Engineering study of a 10 MeV heavy ion linear accelerator

Abstract

LBL's Heavy Ion Fusion Accelerator Research group has completed the engineexing study of the Induction Linac Systems Experiment QSE). ILSE will address nearly all accelerator physics issues of a scaled heavy ion induction linac inertial fusion pellet driver. Desi ned as a series of subsystem experiments, lLSE will accelerate l b parallel carbon ion beams from a 2 MeV injector presently under development to 10 MeV at one pec. This overview paper will present the physics and engineering requirements and describe conceptual design approaches for building ILSE. Major ILSE subsystems consist of electrostatic focusing quadrupole matching and accelerating sections, a 16 to 4 beam transverse combining section, a 4 beam magnetic focusing quadrupole accelerating section, a single beam 180 degree bend section. a drift compression section and a final focus and target chamber. These subsystems are the subject of accompan 'ng papers. Also discussed are vacuum and alignment, diagnostics/&a acquisition and controls. key conclusions and plans for further development Commercial inertial fusion (IF) offers an attractive long-term solution to the problem of future energy supplies. Of the several approaches to a commercial fusion tar4et driver, a multigap heavyion driver has unique advantages in simultaneously offering repetition rate, electrical efficiency. reliability, and long stand-off focusing. Since 1983. the U.S. Heavy Ion Fusion AcceleratorResearch Program (HIFAR) has been assessing the multiple-beam induction linac as an inertial fusion driver. The approach includes a series of increasingly sophisticated experiments to explore, in a scaled way, the accelerator physics of the induction linac approach to a driver, to encourage and develop relevant accelerator technology, and to estimate the capital costs and potential economics of induction linac driven fusion power plants. Earlier experiments1 have yielded significant results on the transport limits of intense ion beams. At present, the multiple ion-beam accelerator experiment2 MBE-4 is examining the longitudinal dynamics of the electric-focused portion of an induction linac driver. In order to complete the HIFAR data base we have designed a sequence of ex nts that collectively are called the Induction Linac Systems G m e n t s or ILSE. The selection of experiments is derived from the mpkements for a driver as developed in the recent IIIFSA study3 of induction linac driven IF for commercial energy production. While ILSE will initially use C+ ions (Al++ may be used later), most of the results will be scalable to ions with different char e twnass ratio such as the mass 200 charge state +3 ions in the $&SA driver. A report of the conceptual en ineering study of the ILSE experiments is contained in refgercnce 4. Descri~tion and Desien DevelopmentA block diagram of the ILSE sequence of experiments is presented in Fig. 1. Sixteen C+ beams from a 2-MV injector are matched to an electrostatic transport system and accelerated to 4 MeV. The beams are then combined to four, and matched ...