Measurement of the intensity ratio of Auger and conversion electrons for the electron capture decay of¹²⁵I

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 describe a measurement of the ratio of the number of conversion electrons (emitted as part of the nuclear decay process) to the number of Auger electrons (emitted as part of the atomic relaxation process after the nuclear decay) for the case of I. Results are compared with Monte-Carlo type simulations of the relaxation cascade using the BrIccEmis code. Our results indicate that forI the calculations based on rates from the Evaluated Atomic Data Library underestimate the K Auger yields by 20%.

Auger Electrons Constructed Active Sites on Nanocatalysts for Catalytic Internal Radiotherapy

“…[ 14–16 ] However, the strong OH bond of H 2 O molecule limits the yield of •OH induced by radionuclides, and especially for 125 I, which emits low‐energy AEs and γ‐rays (35 keV). [ 17,18 ] Fortunately, as mentioned above, the combination of nanocatalysts and AEs emitted from 125 I will construct superficial active sites, which can stretch molecules and decrease the bond energy for H 2 O activation, thus facilitating the occurring of H 2 O radiolysis. Hence, 125 I‐labeled nanocatalysts have the potential to increase the yield of •OH for enhanced IRT.…”

Quantitative electron spectroscopy of 125I over an extended energy range

“…The peak-area ratio obtained in this way is reproduced in Table 2 as well. As discussed elsewhere [12] this intensity ratio is very sensitive to the K-shell fluorescence rate assumed. A slight decrease of this quantity (within its experimental uncertainty) from 0.878 to 0.85 resolves this issue.…”

“…L 1 CE -KLL Auger electron intensity ratio The combined L 1 CE -KLL Auger measurement indicate that in the experiment the relative Auger intensity is about 15-20% too high compared to the calculated one. This has been attributed to a small error in the fluorescence yield used in BrIccEmis [12].…”

Development of a new database for Auger electron and X-ray spectra

“…Low-energy electron spectra from the electron capture decay of 125 I to 125 Te were measured at the Australian National University (ANU) using high-resolution electrostatic spectrometers [10][11][12]. The spectrometers measured the kinetic energy of the electrons directly with no work function correction applied, hence it is expected that the observed spectra are referenced to the vacuum level.…”

“…The BrIccEmis model has been tested by comparing the calculations with available literature values [5] and overall a fairly good agreement was found. This includes our recent electron measurements from the electron capture decay of 125 I [10][11][12]. However, it was realized that the energies used in BrIccEmis are too high [5], due to the lack of quantum electrodynamic (QED) and Breit magnetic electron interaction corrections [13] in the RAINE code.…”