Showing papers on "Linear particle accelerator published in 1982"
TL;DR: In this paper, the authors made an initial survey of target gain versus beam energy, power, focal radius, and ion range for inertial-fusion targets for use with heavy ion accelerators as drivers in fusion energy power plants.
67 citations
01 Feb 1982
TL;DR: The 1981 Linear Accelerator Conference was held at Bishop's Lodge, Santa Fe, New Mexico, October 19-23, 1981 and the texts of the invited and contributed papers are published.
Abstract: The 1981 Linear Accelerator Conference was held at Bishop's Lodge, Santa Fe, New Mexico, October 19-23, 1981. This publication contains the texts of the invited and contributed papers. Abstracts of individual items from the conference were prepared separately for the data base.
40 citations
Patent•
15 Jul 1982
TL;DR: In this article, a linear accelerator system includes a plurality of post-coupled drift-tubes wherein each post coupler is bistably positionable to either of two positions which result in different field distributions.
Abstract: A linear accelerator system includes a plurality of post-coupled drift-tubes wherein each post coupler is bistably positionable to either of two positions which result in different field distributions. With binary control over a plurality of post couplers, a significant accumlative effect in the resulting field distribution is achieved yielding a variable-energy drift-tube linear accelerator.
16 citations
01 Jan 1982
TL;DR: In this article, the effects of desynchronism on coherent pulse propagation were compared and compared with recent Stanford experiments and the same pulse propagation effects were studied for a magnet design with a tapered wavelength in which electrons are trapped in the ponderomotive potential.
Abstract: The Stanford free electron laser (FEL) oscillator is driven by a series of electron pulses from a high-quality superconducting linear accelerator (LINAC). The electrons pass through a transverse and nearly periodic magnetic field, a 'wiggler', to oscillate and amplify a superimposed optical pulse. The rebounding optical pulse must be closely synchronized with the succession of electron pulses from the accelerator, and can take on a range of structures depending on the precise degree of synchronism. Small adjustments in desynchronism can make the optical pulse either much shorter or longer than the electron pulse, and can cause significant subpulse structure. The oscillator start-up from low level incoherent fields is discussed. The effects of desynchronism on coherent pulse propagation are presented and compared with recent Stanford experiments. The same pulse propagation effects are studied for a magnet design with a tapered wavelength in which electrons are trapped in the ponderomotive potential.
16 citations
Patent•
19 Oct 1982
TL;DR: An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles is described in this paper.
Abstract: An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.
12 citations
01 Jan 1982
TL;DR: In this article, the scaling laws of linac behavior with wavelength have been defined, some probably for the first time, and a comparison has been made between a conventional and grating linac.
Abstract: The Workshop has made enormous gains in our understanding. Many scaling laws of linac behavior with wavelength have been defined, some probably for the first time. A comparison has been made between a conventional and grating linac, also probably for the first time. A problem in transverse stability of the grating accelerator was exposed but also solved at the workshop with a great net gain in understanding. Loading of linacs appears not to be independent on wavelength, it had not previously been studied for a laser accelerator. The limits on accelerating field as a function of wavelength have been studied. A gain of a factor of 10 is likely if the wavelength can be reduced to the 1 cm range. After that the gains are small unless it is acceptable to destroy the structure. If this is allowed, as could be the case for a grating consisting of liquid ripples, then plasma development will limit the fields. A first calculation suggests that very high gradients may be attainable. The most remarkable feature of laser driven grating accelerators are the low rf energies required to attain high beam energies for a few particles. One example is of a 1 TeV acceleratormore » driven by a 60 Joule laser.« less
10 citations
TL;DR: The Advanced Technology Accelerator (ATA) as discussed by the authors is a 256-foot linear induction accelerator capable of generating repeated 10kiloamp pulses of 50-MeV electrons, an order of magnitude higher energy than any previous induction linac capable of high current and high repetition rates.
Abstract: Assembly of the Advanced Technology Accelerator (ATA) began in December at an isolated site 15 miles southeast of the Lawrence Livermore Laboratory. When it is completed in October (the project appears to be on schedule), the 256‐foot linear induction accelerator is expected to generate repeated 10‐kiloamp pulses of 50‐MeV electrons—an order of magnitude higher energy than any previous induction linac capable of high current and high repetition rates.
8 citations
TL;DR: In this paper, the ionic charges liberated in an air-equivalent, parallel-plate ionization chamber placed in the pulsed, high-energy X-ray field of extremely high-exposure rate around an electron linear accelerator are measured by applying the correction method previously reported to the observed results.
7 citations
TL;DR: In this article, a multichannel semiconductor detector for high energy X-ray (10 MV) and electron beams (10 − 15 MeV) was developed using surface-barrier diodes fabricated from high purity n-type silicon.
TL;DR: In this paper, an alternate approach to the production of short-lived positron emitters, such as /sup 15/O and /sup 16/O, using bremsstrahlung radiation produced by an electron linear accelerator is presented.
Abstract: The nuclear medicine uses of short-lived positron emitters, such as /sup 15/O and /sup 11/C, rely primarily on the cyclotron production of these radionuclides. This paper presents an alternate approach to production of /sup 15/O by the use of photonuclear reactions on /sup 16/O, using bremsstrahlung radiation produced by an electron linear accelerator. Methods are described which produce useable quantities of relatively high specific activity /sup 15/O (25.1 mCi/4 min at 27.9 Ci/g), using a reboiling H/sub 2/O target, with an electron linear accelerator having an electron beam energy of 26 MeV and a beam current of 100 ..mu..A. Results of this target system are compared to those of a target system developed recently by other investigators.
Patent•
01 Jul 1982TL;DR: In this article, the acceleration energy of an electron accelerator is monitored by monitoring the travelling range of the electrons in the absorber, which is made up of several insulated absorber portions which are arranged one behind another.
Abstract: The apparatus contains a target exposed to a beam of accelerated electrons and an electron absorber positioned behind the target. The acceleration energy of the electron accelerator is monitored by monitoring the travelling range of the electrons in the absorber. For this purpose the electron absorber is made up of several insulated absorber portions which are arranged one behind another. Each of these portions is electrically connected to a separate input of a processing system. The monitoring apparatus is especially well suited for application in electron accelerators in medical radiation therapy, such as linear accelerators.
TL;DR: The 133C(n,γ) cross section was measured at the Oak Ridge Electron Linear Accelerator from 2.66 to 600 keV with 3 to 4% uncertainty as discussed by the authors.
Abstract: The 133Cs(n,γ) cross section was measured at the Oak Ridge Electron Linear Accelerator from 2.66 to 600 keV with 3 to 4% uncertainty. Individual resonance parameters were determined by least-square...
TL;DR: The relationship between electron kinetic energy and current through the energy‐analyzing magnet was found to be linear within 1.0% in this energy range.
Abstract: Photonuclear reactions have been used to calibrate the energy of a Sagittaire clinical electron accelerator between 10 and 30 MeV. Thresholds at 10.8 MeV for the 63Cu(γ,n)62Cureaction and 29.7 MeV for the 32S(γ,3p)29Al reaction provided two energy points. The break in the 16O(γ,n)15O activation yield curve at 17.3 MeV was determined as an intermediate point. The relationship between electron kinetic energy and current through the energy‐analyzing magnet was found to be linear within 1.0% in this energy range.
TL;DR: Radiation leakage levels at and near the surface of the authors' linear accelerator were measured for the available electron energies and found to be unacceptably high at several locations.
Abstract: Radiation leakage levels at and near the surface of our linear accelerator were measured for the available electron energies and found to be unacceptably high at several locations. Leakage levels were quantitated for several field sizes. The clinical problems which could arise due to the leakage are illustrated and a solution to the problem is suggested.
Journal Article•
TL;DR: In this article, a multichannel semiconductor detector for high energy X-ray (10 MV) and electron beams (10 − 15 MeV) was developed using surface-barrier diodes fabricated from high purity n-type silicon.
TL;DR: Depth doses of the scanning electron beams from the Saturne Therac-20 linear accelerator were measured in polystyrene using a thin window parallel plate ionization chamber and central axis depth dose curves are derived and analyzed.
Abstract: Depth doses of the scanning electron beams from the Saturne Therac-20 linear accelerator at nominal energies of 6,9,13,17, and 20 MeV were measured in polystyrene using a thin window parallel plate ionization chamber. Central axis depth dose curves are derived and are analyzed according to the method of Brahme and Svensson. For each of the five electron energies, values are obtained for the most probable energy at the absorber surface Ep,0, the practical range Rp, the 50% range R50, the therapeutic range R85, the electron dose gradients, total collision energy losses, and other radiation parameters, and these are compared to corresponding values for electron beams from a 22 MeV medical microtron and a 20 MeV betatron.
01 Jul 1982
TL;DR: The experimental results show that highly uniform dose fields can be formed, if shadow compensating systems are used, and the role of the initial electron beam size in the choice of the parameters of scattering and compensating filters is evaluated.
Abstract: The methods of forming extended fields in electron therapy using foil systems for scattering electron beams from the LUE-25 medical linear accelerator are discussed. Procedures for calculating shadow compensator parameters are presented. The role of the initial electron beam size in the choice of the parameters of scattering and compensating filters is evaluated. Advantages offered by this beam shaping technique for reducing the bremsstrahlung background level are considered. The experimental results show that highly uniform dose fields can be formed, if shadow compensating systems are used. The depth dose distributions of 27-MeV electrons obtained with a defocusing magnet system and with a system of scattering foils and compensators are compared.
TL;DR: In this paper, the concept of an accelerator using a travelling magnetic wave that acts on magnetized projectiles is discussed, and a linear accelerator for final speeds of 50 km/s needs a length of 2.5 km, and guidance forces sufficient to produce acceleration of 2 \times 10 6 m/s2allow circular accelerators of reasonable size to achieve hypervelocities for small (50-100 mg) projectiles.
Abstract: The concept of an accelerator using a travelling magnetic wave that acts on magnetized projectiles is discussed. Although superconductors potentially may be good projectile material, their low critical temperature makes them unsuitable, Among ferromagnetic materials, dysprosium seems superior. For stable suspension and guidance, a high conductivity (preferrably superconducting) guide sheet is necessary. Magnetic field gradients of 109A/m2travelling at 106m/s should be achievable using present state-of-the-art components; resulting accelerations are ≳500 km/s2. A linear accelerator for final speeds of 50 km/s needs a length of 2.5 km. Guidance forces sufficient to produce acceleration of 2 \times 10^{6} m/s2allow circular accelerators of reasonable size to achieve hypervelocities for small (50-100 mg) projectiles. An accelerator of 170-m diam would surpass the best results from light gas guns. Travelling waves suitable for accelerations of 104m/s2can be produced without switching by means of flux displacing rotors and may be easily adapted to circular accelerators.
01 Mar 1982
TL;DR: In this article, the acceleration and focusing of an accelerator for heavy ions with low charges-to-mass ratio with use of asymmetric variable-phase focusing is discussed, where the accelerator is discussed as a control system and the distribution of the accelerating field along the axis of the acceleration channel is the controlling function.
Abstract: Optimization of the acceleration and focusing channel of an accelerator for heavy ions with low charges-to-mass ratio with use of asymmetric variable-phase focusing is discussed. Here the accelerator is discussed as a control system, and the distribution of the accelerating field along the axis of the acceleration channel is the controlling function. The goal of the optimization was to provide the maximum longitudinal and transverse acceptances. We give a general description of the algorithm, and we find one of the optimal regimes of acceleration of heavy ions with specific charge 1/34 for energies up to 1 MeV/nucleon. The parameters of this variant are compared with the corresponding parameters of the accelerator-injector of a heavy-ion accelerator complex.
TL;DR: At installation and during subsequent quality assurance checks, it was established that the total X-ray contamination in the electron beams was acceptable and that leakage radiation at 1 m from the end of the w...
Abstract: When the Philips SL75/10 linear accelerator is used for electron beam therapy, the X-ray diaphragms are opened to their maximum settings and the narrow electron beam emerging from the output end of the waveguide is converted into a broad beam by scattering from the exit window, monitor ionization chamber and scattering foil. The size and shape of the treatment beam are defined by the last section of the electron applicator. The standard applicators supplied by the manufacturer are made of aluminium and provide electron field sizes from 3.5 × 3.5 cm to 12.5 × 12.5 cm. In this design (shown schematically in Fig. 1) an appreciable part of the applicator is exposed to the electron beam, which contributes to the X-ray contamination inside and outside the treatment volume. At installation and during subsequent quality assurance checks, it was established that, at normal treatment distances, the total X-ray contamination in the electron beams was acceptable and that leakage radiation at 1 m from the end of the w...
01 Nov 1982
TL;DR: In this article, a two-dimensional, fully relativistic particle-in-cell code was used to present time-dependent and fully electromagnetic simulations of the operational characteristics of the XK-5 klystron gun used at the Stanford Linear Accelerator Center.
Abstract: A two-dimensional, fully relativistic particle-in-cell code was used to present time-dependent and fully electromagnetic simulations of the operational characteristics of the XK-5 klystron gun used at the Stanford Linear Accelerator Center The beam current density and perveance were consistent with experimental and numerical results The beam current density exhibited time-dependent noise, but no significant electromagnetic gun oscillations were observed A particle-in-cell simulation of the full klystron, including all cavities, is feasible but expensive
TL;DR: Data indicated possible clinical advantages with the electron beam as compared to an X ray beam, and the central axis depth dose, X ray contamination, field flatness, and isodose distributions were determined at five electron beam energies with film.
Abstract: A 3.0 cm diameter X ray intraoral cone was attached to the end of a 4.0 cm × 4.0 cm electron beam applicator for an 18 MeV linear accelerator. The central axis depth dose, X ray contamination, field flatness, and isodose distributions were determined for this configuration at five electron beam energies with film, using ionization chamber measurements as a check on the dosimetry. These data indicated possible clinical advantages with the electron beam as compared to an X ray beam.
01 Feb 1982
TL;DR: In this paper, a linear accelerator (linac) was proposed for a source of 70-to 90-MeV protons, which can be extended to even higher energies and currents.
Abstract: A 200- to 500-..mu..A source of 70- to 90-MeV protons would be a valuable asset to the nuclear medicine program. A linear accelerator (linac) can achieve this performance, and it can be extended to even higher energies and currents. Variable energy and current options are available. A 70-MeV linac is described, based on recent innovations in linear accelerator technology; it would be 27.3 m long and cost approx. $6 million. By operating the radio-frequency (rf) power system at a level necessary to produce a 500-..mu..A beam current, the cost of power deposited in the radioisotope-production target is comparable with existing cyclotrons. If the rf-power system is operated at full power, the same accelerator is capable of producing an 1140-..mu..A beam, and the cost per beam watt on the target is less than half that of comparable cyclotrons.