A Beam-Spill Monitor for LAMPF

A beam-spill monitor system for the Los Alamos Meson Physics Facility (LAMPF) has been developed to meet the LAMPF requirements of fast action, reliability, long life in the LAMPF beam-channel radiation environment, and a variable sensitivity which can be changed by over 1000:1. Approximately fifty of these systems will be required, hence, low cost per system has been an important consideration in its development. The detector, an all-glass side window multiplier tube immersed in a mineral oil scintillator, has a useful range from 10-3 to 5 × 105 R/h. The electronics consist of a fast nonlinear electrometer, a threshold detector, a fast switch, a peak detector, and an envelope amplifier. The manner in which these interface with the LAMPF Fast Protect System and the analog and binary inputs to the control computer is described.