Abstract: An apparatus and method for using &agr;-particle energy loss to measure the thickness and stoichiometry of films grown by molecular beam epitaxy and other methods. The apparatus for measuring the thickness of films grown on a substrate in a growth chamber, comprises a protective housing having an aperture opening into the growth chamber, a solid state detector disposed in the protective housing, a shutter for opening and closing the aperture, a shield disposed in the housing between the aperture and the solid state detector for shielding the detector, and a calibration source disposed between the shield and the detector for calibrating the measurements made by the detector. A second calibration source disposed between the shutter and the shield, for measuring deposition on the shield.

Abstract: A gamma ray detector for determining the position of gamma ray interactions has at least one module. Each module has a converter for converting gamma rays to charged particles, a scintillator for emitting light in response to charged particles produced by the converter, a photodetector to determine when light has been emitted from the scintillator, a two-coordinate position detector for determining the X and Y coordinates of charged particles interacting with the position detector, and a signal device for signaling the presence of emitted light in the photodetector and for activating the position detector.

Abstract: Light guides (1) capable of encoding the transverse and longitudinal coordinates of light emission induced by the interaction of photons in an array of a plurality of the light guides. Each light guide has at least two discrete crystal segments (4) adjacently disposed along a common longitudinal axis of the light guide (1). Between adjacent segments is a boundary layer (7) having less light transmission than the light transmission of the crystal segments (4). A light absorbing mask (8) increases light adsorption in a segment (4). Photons enter the light guide (1) and cause the emission of scintillation light which is delivered in different and resolvable quantities to light sensing devices. The differences in quantity of delivered light is caused by successive decreases in light in part by the boundary layers (7). The differences in quantity of light establish the segment from which the light emission took place.

Abstract: A composition comprising no-carrier-added 1-(B-D-arabinofuranosyl)-5-(E)-(2-halogenovinyl)uracil wherein the halogen is radioactive iodine or bromine. This composition can be used to diagnose or treat herpes viral infections.

Abstract: A method and apparatus for boundary layer control by sucking air off the vortex chambers established in the trailing-edge portion of an aircraft aerodynamic surface. The rate of air bleed is controlled first by increasing it until the boundary layer is attached to the airstreamed surface, then by decreasing the rate of air bleed until the pressure in the trailing-edge aircraft portion starts decreasing. The aircraft equipped with the boundary layer control system, including a number of vortex chambers accommodating streamlined bodies and communicating, through a common passage and a receiver, with a low-pressure source.

Abstract: An apparatus and method are provided for determining the X, Y and Z positions of a point of gamma ray induced light emission in a pattern of a plurality of scintillating light guides. A plurality of spatially separated, scintillating, crystal, light guides are arrayed in a pattern having known X and Y positions with each of the light guides having a gamma ray receiving end, a light transmitting end, and walls therebetween. A light reflective surface is disposed on at least a portion of the walls having light reflectivity such that a total fraction of light passing through a transmitting end is substantially greater for gamma ray induced light emissions closer to the transmitting end and substantially less for emissions closer to the receiving end.

Abstract: Reacting [.sup.* X]X- with YVaraU in the presence of a cuprous ion catalyst under anaerobic and reducing conditions produces [.sup.* X]XVaraU, where .sup.* X is a radioactive halogen, Y is a second halogen, X and Y are different halogens, and XVaraU is 1-(.beta.-D-arabinofuranosyl)-5(E)-(2-halogenovinyl) uracil, the halogen of which is X. The reaction produces an effective administrable form of [.sup.* X]XVaraU for use in diagnosis and treatment of herpes virus infections.