Increased x-ray production efficiency from transition radiators utilizing a multiple-pass electron beam

• Published in: Review of scientific instruments 1998-06, Vol.69 (6), p.2223-2229
• Main Authors: Piestrup, M. A., Lombardo, L. W., Cremer, J. T., Retzlaff, G. A., Silzer, R. M., Skopik, D. M., Kaplin, V. V.
• Format: Article
• Language: English
• ISSN: 0034-6748; 1089-7623
• DOI: 10.1063/1.1148924

We have observed x-ray emission from transition radiators placed inside an electron storage ring. The radiators were thin (0.18–9 μm) and the electrons were of sufficient energy (118–252 MeV) so that the electrons passed through the radiators many times. This effectively increased the efficiency of the radiators (photons/electron). The electron-beam lifetime in the storage ring was measured, and used to determine the number of passes through each radiator. Multiple passes between 5 and 385 were observed, thus giving a corresponding increase in radiator efficiency. Five electron-beam energies (118, 151, 181, 213, and 252 MeV) were used on a variety of radiators consisting of both single and multiple foils and different materials (C, Al, Cu, Ta). The total output power and the spatial distribution of the x rays were measured. The emission pattern was the typical annular cone of transition radiation. Single-foil transition radiation was observed whose total output power was comparable to that of multiple-foil radiators composed of the same material. Thus, for this range of parameters, the product of the number of foils times the number of passes was a constant.