Laser Acceleration of Protons from Thin Film Targets

Authors

K. Flippo, Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Ml
Sudeep Banerjee, Center for Ultrafast Optical Science, University of Michigan, Ann ArborFollow
V. Yu. Bychenkov, P. N. Lebedev Physics Institute, Russian Academy of Science, Moscow, Russia
S. Gu, Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Ml
Anatoly Maksimchuk, University of MichiganFollow
G. Mourou, Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Ml
K. Nemoto, Central Research Institute of Electric Power Industry, 2-11-1, Iwado-kita, Komae-shi, Tokyo
Donald P. Umstadter, University of Nebraska-LincolnFollow

Date of this Version

11-20-2001

Comments

9th Workshop on Advanced Accelerator Concepts, P L. Colestock, S. Kelley, eds., AIP Conference Proceedings, No. 569 (AIP Press, New York, 2001) p. 553-562. Copyright 2001. Permission to use.

Abstract

A collimated beam of fast protons, with energies as high as 10 MeV and total number of 10⁹, confined in a cone angle of 40°±10° has been observed when a 10 TW laser with frequencies either ω₀ (corresponding to 1 μm) or 2ω₀ was focused to an intensity of a few times 10¹⁸ W/cm² on the surface of a thin film target. The protons, which originate from impurities on the front side of the target, are accelerated over a region extending into the target and exit out the backside in a direction normal to the target surface. Acceleration field gradients of ~10 GeV/cm are inferred. The maximum proton energy for 2ω₀ can be explained by the charge-separation electrostatic-field acceleration due to "vacuum heating." In other set of experiments when a deuterated polystyrene layer was deposited on a surface of a Mylar film and a ¹⁰B sample was placed behind the target, we observed the production of ~10⁵ atoms of positron active isotope ¹¹C from the nuclear reaction ¹⁰B(d,n) ¹¹C.