Absolute Detection Efficiency of a Microchannel-Plate Detector for Ions and Neutrals

Abstract

The absolute efficiencies of a microchannel-plate detector for He+ and He0 were measured in the energy range of 1 to 10 keV. There was no difference between He+ and He0 incidences regarding efficiency, and the efficiency was constant in the above energy range. This value indicates that almost all the particles hitting the entrance wall of the MCP pores were detected.

MeV negative ion generation from ultra-intense laser interaction with a water spray

“…The "zero" points in the spectrometers are formed by neutrals and x-ray photons. 15 While x-ray emission is expected to be almost isotropic, 16 in contrast, the neutral oxygen atoms are emitted mostly in the transverse direction according to our interpretation. The "zero" point signal in the lateral direction is ten times stronger than in the forward direction, which is consistent with a signal due to fast neutrals.…”

Performance of a micro-channel plates position sensitive detector

“…The main difficulty in the measurement of the absolute detection efficiency is the determination of the very low incident currents. For counting rates larger than about 10 9 counts/s m 2 , the detection efficiency decreases due to the non-vanishing time constant needed to transport electrons from the power supply to the depleted channels [6,7]. Higher currents can also damage the MCPs.…”

“…Results of tests performed with several ions, in different charge states and using various MCPs, are available in the literature [4,5,[7][8][9][10]. Different measuring methods have been implemented.…”

“…Different measuring methods have been implemented. For instance, Oberheide and Brehm have used a photoelectron-photoion coincidence technique [7,8], while Gao has sent alternatively the ions to the MCPs and to a femtoampere sensitive Faraday cup [10].…”

MeV negative ion source from ultra-intense laser-matter interaction

“…3) are formed by neutrals and x-ray photons emitted from the interaction region. 11 The x-ray emission is expected to be almost isotropic. Because of lower absorption in the ionized medium encountered in the forward direction, x-rays are preferentially observed in the forward direction.…”