UVC Radiometer for Germicidal UV Sources including 222nm Excimer Lamps


The new X1-1-UV-3727 radiometer is designed to accurately measure the far-UVC irradiance or dose produced by 222nm excimer lamps. This is in addition to the measurement of other germicidal UV source types including low pressure Hg lamps and UV LEDs. Each meter has a wide dynamic range and is supplied with a traceable calibration certificate from the ISO-17025 accredited Gigahertz-Optik laboratory.

Far-UVC radiation, such as the 222nm produced by Kr-Cl excimer lamps, has been the subject of many studies and is known to be effective against a wide range of pathogens.  Significantly, it is also thought to offer less photobiological hazard because far-UVC light cannot penetrate human skin as deeply as the longer wavelength UV radiation produced by low pressure Hg lamps and UVC LEDs.

The X-1-1-UV-3727 radiometer measures UV-C irradiance over a very wide dynamic range from 0.002 µW / cm² to 1000 mW / cm² which permits the investigation of both germicidal efficacy as well as hazard.  It is supplied with calibrations at 222 nm for excimer lamps, 254 nm for low pressure Hg lamps, and wavelength dependent calibration factors given in 5 nm increments 250 nm to 300 nm for UV LEDs. The detector’s flat spectral responsivity ensures lowest measurement uncertainty irrespective of the precise wavelength of UV LEDs which inevitably varies according to operating conditions and manufacturing tolerances.The handheld meter provides a real time display of irradiance (mW / cm²) or dose (mJ / cm²) and includes a peak-hold function. The device may also be operated via its USB interface with optional S-X1 software. To correctly measure irradiance the detector’s entrance optic is a diffuser with a cosine field of view. The detector is pre-aged to significantly reduce solarization effects that results from long term exposure to UV radiation.

Gigahertz-Optik operates an extensive calibration facility that is DIN EN ISO / IEC 17025 accredited. In addition to the absolute radiometric calibration, every UV radiometer produced by Gigahertz-Optik is individually calibrated with regard to its relative spectral responsivity. In accordance with CIE 220:2016 this enables spectral mismatch error to be corrected for, thereby reducing the overall measurement uncertainty.