Title :
Estimation of the contribution of primary and secondary radiation to a pinhole volume from a water phantom
Author :
Gamage, Kelum A. A. ; Taylor, Graeme C. ; Joyce, M.J.
Author_Institution :
Dept. of Eng., Lancaster Univ., Lancaster, UK
Abstract :
The imaging of mixed radiation fields with organic liquid scintillation detectors became feasible as a result of recent advances in digital pulse-shape discrimination methods. The use of a liquid scintillator has significant benefits over other techniques for imaging radiation environments as the acquired data can be analysed to provide separate information about the gamma and neutron emissions from a source (or sources) in a single scan in near real-time. This method has significant potential for the location of radioactive sources in radiation environments in the nuclear industry, nuclear decommissioning and homeland security applications. A further application of the mixed-field imaging system would be to detect, locate and study the secondary radiation produced during proton therapy. Proton therapy uses a particle accelerator to target a tumour within the body with a beam of protons. The presence of materials in the beam path as well as the patient, leads to the production of secondary particles such as neutrons and gamma rays. In this paper the contribution of scattered and secondary radiation from a water phantom to a pinhole volume, as a result of three neutron sources and two gamma sources, is separately estimated using the PTRAC particle tracking option available in MCNP. A spherical tally volume, 2 cm in diameter, was placed equidistantly from a radioactive source and 30×30×15 cm3 water phantom. Monte Carlo simulations have been carried out to investigate the level of primary and secondary radiation contributing to the pinhole volume from interactions in the phantom. This can be used as a simple method to visualise the results expected from the mixed-field imaging system. The results have shown that the percentage of neutrons reflected from the phantom with energies above 1 MeV goes up with mean energy of the source.
Keywords :
gamma-ray detection; gamma-ray production; liquid scintillation detectors; neutron detection; neutron sources; phantoms; radiation therapy; radioactive sources; tumours; MCNP; Monte Carlo simulations; PTRAC particle tracking option; body tumour; digital pulse-shape discrimination methods; gamma sources; homeland security applications; mixed radiation field imaging; neutron sources; nuclear decommissioning; organic liquid scintillation detectors; particle accelerator; pinhole volume; primary radiation contribution; proton therapy; radioactive source location; real-time single scan; secondary radiation contribution; spherical tally volume; water phantom; Gamma-rays; Medical treatment; Neutrons; Phantoms; Protons; Water resources; PTRAC particle tracking; proton therapy; radiation imaging; scattered radiation; secondary radiation; water phantom;
Conference_Titel :
Advancements in Nuclear Instrumentation Measurement Methods and their Applications (ANIMMA), 2013 3rd International Conference on
Conference_Location :
Marseille
Print_ISBN :
978-1-4799-1046-5
DOI :
10.1109/ANIMMA.2013.6727971