Performance of small-radius thin-wall drift tubes in an SSC radiation environment at the MIT Research Reactor

摘要

Drift tubes of 1.9-mm radius and 25- mu wall thickness were exposed to neutrons and associated gamma radiation from uranium fission at the MIT Research Reactor. In 45 hours of irradiation, the drift tubes received a neutron fluence with energy greater than 0.5 MeV of 1.1*10/sup 13/ cm/sup -2/ And accumulated a charge per wire length of 0.08 coul cm/sup -1/, about that expected for three years of operation at the SSC for a lead scintillator calorimeter at a 1-m radius and for drift tubes at a distance of several tens of centimeters from the beam axis. Measurement of the pulse height, pulse shape, counting rates, andcurrents showed no degradation in drift tube performance. Fast (few nanosecond rise time), sharp (20-ns width) pulses were observed at counting rates of 5 MHz using CF/sub 4/ as the drift gas.