The development of a hardware random number generator for gamma-ray astronomy

Abstract

Pulsars, as rotating magnetised neutron stars got much attention during the last 40 years since their discovery. Observations revealed them to be gamma-ray emitters with energies continuing up to the sub 100 GeV region. Better observation of this upper energy cut-off region will serve to enhance our theoretical understanding of pulsars and neutron stars. The H-test has been used the most extensively in the latest periodicity searches, whereas other tests have limited applications and are unsuited for pulsar searches. If the probability distribution of a test statistic is not accurately known, it is possible that, after searching through many trials, a probability for uniformity can be given, which is much smaller than the real value, possibly leading to false detections. The problem with the H-test is that one must obtain the distribution by simulation and cannot do so analytically. For such simulations, random numbers are needed and are usually obtained by utilising so-called pseudo-random number generators, which are not truly random. This immediately renders such generators as useless for the simulation of the distribution of the H-test. Alternatively there exists hardware random number generators, but such devices, apart from always being slow, are also expensive, large and most still don't exhibit the true random nature required. This was the motivation behind the development of a hardware random number generator which provides truly random U(0,l) numbers at very high speed and at low cost The development of and results obtained by such a generator are discussed. The device delivered statistically truly random numbers and was already used in a small simulation of the H-test distribution.