Improved Spectroscopic Gamma Ray Detectors

Spread of the weapons of mass destruction such as nuclear weapons is a serious threat in the world today. Prevention of the spread of radioactive materials and nuclear weapons has reached a state of heightened urgency in recent years, especially since the events on September 11, 2001 and its aftermath. Gamma ray spectrometers are an important tool in homeland defense and monitoring to check the spread of special nuclear materials (such as highly enriched uranium and weapons grade plutonium) and nuclear weapons. An important challenge in homeland security monitoring is not only to detect hidden radioactive materials but also to distinguish them from routinely used radiopharmaceuticals as well as naturally radioactive materials [McDonald]. A number of homeland security systems such as handheld radioisotope identifiers, vehicle portals for radiation detection and personal radiation detection devices rely on availability of high performance gamma-ray spectrometers. Important requirements for the gamma ray spectrometers used in these applications include good energy resolution, high detection efficiency, compact size, light weight, easy portability and low power consumption. None of the available gamma-ray sensors satisfy all these requirements. The goal of the proposed effort is to investigate new scintillators that appear to be very promising for this vital application.