Aluminum metaphosphate

Two recent material science examples of aluminum metaphosphate is as a host for transition metal phosphors in scintillation detectors.

 

Aluminum metaphosphate glass to detect ionizing X-ray radiation

Kei Kagami and coworkers (2018) developed a scintillation glass to detect ionizing X-ray radiation such as might be found in a medical setting. While single crystals have been used as phosphors for detection of ionizing X-ray radiation, glasses are more attractive because

1. high transparency,
2.  low cost
3.  feasibility of large scale production
4. easy to shape
5. thermal, mechanical, and chemical stability

Glasses used as hosts for the phosphors include: silicates, borates, and phosphates.  Phosphate glasses are preferable because:

• high thermal stability,
• high transparency
• low melting point
• high solubility of halide compounds and rare-earth ions

CsPO₃-Al(PO₃)₃ as a host glass because phosphate glasses can easily dissolve halide compounds The phosphor, Ce³⁺, was chosen because  of the high quantum efficiency of luminescence and fast decay attributed to the 5 d–4f transition.

Powders of CeH₂PO₄, Al(PO₃)₃ base and 1-10 mol %  CeCl₃∙7H₂O dopant were  placed in an alumina boat

• melted at 1000 °C in an electric furnacefor 30 min
• transferred to a stainless-steel plate at 300ºC
• quenched at a temperature below the glass transition temperature.

The authors reported glasses becoming yellow as the concentration of CeCl₃ was increased.

 

Aluminum metaphosphate glass to detect nuclear fusion

A group of scientists from  the FIREX project at the Institute of Laser Engineering, Osaka
University and the National Ignition Facility, Lawrence Livermore National Laboratory developed a glass to detect  down-scattered neutrons, a diagnostic tool in neuclear fusion research.

This system uses an APLF80+3Pr glass scintillator pixel type array.   The scintillation glass was prepared from:

• 20%   Al(PO₃)₃, 99.99%  pure
• 80%  LiF, 99.99% pure
•  0-3% PrF₃, 99.9% pure.

These materials, 8 – 80 g, were placed in a glassy carbon crucible with a lid and melted at  at 1100°C for 0.5 – 1 h under nitrogen atmosphere.   The glass melt was allowed to cool and anneal.  Annealed glass was cut and polished.

 

References

Optical properties and structure of Pr3+-doped Al(PO3)3–LiF glasses as scattered neutron scintillator for nuclear fusion diagnostics  T Murata, S Fujino, H Yoshida, Y Arikawa, T Nakazato, T Shimizu, N, Sarukura, M Nakai, T Norimatsu, H Azechi, K Kamada, Y Usuki, T Suyama, A Yoshikawa, N Sato8, H Kan
ICC3: Symposium 8: Glass-Science & Technology and Photonic Applications IOP Publishing IOP Conf. Series: Materials Science and Engineering 18 (2011) 112006

Photoluminescence and radiation response properties of CsPO3-Al(PO3)3-CeCl3-based glass scintillators
Kei Kagamia,∗, Yutaka Fujimotoa, Masanori Koshimizua, Daisuke Nakauchib, Takayuki Yanagidab, Keisuke Asaia. Optical Materials 87 (2019) 127–131