BL-4C

BL-4C X-ray diffraction experiment station for material science

1. Overview

This station is dedicated for x-ray diffraction measurements on material science. For this purpose, a large six-circle diffractometer (Huber 5020-type) is permanently installed. The equipments allow us to make experiments under (1)the temperature region of 4K-1000K, (2) hydrostatic pressure up to 50GPa with temperature region 10K-300K. This diffractometer is designed for measurements on small volume of the reciprocal space with high-resolution, but not for structure analysis. Typical experiment at this station is to measure some superlattice reflections as a function of temperature.

Significant studies of this station are (1)Atomic displacement in multiferroics materials, (2) Resonant x-ray scattering from orbital ordered Mn oxides, (3) Direct observation of quadrupole ordering in f-electron system, (4) Pressure and temperature dependence of spin-Peierls material , etc.

2. Photons at Sample

This station has a bending magnet as a light source. The x-rays are monochromatized by Si(111) double flat monochromator and focused at the sample position by a Rh coated Si troidal mirror.
Beamline optics

Optics	Light source (Bending magnet) + Beam position monitor + x-y Slit + Si(111) monochromator + Toroidal mirror (1:1 focusing)
Energy range	5 keV - 19 keV
Energy resolution	dE/E = 3 x 10^-4
Beam size	vertical 0.3 mm x horizontal 0.5 mm
Acceptance	vertical 0.2 mrad x horizontal 2 mrad

Energy dependence of the photon flux measured with a photodiode. The photon flux has a maximum at 8keV. Flux greater than 10¹¹photons/s is provided for the energy range of 5keV-14keV.

3. Equipments

Diffractometer（HUBER 5020-type）: The high-resolution diffractometer has an analyzer gonio on its 2theta arm so that one can use an analyzer in order to reduce the back ground noise. The scattering plane is set as vertical to reduce the effect of the polarization factor. The chi-circle is off-centered by 63mm in order to attach a cryostat or furnace.
Polarization analyzer :Polarization analyzer using 2theta=90^o scattering is ready to use. We have Ge(111), Graphite(002), Cu(110), Mo(100), and Pt(100) crystals for this analyzer. This attachment is useful for magnetic scattering or resonant scattering.
Detectors :An ion chamber as the incident beam monitor, and a scintillation counter as the scattered x-ray detector are usually used. We have also another ion chamber on 2theta arm, SSD, and YAP detectors. A CCD is available but reservation is needed. An imaging plate is prepared for peak search.
Controller :PC:DELL Dimension, OS：UNIX (LINUX), Software:SPEC(CSS) Monochromator, mirror, diffractometer and its stage, slits, attenuator, detectors, and temperature controllers are controlled with SPEC. This software allows us to use a macro to make an automatic measurement.
Data analysis and transfer : Users can analyze the data by using C-plot (CSS). The data are transferred to user's PC by sftp protocol.

4. Other

Software manuals for SPEC and C-plot are at the beam line.

5. Reference

H. Iwasaki, S. Sasaki, S. Kishimoto, J. Harada, M. Sakata, Y. Fujii, N. Hamaya, S. Hashimoto, K. Ohshima, and H. Oyanagi: Rev. Sci. Instrum. 60 (1989) 2406-2409.

KEK
PF
Home page of BL-4C (written in Japanese)

yusuke.wakabayashi(at)kek.jp

Last modified : 23 Feb, 2005