Discussion of the finite slit length error in positron annihilation experiments

TLDR: In this article, it was shown that the point sample approximation always gives a far too large error under typical experimental conditions, and that the correct error is about 3-7 times smaller than the error calculated in the point sampling approximation.

Abstract: In linear slit measurements of the angular correlation of annihilation photons the use of finite slit lengths gives rise to an error in themeasured curves. It is shown that the point sample approximation, which is usually used in calculations of this error, always will give a far too large error under typical experimental conditions. The numerical values of the error for the free electron case are presented. The correct error is about 3–7 times smaller than the error calculated in the point sample approximation.