APPLICATION SPECIFIC, DISCRETE JUNCTION FET DESIGNED FOR USEIN LARGE PARTICLE DETECTOR PREAMPLIFIER CIRCUITRY

IMPROVED ELECTRONICS IN THE PREAMPLIFIER CIRCUIT OF CALORIMETER DETECTORS IS DESIRED TO IMPROVE THE ABILITY TO COLLECT DATA FROM HIGH ENERGY ACCELERATORS FOR PHYSICS EXPERIMENTS. EXTREMELY LOW NOISE AMPLIFICATION IS REQUIRED TO AVOID POOR SIGNAL TO NOISE RATIOS SINCE ANALOG SUMS OF ALL THE DETECTOR SIGNALS ARE PERFORMED FOR TRIGGER PURPOSES. FAST SIGNAL PROCESSING SPEED IMPOSED BY THE EVENT RATES OF PRESENT AND FUTURE ACCELERATORS REQUIRE THE PREAMPLIFIER TO BE LOCATED AS CLOSE AS POSSIBLE TO THE DETECTOR TO MINIMIZE THE INDUCTANCE OF CONNECTIONS. IN ADDITION, IT MUST BE RUGGED ENOUGH TO WITHSTAND THE EFFECTS OF RADIATION AND ELECTROSTATIC DISCHARGE, AND, IN THE CASE LIQUID ARGON CALORIMETERS, OPERATE AT VERY LOW TEMPERATURES. PRESENT PREAMPLIFIERS ARE MADE ON SMALL HYBRID CIRCUITS LOCATED NEAR THE DETECTOR. JUNCTION FIELD EFFECT TRANSISTORS (JFETS) HAVE TYPICALLY BEEN CHOSEN AS THEACTIVE DEVICE IN THESE CIRCUITS, BECAUSE THEY EXHIBIT ADVANTAGES OVER OTHER TYPES OF TRANSISTORS. THE OBJECT OF THIS PROPOSAL IS TO IMPROVE UPON PRESENT CALORIMETER PREAMPLIFIERS THROUGH THE USE OF NEW JFET DEVICES WHICH EMPLOY DESIGN AND PROCESS CHANGES SPECIFIC TO THIS APPLICATION. THIS WILL BE DONE BY DESINGING A JFET THAT RESPONDS TO THE SPECIAL REQUIREMENTS OF THIS APPLICATION. AREAS OF IMPROVEMENT INCLUDE BETTER NOISE CHARACTERISTICS ATLIQUID ARGON TEMPERATURE, IMPROVED RADIATION HARDNESS, BETTER MATCHING OF DC ELECTRICAL PARAMETERS TO THE NEEDS OF THE CIRCUIT, AND HIGHER RELIABILITY. THESE REQUIREMENTS WILL BE ADDRESSED BY CONSIDERING ISSUES RELATING TO THE DESIGN OR LAYOUT OF THE TRANSISTOR, MANUFACTURING METHODS, SPECIFICATION PARAMETERS OF THE SILICON MATERIALS, AND PACKAGING OF THE TRANSISTOR CHIP.