Abstract: A method of defining at least one scan parameter for an x-ray scan of a single crystal structure, the method comprising: determining a target orientation of the structure for the scan; and defining different non-zero levels of x-ray exposure for different parts of a scan area based on either or both of the target orientation and characteristics of the structure; and, defining the scan area so that substantially all x-rays of the scan are directed to the structure in the target orientation.

Abstract: A quantum key distribution system comprises: a transmitter (10) arranged to transmit a coded photon stream over a free space quantum channel (14), wherein the transmitter comprises a single photon source (30) arranged to generate a coded photon stream comprising photons representing QKD bit values, and attenuation means (32) arranged to attenuate the coded photon stream, the attenuation means being variable so as to provide a variable attenuation of the coded photon stream; a receiver (12) arranged to receive the coded photon stream from the quantum channel; and control means (34, 46) arranged to control the attenuation means so as to vary the attenuation.

Abstract: A method of detecting an anomaly in a crystallographic structure, the method comprising: illuminating the structure with x-ray radiation in a known direction relative to the crystallographic orientation; positioning the structure such that its crystallographic orientation is known; detecting a pattern of the diffracted x-ray radiation transmitted through the structure; generating the simulated pattern based on the known direction relative to the crystallographic orientation; comparing the detected pattern to a simulated pattern for x-ray radiation illuminating in the known direction; and, detecting the anomaly in the crystallographic structure based on the comparison.

Abstract: A method of defining at least one scan parameter for an x-ray scan of a single crystal structure, the method comprising: determining a target orientation of the structure for the scan; and defining different non-zero levels of x-ray exposure for different parts of a scan area based on either or both of the target orientation and characteristics of the structure; and, defining the scan area so that substantially all x-rays of the scan are directed to the structure in the target orientation.

Abstract: A method of detecting an anomaly in a crystallographic structure, the method comprising: illuminating the structure with x-ray radiation in a known direction relative to the crystallographic orientation; positioning the structure such that its crystallographic orientation is known; detecting a pattern of the diffracted x-ray radiation transmitted through the structure; generating the simulated pattern based on the known direction relative to the crystallographic orientation; comparing the detected pattern to a simulated pattern for x-ray radiation illuminating in the known direction; and, detecting the anomaly in the crystallographic structure based on the comparison.