F1 is doubly focused x-ray station with capability to safely handle biohazard materials at the BL2 level. Radiation from a 24-pole 1.2 Tesla wiggler magnet is equally shared between the F1 and F2 stations. A white beam vertical focusing mirror has been installed upstream of the F1 and F2 monochromators to collimate the beam and reduce the heat-loading on the monochromator optics by not reflecting unwanted higher energies. The horizontally focusing monochromator is located 20 meters from the source and a vertically focusing mirror is located 0.68 m downstream of this to further focus the beam for F1. The focused beam has a 1 mrad horizontal and a 0.4 mrad vertical divergence. The working focal point is generally another 4 to 6 meters beyond the focusing crystal. It is not possible to bring white beam into F1.
The station is
particularly suitable for diffraction from small specimens because of
the very high intensity available in the focused beam. Although the
station was designed with a contiguous BL2 facility to enhance the
capability for macromolecular diffraction, it should also be a premier
station for general x-ray scattering.
Equipment assigned to the station includes an optical table that can
precisely align a diffractometer, protein crystal camera, etc. The table
is equipped with air pads in order to reposition the table on the floor
when a major energy change is required. An oscillation camera for
protein crystallography is also available with a nitrogen cryo-system.
The F1 beam is currently tuned to Br absorption edge to facilitate
single-wavelength anomalous diffraction (SAD) phasing. Other pieces of
equipment, such as a 6-circle diffractometer, can be accommodated for
special needs.
The F1 hutch is part of a larger BL2 biohazards handling facility. The
other parts include a control room area, a room with a laminar flow hood
for sample mounting equipped with HEPA filters, a conventional crystal
mounting room and a room where computer facilities are available.
F1
hutch
| F1 Station Summary | |
| Source: | e+s, 24 pole wiggler, 1.0 mrad into F1 |
| Source size: | FWHM (horizontal) = 3.76 mm, FWHM (vertical) = 0.944 mm |
| Distance to source: | 25 m to center of hutch |
| Be windows: | 0.050 inch Be and 0.03 inch Graphite before F1 hutch |
| Flux (200mA)(p/s): | 3.0x1011 thru 300µm collimator |
| Focus Size: | 0.2 mm (vertical), 2.00 mm (horizontal) |
| Monochromators: | Horizontal bent Si(111), asymmetrically cut with water cooled Cu Block |
| Monochromatic Mirrors | |||
| Type | Length | Vertical Focus | E*θ°(keV-mrad) |
| Rh coated Si | 24 inch | Yes | 67.0 |
| Typical Experiments | ||
| Type | Energy Range | Equipment Setup |
| Crystallography | 13.51 keV (0.918 A) | Standard MacCHESS equipment |
| High res. scattering | 13.51 keV | Standard optical table & equipment |
| Small-angle scattering | ||
| Unique Features: | ||
| Biohazard level 2 facility with Laminar Flow Cabinet | ||
● Special A1 and F1
x-ray optics
●
Technical highlight on Macromolecular
Crystallography at CHESS
