The manufacturing of pinhole arrays with diameters 10 m up to 60 m in 100-300 m gold foils is described using LIGA. These structures are used to characterize the electron beam in a storage ring by means of the emitted synchrotron radiation. The source inside the bending magnet 13 at BESSY I (single bunch mode, 70 mA ring current, pinholes: H60 m) is (448<40) m in height and (768<40) m in horizontal width. For BESSY II pinholes with H 10-20 m will be used utilizing bending magnet radiation (resolution :10 m), single pinholes with 1-5 m in diameter are dedicated to insertion device characterization (coherence).
IntroductionAnticipating the high brightness Synchrotron Radiation (SR) source BESSY II, going into operation in 1998, we developed a diagnostic beamline containing imaging systems, which will be used to determine size and position of the electron beam in the storage ring by means of synchrotron radiation [1,2]. The size of the source will be significantly smaller than 100 m FWHM in vertical direction. As measuring system the well known principle of a pinhole camera will be employed. By this means, an image resolution down to 11 m rms can be achieved using hard x-rays, which is sufficient to characterize the BESSY II dipole source properly. Using an array of pinholes, not only size and position information, but also the emission angle distribution of SR can be determined. However, in order to preserve the diffraction limited resolution, high precision pinholes of about 20 m in rather thick carriers (9100 m), being able to withstand the heat load expected, have to be utilized. Proceeding from the above figures the LIGA technique promises best results in performing these small holes, showing remarkably better precision than the tolerable error in diameter [3]. In the following, a description of the diagnostic system as well as details of manufacturing of the pinholes by LIGA and first results of using them in an existing dianostic system at BESSY I will be presented.
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