Spokesperson :Shunji KISHIMOTO
6108(PHS:4439)
syunji.kishimoto@kek.jp

1. Outline

Vertically polarized X-rays of 5-80 keV can be used in this station. At energies lower than 18 keV, a focused beam is available with a Si(111) double crystal monochromator and a bent cylindrical mirror. The X-ray diffraction experiments, such as precise electron-density analysis are executed with a horizontal-type diffractometer installed in an experimental hutch. X-rays of energies higher than 18 keV are available with a Si(311) or a Si(553) monochromator in this station though the beam cannot be focused. Development of a new X-ray detector is also going on, using this wide energy range of X-ray beam. In the detector experiments, an optical bench for setting up a detector can be provided behind the diffractometer. In the summer of 2004, the optical components of the BL-14A were overhauled at rearrangement of the BL-14 beamline.

 

2. Performance

Optics [1]	Double-crystal monochromator (Si(111),(311),(553)), Bent cylindrical mirror (only with Si(111))
Energy range	Si111 ： 5.1-18.5 keV Si311 ： 9.9-35.4 keV Si553 ： 23.0-82.7 keV
Energy Resolution	2x10-4 (Si(111))
Beam Size	< (H)2 x (V)1 mm (with Mirror), (H)5 x (V)35 mm (without Mirror, max.)
Beam Intensity	1ｘ1011 photons/s/mm2 (Si(111) + Mirror, max.)

 

 

 

 

 








 

3. Horizontal-type Four-circle Diffractometer and Other Equipments

A horizontal-type four circle diffractometer is installed in an experimental hutch of (W)2.4 x (L)2.4 x (H)2.5m. The base of the diffractometer can be moved to a position of the beam directly coming from the monochromator or that focused by the mirror. The χ circle of the diffractometer has a diameter of 280 mm and the φ axis is on-center type. A sample put on the φ axis is 30 m far from the light source of the vertical wiggler.


• Angle Range 2θ : -140° - +160°, ω : -60° - +70°, χ : -168° - +168°, φ : -180° - +180°
  
• Rotation Speed 2θ: 1000°/min., ω: 500°/min., χ and φ: 2000°/min.
  
• Precision 2θ: 0.005°, ω: 0.0025°, χ and φ: 0.01°
  
  
• Detector System :
  1. NaI(Tl) Scintillation Detector (φ 25mm,1.5 or 5mm^t)
  2. YAP(Ce) Scintillation Detector (φ 25mm, 5mm^t）
  3. Silicon Avalanche Photodiode Detector[2]
  (see Photograph. This is for Precise Electron-density Analysis.）
  
  

  An x-ray detector that has stacking 8-plates of Si-APD

  4. Ionization Chamber (I₀ and I, 18.5 and 32.5cm long. )
  flow gas : N₂, N₂/25%Ar, Ar, Kr, Xe）
  
  5. HP-Ge Detector (CANBERRA　GL0110P、10mm^t)
  
  
• Control: the diffractometer is controlled by a PC(Windows) through GP-IB using a software written in Visual Fortran/C(in preparation). A CAMAC system collects data from detectors. In an experiment for detector development, another software written in LabVIEW(GP-IB) is provided to control the optics, the base of the diffractometer and some positioning stages. One can easily change the beam energy and adjust the beam intensity in a relatively short time by the software.
  
• An optical bench is set behind the χ circle of the diffractometer. Performance test of a detector and EXAFS measurements are able to be executed on the bench. Moreover, a space downstream the diffractometer is possible to be used with a table for a test of a large detector, such as an area detector. The beam intensity is controlled with a precise slits and metal filters.
  
• A helium-gas circulating refrigerator (15-300K) is available for an EXAFS measurement on the optical bench.
  

   

4. Examples of experiments

• A precise analysis of a crystal structure using a horizontal-type four-axis X-ray diffractometer and a high-rate Si-APD detector [3]
• A test for developing an X-ray detector for high-energy X-rays [4]
• EXAFS measurements for catalytic materials using a vertical polarization [5]

5. References

[1] Y. Satow and Y. Iitaka, Rev. Sci Instrum. 60 (1989) 2390.
[2] S. Kishimoto, N. Ishizawa and T. P. Vaalsta, Rev. Sci. Instrum. 68 (1998) 384.
[3] N. Ishizawa and M. Hayatsu, Physica C 338 (2000) 170.
[4] S. Kishimoto and T. Yamamoto, Nucl. Instr. and Meth. A508 (2003) 425.
[5] K. Asakura, W.-J. Chun and Y. Iwasawa, Topics in Catal. 10 (2000) 209.


 

Last modified:2005-07-28