Compact Linear Accelerator for Intensity Modulated Proton Therapy
Speaker: Dr. Brian Poole
Faculty Host: Professor Spencer Szu-pin Kuo
Proton therapy offers significant treatment benefits to patients, especially those with deep tumors. Proton therapy allows for more localized energy deposition compared with conventional x-ray therapy, which subjects the patient to collateral damage of healthy tissue due to distributed absorption of the x-rays, limiting the amount of dose that can be delivered to the tumor. Proton therapy, requires proton energies up to 200 MeV, compared with the typical 6 MeV electron beam used to generate x-ray photons from a typical electron linear accelerator. These proton facilities are massive, using a synchrotron to accelerate the protons and complex beam transport systems to deliver the beam to several patient treatment rooms. These facilities have a large physical footprint, and cost about $200 million.
LLNL is developing a compact proton accelerator based on a concept called the dielectric wall accelerator (DWA). The DWA is a compact induction accelerator that incorporates a pulse forming structure and photoconductive switches, which deliver energy to an integrated accelerating structure and beam transport system. The DWA can produce accelerating gradients of over 100 MeV/meter, potentially reducing the length of the accelerator to 2 meters, reducing the physical footprint and cost of the system making this treatment more widely available. In this presentation, various technologies to meet the requirements of a DWA based accelerator for IMPT will be discussed. These technologies include, high gradient transmission lines (>100 MV/meter), photoconductive switches to switch the transmission lines to deliver the proton acceleration pulse, and high gradient insulators to support large pulsed surface electric fields in a vacuum beam line of over 100 MV/m. System level issues will also be discussed for a conceptual system design of a sequentially pulsed traveling wave accelerator for IMPT. Computer simulations will be presented for component and system level studies. An integrated approach utilizing theory, computer simulations, and experiments are used in an efficient design cycle.
*This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
About the Speaker
Dr. Brian Poole is currently an Electrical Engineer at the Lawrence Livermore National Laboratory in the Beam Research Program. He obtained his PhD in Electrophysics, MS in Electrophysics, and BS in Electrical Engineering all from Polytechnic Institute of New York. Afterwards, he joined the Lawrence Livermore National Laboratory where he worked on the electron cyclotron resonance plasma heating system for the MFTF-B magnetic fusion system at LLNL. He then he moved the Pulsed Power Group at LLNL and worked on high power beam driven microwave sources including relativistic backward wave oscillators, superradiant SASE Cerenkov sources, and electron beam plasma interactions. After that, he worked in the Beam Research Program at LLNL on high current electron accelerators, charged particle beam dynamics, massively parallel computational electromagnetics, and was responsible for the physics simulations of the DARHT-II linear accelerator beam transport and fast transmission line beam kicker at the Los Alamos National Laboratory. He is currently working on compact high gradient accelerators, and high power microwaves. Dr. Poole is a member of the American Physical Society and IEEE.