RMMD, Inc

United States

Scintillation spectrometers consisting of inorganic scintillation crystals coupled to appropriate optical detectors are one of the most widely used classes of detectors for X-ray, gamma-ray and neutron radiation. Scintillation spectrometers are widely used in a number of important applications including nuclear and particle physics research, nuclear non-proliferation monitoring, geophysical exploration, astronomy, nondestructive evaluation, material science studies and medical imaging. In the search for brighter and more responsive scintillators, a major push has been made in developing improved scintillators from the alkaline earth and the rare earth halide families. Two of the most promising examples of these crystals are CLYC and Strontium Iodide (SrI2).

Avalanche Photodiodes (APDs) are a solid state replacement for traditional photomultiplier tubes (PMTs) and, similar to a PMT, exhibit gain created by the impact ionization process within the device. However, unlike PMTs, APDs can detect both photons and particles while a PMT can only detect optical photons. APDs are also much thinner and more compact than PMTs, and are insensitive to magnetic fields. This insensitivity makes possible the design of hybrid PETMRI systems. RMD’s silicon APDs can achieve and sustain a high gain because they are fabricated using a deep diffused planar manufacturing process and, like other solid state devices, RMD’s APDs have a high quantum detection efficiency, a wide spectral response, and are compact and rugged and are available in discrete devices, arrays, and position sensitive structures.

RMD has developed large area SSPM’s using wide-band-gap semiconductor materials. These materials provide low dark noise, are radiation hard, and have a high sensitivity in the blue to UV spectrum. These photodetectors will also be able to provide large gains (~105-106), an important characteristic for detecting low signals from scintillation materials. CMOS Features Include:

RMD has developed vapor-grown microcolumnar CsI:Tl, which has become the standard for diagnostic digital radiography. Microcolumnar film scintillators channel and conserve scintillation light within densely packaged, highly uniform microcolumns, thereby breaking the sensitivity versus spatial resolution trade-off seen in other scintillator materials such as GOS. The microcolumns are parallel, needle-like structures controllable in diameter from 250 nm to 10 μm. RMD fabricates structured CsI:Tl screens as large as 47×47 cm2 size, and has extensive experience in micro-columnar growth of high resolution screens.

RMD has developed an advanced high frame rate, large-area, modular X-ray detector capable of acquiring high-speed, high-resolution, high-contrast images of dynamic phenomena, for use in hypervelocity projectile tracking, impact analysis, and other important applications such as high-speed medical X-ray CT and time-resolved X-ray analysis.

RMD performs extensive research that benefits the medical imaging equipment market. This market consists of systems such as Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT) and Computed Tomography (CT). Next generation systems require higher energy and timing resolution and higher count-rate performance. These improvements will result in better images, improved background reduction, and potentially lower patient radiation dose. Our research also shows great promise for medical radiology applications such as mammography, general snap-shot radiography, and high frame-rate fluoroscopy.