Many solid particles of various origins are present in the workplace air, which
can have a harmful effect on the health of workers. In the master's thesis, we discussed
the particles produced in the prototype laser chamber during the laser ablation of gallium
arsenide (GaAs) material using a nano- and picosecond laser owned by the high-tech
company LPKF Laser & Electronics d.o.o. The theoretical part presents the theoretical
background of the problem, the essential physico-chemical properties of nanoparticles for
the definition of hazards and harmful effects on health, relevant legal regulations, and
technical measures to limit exposure to nanoparticles at the workplace. The experimental
part describes in more detail the sampling and analysis of particles and the assessment of
worker exposure during the laser ablation process. Particle measurements were carried
out with the help of particle capture according to the principle of impaction. For this
purpose, we used a 10-level low-pressure Berner cascade impactor as a sampler, through
which air was pumped and particles of different sizes were captured on foils. We
determined the mass of the particles, which were caught according to their size at each
stage, and thus also the mass concentration of the individual fraction of particles in a cubic
meter of air. We focused mainly on particles below 100 nm, which were captured on the
1st and 2nd stage of the cascade impactor. To define the hazards of potential exposure to
nanoparticles generated during laser ablation, the particles were also examined by
scanning electron microscopy (SEM) equipped with an energy dispersive X-ray detector
(EDS). The size, shape and elemental composition of the particles were analyzed using
SEM-EDS analysis. The size of the generated particles was mostly below 300 nm. During
laser ablation, agglomerates and aggregates of condensation particles were formed.
Gallium (Ga) and arsenic (As) were the main elements in the resulting particles from the
laser ablation of GaAs material. We also observed the formation of arsenic oxide crystals
(As$_2$O$_3$). We found that the potential exposure of workers to particles is low. This is not
a surprising result, since the laser ablation took place in a closed system (i.e., laser
chamber) that includes a point exhaust of air above the laser table and a high-performance
filter system. Based on the findings, we identified deficiencies, or the challenges faced
by the company in the laser ablation process and the possible exposure to nanoparticles,
suggested possible improvements and gave instructions for safe work in the form of a
guideline.
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