Two-dimensional visualization of cluster beams by microchannel plates

TL;DR

This paper presents a real-time 2D visualization technique for cluster beams using microchannel plates and CCD readout, enabling detailed spatial analysis of beam overlap in accelerator experiments.

Contribution

It introduces a novel detection system combining MCPs and phosphor screens for spatially resolved, real-time visualization of cluster beams and their overlap with accelerator beams.

Findings

Spatial resolution ~100 μm achieved

Allows monitoring of neutral cluster beams in experiments

Provides direct measurement of luminosity distribution

Abstract

An advanced technique for a two-dimensional real time visualization of cluster beams in vacuum as well as of the overlap volume of cluster beams with particle accelerator beams is presented. The detection system consists of an array of microchannel plates (MCP) in combination with a phosphor screen which is read out by a CCD camera. This setup together with the ionization of a cluster beam by an electron or ion beam allows for spatial resolved investigations of the cluster beam position, size, and intensity. Moreover, since electrically uncharged clusters remain undetected, the operation in an internal beam experiment opens the way to monitor the overlap region and thus the position and size of an accelerator beam crossing an originally electrically neutral cluster jet. The observed intensity distribution of the recorded image is directly proportional to the convolution of the spatial ion beam and cluster beam intensities and is by this a direct measure of the two-dimensional luminosity distribution. This information can directly be used for the reconstruction of vertex positions as well as for an input for numerical simulations of the reaction zone. The spatial resolution of the images are dominated by the granularity of the complete MCP device and was found to be in the order of \sigma~100 \mu m.