High-Intensity Deuteron Linear Accelerator (FMIT)
TL;DR: The Fusion Materials Irradiation Test (FMIT) Facility at the Hanford Engineering Development Laboratory (HEDL), Richland, Washington, was designed to provide a high neutron flux and a neutron energy spectrum representative of fusion reactor conditions in volumes adequate to screen and qualify samples of candidate fusion reactor materials as mentioned in this paper.
Abstract: For fusion reactors to become operational, one of the many problems to be solved is to find materials able to withstand the intense bombardment of 14-MeV neutrons released by the fusion process The development of alloys less likely to become damaged by this neutron bombardment will require years of work, making it desirable to begin studies in parallel with other aspects of fusion power generators The Fusion Materials Irradiation Test (FMIT) Facility, to be built at the Hanford Engineering Development Laboratory (HEDL), Richland, Washington, will provide a high neutron flux and a neutron energy spectrum representative of fusion reactor conditions in volumes adequate to screen and qualify samples of candidate fusion reactor materials FMIT's design goal is to provide an irradiation test volume of 10 cm3 at a neutron flux of 1015 n/cm2-s, and 500 cm3 at a flux of 1014 n/cm2-s This will not allow testing of actual components, but samples in the most intense flux region can be subjected to accelerated life testing, accumulating in one year the total number of neutrons seen by a fusion reactor in 10-20 years of operation To produce the neutrons, a 100-mA, 35-MeV deuteron beam will be directed onto a 2-cm-thick, 600-gpm curtain of liquid lithium metal, which strips the deuterons and allows the remaining neutrons to continue on to the test samples The deuterons will be produced by the largest component of the facility, a high-intensity, continuously operating linear accelerator (Linac)
Citations
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TL;DR: A 35-MeV 100-mA cw linear accelerator is being designed by Los Alamos for use in the Fusion Materials Irradiation Test (FMIT) Facility as mentioned in this paper.
Abstract: A 35-MeV 100-mA cw linear accelerator is being designed by Los Alamos for use in the Fusion Materials Irradiation Test (FMIT) Facility. Essential to this program is the design, construction, and evaluation of performance of the accelerator's injector, low-energy beam transport, and radio-frequency quadrupole sections before they are shipped to the facility site. The installation and testing of some of these sections have begun as well as the testing of the rf, noninterceptive beam diagnostics, computer control, dc power, and vacuum systems. An overview of the accelerator systems and the performance to date is given.
10 citations
TL;DR: In this article, a system of mirrors, intensified TV cameras, digitizers, and tomographic reconstruction codes has been described for sensing and digitizing the light projected transversely from the beam of the FMIT accelerator at Los Alamos National Laboratory.
Abstract: Transverse beam-distribution measurements of high-current cw accelerators must be obtained from noninterceptive sensors. For the 100-mA H2 or D beam of the Fusion Materials Irradiation Test (FMIT) accelerator, these transverse properties may be obtained by detecting the visible radiation resulting from beam interactions with residual gas. A system of mirrors, intensified TV cameras, digitizers, and tomographic reconstruction codes has been reported previously. This report describes a new technique for sensing and digitizing the light projected transversely from the beam of the FMIT accelerator at Los Alamos National Laboratory. Figure 1 is a sketch of the main components of the Imagescope to photodiode beam-imaging system. An input lens focuses the beam-profile image onto a bundle of optical fibers that are spatially coherent from end to end. The output end gathers the fibers from the four input legs into a small double-row format. Thus, four different beam-profile images are transferred from this fiber-optic bundle (Imagescope) through a microchannel-plate (MCP) image intensifier with a format arranged so that two linear photodiode arrays (Reticons) receive the intensified images. The photodiode arrays have 512 elements each; thus, each beam profile has a 256-element resolution. An electronic package accepts the electric signal from the photodiodes, digitizes the contribution of each sensitive element, and transmits the digitized profile information over a fiber-optic data link to a memory unit accessible by the CAMAC data-acquisition and processing system. Details of this new beam-profile imaging and digitizing system are presented in the following sections.
10 citations
TL;DR: In this article, a 2.5 MeV proton linac was used to deliver 10 mA to a 7Li target, and the thermal neutron peak flux with an H2O moderator was 2 × 1011 n/cm2.
Abstract: The use of neutrons as a diagnostic tool has become more extensive in radiography, non-destructive analysis, bio-medical investigations and other general research studies. Although most diagnostic neutron work has been conducted at large nuclear research reactors, there is a need for compact and semi-portable neutron sources. Such a neutron source can be based on a low energy proton linac and suitable target. Design of a compact, 100% duty cycle, 2.5 MeV proton linac that delivers 10 mA to a thick 7Li target is described. Calculated thermal neutron peak flux with an H2O moderator is 2 × 1011 n/cm2.s. The associated low gamma ray yield results in the availability of good neutron beam quality for radiography and other purposes.
8 citations
TL;DR: In this article, the limits on current density for continuous operation of indirectly cooled mineral-insulated coils are explored by thermal analysis, and the criteria for cable optimization are established. But the authors do not consider the possibility of using this technique in commercial fusion reactor coils.
Abstract: The limits on current density for continuous operation of indirectly cooled mineral-insulated coils are explored by thermal analysis, and the criteria for cable optimization are established. The insulation system, compacted magnesium oxide powder, has these advantages: 1) Radiation insensitivity - no detectable degradation at 1014rads, with no reason to expect this to be close to any limit. 2) Flexibility - enabling standard coil-winding practice to be followed, without the problems of fired ceramics. 3) Good thermal conductivity - 2.36 W/m.K at room temperature. 4) High-temperature stability - making the metal components of the coil determine the operational temperature limit, rather than the insulation system as in conventional coils. The cooling system avoids oxidation problems caused by radiolysis of water. Other potentially radiation-sensitive components also are discussed. An example is given of the design procedure. The feasibility of extending the technique to commercial fusion reactor coils is examined.
8 citations
01 Jan 1979
TL;DR: In this paper, the authors describe equipment capable of accurately measuring transverse beam profiles over a range spanning more than four orders of magnitude and longitudinal phase profiles over ranges spanning three order of magnitude.
Abstract: In high-current machines, such as LAMPF and the envisioned Hanford Engineering Development Laboratory (HEDL) Fusion Materials Irradiation Test (FMIT) Facility linac, hands-on maintenance is desired. Beam spill must be kept extremely low; therefore, attention must be given to beam fringes (tails). Beam matching to the structure becomes increasingly important. We describe equipment capable of accurately measuring transverse beam profiles over a range spanning more than four orders of magnitude and longitudinal phase profiles over ranges spanning more than three orders of magnitude. Errors in 100-MeV transverse emittance measurements are explored and experimental emittance measurements made with three different methods are compared. Advantages of one nondestructive method are developed.
7 citations
References
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TL;DR: In this article, a method was developed to analyze the beam dynamics of the radio frequency quadrupole accelerating structure, which can accept a dc beam at low velocity, bunch it with high capture efficiency, and accelerate it to a velocity suitable for injection into a drift tube linac.
Abstract: A method has been developed to analyze the beam dynamics of the radio frequency quadrupole accelerating structure. Calculations show that this structure can accept a dc beam at low velocity, bunch it with high capture efficiency, and accelerate it to a velocity suitable for injection into a drift tube linac.
38 citations
TL;DR: In this paper, the results of studies of radio frequency quadrupole accelerating structures are presented, and the results indicate that this is a promising structure for transporting and accelerating ion beams in the energy region of 50 KeV to 2 MeV.
Abstract: The results of studies of radio frequency quadrupole accelerating structures are presented. Measurements indicate that this is a promising structure for transporting and accelerating ion beams in the energy region of 50 KeV to 2 MeV.
17 citations
01 Jan 1979
TL;DR: In this paper, the authors describe equipment capable of accurately measuring transverse beam profiles over a range spanning more than four orders of magnitude and longitudinal phase profiles over ranges spanning three order of magnitude.
Abstract: In high-current machines, such as LAMPF and the envisioned Hanford Engineering Development Laboratory (HEDL) Fusion Materials Irradiation Test (FMIT) Facility linac, hands-on maintenance is desired. Beam spill must be kept extremely low; therefore, attention must be given to beam fringes (tails). Beam matching to the structure becomes increasingly important. We describe equipment capable of accurately measuring transverse beam profiles over a range spanning more than four orders of magnitude and longitudinal phase profiles over ranges spanning more than three orders of magnitude. Errors in 100-MeV transverse emittance measurements are explored and experimental emittance measurements made with three different methods are compared. Advantages of one nondestructive method are developed.
7 citations
TL;DR: In this paper, design considerations and concepts are presented for the accelerating structures for the Fusion Materials Irradiation Test (FMIT) Facility. But the authors do not consider the use of an energy dispersion cavity to spread the energy of the beam slightly.
Abstract: Design considerations and concepts are presented for the accelerating structures for the Fusion Materials Irradiation Test (FMIT) Facility. These structures consist of three major units: a 0.1- to 2-MeV radio-frequency quadrupole based on the Russian concept, a 2- to 35-MeV drift-tube linac made up of two separate tanks designed to generate either 20- or 35-MeV beams, and an energy dispersion cavity capable of spreading the energy of the beam slightly to ease thermal loading in the target. Because of probable beam activation, the drift-tube linac is designed so that alignment and maintenance do not require manned entry into the tanks. This conservatism also led to the choice of a conventional vacuum system and has influenced the choice of many of the rf interface components. The high-powered FMIT machine is very heavily beam loaded and delivers a 100-mA continuous duty deuteron beam to a flowing liquid lithium target. The power on target is 3.5 MW deposited in a 1 × 3 cm spot. Because of the critical importance of the low energy section of this accelerator on beam spill in the machine, a 5-MeV prototype will be constructed and tested at the Los Alamos Scientific Laboratory (LASL).
7 citations
TL;DR: In this paper, the phase and amplitude control of the EIMAC 8973 tetrode was evaluated for the deuteron beam at the FMIT facility and it was shown that it is the most suitable final amplifier tube for each of a series of 15 amplifier chains operating at 0.5-MW output.
Abstract: Preliminary rf system design for the accelerator portion of the Fusion Materials Irradiation Test (FMIT) Facility is in progress. The 35-MeV, 100-mA, cw deuteron beam will require 6.3 MW rf power at 80 MHz. Initial testing indicates the EIMAC 8973 tetrode is the most suitable final amplifier tube for each of a series of 15 amplifier chains operating at 0.5-MW output. To satisfy the beam dynamics requirements for particle acceleration and to minimize beam spill, each amplifier output must be controlled to ±1° in phase and the field amplitude in the tanks must be held within a 1% tolerance. These tolerances put stringent demands on the rf phase and amplitude control system.
6 citations