CONCENTRATION OF SYNCHROTRON BEAMS BY MEANS OF MONOLITHIC POLYCAPILLARY X-RAY OPTICS

Capillary optics are valuable tools for concentrating synchrotron radiation [D.J. Tiel, A.E. Stern, D.H. Bilderback and A. Lewis, Physica B 158 (1989) 314]. Single tapered capillaries are used at several facilities. However, most of these optics collect only over a small area. This can be overcome by using larger capillary structures. Polycapillary optics can deflect X-rays by larger angles than other X-ray optics that use only one or two reflections. Conventional X-ray optics that achieve similar deflections are much more energy selective than capillaries. Therefore, capillaries can achieve very short focal distances for a wide range of energies. The measurements shown here represent first tests performed with polycapillaries with large collection area. The performance with respect to transmission efficiency and spot size was evaluated for a set of four very different prototypes. It is shown that for these prototypes a significant gain may be achieved if a spot size of the order of 0.1 mm is required. Further, some characteristics of the different optics are discussed.