Thallium Bromide – TlBr
In recent years, the semiconductor-material Thallium Bromide (TlBr) has been the focus of considerable research due to its promising electronic properties and extraordinarily high detection efficiency. The high detection efficiency arises from its very high density and effective atomic number. The material had been studied extensively by RMD in the late 80s, early 90s where it showed initial promise. Subsequently, in 2000s, it was discovered that considerably greater purification was essential to demonstrate the full potential of TlBr. Since that point, it has become a sought after alternative material due to lower costs while still playing a significant role in homeland security and nuclear medicine applications.
RMD produces Thallium Bromide detectors in a range of sizes and types – single element devices generally vary from 5 mm3 cubes to ~ 1 cm3 planar devices, and multi-element pixelated arrays can reach as large as 4 cm2. Devices can be fabricated with differing electrode materials and patterns, and high density polymer bump bonds can also be applied.
Depending upon device design, spectroscopic TlBr detectors provide energy resolutions typically within a range of 1.5% to 3% FWHM (at 662 keV), situating their performance between high performing inorganic scintillators such as LaBr3 and very high resolution semiconductor CZT detectors. RMD and its collaborators have also been active in addressing stability issues associated with Thallium Bromide.
RMD’s current work with TlBR extends beyond detector fabrication and now includes exploring instrument designs for security applications such as personal radiation detectors (PRDs) and radioisotope identifiers (RIIDs).