Showing papers on "Angular aperture published in 1977"
TL;DR: Several different axisymmetric aperture shapes have been studied, experimentally and theoretically, for use in the plasma electrode employed in extracting ions from a plasma, and the minimum half-width-half-maximum divergence obtained for the former class was 0.57° at a beam energy of 27 kV, as compared to 1° obtained for a conventional cylindrical bore aperture as mentioned in this paper.
Abstract: Several different axisymmetric aperture shapes have been studied, experimentally and theoretically, for use in the plasma electrode employed in extracting ions from a plasma. Compared to a cylindrical bore aperture, a class of shapes opening away from the source plasma resulted in smaller beam divergence (due to reduced aberration fields), while a class opening toward the source plasma resulted in higher beam power density at optimum divergence. The minimum half‐width‐half‐maximum divergence obtained for the former class was 0.57° at a beam energy of 27 kV, as compared to 1° obtained for a conventional cylindrical bore aperture.
49 citations
TL;DR: In this article, the performance of four-element electrostatic lenses as retarding systems between source and analyzer in ESCA spectrometers is calculated, and the potential distribution in the lens is defined by an axial potential of the type (ϕ(z) = Vo + Σ(Vi - Vi- 1)/2 · tanh (ω/ai (z - zi)).
39 citations
Patent•
22 Mar 1977TL;DR: A post-focusing type color cathode ray tube comprising a quadrupole lens formed in each aperture of the color selection mask is described in this paper, which is a post focusing type of color ray tube.
Abstract: A post-focusing type color cathode ray tube comprising a quadrupole lens formed in each aperture of the color selection mask.
22 citations
CERN1
TL;DR: In this article, a large-aperture X-ray imaging chamber is described, where the position of a photoelectron is measured in a proportional chamber with an accuracy of 0.8 mm in all coordinates.
17 citations
Patent•
06 Jun 1977
TL;DR: In this paper, a lens meter for analyzing suspect lenses in terms of sphere, cylinder and axis by optical beam deflection and without relatively moving optical parts is disclosed, and the power of the suspect lens can be measured by algebraic summing of the resultant angular deviations.
Abstract: A lens meter for analyzing suspect lenses in terms of sphere, cylinder and axis by optical beam deflection and without relatively moving optical parts is disclosed. A light source emanating a substantially collimated beam of light from an entrant aperture into a retroreflecting mechanism includes two important properties. The first property is that an image of the entrant aperture is displayed from and reimaged across the optical axis of the retroreflector to a conjugate location at a real image exit aperture, this aperture being provided with a coincident optical stop. Secondly, in the absence of a test lens in the light path, light entrant to the retroreflector through the entrant aperture along a first path departs the real image of the exist aperture along a second path with a known angularity to the first path. Assuming that a suspect lens containing components of sphere and cylinder is interposed to the entrant and exit aperture, this angular deviation changes across the lens sampling entrant-exit aperture base leg. Specifically, the changed angular deviation is a function of sphere and cylinder present in the suspect lens. By algebraic summing of the resultant angular deviations, the power of the suspect lens can be measured in sphere, cylinder and axis either by notation in sphere and cross-cylinder components or by more conventional sphere, cylinder and axis notation. Provision is easily made to detect prism.
13 citations
TL;DR: In this paper, the authors describe a phase conjugate adaptive optics system which avoids the use of a shared aperture and the attendant difficulties when such a system is used with a high-power laser.
Abstract: We describe a concept for a phase conjugate adaptive optics system which avoids the use of a shared aperture and the attendant difficulties when such a system is used with a high-power laser. The concept consists of measuring the phase of a reference wave around the edge of the aperture and interpolating with a suitable formula to find the phase inside the aperture. We assess the potential of this technique to compensate for atmospheric turbulence when the transmitting aperture is circular or annular. Good correction is indicated, particularly for the case of an annular aperture where perimeter phase measurements can give an estimate of the amount of turbulence-induced misfocus.
8 citations
TL;DR: In this article, the penetration of an electromagnetic wave through an aperture in a cylindrical structure is investigated by using the moment method, and the electrical and magnetic fields in a cavity behind the aperture are determined as a function of frequency of the incident field.
Abstract: The penetration of an electromagnetic wave through an aperture in a cylindrical structure is investigated. By using the moment method, the electrical and magnetic fields in a cavity behind the aperture are determined as a function of frequency of the incident field. The accuracy of the numerical solution is established through tests of satisfaction of the boundary condition, edge condition, and convergence with respect to the number of modes in the aperture. Depending on the frequency and location inside the cavity, the stored electromagnetic energy density varies very rapidly. Its peak value can be two orders of magnitude greater than the incident energy density. The frequencies where the peaks occur can be identified approximately as the resonance frequencies of the cavity when the aperture is closed.
7 citations
Patent•
09 Dec 1977
TL;DR: In this article, an obscuration means is placed between the sample volume and a light collecting means (such as a lens or mirror) to limit the backscattered light collection passed through an aperture to a shorter length along the optical axis.
Abstract: In an optical system, primarily adapted for use in light scattering diagnostics e.g. Raman, Rayleigh, laser fluorescence, an obscuration means is placed between the sample volume (or object) and a light collecting means (such as a lens or mirror) to limit the backscattered light collection passed through an aperture to a shorter length along the optical axis, thereby increasing the spatial resolution of the system. In general, the effective obscuring diameter is determined as twice the ratio of the square of the distance between the image of the aperture within the sample volume and the collection means to the distance between the collection means and the aperture, times the ratio of the aperture diameter to the desired length of sample volume. In refractive embodiments, obscuration is provided by an opaque disc adjacent a collection lens. In a second embodiment, obscuration is provided by a coaxial arrangement of independent fiber optical light pipes. In a third embodiment, Cassegrainian-type reflection optics are used.
7 citations
Patent•
26 May 1977
TL;DR: In this paper, the angular aperture of the film was increased by making the end face of the fiber sloping, which made it possible to measure the microscopic displacement by higher precision.
Abstract: PURPOSE:To make it possible to measure the microscopic displacement by higher precision, by substantially increasing the angular aperture of the film and makign the distance to provide the maximum output small by making the end face of the fiber sloping.
6 citations
TL;DR: The weighted-ordinate method of colorimetry is applied to Fresnel diffraction of white light by a circular aperture to determine the dominant wavelength, purity, and relative luminance of the center of the diffraction pattern.
Abstract: The weighted-ordinate method of colorimetry is applied to Fresnel diffraction of white light by a circular aperture to determine the dominant wavelength, purity, and relative luminance of the center of the diffraction pattern This chromaticity information is compared to experimental results and graphs are included to allow easy determination of these quantities for most combinations of aperture radius, source distance, and observation distance that would be of interest
CERN1
TL;DR: A large-aperture X-ray imaging chamber is described and the photoelectron's position is measured in a proportional chamber of 50 × 50 cm2, with an accuracy of 0.8 mm in all coordinates.
Abstract: A large-aperture X-ray imaging chamber is described. Angular aperture: 90°. Thickness of spherical absorbing drift space: 10 cm. The photoelectron's position is measured in a proportional chamber of 50 × 50 cm2, with an accuracy of 0.8 mm (FWHM) in all coordinates.
Patent•
25 Apr 1977
TL;DR: In this paper, a large-aperture ultra-wide angle photographic lens system which is compatible with filters designed for use with other lens systems and wherein various aberrations are favorably corrected is presented.
Abstract: A large-aperture ultra-wide angle photographic lens system which have such a small lens diameter as to be compatible with filters designed for use with other lens systems and wherein various aberrations are favorably corrected.
Patent•
05 Apr 1977
TL;DR: A gauss type photographic lens system having a large aperture ratio which comprises five components of six lens elements and wherein symmetry of coma is improved and curvature of field, spherical aberration, etc., are favorably corrected by enlarging the airspace comprising a stop and increasing refractive indices of the lens elements arranged on both the sides of said stop.
Abstract: A gauss type photographic lens system having a large aperture ratio which comprises five components of six lens elements and wherein symmetry of coma is improved and curvature of field, spherical aberration, etc., are favorably corrected by enlarging the airspace comprising a stop and increasing refractive indices of the lens elements arranged on both the sides of said stop.
TL;DR: In this article, the vertical side-lobe structure of cylindrical arrays driven in phase is examined, and the physical cause of this phenomenon is identified, and a method of eliminating excessive sidelobe levels is explained.
Abstract: The vertical side‐lobe structure of cylindrical arrays driven in phase is examined. Experimental results demonstrate that the vertical side‐lobe levels are significant when the angular aperture of the array is large. The physical cause of this phenomenon is identified, and a method of eliminating excessive side‐lobe levels is explained. Experimental results showing that this method is successful are presented.
10 Apr 1977
TL;DR: In this paper, a new acousto-optic tunable filter utilizing collinear ACO interaction along the direction near to the optic axis is proposed and demonstrated by using LiNbO3 crystal.
Abstract: A new acousto-optic tunable filter utilizing collinear acousto-optic interaction along the direction near to the optic axis is proposed and demonstrated by using LiNbO3 crystal. Using this near axis interaction lowers the driving acoustic frequency and also expands the angular aperture in the ordinary plane. The acousto-optic figure of merit M2(=n03ne3p2/pv3) of this filter is 7.5 x10-18 sec3/g, and tuning from 7000A to 4200A can be obtained by changing the acoustic frequency from 56MHz to 119MHz. At 5145A, the filter bandwidth of 11 A and the angular aperture of about 6° in the ordinary plane have been obtained.
Patent•
10 May 1977
TL;DR: In this article, the angular aperture of the center part is set to 0 deg. or 360 deg., and transmittance of mesh as well as angular aperture at circumference section is properly selected.
Abstract: PURPOSE:The angular aperture of the center part is set to 0 deg. or 360 deg., and transmittance of mesh as well as angular aperture at circumference section is properly selected. As a result, a filter, the transmittance ratio of which can be set to an optional value between the center and circumference sections, can be obtained.
Patent•
26 Mar 1977
TL;DR: In this article, the angular aperture of a throttle is prevented from falling after an engine completes its starting motion, so that a large quantity of exhaust gas can not be generated at the time when a starting control of an engine over a starting motion is switched over to the control of the car speed.
Abstract: PURPOSE:Devised is to prevent the fall of the angular aperture of a throttle after an engine completes its starting motion, so that alarge quantity of exhaust gas connot be generated at the time when a starting control of an engine over a starting motion is switched over to the control of the car speed
TL;DR: In this article, the authors derived the angle of divergence and the aperture of hollow metallic or dielectric cones under consideration of the total internal reflection at the junction of the core to the surroundings.
Patent•
27 Jul 1977
TL;DR: In this article, a vehicular automatic speed change gear whose over-drive connection element is activated only when the car speed exceeds the fixed level to the angular aperture of a throttle is proposed.
Abstract: PURPOSE:Proposed is a vehicular automatic speed change gear whose over-drive connection element is activated only when the car speed exceeds the fixed level to the angular aperture of a throttle
TL;DR: In this paper, the magnetic field produced by a thick current-carrying toroidal coil having an arbitrary angular aperture was investigated in suitable coordinates, and it was shown that the toroidal coils have a strong magnetic field.
01 Jan 1977
TL;DR: In this paper, a Rayleigh-Sommerfeld integral is developed for the case of relative transverse motion of the medium, assuming a uniform, constant velocity, and used to predict the amplitude distributions for several diffracting screen configurations.
Abstract: The theory of diffraction from a screen in a static medium is well known. The diffraction pattern is altered, however, if there is relative motion between the diffraction plane, the observation plane or the medium between planes. The case of relative transverse motion of the medium is investigated theoretically by generalizing the wave equation to include this motion, assuming a uniform, constant velocity. An equivalent Rayleigh-Sommerfeld integral is developed for this case. It is used to obtain a closed-form solution for the diffraction pattern in the Fraunhofer region for medium velocities less than the speed of sound. This solution is used to predict the amplitude distributions for several diffracting screen configurations. The results of this theory have application in performance characterization for a number of highscan-rate acoustic imaging systems.