[en] The principal problem limiting the use of HgI₂ X-ray detectors is instability. We developed an encapsulation procedure potentially capable of stabilizing devices for 20 years. We also developed an accelerated test procedure to accurately simulate many years of aging. (orig.)

[en] Radiation detectors have been fabricated from crystals of the semiconductor material thallium bromide (TlBr) and the performance of these detectors as room temperature photon spectrometers has been measured. These detectors exhibit improved energy resolution over previously reported TlBr detectors. These results indicate that TlBr is a very promising radiation detector material

[en] Lead iodide shows great promise as an X-ray spectrometer material for use at room temperature and above. The pioneering work on lead iodide detectors was promising but resulted in detectors with poor energy resolution. Later, we discovered that by carefully preparing the starting materials, lead iodide detectors with good energy resolution (< 1 keV FWHM at 5.9 keV) could be fabricated. We have continued to develop these detectors with significant progress being made in the areas of purification, crystal growth and device fabrication. (orig.)

[en] Objective. To define and compare early lesions associated with slipped capital femoral epiphysis (SCFE) on magnetic resonance imaging (MRI), computed tomography (CT) and radiography. Design and patients. Thirteen patients with 15 symptomatic hips due to SCFE underwent radiography and MRI; CT was performed in 12 patients. SCFE was graded on radiographs, head/neck angles and qualitative changes were evaluated on CT, and morphologic/signal abnormalities were determined on MRI. Results. Physeal widening, apparent on T1-weighted MRI, was evident in every case of SCFE, including one presumed ''pre-slip.'' T2-weighted images demonstrated synovitis and marrow edema but obscured physeal abnormalities. CT head/neck angles ranged from 4-57 for symptomatic to 0-14 for asymptomatic hips. Physeal and metaphyseal changes were variably identified on both radiographs and CT in all cases of SCFE, but not in the pre-slip. Conclusion. MRI clearly delineates physeal changes of both pre-slip and SCFE, and demonstrates very early changes at a time when radiographs and CT may appear normal. (orig.)