Techniques and equipment for measuring positron lifetime

Principles for development of equipment to determine positron lifetime as well as criteria for choice of certain elements of the equipment are described. Reasons for systematic errors under lifetime spectrum recording and under their processing are considered. Prospects of improving methods for determination of positron lifetime are discussed. It is recommended that the numerical methods sould be used for multicomponent analysis of spectra ad difference technique when studying negligible variations of average positron lifetime. Reliale data cannot be obtained without account of background annihilation, state of the surface and structure of the sample, required regimes of amplitude and time selections, peculiarities of techniques for experimental data processing, etc. attaining rather high time resolution. It is advisable on the one hand to develop facilities with moderate time resolution (300-400 ps), high response and on the other hand to develop precise apparatus for scientific reasearch with 150-200 ps resolution equipper with systems of long-term mode stabilization, hermostating, obtaining standard spectra, different effects on the studied object, automatic data processing