SPring-8 LEPS2 beamline: A facility to produce a multi-GeV photon beam via laser Compton scattering

TL;DR

The LEPS2 beamline at SPring-8 is a new facility producing high-intensity, linearly polarized multi-GeV photon beams via laser Compton scattering, enabling advanced hadron photoproduction experiments.

Contribution

This paper introduces the design and construction of the LEPS2 beamline, a facility that enhances photon beam intensity and quality for high-energy physics research.

Findings

Photon beam energy range 1.3--2.4 GeV

Suppressed beam size of about 4 mm at 130 m distance

Higher beam intensity achieved by multiple laser injections

Abstract

We have constructed a new laser-Compton-scattering facility, called the LEPS2 beamline, at the 8-GeV electron storage ring, SPring-8. This facility provides a linearly polarized photon beam in a tagged energy range of 1.3--2.4 GeV. Thanks to a small divergence of the low-emittance storage-ring electrons, the tagged photon beam has a size (sigma) suppressed to about 4 mm even after it travels about 130 m to the experimental building that is independent of the storage ring building and contains large detector systems. This beamline is designed to achieve a photon beam intensity higher than that of the first laser-Compton-scattering beamline at SPring-8 by adopting the simultaneous injection of up to four high-power laser beams and increasing a transmittance for the long photon-beam path up to about 77%. The new beamline is under operation for hadron photoproduction experiments.