No abstract

No abstract

No abstract

In an experiment to determine the number of random events in a given time interval, the distribution of results builds up towards a Poisson distribution with a particular mean value. In the experiment described an alpha source and surface barrier detector form the source of random events, while the distribution is built up under microprocessor control to give typically a distribution of 104 points in 10 s. The experimental and theoretical distributions and the numerical results for mean, variance and chi 2 are displayed on a TV monitor. Other functions which can be performed include: a distribution of mean values, from which the standard deviation of the mean is calculated; a distribution of times between random events, which is an exponential; a chi 2 distribution, that is a plot of P( chi 2) against chi 2; a plot of P(> chi 2) against chi 2. Each of these functions gives appropriate numerical results on the TV monitor along with the distributions. The particular function performed is selected by switches, with no operator programming of the microprocessor. Detailed comparison of experiment and theory is performed in each experiment. The effect of small increases in dead time on these comparisons is of particular interest.

No abstract