This paper describes the preliminary analysis and design of a water-cooled multilayer monochromator (MLM) system for the Illinois Institute of Technology’s BioCAT beamline at Argonne National Laboratory. The first substrate is designed to handle the heat load of an undulator beam with low tangential slope errors. The substrates will each have two multilayer coating strips to provide high flux 12 keV beams with either 0.5% or 1% spectral bandwidth. The new multilayer system which will be added to the beamline is expected to provide an increased photon flux of 50 to 100 times compared with the existing double crystal monochromator system and thus enhance beamline throughput and performance for applications where higher bandwidth is acceptable.
Some X-ray instruments require the utilization of large-area windows to provide vacuum barriers. The necessary attributes of the window material include transparency to X-rays, low scattering, and possession of suitable mechanical properties for reliable long-term performance. Kapton is one such material except that it is a polymer and a large window made from Kapton with a pressure differential of one atmosphere across it can undergo substantial deformation at room temperature. In this paper, we report on the mechanical testing of Kapton samples including creep measurements, and comparison with published data. We use of these data together with analytical / numerical models to predict the changes in the profile of Kapton vacuum windows over time, and show good agreement with experimental measurements.
Saw-tooth refractive lens (SRL) provides a comparatively attractive option for X-ray focusing. An SRL assembly
consists of two parts, each with an array of triangular structures (prisms), set tilted symmetrically with respect to the
incoming beam. Its main advantage is a simple, continuous tunability in energy and focal length. SRLs can be used for
both long and short focal length focusing. Long focal distance focusing of an SRL can accurately be predicted using
simple analytical relations. However, the focus size at short focal distances focusing may deviate appreciably from the
expected demagnified source size when: (1) the length of the SRL is comparable with the focusing distance, (2) the
incident beam is not monochromatic, and (3) and the distance between adjacent prism tips, the tip step, is large . The first
factor was considered in a previous work while the other two are addressed is this paper. This preliminary work is aimed
at a better understanding of the SRL lenses for focusing an undulator beamline at the Advanced Photon Source (APS).
Saw-tooth refractive lenses (SRL) provide a comparatively attractive option for X-ray focusing for various reasons, including their simple, continuous tunability in energy and focal length. Optimal focusing of a conventional SRL at short focal lengths is limited by the SRL’s length in relation to the focal length. Three approaches to overcome this limitation are described. Analytical solutions verified with ray-tracing are presented. These are bending, variation of the saw-tooth tip angles, and variation of the period.