Design of a side coupled standing wave accelerating tube for NSTRI e-Linac

摘要

The design and construction of a 6 MeV electron linear accelerator(e-Linac)was defined in the Institute of Nuclear Science and Technology (NSTRI) for cargo inspection and medical applications. For this accelerator, a side coupled standing wave tube resonant at a frequency of 2998.5MHZin π /2 modewasselected. Inthisarticle,theauthorsprovideastep-by-stepexplanation of the process of the design for this tube. The design and simulation of the accelerating and coupling cavities were carried out in five steps; (1) separate design of the accelerating and coupling cavities, (2) design of the coupling aperture between the cavities, (3) design of the entire structure for resonance at the nominal frequency, (4) design of the buncher, and (5) design of the power coupling port. At all design stages, inadditiontofindingthedimensionsofthecavity, theimpactofconstructiontolerancesand simulation errors on the electromagnetic parameters were investigated. The values obtained for the coupling coefficient, coupling constant, quality factor and capture efficiency are 2.11, 0.011, 16203 and 36%, respectively. The results of beam dynamics study of the simulated tube in ASTRA have yielded a value of 5.14 π -mm-mradforthehorizontalemittance, 5.06 π -mm-mradfortheverticalemittance, 1.17mm forthehorizontalbeamsize, 1.16mmfortheverticalbeamsizeand1090keVfortheenergyspread of the output beam.