Abstract Details
MeV positron creation using ultraintense short pulse lasers
Author: Hui Chen
Requested Type: Oral Only
Submitted: 2009-04-13 11:16:37
Co-authors: S.C.Wilks, J.D.Bonlie, L.Elberson, E.P.Liang, J.Myatt, D.F.Price, R.Shepherd, M.Schneider, D.D.Meyerhofer, and P.Beiersdorfer
Contact Info:
Lawrance Livermore National Laboratory
7000 East Ave.
Livermore, CA 94551
USA
Abstract Text:
Positrons are the antimatter counterpart of the electron. When a positron combine with an electron, annihilation occurs and both particles turn to gamma rays photons. To crate positrons, the reverse process happens where a photon split into an electron-positron pair.
At Lawrence Livermore National Laboratory we studied the pairs creation using ultra-intense lasers. Although has been studied in theory [1] and demonstrated experimentally [2], the use of lasers as a valuable new positron source had not been established. In May and September 2008, we performed new experiments on the Livermore Titan laser [3] where we observed billions of positrons by shooting a millimeter thick solid gold target [4]. We found positrons produced predominately by the Bethe-Heitler process and have an effective temperature of 2-4 MeV, with the distribution peaking at 4-7 MeV. The angular distribution of the positrons is anisotropic. In this talk, I will present details of these experimental results.
[1] Shearer et al, PRA, 8, 1582 (1973); E. Liang, AIP Conf. Proc. 318, 79 (1994); Shkolnikov et al, APL, 71, 3471 (1997), E. Liang, S. C. Wilks and M. Tabak, PRL 81 4887 (1998); Nakashima and Takabe, PoP, 9, 1505 (2002); J. Myatt et al, submitted to PRE (2008).
[2] T. Cowan et al, LPB 17, 773 (1999); Gahn et al, APL 73, 3662 (1998)
[3] http://jlf.llnl.gov
[4] Hui Chen, S. C. Wilks, J. D. Bonlie, E. P. Liang, J. Myatt, D. F. Price, D. D. Meyerhofer, and P. Beiersdorfer. PRL 102, 105001 (2009)
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