|
CHESS West
B1 Station
The B1 station is part of the National High Pressure Facility at CHESS. This station is
equipped for x-ray diffraction studies with diamond anvil cells. The source for the B1
station is a bending magnet. The beam is stopped down to about 3 mm before entering the
station. The beam is further reduced by a set of apertures to the final beam size of 5 to
500 microns. The final size depends on the requirements of the experiment.
The High Pressure Facility exists to provide experimental support for high pressure
experiments with diamond anvil cells. In these cells, pressures from around 0.1 GPa
(1 kbar) to well over 100 GPa (1 Mbar) can be generated. The facility has
stages for mounting diamond anvil cells permanently installed in the B1 hutch. In
addition there is a micro-optical system for in situ pressure,
temperature, and Raman spectroscopy measurements in the hutch.
Energy dispersive diffraction is generally used at B1 although some Laue experiments have
also been done.
The main limit on the size of the diamond anvil cells is the beam pipe for station
B2 that
runs through the B1 hutch. The distance from the center of the B1 beam to the edge of the
beam pipe is 3.5 inches (see diffraction stage drawing, below). In general diamond anvil
cells are mounted on a stage which is 2 inches below the x-ray beam. Adapter plates are
available to fit most diamond anvil cells.
Drawing of the diffraction stage for the B1
station. Diamond anvil cells are attached to a holder which in turn is bolted
onto the diffraction stage. In designing a new holder, keep in mind that the
sample needs to be placed 2.0 inches above the point marked by the "X".
A schematic of the diffraction stage and optical system in the B1 hutch is shown below.
Currently a miniature solid state laser (532 nm) is used for ruby pressure and
Raman spectroscopy measurements at high PT. High temperature experiments using
internal resistive heating method are possible (See Rev. Sci. Instrum.
74(3), Part 1, p1255, 2003).
As shown in the photo below, we have a micro-drill press and microscope for precise
drilling of the diamond anvil cell gasket. A pre-indented gasket is clamped in a precision
holder, which is attached to a kinematic mount. The drill position
related to the indentation made by diamond anvil on the gasket can be
precisely centered in a special microscope, which can look straight into
the diamond anvil indentation and adjusted with precise translation stage.
A polarized, photographable, stereo microscope for diamond cell preparing
work and sample loading is available in our on-site high pressure
laboratory. Extra micro-optical system for pressure, temperature,
and Raman spectroscopy measurements is also available on the outside of B1
hutch for the convenience in case of multiple user groups attended.
 
|
B1 station summary |
|
Source: |
e-s,
Hardbend magnet HB6W, 0.4 (horizontal) mrad into B1 |
|
Source size: |
FWHM (horizontal) = 3.78 mm, FWHM (vertical) = 1.00 mm |
|
Distance to
source: |
11.58 m to center of optical table |
|
Be windows: |
0.040 inch to B1 hutch |
|
Aperture sizes: |
4 mm gross; fine apertures: 5-500 microns |
|
|
Typical Experiments: |
|
Type |
Energy
Range |
Equipment Setup |
|
Diamond anvil-cell |
white beam |
High resolution Intrinsic Ge
( E/E=128
eV @ Mn K ) |
|
Last Update:
2006-09-21
|
