Digital Period Meter Utilizing Magnetic Core
A new type of reactor period meter utilizing multi-pulse magnetic counter as a neutron level comparator is described. The counter, which is initially counted for a unit interval at any time, is subtracted by one count for each input pulse after a fixed time-lag. The time required to empty the counter may be converted to reactor period by usage of a logic matrix. Ring ferrite cores are used as high speed shaping element and high speed pental counting element, and Deltamax core (50 Ni-Fe alloy) as decimal counting one. These pental and decimal counting circuits are originated from dividing the total magnetic flux amount (from negative to positive saturation) into 5 and 10 steps, respectively, and changing the flux level in the magnetic core stepwise corresponding to each input pulse. The period meter construction with magnetic cores results in increasing simplicity and reliability, and is much superior to the conventional circuit with a logarithmic amplifier and a differential circuit.