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Title: New x-ray pink-beam profile monitor system for the SPring-8 beamline front-end

Abstract

A new beam profile monitoring system for the small X-ray beam exiting from the SPring-8 front-end was developed and tested at BL13XU. This system is intended as a screen monitor and also as a position monitor even at beam currents of 100 mA by using photoluminescence of a chemical vapor deposition-grown diamond film. To cope with the challenge that the spatial distribution of the photoluminescence in the vertical direction is too flat to detect the beam centroid within a limited narrow aperture, a filter was installed that absorbs the fundamental harmonic concentrated in the beam center, which resulted in “de-flattening” of the vertical distribution. For the measurement, the filter crossed the photon beam vertically at high speed to withstand the intense heat flux of the undulator pink-beam. A transient thermal analysis, which can simulate the movement of the irradiation position with time, was conducted to determine the appropriate configuration and the required moving speed of the filter to avoid accidental melting. In a demonstration experiment, the vertically separated beam profile could be successfully observed for a 0.8 × 0.8 mm{sup 2} beam shaped by an XY slit and with a fundamental energy of 18.48 keV. The vertical beam centroid couldmore » be detected with a resolution of less than 0.1 mm.« less

Authors:
; ; ; ;  [1]
  1. JASRI, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan)
Publication Date:
OSTI Identifier:
22597646
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 87; Journal Issue: 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BEAM CURRENTS; BEAM PROFILES; CHEMICAL VAPOR DEPOSITION; DIAMONDS; FILTERS; HEAT FLUX; IRRADIATION; KEV RANGE 10-100; PHOTOLUMINESCENCE; PHOTON BEAMS; PHOTONS; SPATIAL DISTRIBUTION; SPRING-8 STORAGE RING; THERMAL ANALYSIS; WIGGLER MAGNETS; X RADIATION

Citation Formats

Takahashi, Sunao, Kudo, Togo, Sano, Mutsumi, Watanabe, Atsuo, and Tajiri, Hiroo. New x-ray pink-beam profile monitor system for the SPring-8 beamline front-end. United States: N. p., 2016. Web. doi:10.1063/1.4961548.
Takahashi, Sunao, Kudo, Togo, Sano, Mutsumi, Watanabe, Atsuo, & Tajiri, Hiroo. New x-ray pink-beam profile monitor system for the SPring-8 beamline front-end. United States. doi:10.1063/1.4961548.
Takahashi, Sunao, Kudo, Togo, Sano, Mutsumi, Watanabe, Atsuo, and Tajiri, Hiroo. Mon . "New x-ray pink-beam profile monitor system for the SPring-8 beamline front-end". United States. doi:10.1063/1.4961548.
@article{osti_22597646,
title = {New x-ray pink-beam profile monitor system for the SPring-8 beamline front-end},
author = {Takahashi, Sunao and Kudo, Togo and Sano, Mutsumi and Watanabe, Atsuo and Tajiri, Hiroo},
abstractNote = {A new beam profile monitoring system for the small X-ray beam exiting from the SPring-8 front-end was developed and tested at BL13XU. This system is intended as a screen monitor and also as a position monitor even at beam currents of 100 mA by using photoluminescence of a chemical vapor deposition-grown diamond film. To cope with the challenge that the spatial distribution of the photoluminescence in the vertical direction is too flat to detect the beam centroid within a limited narrow aperture, a filter was installed that absorbs the fundamental harmonic concentrated in the beam center, which resulted in “de-flattening” of the vertical distribution. For the measurement, the filter crossed the photon beam vertically at high speed to withstand the intense heat flux of the undulator pink-beam. A transient thermal analysis, which can simulate the movement of the irradiation position with time, was conducted to determine the appropriate configuration and the required moving speed of the filter to avoid accidental melting. In a demonstration experiment, the vertically separated beam profile could be successfully observed for a 0.8 × 0.8 mm{sup 2} beam shaped by an XY slit and with a fundamental energy of 18.48 keV. The vertical beam centroid could be detected with a resolution of less than 0.1 mm.},
doi = {10.1063/1.4961548},
journal = {Review of Scientific Instruments},
number = 8,
volume = 87,
place = {United States},
year = {Mon Aug 15 00:00:00 EDT 2016},
month = {Mon Aug 15 00:00:00 EDT 2016}
}
  • At the Advanced Photon Source (APS), each insertion device (ID) beamline front end has two x-ray beam position monitors (XBPMs) to monitor the x-ray beam position in both the vertical and horizontal directions. The XBPMs measure photoelectrons generated from the CVD-diamond-based sensory blades and deduce the beam position by comparison of the relative signals from the blades. Using the method proposed by G. Decker, which involves the introduction of a chicane into the accelerator lattice that directs unwanted x-rays away from the photosensitive XBPM blades, the photon source stability has been improved by addition of XBPMs in the storage ringmore » global orbit feedback. In recent years, design updates for the XBPM mechanical structure and geometric configuration have been made to improve its performance. We present these design updates in this paper. Test results of the XBPM design updates are also discussed here.« less
  • A new type of slit has been designed for use in the hard x-ray nanoprobe beamline at the Advanced Photon Source (APS). The design incorporates monolithic GlidCop slit bodies mounted to commercially available x-y drive systems. Long, tapered apertures with adjacent water-cooling channels intercept the x-ray beam, removing the high heat load produced by two collinear APS undulators. The apertures are L-shaped and provide both horizontal and vertical slits. The beam-defining edges, positioned at the end of the tapered surfaces, consist of two sets of tungsten blades. These blades produce an exit beam with sharp corners and assure a cleanmore » cut-off for the white beam edges. The slit assembly is designed to allow overlap of the slit edges to stop the beam.The white beam slit design accommodates 3100 W of total power with a peak power density of 763 W/mm2. The pink beam slit design accommodates 400 W of total power with a peak power density of 180 W/mm2. Detailed thermal analyses were performed to verify the slits' accuracy under full beam loading. The new concept allows beamline operations to 180 mA with a simplified design approach.« less
  • The design of a high-speed movable heat absorber (HA) to protect a fast closing valve (FCV) is presented and a unique safety system to protect the storage ring ultrahigh vacuum from a vacuum break accident in downstream beamlines is proposed. The speed of the incoming shock wave upon a vacuum failure can be measured by two sensors separated by a given distance. If the measured speed does not exceed the prescribed critical speed calculated from both the operating time of the HA and the distance between the sensors and the FCV, the storage ring vacuum can be maintained without dumpingmore » the electron beam. If the measured speed exceeds the critical speed, beam dumping will be requested. Fortunately the vacuum sensor can be installed at a distance 14 m from the FCV for the SPring-8 and the operation of the HA can be completed in 40 ms. The acceleration for moving at 40 ms is approximately 2 G, which is a practical value. Therefore the critical value of the shock wave speed is 350 m/s. In order to perform thermal analysis for the absorber plate, the fluorescent x rays and Compton scattered rays emitted from 3{degree} inclined copper absorber can be calculated as 4.7% and 0.41% of the SPring-8 undulator power, respectively. Hence the highest temperature at the absorber surface exposed to intense undulator radiation of the total power of 2.06 kW was about 350 {degree}C.« less
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