High-speed crystal detection and characterization using a fast-readout detector

Abstract

A novel raster-scanning method combining continuous sample translation with the fast readout of a Pilatus P6M detector has been developed on microfocus beamline I24 at Diamond Light Source. This fast grid-scan tool allows the rapid evaluation of large sample volumes without the need to increase the beam size at the sample through changes in beamline hardware. A slow version is available for slow-readout detectors. Examples of grid-scan use in centring optically invisible samples and in detecting and characterizing numerous microcrystals on a mesh-like holder illustrate the most common applications of the grid scan now in routine use on I24.

Figure 1

(a) The GUI allows the user to define the horizontal and vertical pitch of the grid (‘Box size’ fields) and data-collection parameters such as exposure time and crystal-to-detector distance. (b) shows the same crystal at φ + 90°; optical alignment is not possible. Diffraction data from a 1 × 7 grid have been collected and analysed with DISTL. DISTL results are automatically overlaid on the sample view and the scoring criteria can be chosen by means of a pull-down menu. Right-clicking on any box centres the sample to that position.

Figure 2

AcMNPV polyhedra crystals mounted on a MiTeGen MicroMesh. The 25 × 9 grid scan is recorded over a 250 × 90 µm region of the sample. (a) and (b) show the crystals and measurement grid without and with the DISTL results overlaid.