Contents lists available at ScienceDirect Journal of Luminescence journal homepage: www.elsevier.com/locate/jlumin Spectroscopic properties of Pr 3+ -doped 20Al(PO 3 ) 3 -80LiF glasses as potential scintillators for neutron detection Melvin John F. Empizo a, ⁎ , Marilou Cadatal-Raduban b , Takahiro Murata c , Yuki Minami a , Keisuke Kawano a , Kohei Yamanoi a , Toshihiko Shimizu a , Nobuhiko Sarukura a , Malgorzata Guzik d , Yannick Guyot e , Georges Boulon e, ⁎ a Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871, Japan b Institute of Natural and Mathematical Sciences, Massey University, Albany, Auckland 0632, New Zealand c Faculty of Education, Kumamoto University, 2-40-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan d Faculty of Chemistry, University of Wroclaw, ul. Joliot-Curie 14, Wroclaw 50-383, Poland e Univ Lyon, Université Claude Bernard Lyon1, CNRS, Institut Lumière Matière, Villeurbanne 69622, France ARTICLE INFO Keywords: Fluoro-oxide glass Pr 3+ doping Spectroscopic properties Scintillators ABSTRACT We investigate the spectroscopic properties of praseodymium (Pr 3+ )-doped APLF glasses [ − +x 20Al(PO ) 80LiF PrF 33 3 , = x 0.5 to 3.0mol%] to realize their potential application as scintillators for neutron detection. From the ultraviolet (UV) to the near infrared (NIR) region, the Pr 3+ -doped glasses exhibit absorption and emission peaks which correspond to the different interconfigurational 4f5d and intraconfigurational 4f transitions of Pr 3+ ions usually located within different environments of the glass matrix. The spectroscopy results also indicate that Pr 3+ ions in APLF have a 4f5d excited state configuration which overlaps with the 1 S 0 level of the 4f ground state configuration. Under 217nm excitation, the 267nm emissions of the Pr 3+ -doped APLF glasses which correspond to the 4f5d → 3 H 6 transition have fast lifetimes ranging from 16. 0 to 19. 7ns. In contrast with emission intensities, the emission lifetimes are found to depend only on the doping concentration and not on the sample temperature. Our results suggest that Pr 3+ -doped APLF glasses can be used as neutron scintillators with robustness in a wide temperature range and with fast and intense emissions at low operating temperatures. 1. Introduction Neutron detection plays a significant role in inertial confinement fusion (ICF) research. Several characteristic parameters can be obtained by measuring the neutrons which are generated by the fusion reaction and then elastically scattered in the high-density fusion plasma. The plasma areal density can be estimated from the ratio of the scattered (secondary) neutrons with respect to the primary ones, and the core shape asymmetry can be observed from the scattered neutron images [1–4]. Neutron diagnostics is currently the most viable way of probing the fusion plasma to be able to understand the plasma dynamics and to attain controlled fusion reactions [5]. To effectively distinguish the scattered neutrons from other high- energy particles and intense background signals, time-of-flight (TOF) detectors require scintillator materials with high lithium ( 6 Li) content and fast response and decay times [1,5–13]. A high 6 Li density en- hances the sensitivity for scattered neutrons with 0. 27MeV energies instead of the primary neutrons with 2. 45MeV energies. The exo- thermic reaction of a neutron with 6 Li has a large cross section re- sonance peak around 0. 1 to 0. 6MeV [14] coinciding with the back- scattered neutron energy and a large Q-value of 4. 8MeV producing sufficient scintillation photons. Moreover, fast response and decay times are essential to discriminate the scattered neutrons from x-rays and the overwhelming majority of primary neutrons simultaneously generated by the fusion reaction. Minimizing the effects of other neu- trons scattered by non-target structures such as the chamber walls and instruments inside the reactor, the detector is placed typically around 30cm near the fusion plasma. At this position, the scintillator must have a decay time faster than 20ns considering the 30, 2. 2, and − 0. 7cmns 1 velocities of the x-rays, primary neutrons, and scattered neutrons, re- spectively. The complex fluoro-oxide glass, − 20Al(PO ) 80LiF 33 , hereafter re- garded as APLF, has been investigated as a candidate neutron scintil- lator material due to its high 6 Li content and fast decay times. APLF has http://dx.doi.org/10.1016/j.jlumin.2017.06.029 Received 5 May 2017; Received in revised form 10 June 2017; Accepted 12 June 2017 ⁎ Corresponding authors. E-mail addresses: mjfempizo@ile.osaka-u.ac.jp (M.J.F. Empizo), georges.boulon@univ-lyon1.fr (G. Boulon).