The catalogue was compiled from suitable data available in literature and from the data measured or created by the project "18NRM02 PRISM-eBT" (Primary standards and traceable measurement methods for X-ray emitting electronic brachytherapy devices; http://www.ebt-empir.eu/) of the European Metrology Programme for Innovation and Research (EMPIR). The main goal of the catalogue was to develop a set of harmonised reference X-ray qualities denoted as “eBT equivalent” that would be established for in-laboratory activities by the X-ray tubes usually available for calibration in calibration laboratories, but the tube voltage and the filter are specifically selected to simulate the energy spectrum of the corresponding eBT radiation as closely as possible at the reference point. The catalogue contains the following spectra: 1) Measured spectrum in air, 100 cm source-to-detector distance 2) Measured spectrum in air, 150 cm source-to-detector distance 3) eBT-equivalent spectrum in air, 150 cm source-to-detector distance, calculated by SpekCalc software 4) Intermediate results for eBT-equivalent spectrum in air, 150 cm source-to-detector distance, realized at VSL"