Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Compton cameras are a particularly interesting gamma-ray imaging technology because they have a large field of view and rely on electronic rather than mechanical collimation (lead). These systems produce two dimensional, spectroscopic images using data collected from spatially separated detector arrays. A single acquisition contains data to produce image signatures for each radionuclide in the field of view. Application of Compton cameras in field of astrophysics has proven the systems capability for imaging in the 1 to 30MeV range. Other potential applications, in the 100keV to 1MeV range, include nuclear material safeguards and nuclear medicine imaging. A particularly attractive feature for these applications is that the technology to produce a portable camera is now available due to improvements in solid state room-temperature detectors. The objective of this work is to investigate Compton camera technology for spectroscopic imaging of gamma rays in the 100keV to 1MeV range. To this end, accurate and efficient camera simulation capability will allow a variety of design issues to be explored before a full camera system is built. An efficient, specific purpose Monte Carlo code was developed to investigate the image formation process in Compton cameras. The code is based on a pathway sampling technique with extensive use of variance reduction techniques. In particular, the technique of forcing is used make each history result in a partial success. The code includes detailed Compton scattering physics, including incoherent scattering functions, Doppler broadening, and multiple scattering. Detector response functions are also included in the simulations. A prototype camera was built to provide code benchmarks and investigate implementation issues. The prototype is based on a two-detector system, which sacrifices detection efficiency for simplicity and versatility. One of the detectors is mounted on a computer controlled stage capable of two dimensional motion (14x14cm.