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 inche 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 (ΔE/E=128 eV @ Mn Kα) |
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High-Pressure, High-Temperature
Experiment
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The
X-ray Spectrum Delivered to B1
