Physics

Racing Down the Table

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Science  18 Dec 2009:
Vol. 326, Issue 5960, pp. 1591
DOI: 10.1126/science.326.5960.1591-a

Accelerating particles to very high energy is usually done at large national facilities with the aim of smashing atoms to probe their constituent parts. Accelerators on a smaller, but still rather grand, size scale find use in biomedical applications such as cancer treatment. The availability of high-intensity laser pulses to manipulate electrons offers the possibility of shrinking the size of particle accelerators even further. However, the demonstrations of laser-based acceleration so far have been at large laser facilities and have involved pulses produced at a low repetition rate. Mordovanakis et al. report a technique to produce electrons at faster repetition rates, using a double pulse setup whereby a moderate prepulse (∼1014 W cm−2) is focused onto a target before the arrival of the main pulse (1018 W cm−2). By varying the delay time between the prepulse and the main pulse, the authors can control the 500-Hz production of quasi-monoenergetic electron pulses at relativistic energies (0.8 MeV), thereby offering the prospect of tabletop accelerators.

Phys. Rev. Lett.103, 235001 (2009).

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