Design, Construction, and Test of Compact, Distributed-Charge, X-Band Accelerator Systems that Enable Image-Guided, VHEE FLASH Radiotherapy
Creators: name: Barty, Christopher P. J.
name: Algots, J. Martin
name: Amador, Alexander J.
name: Barty, James C. R.
name: Betts, Shawn M.
name: Castañeda, Marcelo A.
name: Chu, Matthew M.
name: Daley, Michael E.
name: Lopez, Ricardo A. De Luna
name: Diviak, Derek A.
name: Effarah, Haytham H.
name: Feliciano, Roberto
name: Garcia, Adan
name: Grabiel, Keith J.
name: Griffin, Alex S.
name: Hartemann, Frederic V.
name: Heid, Leslie
name: Hwang, Yoonwoo
name: Imeshev, Gennady
name: Jentschel, Michael
name: Johnson, Christopher A.
name: Kinosian, Kenneth W.
name: Lagzda, Agnese
name: Lochrie, Russell J.
name: May, Michael W.
name: Molina, Everardo
name: Nagel, Christopher L.
name: Nagel, Henry J.
name: Peirce, Kyle R.
name: Peirce, Zachary R.
name: Quiñonez, Mauricio E.
name: Raksi, Ferenc
name: Ranganath, Kelanu
name: Reutershan, Trevor
name: Salazar, Jimmie
name: Schneider, Mitchell E.
name: Seggebruch, Michael W. L.
name: Yang, Joy Y.
name: Yeung, Nathan H.
name: Zapata, Collette B.
name: Zapata, Luis E.
name: Zepeda, Eric J.
name: Zhang, Jingyuan
Publisher: name: arXiv
Year: 2024
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: Medical Physics (physics.med-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The design and optimization of laser-Compton x-ray systems based on compact distributed charge accelerator structures can enable micron-scale imaging of disease and the concomitant production of beams of Very High Energy Electrons (VHEEs) capable of producing FLASH-relevant dose rates. The physics of laser-Compton x-ray scattering ensures that the scattered x-rays follow exactly the trajectory of the incident electrons, thus providing a route to image-guided, VHEE FLASH radiotherapy. The keys to a compact architecture capable of producing both laser-Compton x-rays and VHEEs are the use of X-band RF accelerator structures which have been demonstrated to operate with over 100 MeV/m acceleration gradients. The operation of these structures in a distributed charge mode in which each radiofrequency (RF) cycle of the drive RF pulse is filled with a low-charge, high-brightness electron bunch is enabled by the illumination of a high-brightness photogun with a train of UV laser pulses synchronized to the frequency of the underlying accelerator system. The UV pulse trains are created by a patented pulse synthesis approach which utilizes the RF clock of the accelerator to phase and amplitude modulate a narrow band continuous wave (CW) seed laser. In this way it is possible to produce up to 10 $μ$A of average beam current from the accelerator. Such high current from a compact accelerator enables production of sufficient x-rays via laser-Compton scattering for clinical imaging and does so from a machine of "clinical" footprint. At the same time, the production of 1000 or greater individual micro-bunches per RF pulse enables &gt; 10 nC of charge to be produced in a macrobunch of &lt; 100 ns. The design, construction, and test of the 100-MeV class prototype system in Irvine, CA is also presented.
description: Accepted by Frontiers in Physics; Changes: expanded section 6, added numerical spectrum plot to Figure 10, expanded table 2 info, added citations; 29 pages, 13 figures, 2 tables