Microchannel plate unit performances in the regime of heavy particle detection

The characteristics of a block of two microchannel plates (b.m.c.p.) in the regime of registration of ions of various elements, are investigated. The block of microchannel plates consists of two m.c.p. located one after another a collector and on electric circuit. Commercial m.c.p. with the 28 mm diameter 1.1. mm thick have been used. The channels are straight with the 19 μm diameter and the 23 μm structure step. The pressure in the chamber is (2-3)10-6 tor. N2+, O2+, O+, N+ ion beams with the energy of 3170 eV are detected. It has turned out that pulse amplitude distribution does not depend on the particle type and the place of beam detection. Dependences of the relative coefficients of gain K and the resolution r on the voltage and current applied, are presented. It is shown that the voltage increase leads K rise and r decrease. The increase of energy of registrated particles leads to K rise. It is established that b.m.c.p. can be used to detect ions with the energy of several keV at loadings of the first plate channel not exceeding several particles per second