOUS FLOW OF DATA IN ELECTROMAGNETIC CALORIMETERS PROPOSED FOR EXPERIMENTS AT THE SUPERCONDUCTING SUPER COLLIDER (SSC) WILL REQUIRE THE USE OF NEW FAST RADIATION RESISTANT DETECTOR CRYSTALS SUCH AS BAF(2). HOWEVER, THE PRECISION OF THESE CALORIMETERS, AND HENCE THEIR USE FOR PHYSICAL MEASUREMENT, WILL DEPEND ON IN-SITU CALIBRATION. RECENT WORK BY U.S. COLLABORATORS DESIGNING THE LARGE BISMUTH GERMANATE ELECTROMAGNETIC CALORIMETER FOR THE L3 EXPERIMENT ON THE LARGE ELECTRON POSITRON (LEP) COLLIDER AT CERN HAS SHOWN THAT THE PENETRATING PHOTON RADIATION PRODUCED BY THE RADIATIVE CAPTURE OF HIGH ENERGY PROTONS FROM A PULSED RADIO FREQUENCY QUADRUPOLE (RFQ) LINAC IS THE MOST VIABLE CALIBRATION SOURCE. A CALIBRATION PRECISE TO 0.5% CAN BE COMPLETED FOR THOUSANDS OF CRYSTALS AT ONCE, WITHIN ONE TO TWO HOURS. THIS PROJECT WILL DETERMINE THE FEASIBILITY OF A NEW CALIBRATION SOURCE THAT IS APPLICABLE TO THE ENERGY RANGE AND RADIATION ENVIRONMENT OF THE SSC. FLUORIDE TARGETS WILL BE BOMBARDED TO PRODUCE HUNDREDS TO THOUSANDS OF 6 MEV RADIATIVE CAPTURE PHOTONS IN EACH CRYSTALFOR EACH BEAM PULSE, THEREBY SIMULATING A 3 TO 10 GEV ELECTRON OR PHOTON. THE OPTIMUM RFQ CONFIGURATION AND BEAM PARAMETERS WILL BE DETERMINED WITH THE AID OF L3 PHYSICISTS WHO WILL SUPPLY BAF(2) CRYSTALS, THE TARGET DESIGN WILL BE FIXED, AND THE DETECTOR READOUT FOR THE FAST 220 NM SCINTILLATOR COMPONENT WILL BE OPTIMIZED. SINCE THISCALIBRATION SYSTEM WOULD BE REQUIRED DURING THE CALORIMETER ASSEMBLY AS WELL AS DURING EXPERIMENTAL RUNS, RELIABILITY, EASE OF OPERATION, AND TRANSPORTABILITY WILL BE THE MAIN DESIGN REQUIREMENTS, ALONG WITH THE ABILITY TO MAKE A NEUTRAL HYDROGEN BEAM FOR CALIBRATION IN THE PRESENCE OF MAGNETIC FIELDS.