Quasimonoenergetic Deuteron Bursts Produced by Ultraintense Laser Pulses

Abstract

We report on the generation and laser acceleration of bunches of energetic deuterons with a small energy spread at about 2 MeV. This quasimonoenergetic peak within the ion energy spectrum was observed when heavy-water microdroplets were irradiated with ultrashort laser pulses of about 40 fs duration and high (10(-8)) temporal contrast, at an intensity of 10(19) W/cm(2). The results can be explained by a simple physical model related to spatial separation of two ion species within a finite-volume target. The production of quasimonoenergetic ions is a long-standing goal in laser-particle acceleration; it could have diverse applications such as in medicine or in the development of future compact ion accelerators.

Investigations of Field Dynamics in Laser Plasmas with Proton Imaging

“…Spectral dips [91,92] or even quasi-monoenergetic features [15,16] were seen in the measurements. This behavior is fluctuating from shot to shot since it highly depends on laser parameters [16].…”

“…The ana- such a monoenergetic feature, a model related to a spatial separation of two ion species can be used. More details about the experiment and the interpretation can be found in reference [15,16]. The monoenergetic feature was only observed in laser forward direction.…”

“…The proton spectra are usually continuous up to a sharp cut-off representing the highest proton energies. However, for specific target types ion spectra with dips [91,92] or quasi-monoenergetic [13][14][15][16] features have been observed. Since the generation of monoenergetic ion beams is of high interest for many applications, it will be discussed shortly in the next section.…”

“…In reference [14] quasi-monoenergetic ions are accelerated by heating the target and thus manipulating the target surface. At the Max-BornInstitute it was shown for the first time that water-droplet targets can deliver nearly monoenergetic deuteron and proton beams [15,16].…”

“…Manipulated target surfaces or microstructured targets can deliver quasi-monoenergetic ion and proton beams [13,14]. At the Max-Born-Institute it was shown for the first time that also water-droplet targets can deliver quasi-monoenergetic deuteron and proton beams [15,16] (see Chapter 5.2).…”