The threat of (high energy) laser against military combat clothing

The High Energy Laser (HEL) is becoming a technologically mature weapon system. Although high energy lasers are not intended to be used as a direct threat to dismounted personnel, incidental exposure to radiation from high energy lasers will be an increasing (indirect) threat. In the past few years TNO performed research on laser-material interaction, to investigate the effects of lasers against different targets in terms of lethality. Parallel to this, work has been done on laser reflections lrom targets and hazard-risk analyses related to the use of high energy lasers in the field. It was shown that reflections of targets irradiated with high energy lasers show a highly dynamic and irregular intensity distribution in both temporal and spatial manner. A dismounted combat soldier may also be exposed to these laser reflections. Due to the relative novelty of this threat, the influence or effect of indirect exposure of clothing and equipment to a high energy laser was unknown, e.g., the occurrence of melting, smouldering or ignition of the fabric materials. This paper discusses the experiments performed within TNO's high energy laser facility (L30) on a range of single and multi-layered samples taken from military combat clothing and personal equipment (vests and/or helmets). The intensities used during the experiments were calculated from laser safety scenarios and reflected intensities from typical targets determined from earlier test series. These were then translated into the possible reflective intensities that could reach the dismounted combat soldier in the same scenarios. In this paper the experimental set-up and selected results in terms of effect and transmitted heat will be shown and discussed.