Gamma-ray imaging with a time-modulated random coded aperture.

In this article, we present a new industrial gamma-ray imaging system. This system takes advantage of a time-modulated random coded aperture (TMRCA). The gamma-ray detector coupled to the TMRCA can be position-sensitive or non-position-sensitive. The TMRCA imaging system could offer the ability to identify radioactive sources without losing spatial resolution. With a non-position-sensitive BGO detector, a prototype TMRCA imaging system was constructed. The prototype system was investigated with two gamma-ray sources (137Cs, 60Co) and a 238Pu-Be neutron source, which was placed in a paraffin moderator to produce an extended source. The experimental results suggest that the TMRCA imaging system offers the opportunity to achieve high spatial-energy resolution cost-effectively for high-energy gamma rays.

New numerical simulation method to calibrate the regular hexagonal NaI(Tl) detector with radioactive point sources situated non-axial.

Scintillation crystals are usually used for detection of energetic photons at room temperature in high energy and nuclear physics research, non-destructive analysis of materials testing, safeguards, nuclear treaty verification, geological exploration, and medical imaging. Therefore, new designs and construction of radioactive beam facilities are coming on-line with these science brunches. A good number of researchers are investigating the efficiency of the γ-ray detectors to improve the models and techniques used in order to deal with the most pressing problems in physics research today. In the present work, a new integrative and uncomplicated numerical simulation method (NSM) is used to compute the full-energy (photo) peak efficiency of a regular hexagonal prism NaI(Tl) gamma-ray detector using radioactive point sources situated non-axial within its front surface boundaries. This simulation method is based on the efficiency transfer method. Most of the mathematical formulas in this work are derived analytically and solved numerically. The main core of the NSM is the calculation of the effective solid angle for radioactive point sources, which are situated non-axially at different distances from the front surface of the detector. The attenuation of the γ-rays through the detector's material and any other materials in-between the source and the detector is taken into account. A remarkable agreement between the experimental and calculated by present formalism results has been observed.