Mahdi Aghayan; S. Farhad Masoudi; Farshad Ghgasemi; Hamed Shaker
Abstract
Advantage of non-brazing methods in manufacturing of cavities has been considered in high gradient studies because of the softening of copper by brazing cavities at high temperatures. Recent studies with hard copper cavities have been shown that the harder materials can reach larger accelerating gradients ...
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Advantage of non-brazing methods in manufacturing of cavities has been considered in high gradient studies because of the softening of copper by brazing cavities at high temperatures. Recent studies with hard copper cavities have been shown that the harder materials can reach larger accelerating gradients for the same breakdown rate. Shrinking, as a braze-free method for construction of the cavities, was used recently to fabricate and assemble acceleration cavities of an electron linear accelerator at the Institute for Research in Fundamental Science (IPM-Iran). Based on the results obtained in this project, this paper proposes the design of a 3-cell S-band standing wave structure operating at 2.9985 GHz for high gradient tests, considering shrink-fit construction method. The desired cavity consists of three cells so that the maximum gradient in the middle cell is about twice that of the surrounding cells. Simulation with Ansys-HFSS showed that maximum axial electric field 59 MV.m-1 achievable for 2 MW input power in middle cell.
S. Farhad Masoudi; Fatemeh Sadat Rasouli
Abstract
Due to the selectively treating tumors and largely sparing normal neighboring cells, Boron Neutron Capture Therapy (BNCT) continues to be of special significance and interest for wide groups of researchers. One of the most important challenges in this context is to design an optimized ...
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Due to the selectively treating tumors and largely sparing normal neighboring cells, Boron Neutron Capture Therapy (BNCT) continues to be of special significance and interest for wide groups of researchers. One of the most important challenges in this context is to design an optimized beam based on an appropriate neutron source. The recent studies, focused on investigating neutron sources as alternatives for nuclear reactors, revealed the high potential of electron linac-based photoneutron sources to improve the efficiency of this treatment method. Inquiring about the efficiency of a layered model of beam shaping assembly (BSA) for photoneutron sources to be used in BNCT of deep tumors is the main subject of this simulation study. This model, unlike the traditional BSA in which the reflector surrounds the whole moderator, includes many concentric cylinders of reflectors and moderators. The MCNPX simulations for various primary energies show that the layered model results in more appropriate beam characteristics compared with that of the common geometry. Moreover, the parameters governing the beam properties such as the thickness of the layers, moderator/reflector and collimator lengths, and the thickness of the surrounding reflector have been investigated. The results are encouraging and offer new ways to accomplish more researches in studies on the BNCT technique.
