TWO DIFFERENT DETECTORS, BOTH USING THIN, CRACKED-ETHYLENE FOILS, WILL BE MADE.

TWO DIFFERENT DETECTORS, BOTH USING THIN, CRACKED-ETHYLENE FOILS, WILL BE MADE. ONE DETECTOR CONSISTS OF A LOW-PRESSURE GAS CELL, SEALED AT EITHER END WITH ALUMINIZED ETHYLENE FOILS ABOUT 10 MICROGRAMS PER SQUARE CENTIMETER THICK. LIGHT GENERATED WHEN THE PROTON BEAM TRAVERSES THE GAS WILL BE VIEWED THROUGH A SIDE WINDOW; THE INTENSITY OF THE LIGHT, AS MEASURED WITH A PHOTOMULTIPLIER OR PHOTODIODE AND ASSOCIATED ELECTRONICS, WILL INDICATE THE ION BEAM INTENSITY. FOR THE OTHER DETECTOR, ELECTRONS EJECTED FROM A SINGLE, ALUMINIZED FOIL WILL BE MAGNETICALLY DEFLECTED TO ONE SIDE, WHERE THEY WILL BE DETECTED WITH AN ELECTRON MULTIPLIER; THE ELECTRON CURRENT WILL INDICATE THE BEAM INTENSITY. BOTH DETECTORS DEPEND ON THE FACT THAT THIN ETHYLENE FOILS HAVE EXCEPTIONALLY LONG LIFETIMES UNDER PARTICLE BOMBARDMENT. THESE DETECTORS WILL BE LINEAR, DIRECT READING, EASY TO CALIBRATE, AND WILL NOT INTEERFERE WITH THE OTHER USES OF THE TARGET CHAMBER.