A study of the directional response of ultraviolet radiometers: I. Practical evaluation and implications for ultraviolet measurement standards

Abstract

The directional responses of a range of ultraviolet radiometers commonly used for irradiance measurements of UVB and UVC have been studied. Radiometers with 24 diffuser/filter combinations were assessed using a deuterium source, and three different diffuser/filter designs were assessed using a monochromatic source. The directional responses of the radiometers have been calculated and expressed in terms of figures of merit similar to those described for (photopic) illuminance meters in BS 667 and CIE 69. Those radiometers that performed best for the measurement of both small and extended sources of UVB and UVC had raised PTFE diffusers. We conclude that UV radiometers with a directional response error f2 < 10% are readily available commercially, and that it would be appropriate for future ultraviolet standards to set an upper limit of 5% on f2. This would ensure that the overall uncertainty in irradiance measurements of extended ultraviolet sources is not dominated by the error in the directional response of the radiometer.

Nine out of 10 sunbeds in England emit ultraviolet radiation levels that exceed current safety limits

“…Technical difficulties prevented measurement over the full 180°. The measured angular response was used to calculate the cosine error, 10 f 2 = 6·69%, which is below the 10% maximum recommended for commercial UV radiometers 11 . All on‐site sunbed lamps were allowed 2 min to warm up and stabilize outputs.…”

“…The measured angular response was used to calculate the cosine error, 10 f 2 = 6AE69%, which is below the 10% maximum recommended for commercial UV radiometers. 11 All on-site sunbed lamps were allowed 2 min to warm up and stabilize outputs. The time for each measurement varied between 10 and 50 s. In order to increase the dynamic range, measurements were taken over short and long time periods, using the technique described by Gaigalas et al 12 The calibration of the device, traceable to the National Physical Laboratory, was carried out in the Optical Calibration Laboratory of the Photobiology Unit, University of Dundee.…”

A study of the correction factor for ultraviolet phototherapy dose measurements made by the indirect method

“…For these, a black plastic ring was manufactured to fit snugly around the diffuser on the face of the radiometer probe. This left the surface of the diffuser flush with the probe surface and so cut down the component of the irradiance that could be detected at high angles of incidence 9 . An assessment of the angular response of this modified probe to banks of lamps with different sections shielded indicated that f 2 for the modified probe was in the range 15–20% 10 .…”

A Model for Inactivation of Microbes Suspended in the Atmosphere by Solar Ultraviolet Radiation

“…''plane irradiances'' measurements) to the ''true'' spherical irradiances (Waldman 585-100 radiometer ⁄ detector measurements in Fig. 5 of reference [50]).…”