Monochromatic X-ray irradiation system (0.08-0.4nm) for radiation biology studies using synchrotron radiation at the Photon Factory.

A monochromatic X-ray irradiation system in the 0.08-0.4 nm wavelength range is described. This uses for the first time, synchrotron radiation at the Photon Factory as an X-ray source (2.5 GeV electron storage ring). It consists of a beam shutter, a Si crystal monochromator, ionization chambers for monitoring exposures, a sample stage, and a control system. The beam is 2.7 × 30 mm at the sample position with a fairly uniform intensity of several kR/min (one C · kg-1 · min-1). The wavelength is an extremely pure Δλ/λ ∼ 10-3. A 35 mm culture dish is moved across the vertical height (2.7 mm) of the X-ray beam using a sample scanning stage. This improves the uniformity of the radiation intensity on the sample. The sample can be irradiated under normal or controlled atmospheric conditions. Since 1984, a variety of biological materials have been irradiated, including cultured mammalian cells. Results of yeast cells are presented to illustrate the performance of this irradiation system.