Vol.:(0123456789) 1 3 Journal of Materials Science: Materials in Electronics https://doi.org/10.1007/s10854-019-01212-4 X‑ray induced Sm‑ion valence conversion in Sm‑ion implanted fuoroaluminate glasses towards high‑dose radiation measurement Farley Chicilo 1  · Cyril Koughia 2  · Richard Curry 3  · Russel Gwilliam 5  · Ruben Ahumada‑Lazo 4  · Andy Edgar 6  · David J. Binks 4  · Dean Chapman 7  · Safa Kasap 2 Received: 1 March 2019 / Accepted: 23 March 2019 © Springer Science+Business Media, LLC, part of Springer Nature 2019 Abstract Ion implantation of Sm-ions has been tested in fabricating 2D detectors for microbeam radiation therapy (MRT). Sm-ions have been successfully implanted into fuoroaluminate (FA) glasses. The implantation concentration was chosen to be 5 × 10 15 ions/cm 2 and the ions were implanted at an energy of 2 MeV. After implantation, samarium ions resided within a thin plane very near the surface in the glass, which is expected to be benefcial for 2D imaging. Following implantation, photolumi- nescence (PL) spectra indicate that the embedded Sm-ions are in the form of Sm 2+ and Sm 3+ . Subsequent annealing around the glass transition temperature (475 °C) converts all Sm 2+ ions into Sm 3+ . Under X-ray irradiation, a partial conversion of Sm 3+ into Sm 2+ has been observed which may be used as measure of the X-ray dose delivered into the sample. QFRS (quadrature-frequency-resolved-spectroscopy) measurements on PL prominent emissions from Sm 3+ and Sm 2+ ions show that the PL decays associated with various transitions are in the 0.1 to 100 ms range (slow transitions). X-ray irradiation has led also to the appearance of broad and intense photoluminescence bands associated with X-ray induced structural defects in the host glass as confrmed in the unimplanted FA glasses. The generation of hole trapping centers in the host glass leads to the capture of photogenerated holes and thus allows the electrons to convert Sm 3+ to Sm 2+ . Defect related PL decay signals were measured to be in the nanosecond region. These unwanted defect related fast decaying signals have been separated from slow Sm 2+ and Sm 3+ photoluminescence signals by using an “out-of-phase” PL measurements through a phase-sensitive photodetection technique with a modulated excitation laser diode and a lock-in amplifer. Overall, the Sm-ion implanted fuoroaluminate glass shows the successful conversion from the trivalent form of samarium (Sm 3+ ) to the divalent form (Sm 3+ ) under X-ray irradiation over a large dynamic range of X-ray intensities (800 Gy in air). 1 Introduction Microbeam radiation therapy (MRT) is a new and promising form of cancer radiation treatment which has the potential to greatly improve existing radiation therapy techniques. MRT relies on the difering responses of healthy tissues Author Russel Gwilliam died before the publication of this work was completed. * Farley Chicilo fhc246@mail.usask.ca 1 Division of Biomedical Engineering, College of Engineering, University of Saskatchewan, Saskatoon S7N 5A9, Canada 2 Department of Electrical and Computer Engineering, College of Engineering, University of Saskatchewan, Saskatoon S7N 5A9, Canada 3 Photon Science Institute, School of Electrical and Electronic Engineering, University of Manchester, Manchester M13 9PL, UK 4 School of Physics and Astronomy, Photon Science Institute, University of Manchester, Manchester M13 9PL, UK 5 Department of Electronic and Electrical Engineering, Surrey Ion Beam Centre, University of Surrey, Guildford GU2 7XH, UK 6 School of Chemical and Physical Sciences, Victoria University of Wellington, Wellington 6140, New Zealand 7 Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, Saskatoon S7N 5E9, Canada