Developent of dosimetry method for synchrotron radiation X rays using photoacoustic spectroscopy

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Original purpose of the photoacoustic spectroscopy is to use light to examine material surface by heat that is created by the absorprion of the light. The aim of this study is to apply this methed to the detection of the radiation. Merits of this method are (1) to measure heat by the absroption of radiation and (2) any sort of material can be used as target samples. From the equality of heat and the absorbed energy, this detector would have a chracteristics as a calorimeter. We tested three types of radiations, such as synchrotron radiation X rays, 200 kVp X rays and cyclotron proton beams. As for the target materials, metal foils, metal powdwes, organic films and organic powders were tested. At first, we constructed a photoacoustic dosimeter system combining a detector, a preamp, a lock-in-amp and a personal computer. Signal intensity from the metal foils and metal powders were enough for the use as a dosemeter, however, low signal intensities were obserbed from orginic materials. We found good linear relationship between the input X-ray imtensities and output photoacoustic signal intensities. In the case using metal samples as targets, this system can be used as a new type of an absorbed dosemeter. However, in the case using organic materials as targets, improvemant of the detector sensitivity more than 10 times is necessory to be used as a absorbed dosemeter.