In-air micro-PIGE measurement system for fluorine analysis of the tooth

Abstract An in-air micro-PIGE and micro-PIXE measurement system for fluorine analysis of tooth have been developed at the Wakasa Wan Energy Research Center. A proton microbeam is extracted through a thin silicon nitride window into the air and used to irradiate a tooth sample mounted on a sample stage set in air. Gamma-rays from a 19 F(p, αγ ) 16 O reaction and characteristic X-rays are detected with a BGO detector and a Ge X-ray detector, simultaneously. The sample stage and beam scanner allow us to analyze the tooth sample over a range of 20 mm at maximum. Spot sizes of a proton beams in air at an energy of 2.5 MeV was 4 μm, in the case of a distance between the silicon nitride window and the sample of 0.2 mm and 13 μm in the case of 1.7 mm. Fluorine analysis was performed over an area of about 3 mm × 3 mm of the tooth sample. One- and two-dimensional distributions of fluorine and calcium were obtained successfully. Quantitative analysis was also performed using data for measurements of reference materials Ca 10 (PO 4 ) 6 (OH) 2−2 x F 2 x .