A new method of angular correlation measurements

Abstract

A new type of angular correlation apparatus is described, and a mathematical model of its statistics is given. The angular correlation of coincident nuclear radiations can be measured by detecting intensity correlations in the output of two counters. For prompt coincidences, the detector currents are mixed in a broadband circuit whose output is the product of the two inputs. The time-average output of the mixer is shown to be proportional to the rate of true coincidences, and therefore to the angular correlation function. Furthermore, the fluctuation of this output has the same ratio to the average current as the rate of random to true coincidences both for weak and strong sources. For delayed coincidences, other circuits give the time spectrum and the frequency spectrum of the perturbed correlation function. Possible applications are mentioned, and the relation to the Brown-Twiss interferometer is clarified.