Quantitative electron spectroscopy of ¹²⁵I over an extended energy range

Highlights: • The Auger conversion electron spectrum of ¹²⁵I was measured from over 30 keV down to very low energies. • The Auger intensity was calibrated in terms of Auger electrons per nuclear decay, based on the K and L conversion electron intensity. • The obtained intensities were compared with those obtained by the Monte Carlo program BrIccEmis, and a good agreement was found. - Abstract: Auger electrons emitted after nuclear decay have potential application in targeted cancer therapy. For this purpose it is important to know the Auger electron yield per nuclear decay. In this work we measure the ratio of the number of conversion electrons (emitted as part of the nuclear decay process) and the number of Auger electrons (emitted as part of the atomic relaxation process after the nuclear decay) for the case of ¹²⁵I. Results are compared with Monte-Carlo type simulations of the relaxation cascade using the BrIccEmis code. With the appropriate choice of parameters this program describes the observed spectra quite well over the whole energy range.