CERN Accelerating science

Ra

\textbf{Top: }Picture of one of the \isotope{226}{Ra} implanted stainless steel samples. \textbf{Bottom: }Expected implantation depth distribution as simulated using SRIM \cite{Ziegler:2010, Joerg:2017}.

\textbf{Top: }Picture of one of the \isotope{226}{Ra} implanted stainless steel samples. \textbf{Bottom: }Expected implantation depth distribution as simulated using SRIM \cite{Ziegler:2010, Joerg:2017}.

Alpha spectrum acquired for \textit{sample A} long (1.7\,years) after the implantation~\cite{Lecher:2019}. Alpha emission lines from isotopes belonging to the uranium (blue) and thorium (orange) decay chains are visible.

Cutaway view of the interleaved shielding of the HPGe spectrometer used in this work (figure adapted from~\cite{budjavs:2009}).

HPGe gamma spectrum acquired for \textit{sample B}. The most prominent emission lines of $^{226}$Ra (red) as well as its short-lived daughter isotopes $^{214}$Bi (blue) and $^{214}$Pb (yellow) are highlighted. The region around the 186.2\,keV emission line of $^{226}$Ra is shown enlarged in the inset.

Emanation vessel used for the measurement of the sample's radon emanation rates. The aluminum ring (front) is used to fix the sample in place.

Equilibrium emanation rate of \isotope{222}{Rn} at room temperature for both samples. Measurements carried out in helium atmosphere at pressure of 1050\,mbar (except for indicated measurement) using miniaturized proportional counters~\cite{Kiko:2001}.

Sketch of the setup used for the study of temperature dependence of radon emanation rate.

Temperature dependence of the radon emanation rate of the \isotope{226}{Ra} implanted stainless steel \textit{sample B} as measured using an electrostatic radon monitor.

Alpha emission spectrum of the implanted stainless steel \textit{sample B} 13\,weeks after the implantation~\cite{Herrero:2018}. Most intense alpha emission lines (solid lines) are fit using a sum of Crystal Ball functions~\cite{Skwarnicki:1986xj} with the residuals between data and fit function shown in the lower panel. Data falling in the gray bands were excluded from the fit. Dashed lines indicate possible subdominant contributions.

Time evolution of the $^{139}$Ce activity found in \textit{sample B}. The inset shows the corresponding region of the gamma spectrum for the second measurement.