Detectors for microbeam applications at medium ion energy

Abstract

Nuclear microprobes with excellent lateral resolution can be realized using a liquid metal ion source and electrostatic einzel lens system in a few hundred keV energy range. In case of ion beam analysis it is better to provide a special detector for Rutherford Backscattering (RBS) analysis or elastic recoil detection. Good mass and depth resolutions should be attained while keeping the damage caused by the beam at tolerable level. Two solutions are considered in the present work: (1) toroidal electrostatic analyzer combined with simultaneous Time-of-Flight (TOF) measurement for mass identification; (2) TOF measurement only, using a large area microchannel plate. Both solutions can be combined with 2D position sensitive anode plates for excellent performance. In case of the first solution, it is possible to distinguish the different mass atoms by the scattering angle where their peak in the angular distribution appears. Similarly to the energy distribution at a fixed scattering angle the angular distribution at a fixed energy represents mass and depth distribution. In case of the second solution the huge acceptance angle will make it possible to analyze submicron spot size without serious beam effects and both heavy and light elements can be investigated.