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NIST Transportable Tunable UV Laser Irradiance Facility for Water Pathogen Inactivation



Thomas C. Larason


A method of ultraviolet germicidal irradiation (UVGI) for water pathogen inactivation effectiveness using tunable, narrowband laser light is described. A transportable tunable UV (TTUV) laser system for providing a known irradiance (µW/cm2) or dose (mJ/cm2) suitable for irradiating water samples in Petri dishes over the wavelength range of 210 nm to 300 nm was developed by the National Institute of Standards and Technology (NIST). The TTUV facility, consisting of a 1 kHz pulsed UV laser and light-tight enclosure containing the optics necessary to uniformly irradiance a water sample, was used in a microbiology laboratory to dose drinking water pathogens and surrogates as part of a Water Research Foundation study in the summer and fall of 2012. The approach demonstrated improved accuracy and simplified spectral analysis over conventional pathogen inactivation sources consisting of broadband UV sources and bandpass filters. In this work, the TTUV facility design and key components are described, including modifications in the field to provide the required irradiance levels. The irradiance and dose levels produced by the tunable UV laser during the project will also be presented. The transportability of the TTUV system enabled it to be brought to a microbiology facility allowing the water samples (microbial suspensions) to be irradiated in a location with experienced staff and facilities for preparing, handling, analyzing, storing, and shipping the many samples studied. These results, published elsewhere, established that the tunable UV laser system provides unique UVGI capabilities for use with water pathogens and has applications for other pathogens experiments, for example air-purification studies.
Review of Scientific Instruments


Action Spectra, Ultraviolet Light, Tunable Laser, Water Disinfection, Medium Pressure UV, Low Pressure UV, Water Pathogens


Larason, T. (2020), NIST Transportable Tunable UV Laser Irradiance Facility for Water Pathogen Inactivation, Review of Scientific Instruments, [online], (Accessed June 13, 2024)


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Created July 20, 2020, Updated October 21, 2020