Abstract: Dual-beam comparison of gas absorption characteristics in which a single source and single detector of radiant energy and single chopper disc are used in sample gas and reference gas paths. Ambient atmosphere or gas directed through a sample gas chamber can be analyzed. Multiple gas analyses, of a plurality of gases or a plurality of constituents of a gas, can be performed simultaneously utilizing the single chopper disc with a plurality of optical gas assemblies. Each such assembly includes a single source of radiant energy, means for directing the radiant energy along sample and reference gas paths to a single detector for such radiant energy. The multiple units are mounted so that the single chopper disc cyclically interrupts radiant energy in the respective sample and reference gas paths in predetermined phase relationship. The combined sample gas and reference gas path response of the single detector for each gas analyzing unit is directed to phase-sensitive signal-separation circuit means.

Abstract: A generally tubular shroud of rectangular cross-section having flat side walls formed by inner and outer tubes of rectangular cross-section spaced apart to provide a substantially uniform space therebetween, a flat aluminum-boron carbide sandwich received in and substantially filling the spaces at the four sides of the shroud. The inner and outer tube walls are in pressure contact with the inner and outer surfaces of the sandwiches. The side walls of the tube and sandwiches are interlocked by transversely extending elongated channels formed in the shroud walls including the inner and outer tube walls and the sandwiches. The invention includes a method in which after assembly, the parts are expanded in a die by very high pressure hydraulic pressure by means of a flexible bag, establishing the pressure contact and suitably folding end portions of the inner and outer tubes.

Abstract: An apparatus for the safe storage of a plurality of fissionable masses including an array of discrete neutron absorbing shields which utilizes the principle of the neutron trap to reduce the multiplication factor of the storage array to a subcritical value when immersed in a neutron moderating medium. Each discrete neutron absorbing shield is designed to perimetrically encircle each of the stored fissionable masses. Each shield is spaced such that the encircled fissionable mass is spaced from the next adjacent neutron absorbing shield by a distance determined by the enrichment of the fissionable masses and attenuation of the moderating medium.

Abstract: A beam of electrically charged particles for illuminating a specimen is deflected by a deflection means so that the specimen is scanned with the beam bi-dimensionally. The information signal thus produced by the specimen is detected by a detector means and fed to a display apparatus incorporating therein another deflection means. The information signal is deflected by the latter deflection means to scan the display screen and is displayed thereon as an information image. A wave form of a signal produced in the latter deflection means is detected by a wave form detector means, the output of which is applied to the first mentioned deflection means to thereby deflect the electrically charged particle beam with a signal having a wave form similar to the detected one.

Abstract: A borehole logging tool includes a source of fast neutrons and two thermal neutron detectors. A count rate meter is connected to each thermal neutron detector. A ratio detector provides a first signal indicative of the ratio of the count rates of the two thermal neutron detectors. A first comparator provides a signal indicative predominantly of the macroscopic absorption cross section of the formation by combining both such ratio signal and the count rate from one of the thermal neutron detectors. A second comparator provides a signal indicative predominantly of the porosity of the formation by combining both such ratio signal and such macroscopic absorption cross-section signal.

Abstract: A flux of neutrons is measured by disposing a detector in the flux and applying electronic correlation techniques to discriminate between the electrical signals generated by the neutron detector and the unwanted interfering electrical signals generated by the incidence of a neutron flux upon the cables connecting the detector to the electronic measuring equipment at a remote location.

Abstract: A data analyzing system for scintillation spectrometers of the type for measuring activity levels of samples containing radioactive isotopes and subjected to varying degrees of quench, including methods and apparatus for optimizing counting conditions and thereby improving statistical counting validity irrespective of the degree of quenching present in any given sample, and wherein a measured parameter indicative of the effective quench condition of each sample is utilized to automatically adjust, by preselected preset amounts, the counting window for any given isotope relative to the observed energy spectrum for that isotope. Various methods and apparatus are described which, although suitable for optimizing counting conditions for both multiple-labeled and single-labeled test samples, are particularly effective in creating significantly improved isotope separations when dealing with multiple-labeled samples -- for example, a double-labeled sample containing tritium (.sup.3 H) and carbon-14 (.sup.14 C).

Abstract: In an optic relay device having a memory the image to be treated is projected on a photoconductive element and is transformed into a charge image stored in a memory in the proximity of a plate of electro-optical material brought at its Curie point.The electro-optical material and the photoconductive element are such that the Curie temperature of the electro-optical material is near the temperature of the maximum sensitivity of the photoconductor.

Abstract: A radioactive source of heat which is resistant to cremation conditions is made by encapsulating a radioisotope within a containment vessel and forming a refractory metal silicide diffusion coating exterior thereof. A secondary molybdenum vessel may be provided with a molybdenum silicide coating and then heated in air to oxidize its outer layer. A layer is applied exterior of the diffusion-coating which provides a continuous ceramic oxide layer upon subjection to cremation. This outer layer may be discrete silica carried in a hardenable binder of an organic polymer, and a minor amount of antimony is preferably also included.

Abstract: A sample conveyor for a liquid scintillation spectrometer or gamma counting system comprises a plurality of cassette carriers and a mechanism for moving the carriers step by step along a closed path which includes a transfer station. Each carrier has an open bottom and may receive a cassette whose bottom wall consists of lips which may be opened by a mechanism when the corresponding location is at the transfer station.

Abstract: An improved system is described for providing approximately equalized illumination at all points between first and second opposite portions of a total internally reflecting cell. The system comprises in addition to the cell, a source of radiation of at least one selected wavelength, means for directing the radiation along a plurality of paths, and means for introducing the radiation in at least two of the paths into first and second opposite portions of the cell. Means can be provided for varying the penetration angle of the radiation into the cell.

Abstract: An optical measuring system is described for automatically operating an electrometer. A binant electrometer is employed with a quartz fiber mounted at one end but free to vibrate at the other in an AC field. The fiber oscillates if a charge is placed upon it. An optical slit replaces the ordinary eyepiece reticule scale. With the quartz fiber adjusted so its image is in focus at the optical slit, photoelectric signals are obtained at null charge on the fiber. The quartz fiber is repeatedly charged and allowed to discharge by collecting ions from a source under measurement. Each photoelectric signal causes a digital time reading to be taken. The time readings are used to evaluate the current due to the collected charge. The photoelectric signals, by feedback, also operate the electrometer for continuous or intermittent-continuous operation. Basically the system is a current digitizer. The method is applied to the measurement of force in other types of fields.

Abstract: Apparatus is described for performing a computerized axial tomographic examination of a body. The apparatus contains a source of x-radiation and detector devices mounted to face one another across an opening for the body, the source being arranged to project said radiation in a plane towards the detector devices. The source and detector devices are rotated about an axis passing through said opening and means are disclosed for locating the body in said opening and for adapting the apparatus to accommodate a body which is not centrally located in said opening.

Abstract: A rotary pulse transducer includes a housing having a pair of halves of similar dimensions. An annular photoelectric stator formed from a plastic sheet is employed as a sealing gasket between the halves of the transducer housing. During assembly of the transducer, the stator may be easily moved relative to the housing for alignment purposes by grasping exterior portions of the stator.

Abstract: A flexible light guide of the liquid filled type is provided with a liquid supply container outside the light guide.

Abstract: A rig for high-temperature testing of specimens subjected to gamma radiation in a nuclear reactor comprises two coaxial casings having cylindrical side walls. The inner casing which contains the specimen is supplied with an environment gas while the annular gap between the two casings is supplied with a gas having variable thermal conductivity. The casings have convex frusto-conical top and bottom walls joined together in pairs at a short and constant distance. The frusto-conical top wall of the outer casing is connected to its cylindrical side wall by means of a thermal expansion bellows seal.

Abstract: A fiberoptic fluid level sensing mechanism is provided which is operable for performing fluid level sensing as applied particularly to a mixing and dispensing device. The mechanism embodies light projecting means supported in the device so as to be positionable in juxtaposed relation to an external light source and operable to project the light rays received from the light source towards the exposed end of the fiberoptic rod. Photoelectric means is supported in juxtaposed relation to the opposite end of the shaft, and more particularly the other end of the fiberoptic bundle. In accord with the mode of operation of the mechanism, light rays from the external light source are projected through the light projecting means into the interior of the mixing chamber wherein they are operable to light the latter. As the opaque material in the chamber is dispensed, the level thereof decreases until the exposed end of the fiberoptic bundle is rendered visible.

Abstract: The present invention relates to a method of and apparatus for the radionuclide imaging of the whole body of a patient using an unmodified scintillation camera which permits a patient to be continuously moved under or over the stationary camera face along one axis at a time, parallel passes being made to increase the dimension of the other axis. The system includes a unique electrical circuit which makes it possible to digitally generate new matrix coordinates by summing the coordinates of a first fixed reference frame and the coordinates of a second moving reference frame.

Abstract: This invention provides a target jet for charged particles. In one embodiment the charged particles are high energy deuterons that bombard the target jet to produce high intensity, high energy neutrons. To this end, deuterons in a vacuum container bombard an endlessly circulating, free-falling, sheet-shaped, copiously flowing, liquid lithium jet that gushes by gravity from a rectangular cross-section vent on the inside of the container means to form a moving web in contact with the inside wall of the vacuum container. The neutrons are produced via break-up of the beam in the target by stripping, spallation and compound nuclear reactions in which the projectiles (deuterons) interact with the target (Li) to produce excited nuclei, which then "boil off" or evaporate a neutron.

Abstract: A pyroelectric radiation detector which is relatively immune to the effects of microphonic vibrations includes within an evacuated envelope a triglycine sulphate (TGS) target secured by silicone grease to a thin (3-6 .mu.M) mica support plate. The mica support plate is adhesively secured by means of an enamel to a titanium annulus which, in turn, is epoxied to the window of the evacuated envelope. The coefficients of expansion of the annulus and the support plate are selected such that after they are joined on to the other the support plate is stretched tightly across the annulus and therefore has a natural period substantially higher than the natural period of the annulus which supports it.