In this review, the major achievements and research and development (R&D) trends from the last decade in the field of single crystal scintillator materials are described. Two material families are included, namely, those of halide and oxide compounds. In most cases, the host crystals are doped with Ce3+, Pr3+ or Eu2+ rare earth ions. Their spin- and parity-allowed 5d–4f transitions enable a rapid scintillation response, on the order of tens to hundreds of nanoseconds. Technological recipes, extended characterization by means of optical and magnetic spectroscopies, and theoretical studies are described. The latter provide further support to experimental results and provide a better understanding of the host electronic band structure, energy levels of specific defects, and the emission centers themselves. Applications in medical imaging and dosimetry, security measures, high-energy physics and the high-tech industry, in which X(γ)-rays or particle beams are used and monitored, are recognized as the main driving factor for R&D activities in this field.

Recent R&D Trends in Inorganic Single-Crystal Scintillator Materials for Radiation Detection

Focusing on the use of nanophosphors for in vivo imaging and diagnosis applications, we used thermally stimulated luminescence (TSL) measurements to study the influence of trivalent lanthanide Ln3+ (Ln = Dy, Pr, Ce, Nd) electron traps on the optical properties of Mn2+-doped diopside-based persistent luminescence nanoparticles. This work reveals that Pr3+ is the most suitable Ln3+ electron trap in the diopside lattice, providing optimal trap depth for room temperature afterglow and resulting in the most intense luminescence decay curve after X-ray irradiation. This luminescence dependency toward the electron trap is maintained through additional doping with Eu2+, allowing UV-light excitation, critical for bioimaging applications in living animals. We finally identify a novel composition (CaMgSi2O6:Eu2+,Mn2+,Pr3+) for in vivo imaging, displaying a strong near-infrared afterglow centered on 685 nm, and present evidence that intravenous injection of such persistent luminescence nanoparticles in mice allows no...

Controlling electron trap depth to enhance optical properties of persistent luminescence nanoparticles for in vivo imaging.

Focusing on the use of nanophosphors for in vivo imaging and diagnosis applications, we used thermally stimulated luminescence (TSL) measurements to study the influence of triva- lent lanthanide Ln 3+ (Ln = Dy, Pr, Ce, Nd) electron traps on the optical properties of Mn 2+ -doped diopside-based persistent lumi- nescence nanoparticles. This work reveals that Pr 3+ is the most suitable Ln 3+ electron trap in the diopside lattice, providing optimal trap depth for room temperature afterglow and resulting in the most intense luminescence decay curve after X-ray irradiation. This luminescence dependency toward the electron trap is maintained through additional doping with Eu 2+ , allowing UV-light excitation, critical for bioimaging applications in living animals. We finally identify a novel composition (CaMgSi2O6:Eu 2+ ,Mn 2+ ,Pr 3+ ) for in vivo imaging, displaying a strong near-infrared afterglow centered on 685 nm, and present evidence that intravenous injection ofsuchpersistentluminescencenanoparticlesinmiceallowsnotonlyimprovedbuthighlysensitivedetectionthroughlivingtissues.

Controlling Electron Trap Depth To Enhance Optical Properties of Persistent Luminescence Nanoparticles for In Vivo Imaging ThomasMaldiney, † AurelieLecointre, ‡ BrunoViana,* ,‡ AurelieBessiere, ‡ MichelBessodes, † DidierGourier, ‡

State of the art and challenges of time-of-flight PET

Scintillation materials and detectors that are used in many applications, such as medical imaging, security, oil-logging, high energy physics and non-destructive inspection, are reviewed. The fundamental physics understood today is explained, and common scintillators and scintillation detectors are introduced. The properties explained here are light yield, energy non-proportionality, emission wavelength, energy resolution, decay time, effective atomic number and timing resolution. For further understanding, the emission mechanisms of scintillator materials are also introduced. Furthermore, unresolved problems in scintillation phenomenon are considered, and my recent interpretations are discussed. These topics include positive hysteresis, the co-doping of non-luminescent ions, the introduction of an aimed impurity phase, the excitation density effect and the complementary relationship between scintillators and storage phosphors.

https://www.jstage.jst.go.jp/article/pjab/94/2/94_PJA9402B-02/_pdf

Inorganic scintillating materials and scintillation detectors.

Cerium doped lutetium pyrosilicate Lu/sub 2/Si/sub 2/O/sub 7/ (Ce: LPS) scintillator presents high light output (average value: 26,300 ph/MeV), a relatively good energy resolution (10%) and a fast decay time (38 ns) without afterglow. The luminescence efficiency remains very high when the temperature increases up to 450 K. It makes this new scintillator very attractive. We compare its properties to those of another recently developed cerium doped silicate, Ce: Lu/sub 2(1-x)/Y/sub 2x/SiO/sub 5/ (LYSO).

High efficiency of lutetium silicate scintillators, Ce-doped LPS, and LYSO crystals

Cerium doped lutetium pyrosilicate Lu2Si2O7:Ce3+ (LPS), a new inorganic scintillator, displays particularly promising performance. This material can be readily pulled from the melt. A high light output (average value: 26 300 ph MeV−1), a relatively good energy resolution (9%) and a fast decay time (38 ns) without afterglow make this new scintillator very attractive, in particular for medical imaging. Optical characterizations and scintillation properties of LPS:Ce large single crystals are presented, including timing properties and study of the scintillation yields as a function of incident energy.

https://iopscience.iop.org/article/10.1088/0953-8984/15/12/326/pdf

Scintillation properties of Lu2Si2O7:Ce3+, a fast and efficient scintillator crystal

MicroLEDs Are Reaching Escape Velocity – A Focus On Transfer Processes and Equipment

Among the benefits of microLED displays, the possibility of integrating a variety of sensors directly on the front plane is probably the most intriguing and exciting.

E. Virey

Papers

High efficiency of lutetium silicate scintillators, Ce-doped LPS, and LYSO crystals

Scintillation properties of Lu2Si2O7:Ce3+, a fast and efficient scintillator crystal

MicroLEDs Are Reaching Escape Velocity – A Focus On Transfer Processes and Equipment

Can MicroLEDs Help Displays Better Sense the World?

Trends Toward Integrated RGB Microsystems for Mini and MicroLEDs