STATION 14.2NOT AVAILABLE

Description

High throughput protein crystallography

Functional Description

Station 14.2 provides a focused, collimated, monochromatic, X-ray beam with high energy resolution at wavelengths of 0.98 Å and 1.2 Å. The station is designed for protein crytallography data collection from crystals as small as 20 microns. A crystal mounting robot allows high throughput screening, and the high X-ray intensities allow rapid data collection for MAD or SAD projects.

Technical Description

Multipole Wiggler Source:
2 tesla on-axis field (2.1 Tesla possible); power 182 W/mrad at 300mA in the centre of the fan; 200mm period; 9 poles plus 2 side poles; K value 37.36; Gamma 3914; max angle 6.5 mrad; critical wavelength 2.33Å; integrated flux 4 x 1013 photons/sec/mrad/0.1% at 300mA; 1.2Å on axis aperture used 1.0 to +3.0 mrad horizontal, -0.11 to + 0.11 mrad vertical; on-axis source size 2.4 x 0.3 mm2; projected source size 3.0 x 0.3 mm2 approx.

Optics

mirror; vertical focusing, glancing angle 3.5 mrad, 7.0 Ang. cut off, 1.2m long silicon substrate, rhodium coated, distance from source 16m, distance to focus - variable, typically 5m.

Monochromator

si 111 optimised for 0.979Å or 1.2Å wavelength, horizontally focusing, distance from source 18m, distance to focus - variable, typically 2.3m, asymmetry at 1.2Å is 8:1.

• Focal spot size <0.3 (V) x 0.4 (H) mm2.
• Horizontal divergence 4mrad.
• Flux 1.4 x 1013photons/sec.
• Intensity 9 x 1013 photons/sec/mm2.

Detectors

ADSC Q4R CCD; photo-multiplier tube and Amptek fluorescence detectors for MAD and SAD experiments.

Additional Equipment

• Huber single axis (ø) rotation camera
• crystal viewing camera
• ACTOR automatic sample changer
• sample storage dewar
• Oxford Instruments Cryojet

Benchmark

With the collimating slits set to 200 x 200 microns near the sample, and at an SRS current of approx. 200mA, the expected ion chamber reading on 14.2 is 3.0 to 4.00 volts.

Typical exposure times per image on the station range from a few seconds to a few minutes, depending on the strength of diffraction. Complete data sets can be collected in anything between 20 minutes and a few hours.