Development of Energy-Resolved Beam Monitoring System - Researchers Monitored Center of Beam That Had Been Too Bright to Monitor! - (Press Release)
- Release Date
- 22 Apr, 2022
- BL05XU (R&D-ID)
April 22, 2022
Japan Synchrotron Radiation Research Institute (JASRI)
RIKEN
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A research group led by Togo Kudo (senior scientist), Mutsumi Sano (senior scientist), Toshiro Itoga (senior scientist), and Shunji Goto (coordinator) of the Beamline Division, Japan Synchrotron Radiation Research Institute (JASRI); Takahiro Matsumoto (senior scientist) of the Information-Technology Promotion Division, JASRI; and Sunao Takahashi (senior engineer) of the Innovative Synchrotron Radiation Facility Division, RIKEN SPring-8 Center, has developed a system for the nondestructive monitoring of the center of a high-brightness beam that had not been possible to monitor before because it was 100 million times brighter than the sun. This system will enable the accurate measurement of ultrahigh-brightness beams required at a diffraction-limited synchrotron radiation ring, marking a major advance in the realization of a wide range of scientific technologies utilizing synchrotron radiation. The use of synchrotron radiation*1 is helping achieve countless achievements not only in basic science, including the X-ray structural analysis of proteins, but also in industry. A system for directly monitoring the center position of a beam generated by an undulator*2 (light source) had been desired for many years. An undulator beam is a quasi-white beam containing light of various wavelengths. Because of the thermal load caused by the ultrahigh brightness of the beam, as well as the difficulty in distinguishing it from the deflected electromagnetic radiation specific to a ring accelerator, the monitoring of the center position of the beam had been a long-standing difficulty. The research group has solved this problem by adopting an unconventional approach. The research group placed a single-crystal diamond film in the vacuum chamber in the most upstream position of the optical hutch in BL05XU at SPring-8*3, a large synchrotron radiation facility, and transmitted the undulator beam through the film. They found that the spatial distribution of each energy component of the undulator beam, which had never been monitored before, can be visualized by analyzing the scattered X-rays emitted from the transmission point through spectroscopic imaging using a pinhole camera and a two-dimensional (2D) detector. Thus, they overcame the limitation of conventional mainstream approaches, such as the use of multiple metal blades, and monitored the center of the beam for the first time. In this study, spectroscopic imaging using the energy resolution of a 2D detector, a cutting-edge X-ray photon detection technology, was applied to beam monitoring for the first time. This technology will be employed around the world as a key technology to dramatically improve the performance of synchrotron radiation. This achievement was published in Journal of Synchrotron Radiation, an international scientific journal, on May 1 (April 20 online). 【Publication information】 |
Figure 1:Layout of experiment.
Figure 2: (A) Water-cooled diamond film (the black area in the upper half is polycrystal and the transparent area in the lower half is single crystal).
(B) Pinhole camera image obtained through polycrystal (without energy resolution).
(C) Pinhole camera image obtained through single crystal (without energy resolution).
Figure 3: Measured cross-sectional shape of beam
Figure 4: Cross-sectional shape of beam calculated by SPECTRA, an application program to calculate various characteristics of synchrotron radiation (Note 3)
Note 1）Hatsui et.al., Proc. Int. Image Sensor Workshop, Art. No. 3.05 (2013)
Note 2）Hatsui and Graafsma, IUCrJ, 2, (3), 371-383 (2015)
Note 3）Tanaka and Kitamura, J. Synchrotron Radiation, 8, 1221 (2001)
【Glossary】
*1. Synchrotron radiation
Synchrotron radiation was originally found as a powerful light emitted by charged particles when their traveling direction is bent by a particle accelerator constructed for research on high-energy physics. This light was considered undesirable because it reduces the efficiency of particle acceleration. However, synchrotron radiation was found to be a useful light source in research on material sciences etc. and is now widely used in research. Accelerators dedicated to synchrotron radiation have been constructed in many countries.
*2. Undulator
An undulator is a device that uses an electron accelerator to deflect an electron beam accelerated to near the speed of light (“wiggle”). This is done using a powerful neodymium magnet array that forms a periodic magnetic field. Then, the electron beam emits strong synchrotron radiation. Undulators play an important role in SPring-8 (see below).
*3. Large synchrotron radiation facility (SPring-8)
SPring-8, owned by RIKEN, is a large synchrotron radiation facility that delivers one of the most powerful synchrotron radiations in the world. It is located in Harima Science Garden City, Hyogo Prefecture, Japan. JASRI operates and supports users of the facility. The name “SPring-8” is derived from “Super Photon ring-8 GeV”. The research conducted at SPring-8 covers a wide range of fields including nanotechnology, biotechnology, and industrial applications.
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