The design of two dimensional gamma ray tomography system hardware based-on PIN photodiode detector

摘要

In this research, two dimensional gamma ray computed tomography (CT) hardware system design based on of PIN photodiode detector had been done. The developed hardware is first generation of CT which consists of single PIN photodiode detector (Teviso RD3024) and collimated source of gamma radiation (Cs-137), radiation counter system (built based-on timer and counter units of a microcontroller), and mechanical control system (to control motor steppers) to move the test material by rotation and translation. Timer, counter, motor control system and serial communication had been arranged and conducted through microcontroller Atmega16. A series of calibration process had been done to make sure that this system worked well. The counter system on this hardware has low relative error value which is 0,6% for repetitive measurement of gamma radiation, and it also can move the test material for shortest distance which is 4,2 mm and 7,2° for rotation. With that step size motion value, it had been obtained a data measurement matrix with the size of 24 (rotation motion) × 29 (translation motion) or move by rotation of 180° to every shift of test material to the distance of 12.18 cm. The collected data had been used for image construction process so the image of test material can be obtained.