X-ray dosimetry during low-intensity femtosecond laser ablation of molybdenum in ambient conditions
Title | X-ray dosimetry during low-intensity femtosecond laser ablation of molybdenum in ambient conditions |
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Abstract | The absorbed X-ray dose was measured during 35 fs pulsed laser ablation of a high purity molybdenum target in ambient conditions for optical intensities from 1.8 × 10 14 to 1.6 × 10 15 W/cm 2 (0.5-4.5 mJ per pulse) at a repetition rate of 1 kHz. During 1 s of ablation, at a distance of 6 cm from the source, appreciable X-ray dose was observed at all optical intensities, ranging from 0.08 μGy, at the minimum intensity, to 0.97 μGy at the maximum intensity, corresponding to equivalent dose rates of 0.3-3.5 mSv/h. At the highest optical intensity, an absorbed dose of 0.29 μGy was measured at a distance of 12 cm from the source, corresponding to an equivalent dose rate of 1.1 mSv/h. Characterization of the laser plasma emissions showed X-rays with energies approaching 20 keV at higher laser pulse energies. In Canada, the annual equivalent dose limit for nonradiation workers is 1 mSv. Our findings suggest that under certain conditions it is possible to exceed this dosage in as little as an hour of fs-laser material processing in ambient conditions. As such, workers in these environments may need to be trained in radiation safety, equipped with personal dosimeters, and provided proper radiation shielding. |
Year of Publication |
2017
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Journal |
IEEE Transactions on Nuclear Science
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Volume |
64
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Start Page |
2519-2522
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Issue |
9
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URL |
https://ieeexplore.ieee.org/abstract/document/8010306
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DOI |
10.1109/TNS.2017.2739156
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