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8482117 
Journal Article 
Nonlinear response of phosphor screen used in velocity map imaging spectrometry 
Li, YuFan; Zhao, DMei; Zhou, WenC; Qian, DBin; Yang, Jie; Zhang, SF; Zhu, XL; Ma, XinWen; , 
2019 
Yes 
International Journal of Mass Spectrometry
ISSN: 1387-3806 
ELSEVIER SCIENCE BV 
AMSTERDAM 
23-28 
WOS:000472151800004 
We present an approach to experimentally investigate the nonlinear response of phosphor screen (PS) module applied in velocity-map-imaging spectrometry under the condition of microchannel plate (MCP) module working in an appropriate amplifier voltage to ensure a constant unsaturation gain. Our approach, taking the Photek's VID240 detector system as an example, is based on the measurements of the position spectra of Rb-87(+) photoion pulses with well-determined numbers of ions and duration times at various voltage differences (U-f) between MCP and PS modules. The measured spectra allow us to obtain the relationship between the two-dimensional distribution of luminescence (the luminescence intensity in the kth pixel) and the total number of ions in one pulse at a given Uf value. The obtained relationship leads to the luminescence efficiency and the acceptable limit of input ion flux density (the maximal number of ions arriving at MCP per unit time per unit area to avoid the nonlinear response) for a particular PS to be determined. (C) 2019 Elsevier B.V. All rights reserved.