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Title: Double-crystal monochromator for a PF 60-period soft x-ray undulator (abstract)

Abstract

Since undulator light is sharply collimated itself, it can be effectively monochromatized by a perfect crystal. An x-ray double-crystal monochromator with a fixed exit has been designed and built for the use of undulator light from a 60-period undulator at Photon Factory (beamline 2A). Available Bragg angle ranges from 7/degree/ to 80/degree/. Angle scan is made by means of a goniometer outside the vacuum chamber, with the finest step of 0.1 arcsec. Magnetic fluid is used as the vacuum seal of the feedthrough. The fixed exit beam position is kept by translating the second crystal along the two mechanical guides: one for normal and the other for parallel to the crystal surface. Adjustment of the parallelity of two crystals is made manually with flexible wires. Since a total power in the central coherent portion which is limited by a 1/times/1-mm/sup 2/ slit is not so much, a stable operation is possible without cooling the crystal. Currently, InSb (111) reflection is used. The diffracting planes of the first cyrstal is 1/degree/ off from the surface and the second is the symmetric reflection. At its fifth harmonics, brilliant undulator light of approximately 10/sup 12/ photons/s mm/sup 2/ with 1-eV energy resolution ismore » available (/ital E/=2 keV).« less

Authors:
; ; ;
Publication Date:
Research Org.:
Photon Factory, National Laboratory for High Energy Physics, Japan (US)
OSTI Identifier:
5830010
Resource Type:
Journal Article
Resource Relation:
Journal Name: Rev. Sci. Instrum.; (United States); Journal Volume: 60:7
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; MONOCHROMATORS; ENERGY RESOLUTION; SOFT X RADIATION; DIFFRACTION; BICRYSTALS; BRAGG REFLECTION; GONIOMETERS; HARMONICS; KEV RANGE 01-10; RADIATION FLUX; COHERENT SCATTERING; CRYSTALS; ELECTROMAGNETIC RADIATION; ENERGY RANGE; IONIZING RADIATIONS; KEV RANGE; MEASURING INSTRUMENTS; OSCILLATIONS; POLYCRYSTALS; RADIATIONS; REFLECTION; RESOLUTION; SCATTERING; X RADIATION; 440300* - Miscellaneous Instruments- (-1989)

Citation Formats

Ishikawa, T., Maezawa, H., Nomura, M., and Ando, M.. Double-crystal monochromator for a PF 60-period soft x-ray undulator (abstract). United States: N. p., 1989. Web. doi:10.1063/1.1140848.
Ishikawa, T., Maezawa, H., Nomura, M., & Ando, M.. Double-crystal monochromator for a PF 60-period soft x-ray undulator (abstract). United States. doi:10.1063/1.1140848.
Ishikawa, T., Maezawa, H., Nomura, M., and Ando, M.. Sat . "Double-crystal monochromator for a PF 60-period soft x-ray undulator (abstract)". United States. doi:10.1063/1.1140848.
@article{osti_5830010,
title = {Double-crystal monochromator for a PF 60-period soft x-ray undulator (abstract)},
author = {Ishikawa, T. and Maezawa, H. and Nomura, M. and Ando, M.},
abstractNote = {Since undulator light is sharply collimated itself, it can be effectively monochromatized by a perfect crystal. An x-ray double-crystal monochromator with a fixed exit has been designed and built for the use of undulator light from a 60-period undulator at Photon Factory (beamline 2A). Available Bragg angle ranges from 7/degree/ to 80/degree/. Angle scan is made by means of a goniometer outside the vacuum chamber, with the finest step of 0.1 arcsec. Magnetic fluid is used as the vacuum seal of the feedthrough. The fixed exit beam position is kept by translating the second crystal along the two mechanical guides: one for normal and the other for parallel to the crystal surface. Adjustment of the parallelity of two crystals is made manually with flexible wires. Since a total power in the central coherent portion which is limited by a 1/times/1-mm/sup 2/ slit is not so much, a stable operation is possible without cooling the crystal. Currently, InSb (111) reflection is used. The diffracting planes of the first cyrstal is 1/degree/ off from the surface and the second is the symmetric reflection. At its fifth harmonics, brilliant undulator light of approximately 10/sup 12/ photons/s mm/sup 2/ with 1-eV energy resolution is available (/ital E/=2 keV).},
doi = {10.1063/1.1140848},
journal = {Rev. Sci. Instrum.; (United States)},
number = ,
volume = 60:7,
place = {United States},
year = {Sat Jul 01 00:00:00 EDT 1989},
month = {Sat Jul 01 00:00:00 EDT 1989}
}
  • The design and performance of a new double crystal monochromator for x-ray undulator beamline at the PF-AR are described. The monochromator consists of flat silicon (111) crystals, which are cooled by liquid nitrogen in order to reduce the deformation caused by a heat load problem. One of the characteristic points of the monochromator is a usage of a relatively long size of second silicon crystal ({approx}200mm long) along the beam direction. The long crystal makes it possible to eliminate a mechanical translation stage, which is needed to realize the fixed exit position for the monochromatized x-rays. The simplicity of themore » designing contributes to the stability of the monochromator, and there is no problem about vibration and so on. The fixed exit can be achieved by the adjustment of the height of the first crystal. It is possible to keep the deviation of the beam position at the experimental hatch less than 0.01 mm and 0.075mm at vertical and horizontal directions, respectively, under scanning the monochromatized energy from 5 to 20 keV.« less
  • A cooling system for the first crystal of a double-crystal monochromator for a 60-period soft x-ray undulator at the Photon Factory is newly designed and installed. In order to keep smooth movements of the original mechanism in a high-vacuum chamber, heat pipes and a liquid-metal bath are utilized. A fear for melting of an InSb crystal and the instability caused by warming of mechanisms have vanished and significantly improved energy resolution of 5000--8000 is achieved by Si crystals for high photon flux of about 10{sup 11} photons/s in a beam size of 3{times}3 mm{sup 2} at a sample position withmore » the cooling system.« less
  • Progress in performance of a beamline for a 60-period soft x-ray undulator of the 2.5-GeV Photon Factory storage ring was made by implementation of low emittance operation of the storage ring and improvements of beamline and monochromator units. Monochromated photon flux of up to 10/sup 12/ photons/s has now been achieved at maximum in ordinary operating conditions of the ring current of /approx/200 mA with resolution of 500--1000 over the soft x-ray region from 410 eV to a few keV of photon energy.
  • The double-crystal monochromator on beam line 3.4 at the Daresbury synchrotron radiation source covers the energy region 0.8--4 keV, routinely using crystal pairs of beryl, quartz, InSb, Ge, and Si. The beam line has a unique system to cut off high-energy radiation. The whole beam line has been built on a swinging arm, which allows the glancing angle on a chromium coated premirror to be varied between 0.5{degree} and 3{degree}. This not only reduces the heat load on fragile crystals, but also reduces the higher order contributions. We have made a thorough study of the alignment problems arising in themore » double-crystal geometry. Crystal misalignment, Bragg angular offset, as well as heat-load effects, can cause severe beam movements. A beam-position monitor, which has recently been commissioned, is an invaluable diagnostic tool for these beam movements.« less
  • The design and commissioning of a new soft X-ray beamline, BL-16A, at the Photon Factory is presented. The beamline consists of a pre-focusing mirror, an entrance slit, a variable-included-angle varied-line-spacing plane grating monochromator, and a post-focusing system as usual, and provides circularly and linearly polarized soft X rays in the energy range 200-1500 eV with an APPLE-II type undulator. The commissioning procedure for the beamline optics is described in detail, especially the check of the focal position for the zero-th order and diffracted X rays.