UVSOR Synchrotron Facility Update

Abstract

UVSOR is a Japanese low-energy synchrotron light source that has been operational since 1983. It has 750 MeV electron beam energy and a circumference of 53 m. The machine has undergone two major upgrades and is now called UVSOR-III, with a moderately small emittance of 17 nm·rad and is operated in the top-up mode at 300 mA. It has six undulators. Three in-vacuum undulators provide high-brightness VUV-SX light to the beamlines BL3U, BL4U, and BL6U. BL3U and BL4U are actively used for chemistry and life sciences using in situ and operando measurements, such as soft X-ray absorption and photoelectron spectroscopy. Since 2020, a unique photoelectron analyzer called the Momentum Microscope has been in operation in BL6U. Two variable polarization undulators provide high-brightness VUV light to the beamlines, BL5U and BL7U, which are used for solid-state physics through angle- and spin-resolved photoelectron spectroscopy. BL1U is equipped with two APPLE-II undulators in tandem and is used for various research purposes, including laser Compton scattering gamma rays. In addition to these beamlines, eight beamlines are operational which use bending magnet radiation, ranging from THz to tender X-rays. In 38 years of operation, we have dealt with and properly resolved machine problems, such as water leakage from magnet coils and cooling water flow paths in ultrahigh vacuum. Considering the machine’s declining competitiveness as a light source due to its aging and emerging demands in the low-energy area, we have started a design study on the future plan, as well as discussing it closely with the user community.

Light Source Developments at UVSOR BL1U

“…Moreover, we have demonstrated generating spatially structured light from undulators, such as optical vortex beam as shown in Figure 4 [23] and optical vector beam as shown in Figure 5 [24]. It should be noted that all these experiments became possible thanks to that UVSOR-III is diffraction-limited in the ultraviolet range [1].…”

“…UVSOR, a low energy synchrotron light source, has been operational for about 40 years. After the two major upgrades, now it is called UVSOR-III [1]. The nominal operation energy is 750 MeV and the circumference is 53.3 m. It has four straight sections of 4 m long and four of 1.6 m long.…”

Time domain double slit interference of electron produced by XUV synchrotron radiation

“…Tandem-undulator system. The experiments were performed at the light source development beamline BL1U of the UVSOR-III synchrotron 29 . The tandem-undulator system consists of two identical APPLE-II undulators with a phase shifter magnet between them.…”

Bayesian optimization of the dynamic aperture in UVSOR-IV design study

“…UVSOR is a low energy synchrotron light source, which had been operated since 1983. After two major upgrades [1][2][3][4], now it is called UVSOR-III [5]. The circumference of the storage ring is 53 m and the electron beam energy 750 MeV.…”