問い合わせ番号

INS-0000000566

ABSTRACT

  BL12XU is designed primarily for inelastic X-ray scattering (IXS) experiments on electronic excitations in correlated electron systems with variable energy resolution from 10 ∼ 1000 meV. Major experimental capabilities have been developed for both resonant and non-resonant IXS experiments. The initial setup for resonant IXS (RIXS) experiments has a total energy resolution of ∼ 1 eV and covers the K absorption edges of the late transition metals (Co, Ni and Cu). For non-resonant IXS (NRIXS) experiments, a total energy resolution of 70 meV has been achieved at the Si (555) near-backscattering energy of 9.886 keV. Furthermore, a 15-element multiple-analyzer system for NRIXS is available to increase the counting efficiency by up to 15 times. These experimental capabilities can be used to study a variety of fundamental problems in solid state physics, electronic properties in materials science, and phase transitions under extreme thermodynamic conditions. The secondary purposes of the beamline includehigh Q-resolution scattering,X-rayphysics and opticsdevelopment.

AREA OF RESEARCH

• Elementary electronic excitations, quasiparticle behaviors, and electron-correlation effects in correlated electron systems investigated usinghigh resolution non-resonantorresonant inelastic X-ray scattering
• Local electronic structure of molecular solids of low-Z elements (e.g., biomaterials) investigated by high resolution near-edge X-ray Raman scattering
• Phase transitionsunderhigh-pressure, low and high temperatures
• Materials science usinghigh-resolution X-ray absorption and emissionspectroscopy
• X-ray physics and optics

KEYWORDS

• Scientific field
  Inelastic X-ray scattering, Near-edge X-ray Raman scattering, X-ray resonant Raman scattering, Electronic excitations, Correlated electron systems, Pressure and temperature induced phase transitions, High-resolution X-ray absorption spectroscopy and X-ray emissionspectroscopy.
• Equipment
  Triple axis spectrometer, Eulerian goniometer, Cryorefrigerator, Spherical crystal analyzers, Multiple analyzer system, AMPTEK X-ray detector,MCA, Microscope.

SOURCE AND OPTICS

  The radiation source is a SPring-8 standard 4.5-m long in-vacuum undulator with a magnet period of 32 mm. The minimum gap allowed is 8.1 mm with a front-end slit aperture of 0.5 (V) × 1.5 (H) mm². Within 8.1 ∼ 19.3 mmgap range, the 1st harmonic covers 4.5 ∼ 14 keV, the 3rd harmonic 13.5 ∼ 42 keV, and the 5th harmonic 22.5 ∼ 70 keV. At 100 mA ring current, the maximum on-axis brilliance reaches 1.2 × 10²⁰ phs/s/mrad²/mm²/0.1%BW at 9 keV.

Fig.1. Schematic view of the beamline (upper panel) and the optical path (lower panel)

 The beamline consists of a sideline and a mainline (Fig.1). The sideline, to be built later, operates in parasitic mode with a single-bounce diamond monochromator (DM). Monochromatic X-rays of about 1 eV width over 8 ∼ 32 keV can be obtained using Bragg or Laue diffraction geometries of diamond (111) or (100) crystals for diffraction experiments or other emerging experimental techniques.
  The mainline is designed primarily for inelastic X-ray scattering experiments. The optical system consists of five major elements, which include a high heat-load Si (111) double-crystal pre-monochromator (DCM), a cylindrical collimating mirror (CM), a high-resolution monochromator (HRM), a phase retarding plate (PRP), and a toroidal focusing mirror (FM). The Si (111) DCM operates over the energy range of 4.5 ∼ 35 keV. The CM collimates the beam vertically. It also functions as a higher-order light filter by having two stripes: Si and Pt for the energy ranges of 5 ∼ 12 keV and 12 ∼ 30 keV, respectively. To achieve variable energy resolutions of 10 ∼ 1000 meV, the HRM consists of two high-precision co-axial goniometers to form various combinations of 2-bounce or 4-bounce (inline or nested) channel-cut crystals. An in-line combination of two symmetric Si (333) or Si (400) channel-cut crystals are now available to provide energy resolutions of 50 or 153 meV, respectively, at 9.886 keV (see Table 1). Additional HRM crystals can be designed for different energy resolutions and scanning energy ranges. After the HRM and the PRP (to be implemented later), the beam is delivered to the Pt-coated focusing mirror and focused both vertically and horizontally to ∼ 80 (V) × 120 (H) µm² at the sample position. Total flux obtained at the sample is 1.2 × 10¹³ phs/sec/1.4 eV at 9.886 keV scaled to 100-mA ring current with the DCM direct beam, and reduced proportionally with the HRM energy bandwidth.

• X-rays at sample

  Energy range	4.5 ∼ 30 keV
  Energy resolution (ΔE/E)	1.4 × 10-4 after DCM 10-5 ∼ 10-7 after HRM (optics dependent)
  Flux	∼ 1010 photons/sec/meV below 26 keV after DCM Optics dependent at sample
  Beam Size	0.12(H) × 0.08(V)

EXPERIMENTAL STATIONS

  The IXS spectrometer (Fig. 2) is custom designed and built to accommodate a wide range of experimental requirements. This instrument is basically a triple-axis spectrometer with a 3-m horizontal arm, and consists of a heavy-duty Eulerian goniometer tower designed to accommodate a range of sample environments with a load capacity for a cryomagnet. In addition, a custom designed cryostat provides a sample environment down to 4 K (Fig. 3). The 3-m horizontal arm supports the post-sample slits, the analyzer stage, the detector stage and the flight paths. Spherically bent crystal analyzers are used to analyze the inelastically scattered photons. The analyzer stage can be translated continuously along the arm to accommodate three radii of the analyzer for different resolution and angular acceptance requirements of the experiment. A 15-element multiple analyzer system is available to increase the counting efficiency by up to 15 times at the expense of momentum resolution (Fig. 3).

Fig.2. Schematic view of the IXS spectrometer and photo of the real thing

Fig.3. The 4-K cryostat and carrier (upper), and the 15-element multiple analyzer system (lower)

• Endstations and sample environments
  • Custom-built 3 m arm triple axes spectrometer for IXS
  • CRYOMECH 4K PT407 pulse tube cryorefrigerator
  • Various sample chambers

PUBLICATION SEARCH

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BL12XU PUBLICATION SEARCH

CONTACT INFORMATION

Nozomu Hiraoka
NSRRC Taiwan Beamline Office at SPring-8
1-1-1 Kouto, Sayo, Hyogo 679-5148
Phone : +81-(0)791-58-1867
Fax : +81-(0)791-58-1868
e-mail : hiraokaspring8.or.jp

Ku-Ding Tsuei
National Synchrotron Radiation Research Center
101 Hsin-Ann Road, Science-Park, Hsinchu 30076, Taiwan
Phone : +886-(0)3-5780281 ext. 7105
e-mail : tsueinsrrc.org.tw

Masato Yoshimura
NSRRC Taiwan Beamline Office at SPring-8
1-1-1 Kouto, Sayo, Hyogo 679-5148
Phone : +81-(0)791-58-1867
Fax : +81-(0)791-58-1868
e-mail : yoshimuraspring8.or.jp

Website

http://www.nsrrc.org.tw/