A High-Efficiency Photon Collection Module for Vacuum Ultraviolet Monochromators

The accurate measurement of both the photoelectron emission yield spectrum (PEYS) and energy spectrum (ES) relies significantly on the energy intensity of ultraviolet monochromatic light. The signal-to-noise ratio of the test results is greatly influenced by the efficiency of the monochromator, which is crucial in constraining the energy of the ultraviolet monochromatic light. Consequently, the design of a high-efficiency vacuum ultraviolet (VUV) monochromator holds paramount importance. Addressing the demand for high-energy ultraviolet monochromatic light, this article introduces a structure for a photon collection module. The study involves an analysis of factors impacting the efficiency of ultraviolet monochromatic light, the establishment of a mathematical model, and the proposal of a straightforward design approach for slicer mirrors and pupil mirrors. The designed structure underwent ray tracing and nonsequential simulation. Results from the design show that the module effectively spans the required 115–400 nm wavelength range for testing, demonstrating high efficiency. Specifically, there is a 2.85 times increase in photon collection efficiency within the 115–145 nm range and a 6.03 times increase within the 145–400 nm range. This research is anticipated to offer valuable insights for enhancing the energy efficiency of future grating spectrometers.

I. Introduction

With the advancements in space technology and semiconductor technology, the analysis of surface characteristics of materials has become increasingly crucial [1], [2]. Addressing this challenge, the photoelectron emission yield spectrum (PEYS) and energy spectrum (ES) testing methods have been employed. Traditionally, these tests utilized mercury lamps, deuterium lamps, or xenon lamps as light sources. However, as technology progresses, there is a growing demand among researchers for more precise test results, necessitating the use of continuously adjustable high-resolution ultraviolet monochromatic light as a light source, typically covering the range of 115–400 nm. Unfortunately, the efficiency of the currently available instruments providing ultraviolet monochromatic light is often suboptimal, significantly limiting testing efficiency and the signal-to-noise ratio. Therefore, designing a highly efficient photon collection module becomes a meaningful endeavor.