Abstract: A resolving cone-axis camera which imparts an additional translation motion to the film as the diffraction spots from the precessing crystal impinge upon the film. This translation motion is in the plane of the film and is such that a predetermined offset point on the film is caused to move along a circular path having the intersection of the crystal axis and the film plane as its center. The additional motion of the film results in a photograph having concentric annuli of given width formed by the diffraction spots from successive levels of the reciprocal lattice. The distance between the chosen offset point and the crystal axis intersection point determines the width of the annuli, and the offset point may be chosen at any point on the film which is within a circle having the crystal axis intersection point as its center and having a radius equal to the distance between the crystal axis intersection point and the beam axis intersection point.

Abstract: The present invention is directed to an improved method of measuring oxygen concentration in molten metal using the galvanic oxygen concentration cell method. It consists of providing a layer of inert gas between the cell electrolyte and the melt, this prevents contamination of the electrolyte while at the same time allows it to be in thermal and chemical equilibrium with the melt, resulting in continuous measurements of oxygen activity from which oxygen concentration may be calculated. Novel probes are disclosed which include a solid electrolyte oxygen concentration cell, a cavity for containing the inert gas adjacent the cell electrolyte to prevent contact between it and the molten metal and a thermocouple for temperature measurements.

Abstract: A double pass linear accelerator which is used in a radiation therapy unit to provide electron radiation or photon bremsstrahlung radiation when combined with an appropriate target. The accelerator operates in a standing wave mode and includes an accelerating section, a charged particle source and injection section, a microwave source operating in the S band and adapted to excite the accelerating section and a reflector system which is mounted at one end of the accelerating section to reflect a particle beam which has been accelerated due to one pass, back into the accelerating section such that it may be further accelerated. The distance between the reflector is made adjustable to provide for output particle energy variation.

Abstract: An X-ray beam flattener of predetermined symmetrical shape for attenuating the radiation intensity of the beam in decreasing amounts as the angle from the central axis increases. The symmetrical shape is made from a low Z, high density material such as Al.sub.2 O.sub.3 BeO, BeAl.sub.2 O.sub.4, B.sub.4 C or SiC. A further thin layer of high Z material may be coated on the forward end of the symmetrical shape to absorb low energy photons.

Abstract: A grain flow rate monitor has a high sensitivity for the detection of seed loss in the chaff ejected from a thresher, which may be used for monitoring heavy or light seed grains. The monitor includes an acousto-electric sensor upon which the chaff impinges to produce a wide frequency spectrum signal. This signal is passed through two or more band pass filters which are centered at predetermined frequencies. When two filters are utilized, they will each have a predetermined bandwidth, one of which is contained in the 0 to 25 kHz range and the other contained in the 25 to 100 kHz range. The filter outputs are coupled to detectors for detecting either the peak amplitudes in each band or the average amplitude. These detector amplitudes are compared in a comparator to determine whether the ratio of their magnitudes fall within a predetermined ratio range which is indicative of a seed striking the sensor.

Abstract: A fluid velocity measuring device for the accurate fast measurement of the velocity of a fluid whether liquid or gas using the time of passage of acoustic energy through the fluid as the frequency determining element in a continuous wave oscillator. The frequencies or periods of oscillations of two anti-parallel acoustic paths are used to compute fluid velocity between the electro-acoustic transducers at the ends of the acoustic paths. The device in accordance with this invention may utilize a single reversing acoustic path or two anti-parallel acoustic paths. The velocity resolution can be selected by the operator in accordance with a stated uncertainty principle limiting the ratio of frequency response to velocity resolution. Mode ambiguities due to fluid phase velocity variations are avoided by varying the path lengths. The frequency range of the oscillator is limited by a phase locked loop.

Abstract: A target for converting kinetic energy of a beam of high energy electrons into bremsstrahlung radiation in the forward direction which consists of a first layer of high or medium Z material that converts the electron energy to bremsstrahlung, a second layer of low Z material that is positioned in the forward direction with respect to the first layer and stops electrons which are transmitted through the first layer, and a third layer of high Z material that is positioned in the forward direction with respect to the second layer and absorbs low-energy photons. The first layer which is of uniform thickness, may be optimized to produce a maximum photon intensity at any desired angle including 0.degree.. The second layer need not be uniform, however has a minimum thickness to stop all electrons. The third layer may be approximately 0.06 g/cm.sup.2.

Abstract: A radiant energy integrating meter having one or more parallel connected reversed biased radiant energy sensor cells connected to an integrating circuit having an integrating capacitor. A trigger circuit having a differential amplifier, connected to the integrating capacitor, which drives a further amplifier, is adapted to close a first switch such as a silicon controlled rectifier in response to a predetermined integrated sensor current. A counter circuit is coupled to the first switch and advances by one each time the first switch is closed. A second switch such as a relay is coupled to the first switch to provide a discharge path for the integrating capacitor. Finally, a delay circuit is coupled across the first switch to open the first switch after a predetermined time delay.

Abstract: This invention is directed to an electro-optical apparatus for determining the position of an opaque surface without contact with the surface. It includes a light beam system which projects a well defined beam having a rectangular cross-section, obliquely onto the surface such that any movement of the surface in the perpendicular direction will result in a displacement of the illuminated area on the surface, and a detector which converts this displacement into a proportional light intensity. The detector has a field stop with an aperture of specific shape onto which the illuminated area is imaged such that only a portion of the image will pass through the aperture depending on the displacement of the illuminated area. A photosensitive device is used to measure the light intensity passing through the aperture.

Abstract: The magnetic beam deflector system of this invention consists of two identical mirror image sections positioned about a symmetry plane. The sections are energized such that the zeroth order beam path through one section is a mirror image of the beam path through the other section resulting in a beam exit axis which is symmetrically located on one side of the symmetry plane with respect to the entry axis on the other side. In a 180.degree. deflector system, the entry and exit axes are coincident and lie in the symmetry plane. The preferred embodiment consists of four dipole magnets, forming a 180.degree. deflector system symmetrical about a symmetry plane in which the zeroth order beam path is defined by:.theta..sub.2 = .theta..sub.1 + .theta..sub.3 + 90.degree. and ##EQU1## WHERE .theta..sub.1, .theta..sub.2 AND .theta..sub.3 ARE THE BENDING ANGLES OF THE FIRST, SECOND AND FOURTH, AND THIRD MAGNETS RESPECTIVELY, .rho..sub.1, .rho..sub.2 AND .rho..sub.

Abstract: In the 2.pi./3 standing wave mode of energizing resonant cavities, a regular field pattern is set up between adjacent cavities which follows the sequence + (or -), - (or +) and zero. In the novel system of this invention, two series of cavities are used to form accelerating sections wherein the standing wave is propagated successively from one section to the other such that adjacent cavities in each of the sections have positive and negative fields and the resonant coupling cells between the sections have zero fields. This system is used in the acceleration of two beams by a single driving source or in a double track race-track microtron.

Abstract: Eddy-current inspection for cracks, flaws, etc, in rails, rods, etc. is conventional. For ferromagnetic material structures, it is found to be advantageous to magnetically saturate the material during inspection. The inventive eddy current probe facilitates the inspection of ferromagnetic tubing by saturating the tubing from within and only in the region of the test coils. Inspection may therefore be carried out on tubing which is installed in systems such as steam generators. The probe includes a bobbin on which test coils are wound. The bobbin may consist of a permanent magnet having a field of sufficient stength to provide the necessary magnetic saturation, or the field may be supplemented by driving a direct current through one or more of the coils. In a third embodiment, the bobbin may be made from high .mu. material and the entire saturating field is provided by driving a direct current either through the test coils or through additional dc bias coils located on the bobbin.

Abstract: A novel method and apparatus for monitoring an isolated system for ground faults which provides greater sensitivity and accuracy and at the same time does not provide a detector hazard index which would add to the fault hazard index. The monitor connects one of the lines in the isolated system to ground through a non-linear detector. The detector allows current below a predetermined level to flow freely to ground and prevents current which is above a predetermined level from flowing to ground. This is achieved by immediately disconnecting the line in question from ground, by limiting the amplitude of the ground current to the predetermined level, or both. This predetermined current level sensed may be adjusted by the operator. In addition, the monitor includes an alarm circuit which indicates the existence of an unacceptable ground fault in the isolated system.

Abstract: A two reference cavity structure for tracking the frequency of a high power liquid cooled cavity structure, consisting of two low power cavities tuned to frequencies slightly above and slightly below the resonant frequency of the high power structure. Each of the cavities has a first and a second section, with the first sections maintained at a first temperature and the second sections maintained at a second temperature such that the reference cavities track the frequency shifts in the high power structure caused by temperature differentials between regions of that high power structure. The first section of each reference cavity may have a cylindrical outer wall and a first end wall whose temperature is governed by the temperature of the liquid coolant before it enters the high power structure.