The Neutron Digital Radiography Facility Based CCD in SPRR-300

摘要

SPRR-300 is a Swimming Pool Research Reactor in China. The neutron digital radiography facility has been set up in it. The facility is made up of collimator system, the table for sample, the imaging system, the controlling system and so on. In the collimator system, the graphite is used as a moderator, and the bismuth as a gamma filter and the material made of lead, boron, polyethylene and cadmium as the diaphragm. The table for sample is used to modify the tested part and orientation of the sample. The converter is NNU-2(~6LiFZnS(Ag)) made in China. The CCD is used in the imaging system. To improve Signal-to-Noise of CCD imaging system, the double thermocouple refrigeration is used to cool CCD below -30°C. To improve resolution power, the high quality lens with small field of view is used to cover 10cm×10cm or 3cm×3cm. To improve dynamic range, the image grabbing, processing and analyzing technology of 14bit (16383) gray-data is used. A 10mm thick glass coated with Al and TiO_2 as the protecting layer is used to protect CCD directly irradiated by neutron. A light shielded box which material is Al to avoid long term activation is used. To improve dynamic range, the image grabbing, processing and analyzing technology of 14bit data is used. In the controlling system, PLC (Programmable Logic Control) is used to improve the facility automation and the radiation shielding of researchers and instruments. The neutron digital radiography has been utilized in SPRR-300 to detect internal structures or defects of some components, and some good effects were obtained.