Gas gain operations with single photon resolution using an integrating ionization chamber in small-angle X-ray scattering experiments

In this work a combination of an ionization chamber with one-dimensional sp atial resolution and a MicroCAT structure will be presented. Initially, Mic roCAT was thought of as a shielding grid (Frisch-grid) but later was used a s an active electron amplification device that enables single X-ray photon resolution measurements at low fluxes even with integrating readout electro nics. Moreover, the adjustable gas gain that continuously covers the entire range from pure ionization chamber mode up to high gas gains (30 000 and m ore) provides stable operation yielding a huge dynamic range of about 108 a nd more. First measurements on biological samples using small angle X-ray s cattering techniques with synchrotron radiation will be presented. (C) 2000 Elsevier Science B.V. All rights reserved.