Modelling of the reflectance profile of axisymmetrical radiolocation objects using the integral equation method

Based on the first-kind integral equation method for the electric field, the procedure and software for calculating the radar cross-section of axisymmetrical objects, bodies of revolution, are developed. Algorithms are proposed for computation of the matrix of mutual impedances and Green's function of a ring source providing the computation accuracy required for obtaining a stable solution. The method of solution approximation accuracy evaluation by azimuthal harmonics is proposed. Comparison with test examples is carried out and the applicability for solving real-world problems is shown.

Features of device cooling in wiggler synchrotron workstations

The construction of the «Siberian Photon Ring Source», the SKIF synchrotron, in Novosibirsk is underway. At the first stage, six research workstations will be created, most of the devices of which work in a high vacuum. Synchrotron radiation is generated by superconducting Wigglers for two stations. The total radiation power is approaching 49 kW, and the power density on the axis is 92 kW/mrad2. The high energy density of the beam creates quite difficult conditions for the thermal management of optical elements at the workstations. The article presents specific requirements for cooling devices, an overview of the used and promising cooling systems is made, an example of calculating the temperature, stress and strain distribution in a diamond filter with a thickness of 300 microns using the ANSYS Fluent software package is given.

Fixed-target serial oscillation crystallography at room temperature

A fixed-target approach to high-throughput room-temperature serial synchrotron crystallography with oscillation is described. Patterned silicon chips with microwells provide high crystal-loading density with an extremely high hit rate. The microfocus, undulator-fed beamline at CHESS, which has compound refractive optics and a fast-framing detector, was built and optimized for this experiment. The high-throughput oscillation method described here collects 1–5° of data per crystal at room temperature with fast (10° s−1) oscillation rates and translation times, giving a crystal-data collection rate of 2.5 Hz. Partial datasets collected by the oscillation method at a storage-ring source provide more complete data per crystal than still images, dramatically lowering the total number of crystals needed for a complete dataset suitable for structure solution and refinement – up to two orders of magnitude fewer being required. Thus, this method is particularly well suited to instances where crystal quantities are low. It is demonstrated, through comparison of first and last oscillation images of two systems, that dose and the effects of radiation damage can be minimized through fast rotation and low angular sweeps for each crystal.