A two mode high speed time analyzer with a plated wire memory

Abstract

A 1024 channel high speed time analyzer was made by using a plated wire as a memory element. This time analyzer has two operation modes, TOF mode (add-one mode) and MS mode (multi-scaler or add- N mode), both of which use a 133 MHz crystal oscillator. The channel width of the former mode can be selected from 15 ns to 3.84 μs (9 stages) and that of the latter from 1 μs to 65.536 ms (9 stages). For background counting, the last eight channels have longer channel widths and selective delays. These channel widths and delay times were tested with random pulses from a liquid scintillation counter and a weak radioactive source, and periodic pulses from a pulser. The results agreed satisfactorily with the designed values. The dead time for the TOF mode was found to be about 270 ns and that for the MS mode was about 19 ns in counting and about 250 ns in memory cycle. These values are drastically shorter than previous time analyzers, such as TMC-211. This time analyzer has been applied to fast neutron time-of-flight experiments with an electron linear accelerator, and pulsed neutron experiments in beryllium-oxide piles. In this case, no correction for count losses by dead time of a time analyzer is required.