scope:

The aim of the present Recommendation is to establish recommendations concerning the particular characteristics and test methods of d.c. periodmeters. A periodmeter is an "electronic sub-assembly which, in association with one or more detectors, is used to indicate the time constant (period) of a nuclear reactor. Its indication may be given in units of time-constant, doubling time, decades per minute, etc." The periodmeter considered in this Recommendation consists essentially of: - a d.c. log amplifier with a voltage output, including possibly a preamplifier and connecting cable. In the following, this assembly is treated as a unit and termed "amplifier"; - a time derivative unit with a voltage output.