Iron plasma generation using a Nd:YAG laser pulse of several hundred picoseconds

Jun Tamura; Masafumi Kumaki; Kotaro Kondo; Takeshi Kanesue; Masahiro Okamura

doi:10.1063/1.4938258

Iron plasma generation using a Nd:YAG laser pulse of several hundred picoseconds

Rev Sci Instrum. 2016 Feb;87(2):02A919. doi: 10.1063/1.4938258.

Authors

Jun Tamura¹, Masafumi Kumaki², Kotaro Kondo³, Takeshi Kanesue⁴, Masahiro Okamura⁴

Affiliations

¹ J-PARC Center, Japan Atomic Energy Agency, Ibaraki 319-1195, Japan.
² Research Institute for Science and Engineering, Waseda University, Tokyo 169-8555, Japan.
³ Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, Tokyo 152-8550, Japan.
⁴ Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973, USA.

PMID: 26931980
DOI: 10.1063/1.4938258

Abstract

We investigated the high intensity plasma generated by using a Nd:YAG laser to apply a laser-produced plasma to the direct plasma injection scheme. The capability of the source to generate high charge state ions strongly depends on the power density of the laser irradiation. Therefore, we focused on using a higher power laser with several hundred picoseconds of pulse width. The iron target was irradiated with the pulsed laser, and the ion current of the laser-produced iron plasma was measured using a Faraday cup and the charge state distribution was investigated using an electrostatic ion analyzer. We found that higher charge state iron ions (up to Fe(21+)) were obtained using a laser pulse of several hundred picoseconds in comparison to those obtained using a laser pulse of several nanoseconds (up to Fe(19+)). We also found that when the laser irradiation area was relatively large, the laser power was absorbed mainly by the contamination on the target surface.