Double-Slit Interferometer Measurements at SPEAR3

TL;DR

This paper presents the development and experimental validation of a double-slit interferometer at SPEAR3, enhancing synchrotron radiation imaging resolution by analyzing beam coherence through fringe contrast measurements.

Contribution

It introduces a theoretical framework and experimental setup for a double-slit interferometer at SPEAR3, including a novel rotation method to map beam coherence.

Findings

Successful measurement of photon beam coherence at SPEAR3

Validation of the theoretical model with experimental data

Demonstration of improved resolution techniques

Abstract

The resolution of a conventional telescope used to image visible-light synchrotron radiation is often limited by diffraction effects. To improve resolution, the double-slit interferometer method was developed at KEK and has since become popular around the world. Based on the Van Cittert-Zernike theorem relating transverse source profile to transverse spatial coherence, the particle beam size can be inferred by recording fringe contrast as a function of interferometer slit separation. In this paper, we describe the SPEAR3 double-slit interferometer, develop a theoretical framework for the interferometer and provide experimental results. Of note the double-slit system is 'rotated' about the beam axis to map the dependence of photon beam coherence on angle.