Accelerating protons to therapeutic energies with ultraintense, ultraclean, and ultrashort laser pulses.
Proton acceleration by high-intensity laser pulses from ultrathin foils for hadron therapy is discussed. With the improvement of the laser intensity contrast ratio to 10(-1) achieved on the Hercules laser at the University of Michigan, it became possible to attain laser-solid interactions at intensities up to 10(22) W/cm2 that allows an efficient regime of laser-driven ion acceleration from submicron foils. Particle-in-cell (PIC) computer simulations of proton acceleration in the directed Coulomb explosion regime from ultrathin double-layer (heavy ions/light ions) foils of different thicknesses were performed under the anticipated experimental conditions for the Hercules laser with pulse energies from 3 to 15 J, pulse duration of 30 fs at full width half maximum (FWHM), focused to a spot size of 0.8 microm (FWHM). In this regime heavy ions expand predominantly in the direction of laser pulse propagation enhancing the longitudinal charge separation electric field that accelerates light ions. The dependence of the maximum proton energy on the foil thickness has been found and the laser pulse characteristics have been matched with the thickness of the target to ensure the most efficient acceleration. Moreover, the proton spectrum demonstrates a peaked structure at high energies, which is required for radiation therapy. Two-dimensional PIC simulations show that a 150-500 TW laser pulse is able to accelerate protons up to 100-220 MeV energies.
FOCUS Center and Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109, USA. sbulanov@eecs.umich.edu
Stepan S
SS
Bulanov
Andrei
A
Brantov
Valery Yu
VY
Bychenkov
Vladimir
V
Chvykov
Galina
G
Kalinchenko
Takeshi
T
Matsuoka
Pascal
P
Rousseau
Stephen
S
Reed
Victor
V
Yanovsky
Karl
K
Krushelnick
Dale William
DW
Litzenberg
Anatoly
A
Maksimchuk
D003198:Computer Simulation; D004867:Equipment Design; D006801:Humans; D007477:Ions; D007834:Lasers; D008962:Models, Theoretical; D010315:Particle Accelerators; D011522:Protons; D011878:Radiotherapy / Q000295:instrumentation / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D020266:Radiotherapy, Conformal / Q000295:instrumentation* / Q000379:methods; D013997:Time Factors
D007477:Ions; D011522:Protons