Development of High Intensity Laser-Electron Photon Beams up to 2.9 GeV at the SPring-8 LEPS Beamline

TL;DR

This paper reports on the successful upgrade of a laser-electron photon beam at SPring-8, achieving higher intensities and energies up to 2.9 GeV, enabling advanced hadron photoproduction experiments.

Contribution

The paper introduces new methods for increasing laser-electron photon beam intensity and energy at the LEPS beamline, including dual laser injection and higher power lasers, with plans for further upgrades.

Findings

Beam intensity increased by factors of 1.5–1.8

Maximum photon energy extended to 2.9 GeV

Projected intensities near 10^7 sec^-1 for 2.4 GeV photons

Abstract

A laser-Compton backscattering beam, which we call a `Laser-Electron Photon' beam, was upgraded at the LEPS beamline of SPring-8. We accomplished the gains in backscattered photon beam intensities by factors of 1.5--1.8 with the injection of two adjacent laser beams or a higher power laser beam into the storage ring. The maximum energy of the photon beam was also extended from 2.4 GeV to 2.9 GeV with deep-ultraviolet lasers. The upgraded beams have been utilized for hadron photoproduction experiments at the LEPS beamline. Based on the developed methods, we plan the simultaneous injection of four high power laser beams at the LEPS2 beamline, which has been newly constructed at SPring-8. As a simulation result, we expect an order of magnitude higher intensities close to 10$^7$ sec$^{-1}$ and 10$^6$ sec$^{-1}$ for tagged photons up to 2.4 GeV and 2.9 GeV, respectively.