Recent research in the field of phosphor and scintillator materials and related detectors is reviewed. After a historical introduction the fundamental issues are explained regarding the interaction of x-ray radiation with a solid state. Crucial parameters and characteristics important for the performance of these materials in applications, including the employed measurement methods, are described. Extended description of the materials currently in use or under intense study is given. Scintillation detector configurations are further briefly overviewed and selected applications are mentioned in more detail to provide an illustration.

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Scintillation detectors for x-rays

A review of medical diagnostic imaging methods utilizing x-rays or gamma rays and the application and development of inorganic scintillators is presented.

https://iopscience.iop.org/article/10.1088/0031-9155/47/8/201/pdf

Inorganic scintillators in medical imaging.

Rare-earth-doped oxynitride or nitride compounds have been reported to be luminescent and may then serve as new phosphors with good thermal and chemical stabilities. In this work, we report the photoluminescence (PL) spectra of europium-, terbium-, and praseodymium-doped Ca-α-SiAlON ceramics. The highly dense ceramics were prepared by hot pressing at 1750°C for 1 h under 20 MPa in a nitrogen atmosphere. Europium-doped Ca-α-SiAlON displayed a single broad emission band peaking at λ = 550-590 nm depending on the europium concentration. The emission bands in the spectra of europium-doped Ca-α-SiAlONs were assigned to the allowed transition of Eu 2+ from the lowest crystal field component of 4f 6 5d to 8 S 7/2 (4f 7 ) ground-state level. The emission spectra of terbium- and praseodymium-doped Ca-α-SiAlON ceramics both consisted of several sharp lines, which were attributed to the 5 D 4 → 7 F j (j = 3, 4, 5, 6) transitions of Tb 3+ and 3 P o → 3 H j (j = 3, 4, 5) transitions of Pr 3+ , respectively. In particular, the terbium-doped α-SiAlON ceramics showed a strong green emission among these phosphors.

Preparation and Luminescence Spectra of Calcium- and Rare-Earth (R = Eu, Tb, and Pr)-Codoped α-SiAlON Ceramics

Due to events of the past two decades, there has been new and increased usage of radiation-detection technologies for applications in homeland security, nonproliferation, and national defense. As a result, there has been renewed realization of the materials limitations of these technologies and greater demand for the development of next-generation radiation-detection materials. This review describes the current state of radiation-detection material science, with particular emphasis on national security needs and the goal of identifying the challenges and opportunities that this area represents for the materials-science community. Radiation-detector materials physics is reviewed, which sets the stage for performance metrics that determine the relative merit of existing and new materials. Semiconductors and scintillators represent the two primary classes of radiation detector materials that are of interest. The state-of-the-art and limitations for each of these materials classes are presented, along with possible avenues of research. Novel materials that could overcome the need for single crystals will also be discussed. Finally, new methods of material discovery and development are put forward, the goal being to provide more predictive guidance and faster screening of candidate materials and thus, ultimately, the faster development of superior radiation-detection materials.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0884291400030016

Radiation Detector Materials: An Overview

This paper presents new developments in inorganic scintillators widely used for radiation detection. It addresses major emerging research topics outlining current needs for applications and material sciences issues with the overall aim to provide an up-to-date picture of the field. While the traditional forms of scintillators have been crystals and ceramics, new research on films, nanoparticles, and microstructured materials is discussed as these material forms can bring new functionality and therefore find applications in radiation detection. The last part of the contribution reports on the very recent evolutions of the most advanced theories, methods, and analyses to describe the scintillation mechanisms.

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Needs, Trends, and Advances in Inorganic Scintillators

Preparation d'un scintillateur de type Gd 2 D 2 S:Pr, Ce, X (avec X=F, Cl), utilise comme detecteur pour tomographie RX digitale. Le dopage du scintillateur par des ions halogene provoque un accroissement du pouvoir emissif de l'ordre de 30% tandis qu'un dopage avec du Ce reduit la phosphorescence du systeme. Une pression isostatique exerce sur ce materiau a l'etat de poudre, donne un scintillateur ceramique translucide

https://iopscience.iop.org/article/10.1149/1.2097566/pdf

A Scintillator Gd2 O 2 S : Pr , Ce , F for X‐Ray Computed Tomography

The quality of CT images depends on the characteristics of the X-ray detector. In place of conventional xenon ionization detectors, we have designed a highly efficient solid state detector with low detector noise by using a Gd2O2S ceramic scintillator.

https://iopscience.iop.org/article/10.1143/JJAP.27.L1572/pdf

Application of Gd2O2S ceramic scintillator for X-ray solid state detector in X-ray CT

Translucent scintillator ceramics of Gd2O2S:Pr, Ce, F were fabricated using a hot isostatic pressing (HIP) technique. The optical transmission is about 60% of the incident light and the X-ray stopping power is also quite high. Owing to the enhancement of these properties by the HIP densification process, the highest light output from a 1 mm thick specimen combined with a silicon photodiode, when excited by 120 kV X-rays, has reached 1.8 times that of CdWO4 single crystals. The present ceramics are very promising candidates for scintillator materials in X-ray computed tomography (CT) detector applications.

https://iopscience.iop.org/article/10.1143/JJAP.27.L1371/pdf

Hot isostatic pressed Gd2O2S:Pr, Ce, F translucent scintillator ceramics for X-ray computed tomography detectors

PURPOSE: To obtain an amorphous thin film with low coercive force and high initial permeability by sputtering or vapor-depositing an alloy consisting of a nonmetallic element and a rare earth element replaced partially by a metallic element such as Ti, Zr or Hf and the balance essentially transition metallic element. CONSTITUTION: An alloy expressed by a formula M a T b X c Z d is prepared. In the formula M is ≥1 kind of element selected from Fe, Ni and Co, T is ≥1 kind of element selected from Mn, Cr, W, etc., X is ≥1 kind of element selected from Zr, Ti, Y, etc., Z is ≥1 kind of element selected from P, B, C, etc., a+b+c+d= 100, 0≤b≤95, 30≤a+b≤95, 0≤c≤70and 0≤d≤30. The alloy is sputtered or vapor-deposited to manufacture an amorphous thin film. This film is different from a conventional amorphous thin film in alloy composition and has high thermal stability. when the film is magnetized, it shows superior magnetic characteristics, that is, low coercive force and high permeability. COPYRIGHT: (C)1983,JPO&Japio

Manufacture of amorphous thin film

A film resistor heater comprising a sprayed film resistor comprisng NiCr particles uniformly dispersed and partly contacted with each other in an insulating ceramic matrix The film resistor heater may further comprise a bonding layer, an insulating layer and a protective layer The film resistor heater is prepared by spraying, particularly plasma spraying It may be used advantageously for home electric appliances such as hot plates, rice cookers and vacuum kettles, heat rolls for electrostatic copiers, etc

Yasuo Tsukuda

Papers

A Scintillator Gd2 O 2 S : Pr , Ce , F for X‐Ray Computed Tomography

Application of Gd2O2S ceramic scintillator for X-ray solid state detector in X-ray CT

Hot isostatic pressed Gd2O2S:Pr, Ce, F translucent scintillator ceramics for X-ray computed tomography detectors

Manufacture of amorphous thin film

Plasma sprayed film resistor heater