Scintillator Materials

-----Our ongoing research into advanced scintillator materials includes inorganic, semiconductor, ceramic, plastic, and hybrid scintillators, and we are constantly developing and refining novel, advanced forms of these materials for detecting X-rays, gamma-rays, neutrons, alpha particles, beta particles, protons and their combinations. We typically grow our materials using approaches beyond conventional crystal growth techniques, in either crystalline form (generally best suited to radiation detection, monitoring and energy-measurement applications) or microcolumnar form (best suited for imaging applications). We often pre- and post-process the resulting materials to the needs of targeted applications. Scintillators presently may be small and compact, up to 3 x 3 cm², suited to the requirements of applications such as dentistry, to as large as 50 x 50 cm², for large-field imaging such as chest radiography. Certain applications, such as in-flight missile/projectile X-ray imaging, require particularly sizable sensors (up to 90 x 90 cm² or larger), which we typically fabricate by tiling multiple sensors on suitable support structures. Currently in production and pilot production, our scintillators typically provide better contrast, finer resolution, greater brightness, higher sensitivity and faster performance than the imaging screens and scintillators traditionally used in radiography and in radionuclide imaging.

Our current research and development is focused on a comprehensive variety of scintillator materials and forms, including:

Co-doped inorganic scintillators, including CsI:Tl,Sm, CsI:Tl,Eu and CsI :Tl with other co-dopants. Our work has yielded important new forms of the widely used CsI:Tl scintillator, with both afterglow and hysteresis reduced to insignificant levels. We are now fabricating both crystalline and microcolumnar film forms of these materials.

Lanthanum halide scintillators, including LaBr₃:Ce and LaCl₃:Ce. We synthesize these materials using our proven co-evaporation vapor deposition approaches.

New bright semiconductor scintillators, including ZnSe:Te and other Group II-VI materials with various dopants. These are fabricated in microcolumnar and other forms.

Ceramic scintillators, including Lu₂O_3:Eu, Gd₂O₂S:Tb and ZnSe:Te. Up to 3" diameter, 3 mm thick transparent optical ceramics of Lu₂O₃ have been fabricated. This material has the highest known density among scintillators, measuring 9.59 gm/cc, and its 630 nm red emission is well suited for silicon photodetectors. Synthesis of Gd₂O₂S:Tb and ZnSe:Te in ceramic form is currently under way.

Neutron scintillators, including LiI:Eu, boron- or gadolinium-loaded plastic scintillators, and microcolumnar CsI:Tl sandwiched within transparent compounds containing boron (B) or gadolinium (Gd). The scintillators at the heart of these neutron sensors may be fabricated using alternate techniques, but at present the most common forms are microcolumnar film and pixelated slab.

Hybrid scintillators, consisting of layers of microcolumnar scintillator films of different materials, or films deposited on scintillating fiberoptic substrates. Hybrid scintillators may be fabricated effectively by the vapor deposition of one material atop another, in which case the columnar growth of the second material begins exactly atop the microcolumns of the first material deposited, yielding continuity in the light path and preserving spatial resolution and light conservation.

Our research and development also focuses on improving key aspects of scintillator material characteristics and performance, including: