Abstract: In a method of distance measuring and an optical distance measuring apparatus, a pulse-modulated infrared light beam is irradiated to an object to produce a reflected light beam, which is then received by a resonance circuit, and intensity of output of the resonance circuit is measured, wherein the modulation of frequency is sweepingly varied within a predetermined narrow frequency range; thereby, even when the circuit constants of the resonance circuit varies due to temperature change and so on, the distance measurement result is not affected, and stable measurement of a long distance is possible.

Abstract: In a radiation image recording and read-out system in which a stimulable phosphor sheet is repeatedly used for recording radiation images, and noise developing due to residual radiation energy on the phosphor sheet is eliminated by exposing the phosphor sheet to erasing light prior to radiation image recording step, the level of residual radiation energy is detected, and the amount of exposure of the phosphor sheet to erasing light is controlled according to the detected level of residual radiation energy. The exposure amount is controlled to erase residual radiation energy to a level within the range between 0.01 and 0.0001 with the maximum of the originally stored radiation energy taken as 100.

Abstract: The present invention is directed to a rotating anode x-ray source assembly which is particularly adapted for effecting high x-ray emission from a conventional x-ray source for use in replicating VLSI circuits, and comprises a rotatable anode target ring, cooling water flow channels dispose adjacent the target ring for cooling the target ring during operation, an E-beam directed to a spot on the target ring towards the periphery thereof, the cooling water flow channel being constructed and arranged so that on a transverse plane with respect to the axis of rotation all diametrically opposed points on any diameter have the same cooling water density, thereby dynamically balancing the anode under all thermal conditions.

Abstract: The internal stress state of a plate of heat tempered plate glass is tested by means of a device which uses a source of polarized monochromatic infrared radiation. This radiation passes through the glass in a point, and the variation of the polarization state is determined by means of an analyzer with the polarization axis at 90.degree. with respect to the polarizing filter.

Abstract: A method of, and apparatus for, detecting voids in or on the surface of cast metal comprises passing a substantially collimated beam of photons through the cast metal, detecting the photon flux emerging from the cast metal with a photon detector, and estimating the size and location of any void present in or on the cast metal from the standard deviation of the output of the photon detector with calculating means.

Abstract: An apparatus for reading out an image by scanning comprises a stimulating ray source, a device for scanning a stimulable phosphor sheet carrying an image stored therein by stimulating rays forwardly and backwardly in a main scanning direction, a device for scanning the stimulable phosphor sheet by the stimulating rays in a sub-scanning direction normal to the main scanning direction, and a read-out device for detecting light emitted by the stimulable phosphor sheet when it is exposed to stimulating rays. A converging lens is positioned to converge the stimulating rays, and a light shielding member is positioned at the converging point to intercept the stimulating rays during the backward scanning period. Or, an acousto-optic modulator is positioned between the stimulating ray source and the converging lens to diffract the stimulating rays and generate diffracted light components other than a zero-order diffracted light component during the backward scanning period.

Abstract: In a system for generating thermal (14 MeV) neutrons containing an ionic accelerator, a novel thermal neutron collimator for producing a beam of collimated thermal neutrons is disclosed. The apparatus includes a substantially hollow collimator tube (10) having a closed, neutron permaeable inlet portion (20) communicating with a source of thermal neutrons (12) and an open outlet portion (22) disposed downstream of the inlet portion at the opposite end of the tube. The collimator walls (14,16,18) diverge outwardly toward the outlet portion of the tube and are formed of three radial layers comprising an outer layer of thermal neutron absorbing material (26) for absorbing off-axis thermal neutrons, an intermediate layer of lead (24) for absorbing X-rays and gamma rays and an inside layer of aluminum (23) for structural support.

Abstract: A digital acquisition system for use in a computerized radiation tomography system employs track and hold means associated with each channel of the radiation detector in the tomography system. Each channel of the radiation detector is connected to a voltage follower transistor and resistor. A signal from the voltage follower transistor and resistor is applied through a Butterworth filter and amplifier to a transconductance amplifier which provides a signal for application to a charge storage capacitor. The capacitor is connected to the detector channel except during each limited period of time when the charge is held for measurement and conversion to a digital form. The data acquisition system has fewer components, and the simplicity of the circuitry increases the circuit reliability.

Abstract: In a gamma camera at least a part of an outer shell of lead and preferably also of the inner casing of steel surrounding a scintillation crystal is cut away on one side and is replaced with a flat but thinner plate of a material having better radiation absorbing characteristics, such as tungsten. In this way, the distance from the outside edge to the useful central measuring area is reduced on that side such that the camera can be rotated in the smallest possible circle around the head of a patient to perform a more complete and precise measurement on the majority of the head.

Abstract: A method of measuring the density of a first material containing a moderator of fast neutrons comprising the steps of: emitting fast neutrons into a sample having a predetermined volume confined in a predetermined shape and sensing the rate of slow neutrons emerging from the sample for each of a plurality of samples of a second material, each of the plurality of samples of the second material having a different known density and neutron moderating and absorbing characteristics that are substantially the same as the neutron moderating and absorbing characteristics of the first material; emitting fast neutrons into a sample of the first material having a predetermined volume confined in a predetermined shape; sensing the rate of slow neutrons emerging from the sample of first material; and comparing the rate sensed in the sensing of the sample of the first material with the rates sensed in the sensing of the plurality of samples of the second material to determine the density of the first material.

Abstract: A complete PGNAA bulk material analyzer is self contained in a sealed and air conditioned housing. Bulk material is channeled by an open-ended vertical chute having a one-foot-by-three-foot cross-sectional dimension through an activation region between three neutron sources and two gamma ray detectors. The sources are symmetrically disposed on one of the three-foot long sides of the chute from one end of such side to the other. The detectors are symmetrically disposed on the opposite side of the chute between positions opposing the positions of the sources on the one side of the chute. The chute is dimensioned to enable free flow of various bulk materials. It handles coal of up to a top size of four inches and with typical surface moisture contents and agglomeration characteristics. The relative disposition of the sources and detectors results in the measurements being independent of the lateral distribution of the bulk material within the chute.

Abstract: A gamma counter linearly moving two rows of linked trays each having a two-dimensional array of sample tubes. A noncantilevered crane plucks each of the tubes and carries them to the counting well. A coupling mechanism between trays allows the operator to add further trays while the instrument performs analyses on previously added sample tubes. A microprocessor in the instrument allows the operator to place into memory information for the assay contemporaneously with the addition of the new trays. Tabs on the tray interrupt photosensors on the instrument associated with the two channels of trays to properly stop the trays where the fingers on the crane can reach the rows of tubes. The fingers on the crane, when descending to grip a tube, do so off to the side of the tray to avoid contacting and possibly damaging the tops of the tubes. An internal standard of Iodine.sup.129 provides gamma particles and acts as a known sample.

Abstract: A method for correcting predictable errors in the location of detected scintillation events acquired during emission computed tomography by a rotational scintillation gamma camera system. The method includes calibrating the rotational scintillation camera system and generating a look-up table comprising a set of pairs of x and y offset values, one pair for each viewing angle. The calibration reflects systemic deviations in the location of the rotating camera head detector measured in terms of x and y coordinates in the frame of reference of the detector for a plurality of view angles relative to the geometric ideal expected path. Once a look-up table is generated for a camera system, the detected location of each gamma event is altered in real time by adjusting in the camera head the x,y coordinate location of each event by the x,y offset values previously generated for the corresponding viewing angle associated with the detected event.

Abstract: Due to aging of the insulating materials arranged between the electrodes in ionization fire alarms or detectors the insulating efficiency of these thus formed so-called insulating paths or spans deteriorates in the course of time despite, or maybe even due to the cleaning operations performed upon such ionization fire alarms. To ensure that the insulating capacity does not fall below a critical value the insulating path or span is formed by at least two different insulating materials. The materials are arranged in such a manner that the creepage path between the electrodes extends across all the different insulating materials. This principle also may be applied to other measuring devices which require a high input resistance of an amplifier stage.

Abstract: This invention relates to an image display system for a stroboscopic scanning electron microscope. In a stroboscopic scanning electron microscope having a pulse gate mechanism for chopping an electron beam and a mechanism for arbitrarily changing the phase relation between a voltage applied to a sample and the chopping, the phase change of chopping is carried out periodically and continuously and a gate circuit provided between a detector for detecting scondary electrons or deflected electrons and an image display for displaying a video signal of the secondary electron or the reflected electron to be in synchronism with the phase change allows the video signal to pass therethrough only during a certain period of phase change and to be displayed.

Abstract: Radiation detection tube having a glass envelope surrounding an anode and cathode, and having a further conductive surface surrounding a portion of the glass envelope in the region of the anode-cathode gap, the exterior conductor electrically coupled to the anode.

Abstract: An aerial natural gamma radiation survey is conducted over an exploration region. A change in the measured T1-208/K-40 ratio in the exploration region in contrast to a region known not to be hydrothermally altered identifies the exploration region as a hydrothermal alteration. A surface natural gamma radiation survey is conducted over the hydrothermally altered exploration region. A change in the T1-208/K-40 ratio at specific sites within the exploration region indicates the location of alteration products.

Abstract: A cylindrical probe for insertion into a drill hole for detecting the presence of mineral deposits. A source of radioactive irradiation and a detector are mounted concentrically within the housing of the probe, the detector being shielded from direct radiation by a wall having an upper conical surface which directs fluorescent radiation reflected from the wall of the drill hole to the detector. A disc-shaped slot concentrates the rays from the radioactive source on an area of the drill hole wall which is in the shape of a ring surrounding the probe. The concentration and close proximity of the radiation source and the detector permit precise scanning and analyzing, simply, cheaply and quickly.

Abstract: A neutron detector system is disclosed wherein a neutron charge amplifier discriminator circuit is used in conjunction with a neutron detector enabling detection of nuclear events, amplification of extremely small signals, conditioning of the signals, further amplification of the signal, discrimination of the signals, conversion into digital form and counting for a predetermined time period.

Abstract: A thermal energy imaging system includes an optical system for focusing thermal energy emanating from a scene on an array of bulk semiconductor photodetectors. The detector array outputs electrical signals representative of the impinging thermal energy, a video electronic circuit and a pseudo ac coupling circuit interconnecting the detector array and video electronic circuit for reducing the required dynamic range of the video electronic circuit. The pseudo ac coupling circuit includes first and second electrical paths to an sychronous clamp. The first path includes a switch to the synchronous clamp; the second clamp includes first and second integrator circuits and a switch; the switch is connected to the synchronous clamp. The synchronous clamp includes an amplifier, capacitor and grounded switch.