Showing papers by "Varian Associates published in 1969"

Quantitative interpretation of transient electromagnetic fields over a layered half space

Abstract: The transient fields from a finite horizontal loop excited by a half sine wave current pulse have been computed numerically for a particular source receiver configuration at a height of 100 meters above a layered ground. The amplitude of the vertical component of the magnetic field has been chosen for the interpretation. Curves of apparent conductivity vs. time, plotted during the off-time of the signal, show that layering is easily resolved, that resonance effects are present and that polarization effects are detectable for certain types of polarization.

Support structure for electron accelerator with deflecting means and target and cooperating patient support

Abstract: Improved linear accelerator apparatus for directing ionizing radiation on an object is realized by utilization of a horizontal axis of rotation about which the linear accelerator axis rotates while the accelerator axis maintains a horizontal spatial orientation at different circumferential points of rotation in conjunction with beam deflection means disposed at the downstream end portion of the accelerator which produce beam deflection along an axis different than the accelerator axis and preferably substantially 90* with respect thereto.

Microwave applicator employing flat multimode cavity for treating webs

Abstract: A microwave applicator is disclosed. The applicator includes a flat multimode cavity having openings on opposite sides thereof for passing therethrough a web of material to be treated with microwave energy. The cavity is both designed and fed so as to be excited at its operating frequency only in those TEl, m,n and TMl, m,n classes of modes such that the value of l is limited to 1 and m or n or both have a value greater than zero (preferably both m and n have a range of values which includes 10) and such that the E-vector of the microwave energy lies generally in the plane of the treatment zone and has maximum intensity in the treatment zone. The flat multimode cavity resonator is fabricated in two half sections an upper half and a lower half which are joined together at their edges. A mode-damping means is provided for attenuating a certain undesired class of modes that could otherwise be supported within the cavity. Air ducts are provided at opposite ends of the resonator for directing air either parallel or antiparallel to the direction of movement of the web to be treated.

High efficiency klystron amplifier

Abstract: A klystron amplifier yielding above 65 percent efficiency at the 100 kW power level at a frequency of 800 MHz will be described. The high efficiency is obtained by using a novel combination of second harmonic and fundamental frequency cavities in the buncher system.

ENDOR of biradicals: A chemical solution to the biradical paradox

Abstract: The ENDOR spectra of Tschitschibabin's hydrocarbon and certain of its specifically deuterated derivatives have been measured. To interpret these spectra the factors determining the ENDOR spectrum of a biradical are discussed in detail. The analysis reveals that the paramagnetic species present in solutions of Tschitschibabin's hydrocarbon and responsible for the solution electron resonance spectrum is a substituted p-biphenyldiphenylmethyl radical, thus resolving the biradical paradox. The substituent is thought to be the diphenylmethyl group in which case the radical could be formed through hydrogen abstraction by a thermally populated triplet.

Linear beam tube with plural cathode beamlets providing a convergent electron stream

Abstract: A gridded electron gun for linear beam tubes is disclosed The electron gun includes a concave cathode emitter formed by a mosaic of a multitude of lesser cathode emitting surfaces The lesser cathode emitting surfaces are concave with a radius of curvature substantially less than the radius of curvature of the composite cathode emitter A multiapertured control grid is closely spaced to and shaped to conform to the concave surface of the cathode emitter The apertures in the control grid are in alignment with the individual ones of the cathode emitting surfaces to produce a multitude of convergent beamlets passing through the apertures in the grid in a substantially nonintercepting manner The beamlets converge together into a confluent electron stream passing through a central aperture in an accelerating anode to form a unitary electron beam for a linear beam tube The control grid may have a Mu of between 20 and 100 and provide grid interception of less than 02 percent of the beam current In a dispenser cathode a second grid, which is essentially identical to the control grid, is incorporated in or on the surface of the cathode either in contacting or noncontacting relation therewith

Paramagnetic Unit in Spinach Subchloroplast Particles: Estimation of Size

Abstract: A pulsed ruby laser (wavelength, 694.3 nanometers) was used to measure the dependence on light intensity of light-induced electron paramagnetic resonance (ERR) signal 1 for short flashes of uniform duration (400 microseconds). Approximately 10(18) photons per square centimeter per flash from the unattenuated beam were available to the sample of subchloroplast "system 1" particles from spinach. The experimental dependence of the EPR signal height plotted as a function of the total number of incident photons per flash was exponential. From measurement of the slope at a very low relative photon flux and the saturated EPR signal amplitude, the value for the cross section or "effective size" of the light-induced paramagnetic unit, sigma(EPR), was found to be 300 x 10(-17) square centimeter. This result is compared with a measured optical absorption cross section, sigma(694nm), of 2.5 x 10(-17) square centimeter, for the identical sample at the laser wavelength. The hundredfold difference in size supports the thesis that the paramagnetic state is a property of an aggregate of chlorophyll molecules of the same general size as the photosynthetic unit.

High-power microwave excited plasma discharge lamp

Abstract: A high-power microwave plasma discharge lamp is disclosed. The lamp includes a ceramic tube filled with gas and closed at one end by a window transparent to the optical radiation output of the lamp. The ceramic tube extends through a cavity resonator excited with microwave energy for exciting a plasma discharge within the lamp.

Scintillation Processes in Thin Films of CsI(Na) and CsI(Tl) due to Low Energy X-rays, Electrons and Protons

Abstract: Publisher Summary This chapter focuses on scintillation processes in thin films of CsI(Na) and CsI(Tl) because of low energy x-rays, electrons, and protons. The use of CsI(Na) and CsI(T1) as scintillator materials of high efficiency for charged and uncharged particles has been reported in the past. Usually, this work has been performed on bulk samples. This chapter reports for the first time measurements made on thin films of these materials varying in thickness from 5000 Ǻ to 0.25 mm, deposited on glass, aluminum, and plastic substrates. The host crystal (CsI) is transparent to the impurity emission for both the thallium-activated material and the sodium-activated material, having an absorption edge at 2000 Ǻ so that self-absorption is small and thus the luminescent efficiencies are determined solely by the processes of excitation and emission. The experimental results obtained demonstrate that it has been possible to produce thin films of CsI(Na) and CsI(Tl) which fluoresce with the same efficiency as the bulk materials. The ease with which these materials may be prepared in thin film form and their ability to perform satisfactorily in various environments suggests a wide range of applications in photoelectronic devices.

Complex motion mechanism for thin film coating apparatuses

Abstract: Apparatus is described for providing complex rotation about three axes of a plurality of objects being coated by deposition. The apparatus includes a frame adapted to be supported within a conventional deposition coating chamber having a source providing within the chamber an atmosphere of molecularly-sized particles of the desired coating material. A substrate holding disc having a face to which a plurality of substrate objects can be secured is mounted to the frame for rotation with the face in line-ofsight of the material source. The disc is mounted to the frame for orbiting about an axis which extends toward the source and rotation about its own axis. Each of the substrate object supporting members on the face of the disc is rotatably mounted thereon for rotation of the surface of the object to be coated about an axis which is oblique to the source. A prime mover is provided causing rotation about the various axes during the coating operation with the result that the surfaces being coated of the substrate objects will receive a uniform coating irrespective of irregularities in such surfaces.

Substrate Bombardment During RF Sputtering

Abstract: It is shown, that for the conditions relevant to the “peak” type of rf sputtering arrangement, and in fact most rf sputtering devices, that ions are essentially unaware of the existence of the rf fields and respond only to the dc fields generated. This enables the sputtering parameters to be viewed in a simple, physical way and calculations based on this approach are shown to be fairly exact. A deduction from the theory is that the majority of the secondary electrons released by ion bombardment of the target plates strike the substrate table with considerable energy. A special gridded probe in the substrate table enabled the simple theory to be verified quantitatively and also verified the existence of the high-energy electrons. By controlling substrate bombardment during sputtering with another grid arrangement, the effects of this high-energy electron bombardment on film adherence and appearance was demonstrated.

Magnetic field homogenizing coil sets having spatial independence and spectrometer means using same

Abstract: MAGNETIC FIELD HOMOGENIZING COIL SETS ARE PROVIDED WHEREIN EACH COIL SET DEFINES A GEOMETRICAL CONFIGURATION OF CURRENT PATHS TO BE ENERGIZED TO PRODUCE SEPARATE ASYMMETRIC DISTRIBUTIONS OF CURRENT RELATIVE TO A CERTAIN REGION OF MAGNETIC FIELD TO BE CORRECTED. THESE ASYMMETRIC DISTRIBUTIONS OF CURRENT PRODUCE SEPARATE HOMOGENIZING MAGNETIC FIELD GRADIENT COMPONENTS WHICH ARE SUBSTANTIALLY CONFINED TO SEPARATE PORTIONS OF THE REGION OF FIELD TO BE CORRECTED FOR CANCELLING CERTAIN RESIDUAL MAGNETIC FIELD INHOMOGENEITIES IN THE SEPARATE PORTIONS OF THE FIELD TO BE CORRECTED. IN THIS MANNER, THE FIELD HOMOGENIZING GRADIENT COMPONENTS ARE SPATIALLY INDEPENDENT TO PREVENT MUTUAL INTERFERENCE OF THEIR ADJUSTMENT AND WHEREBY THE ADJUSTMENTS PRODUCE UNAMBIGUOUS CORRECTIONS OF THE FIELD WHEN SENSED BY GUROMAGNETIC RESONANCE OF A SAMPLE WITHIN THE REGION OF FIELD BEING CORRECTED.

Phase correlation for an rf spectrometer employing an rf carrier modulated by a pseudorandom sequence

Abstract: The radio frequency spectrometer is disclosed employing a radio frequency transmitter which transmits a wide band of energy to the sample for simultaneously exciting radio frequency resonance of different spectral lines of the sample. The wide band transmitter energy is generated by a radio frequency carrier which is modulated by a pseudorandom binary sequence to produce the wide bandwidth for exciting the sample. The pseudorandom binary sequence is repetitive and the excited composite resonance signal is repetitively time scanned and sampled at a multiplicity of intervals during each scan. The sampled data derived from repetitive scans are digitized and sequentially stored and added in their respective channels of a storage unit to produce a time average for improving the signal noise ration. The pseudorandom binary sequence is synchronized with the time scan of the composite resonance signal to preserve the phase relation between successively sampled and stored data from successive scans, whereby either pure absorption or pure dispersion mode resonance data is obtained.

Electrographic writing head of plural printed circuit construction

Abstract: An electrographic writing head is disclosed which employs a plurality of elongated flexible printed circuit boards each supporting thereon a portion of an array of closely spaced electrographic styli. Each circuit board is tapered from a wide end to a relatively narrow end. The narrow ends of the boards are arranged in side-by-side coplanar relation to define the exposed styli electrodes, whereas the wide ends of the boards contain the terminals for connecting to electrical connector assemblies, such wide ends being arranged in noncoplanar overlapping relation to accommodate connector assemblies.

Leak detection cyclic pumping control

Abstract: MASS SPECTROMETER LEAK DETECTOR (OR VACUUM APPARATUS) GENERALLY CONTROLLED IN ITS PUMPING CYCLES BY SOLENOID OPERATED ROUGHING AND ISOLATION VALVES AND UTILIZING ROUGHING LINE SUCTION FOR EFFECTIVE OPERATION OF THE ROUGHING VALVE IN OPENING AND SEALING. THE ROUGHING VALVE IS ALSO USED FOR TEST PORT AIR RELEASE IN CONJUNCTION WITH SEALING OF THE ROUGHING VALVE PER SE. AUTOMATIC, PRESSURERESPONSIVE, CONTROL OF THE SYSTEM IS PROVIDED TO ALLOW COMPLETE CONTROL OF PUMP-DOWN, TEST AIR RELEASE AND STAND-BY PHASES OF A SINGLE CYCLE USING A SINGLE ELECTRICAL SWITCH.

Microwave applicator employing a broadside radiator in a conductive enclosure

Abstract: A microwave applicator for treating material with microwave energy is disclosed. The applicator includes a relatively large conductive enclosure containing a large broadside microwave radiating antenna disposed for directing the radiated microwave energy onto the load of lossy material for treating same. The applicator is particularly useful for treating relatively large amounts of lossy material.

Method and apparatus for producing halftone electrographic prints

Abstract: Method and apparatus are disclosed for producing halftone electrographic prints from continuous tone charge image patterns deposited on the charge-retentive surface of an electrographic recording medium. The continuous tone image patterns are developed in the halftone rendition by developing the charge image pattern in the presence of a closely spaced development electrode having a development surface, facing the charge image pattern to be developed, constituted of an array of projections in the form of a halftone screen pattern. The projections concentrate the electric field over the surface of the continuous tone charge image pattern into a halftone image pattern which is developed by the pigment particles of the electroscopic ink used for developing the charge image patterns.

High-speed coincident pulse electrographic printer with gray scale printing capability

Abstract: The printer includes an array of electrographic styli electrodes disposed overlaying a backup electrode. An electrographic recording web is passed between the styli and the backup electrode. The recording web comprises a dielectric charge retention film facing the styli, such film being supported on a conductive paper backing which makes electrical contact with the backup electrode. A pulsed first writing potential is produced across the styli and the backup electrode, such first pulsed potential having a pulse amplitude and duration which is less than that which is sufficient to deposit a charge image on the recording medium but which has an amplitude and/or duration which varies in variable accordance with the density of the incremental charge image to be printed by a selective one of the styli on the recording web. A second pulsed potential is applied across the selected one of the styli and the backup electrode, such second pulsed potential being of generally invariant amplitude and/or duration and which, by itself, is insufficient to produce a charge image on the recording medium but which when combined with the first potential produces a total pulsed voltage of an amplitude and/or duration sufficient to deposit an incremental charge image on the recording medium, such deposited charge image having an average charge density in accordance with the density of the image to be printed to produce a gray scale printing capability.

Vacuum connector for connecting replaceable evacuated devices to an evacuated system

Abstract: A vacuum connector is disclosed for connecting secondary replaceable evacuated devices to a primary evacuated system without contamination of the primary system. A gas passageway is connected to the primary evacuated system. A valve spring loaded to the normally closed position, is provided in the gas passageway closing same. The secondary evacuated structure, to be connected to the primary evacuated system, is sealed by means of a diaphragm. An O-ring seal is provided for sealing the secondary replaceable evacuated structure to the wall of the gas passageway. A cutting tool is provided in the gas passageway between the valve and the diaphragm for cutting the diaphragm, thereby opening same. The cutting tool also engages the valve for opening the valve against the spring bias to place the secondary evacuated structure into gas communication with the primary evacuated system through the valve. Removal of the secondary evacuated structure causes the spring bias force to close the valve, thereby sealing the primary evacuated system for subsequent connection to a second replaceable secondary evacuated device.

Method and apparatus for ensemble averaging repetitive signals

Abstract: A spectrometer or similar device is scanned repetitively to produce a series of repetitive output signals either of analog or digital form. Each output signal includes an ensemble of timedisplaced components and is identical to the other output signals except for noise. The series of output signals is ensemble averaged (time averaged) by an ensambled-averaging digital computer which scans each output signal of the series and samples each output signal at a plurality of sampling points at the same relative position in each output ensemble. Digital data for each sampling point is accumulated in a separate channel of the memory to improve the signal-to-noise ratio. An extra bit is added into the sampled data for each sampling point, such added bit being less than the least significant bit to be stored in the memory. The accumulation of added bits of each sampling point, over a series of scans, adds to zero to some number which is the same for each sampling point, whereby the digitization error is reduced.