TRIUMF, Vancouver
DAE/VECC, Calcutta
TRIUMF (Canada) and VECC (India) are planning to each build a 1.3GHz 50MeV/500kW superconducting electron linac as a driver for producing radioactive ion beams through photo-fission. The two institutes have launched a collaboration with the initial goal to design, build and test a 5-10MeV superconducting injector cryomodule capable of accelerating up to 10mA. A testing area is being set-up at TRIUMF to house the electron gun, rf buncher, injector cryomodule, diagnostic station and beam-dump for beam studies. The project will test all critical elements of the final linac; beam halo generation, HOM excitation, LLRF and rf beam loading and cavity and cryomodule design/performance. The scope and status of the project will be described.
TRIUMF, Vancouver
The medical isotope Molybdenum-99 is presently used for 80-85% of all nuclear medicine procedures and is produced by irradiating highly enriched uranium U-235 targets in nuclear reactors. It has been proposed* that an electron linac be used for the production of 99Mo via photo-fission of a natural uranium target. The nominal linac parameters are 50 MeV electron energy, 100 mA beam current and 100% duty factor. This paper describes two possible superconducting RF accelerator design concepts based on the frequencies of 704 MHz and 1.3 GHz. We present design parameters, efficiency and reliability estimates, and comparisons between the two options. Finally, we describe how the proposed e-linac project at TRIUMF can be used for proof-of-principle demonstration and critical validation tests of the accelerator-based production of 99Mo.
*Making Medical Isotopes: Report of the Task Force on Alternatives for
Medical-Isotope Production (2008)
Fermilab, Batavia
MSU, East Lansing, Michigan
TRIUMF, Vancouver
PAC, Batavia, Illinois
UCR, Riverside, California
The quest for higher beam power and duty factor and precisely controlled beams at reasonable cost has generated world-wide interest in Fixed-field Alternating Gradient accelerators (FFAGs). A new concept in non-scaling FFAGs to stabilize the betatron tune is under development. The emphasis to date has been on electron and proton accelerators, yet many facilities utilize H- front ends. This concept naturally extends to H- FFAGs and under conditions of rapid acceleration, the FFAG functions essentially as a recirculating linac with a common-aperture arc. As such it may be suitable for replacement of aging H- linac sections. For a slow acceleration cycle, an H- FFAG machine can exploit H- techniques to control extraction and intensity, and represents an innovation in proton therapy accelerators. Prototype RF and magnet component design have been initiated. For ten-turn acceleration, the rf cavities in a 10-100 MeV FFAG cannot be re-phased on the revolution time scale, and local adjustment of the pathlength is the proposed approach. For slow acceleration, broad-band, low-frequency rf can be applied. The basic optics and components for such FFAGs are presented.
TRIUMF, Vancouver
DAE/VECC, Calcutta
A 0.5 megawatt electron linear accelerator is being designed at TRIUMF in support of its expanding rare isotope program, which targets nuclear structure and astrophysics studies as well as material science. The first stage of the project, a 25 MeV, 5 mA, cw linac matching the isotope production target power-handling capability in the next five-year plan, is planned to be completed in 2013. The injector cryomodule development, which is being fast tracked, is the subject of a scientific collaboration between TRIUMF and the VECC laboratory in Kolkata, India. The paper gives an overview of the accelerator design progress.
TRIUMF, Vancouver
DAE/VECC, Calcutta
TRIUMF proposes a 1/2 MW electron linac (e-linac) for radioactive ion beam production via photofission. The e-linac is to operate CW using 1.3 GHz superconducting (SC) technology. The accelerator layout consists of a 100 keV thermionic gun, a normal conducting buncher, an injector module, and main linac modules accelerating to a final energy of 50 MeV. The design beam current is 10 mA. The beam dynamics of the injector, where electrons make the transition to the fully relativistic state, has been identified as the most critical part of the design and is the subject of simulations (starting at the gun cathode) using realistic EM fields in PARMELA and TRACK. CW operation demands the novel choice of adopting an SC capture section. A preliminary design of the injector foresees a capture section composed either of two independent or two coupled single-cell cavities, beta <1, that increase the energy to about 500 keV, followed by one nine-cell cavity that boosts the energy up to 10 MeV. The design parameters are subjected to a global optimization program. In this paper we present results from the beam dynamics study as well as details and final outcome of the optimization process.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
BNL, Upton, Long Island, New York
Fermilab, Batavia
TRIUMF, Vancouver
EMMA (Electron Machine with Many Applications) is a prototype non-scaling electron FFAG to be hosted at Daresbury Laboratory. NS-FFAGs related to EMMA have an unprecedented potential for medical accelerators for carbon and proton hadron therapy. It also represents a possible active element for an ADSR (Accelerator Driven Sub-critical Reactor). This paper summarises the commissioning plans for this machine together with the major steps and experiments involved along the way. A description of how the 10 to 20 MeV beam is achieved within ALICE is also given, as well as extraction from the EMMA ring to the diagnostics line and then dump.
TRIUMF, Vancouver
Fixed-Field Alternating-Gradient (FFAG) accelerators span a large range of momenta and have markedly different reference orbits for each momemtum. In the non-scaling (NS) versions proposed for rapid acceleration, the orbits are geometrically dissimilar. In particular, none of the orbits within bending magnets are arcs of circles and this complicates tune calculation. One approach to NS-FFAG design is to employ alternating combined-function magnets. Second generation NS-FFAGs designs attempt to mitigate the variation of betatron tunes; and careful calculation of orbits and tunes is essential. Starting from an analytic magnetic potential for the combined-function magnet, we elucidate expressions for orbit calculation which are second order in the cyclotron motion and arbitrary order in the momentum (no expansion is used).