BL-7C
Versatile Hard X-ray Experimental Station

BL-7C photo 1BL-7C photo 2

This beamline is equipped with a double-crystal monochromator. Wide horizontal acceptance, 4 mrad, can be realized by using sagittal focusing when Si(111) crystal is used. Vertical focusing can be achieved by using a focusing double mirror, which is usually used to reduce the higher order reflections. Intense, higher-order free, and monochromatic X-rays can be obtained at this station.

Contact Person: SUGIYAMA Hiroshi (Photon Factory)
phone: +81-29-864-5200（ext. 4421）, FAX: +81-29-864-2801,
e-mail: hiroshi.sugiyama@kek.jp

BL-7C diagram

Construction of the beamline and the control system

Area of Research

* Standard XAFS measurements can be performed tentatively.  Please use dedicated XAFS experimental station, if you need reliable XAFS experiments.

Light Source

Photon Flux at Sample


The available monochromator crystal lattice plane, the X-ray energy range, the X-ray energy resolution, and the photon flux are given below. The photon flux is measured under the electron energy of 2.5 GeV and stored current of 300 mA.*

condition

energy range

resolution（ΔE）

photon flux

Si(111) focused

4 - 12 keV

ca. 2 eV at 9 keV

ca. 1 x 1011 ph/s

Si(111) unfocused

4 - 20 keV

ca. 2 eV at 9 keV

ca. 1 x 1010 ph/s

The low energy limit is determined by the absorption by beryllium windows (total 0.6 mm). However, we have an example of the fluorescent XANES measurement of argon in atmosphere, whose absorption edge exists at 3.2 keV.

The energy-dependent X-ray photon flux can be found here.


The mirrors are made of 70 cm long fused quartz, without any coating. The content of the third order harmonics can be reduced to be less than 3 x 10-6 when Si(111) double crystal monochromator and the focusing double mirror are employed. The typical beam size is 1.5 mm(H) x 1 mm(V) when focussed and 5 mm(H) x 1 mm(V) when unfocussed.
The horizontal divergence of X-ray beam becomes three times of that of incoming beam. Thus becomes 12 mrad at maximum.

Designed beam height is ca. 1225 mm from the floor. The size of the experimental hutch is 3.0 m (optical axis) x 2.1 m (width) x 2.5 m(height). The size of entrance to the hutch is 1.3 m (width) x 2.5 m (height).

*PF is normally operated on Top-Up mode with 2.5 GeV / 450 mA as of Feb. 2013.  Photon flux increases roughly in proportion to stored current.

Facilities in Experimental Station

BL-7C: XAFS set up

This is shared with the above described control system. This system can be used for taking and output of experimental data. Data are stored in a 3.5" floppy disk or a USB memory. This setup is assembled on an optical bench. The bench is mounted on a motor driven table, which can be used as a flat table (1200 mm(L) x 1000 mm(W), maximum load of 150 kg) when the XAFS setup is removed. The beam height is ca. 348 mm and ca. 188 mm from the top of the flat table and the optical bench, respectively.

BL-7C: Ionization Chambers

Three chambers (gas length = 17 cm x 1 and 31 cm x 2) are prepared. Six kinds of flowing gases (N2(100 %), N2+Ar(15 %), N2+Ar(25 %), N2+Ar(50 %), Ar(100 %), and N2(30 %)+He) are prepared as default.

 

References

update: 2009.3.19, 2008.3.31, 2005.3.25, 2005.2.24