Metrology Performance Test of Phosphor Screen Imaging and Its Application on Uniformity Evaluating of Large-Area Sources

According to the application requirement of the phosphor screen imaging technology in the field of radioactivity measurement, tests of the repeatability, consistency and linearity with time and radioactivity involving the imaging of phosphor screen are carried out under laboratory conditions. The results show that the repeatability of imaging gray value is 8.6% (k=2), the response of a phosphor screen imaging to point source in the sensitive area of 190 mm×200 mm is equivalent, the gray value of imaging phosphor screen becomes proportional with the exposure time, and the gray value created by the equal exposure time is proportional to the emission rate of the source. Based on these performance as well as strictly respecting to the uniformity evaluation rules of ISO 8769∶2010, the uniformity measurement to a large area source of 150 mm×100 mm is executed, the quantitative and intuitive expression method to the uniformity of a plane source is established, so as to develop a reference method of improving the preparation process to plane source in accordance with the ISO 8769∶2010 international standard.