Design and Characterisation of a Low-Photon Flux UV-Radiance Standard for the Calibration of Radioluminescence Detection Systems

Abstract For the calibration of the radioluminescence detection systems developed within 19ENV02 RemoteALPHA EMPIR project, two purely optical radiation-based devices, which accurately simulate the radioluminescence induced in air nitrogen by an alpha-particle emitted from a planar radionuclide-based sample, were designed, manufactured, and characterized. The variable low-photon flux radiance sources are based on a combination of two integrating spheres and LEDs as UV-A and UV-C radiation sources. The calibrated maximum integrated photon radiances are 7.5·10 11 s −1 ·m −2 ·sr −1 for the UV-A (CWL = 337 nm, FWHM = 10 nm) and 3.0·10 10 s −1 ·m −2 ·sr −1 for the UV-C (CWL = 260 nm, FWHM = 20 nm) spectral range with relative standard uncertainties ( k =1) from 5 % (UV-A) to 8 % (UV-C).