CAMAC modules for recording arbitrarily long time series

Abstract

Two CAMAC modules have been designed to record the time of arrival of up to 32768 sequential events. the system consists of a clock module to generate a gated clock pulse train and a memory module to record event arrival time. Two memory modules can be operated in ping-pong mode to capture a time series of indefinite length, limited only by the capacity of the data acquisition computer storage medium. The maximum clocking frequency of 25 MHz provides a minimum digitization period of 40 ns and an inter-event deadtime of 2 clock cycles. these circuits have been used in a number of experiments for a wide variety of time measurements. They are particularly suited for interpolating event occurences relative to high precision UTC time signals distributed by satellites. A synchronized output pulse has also been provided to allow an external time-to-digital converter to determine event arrival time relative to the clock phase. This permits time-of-flight measurements over long baselines with a fraction of a nanosecond accuracy.