Abstract
We already developed an X-ray microbeam irradiation system using monochromatic SR X-rays. Energy of X-rays is restricted to 5.35 keV, since the beam is deflected right angle upward using diffraction of Si(311), in order to irradiate the samples through the bottom of the dish. Presently we are usually using a microbeam cut out by a slit system, and beam shape is 5 micron square(minimum) or larger. Dose rate is about 40 R/s, which corresponds to about 104 photons/s/100 micron2. In region scan mode we can obtain survival data with statistical significance. We have another microscope, into which information of the coordinate of the cells irradiated by the irradiation system can be transferred. Recently, we have installed a confocal laser microscope into this system, which enables highly sensitive detection of fluorescent image of the irradiated cells.
One of the advantages of using SR as light source is that we can choose any energy of monochromatic X-rays with practical intensity. In order to study the signal induction process from energetic viewpoint, we are planning to build an energy-tunable X-ray microbeam system, by which we can irradiate with monochromatic X-ray of inner-shell absorption edges of certain elements. We have to use the horizontal beam as emitted from the electron storage ring, hence we need to overcome some difficulties such as vertical positioning and sample chamber containing cells. This system will be tested this autumn.
