Mixed Barium Halide Scintillators for Gamma Ray Spectroscopy

The proliferation of weapons of mass destruction such as nuclear missiles and “dirty bombs” is a serious threat in the world today. Preventing the spread of these nuclear weapons has reached a state of heightened urgency in recent years, more so since the events on September 11, 2001 and its aftermath. Gamma-ray spectrometers are an important tool in monitoring the proliferation of nuclear weapons. Important requirements for the gamma-ray spectrometers used for nuclear non-proliferation include high energy resolution, high detection efficiency, low cost and reasonably fast response. None of the existing classes of detectors satisfy all these requirements. Recently, mixed barium halide compositions doped with Eu2+ have emerged as promising scintillators for gamma-ray spectroscopy. The goal of the proposed effort is to explore this family of scintillators for eventual use in nuclear monitoring. Anticipated Benefits New scintillator materials with high light output, excellent proportionality, very high energy resolution and reasonably fast response would offer unique advantages over many of the existing scintillators used in gamma-ray studies. The application addressed in this proposal is nuclear non-proliferation, where the proposed scintillators would offer better isotope identification with fewer false alarms. These scintillators will be useful in other areas too. Clinical SPECT systems and gamma-cameras, surgical probes, small animal imaging systems, and dedicated organ imaging systems would all benefit from the proposed innovation due to possibility of improved scatter rejection and higher spatial resolution. These sensors also have critical applications in other areas. The increased interest and commitment to quality control has motivated many industrial groups to develop gamma-ray based nondestructive testing equipment. High counting rates, wide dynamic range, high sensitivity, and low noise performance are important to minimize the required source strength which must be located on the production floor. This is an area in which the compactness, and flexibility of a high performance detector will have a major impact. Other applications include nuclear physics research, environmental monitoring, nuclear waste clean-up, astronomy and well-logging. References Dr. Stephen Payne, LLNL, 7000 East Avenue, Livermore, CA 94550, 925-423-0570, payne3@llnl.gov Dr. Zhong He, U. Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI, 48109, 734-764- 7130, hezhong@umich.edu Dr. William Moses, LBNL, 1 Cyclotron Road, Berkeley, CA 94720, 510-486-4432, WWMoses@lbl.gov