Toray Resolves Brightness Degradation with Brightest and Most Durable Scintillator Panel for High-Speed Nondestructive X-ray Inspections

Toray Industries, Inc., announced that it has developed a highly durable short-afterglow scintillator panel (see note 1) that accelerates non-destructive X-ray inspections (see note 2) and enhances their operational efficiency. It launched this offering in Japan and abroad in June 2024.

Companies frequently use non-destructive X-ray inspections to ensure the quality of such critical products as semiconductors, electronic components, and food products. Defects or contamination can create major social issues. These include infrastructure disruptions, automobile accidents, and health hazards. The market for X-ray inspection systems should expand around 10% annually. Key growth drivers are the expanding scope of product inspections, broader inspection targets, and the adoption of complete in-line inspections.

Moving products and cameras swiftly and capturing images at high speeds reduces item inspection times. The downside with scintillator panels using general-purpose terbium-doped gadolinium oxysulfide (GOS) phosphors (note 3) is blurred images (see Figure 1), such as transfer direction tails. Praseodymium-doped GOS phosphors (note 5) have short afterglows (note 4) and can sharpen images. They are less bright, however, than terbium-doped GOS phosphors. Another challenge is that non-destructive high-speed X-ray inspections are often around the clock, and X-ray irradiation erodes scintillator panel brightness, increasing X-ray detector replacement frequency.

Toray boosted initial scintillator panel brightness (note 6) by as much as 21% (see Table 1) by using a highly reflective proprietary base film. By identifying and addressing luminance degradation causes, luminance (note 7) after acceleration tests was up to 30% greater than with conventional technologies (see Graph 1).

By delivering high brightness and controlling luminance degradation, Toray created a highly durable scintillator panel for fast non-destructive X-ray inspection, commercializing it in response to customers finding it valuable for them.

• Initial luminance: Measured with Toray equipment at a tube voltage of 70 kilovolts, with no additional filter
• Relative values benchmarked against the conventional technology’s initial luminance of 100%.
• Luminance after acceleration testing: Luminance value after 50 days of X-ray irradiation at 60 kilovolts with a cumulative dose of 1.1 MGy benchmarked against an initial luminance of 100%

Toray will maintain its leading position in this area by developing and supplying new X-ray scintillator panel products that meet customer needs. It will keep innovating materials that contribute to a better society in keeping with its commitment to delivering new value and contributing to social progress.

Notes

1. A short afterglow scintillator panel incorporates a scintillator that emits fluorescence when excited by X-rays, and whose time until afterglow emissions reach a certain level after X-rays are stopped is shortened.
2. Nondestructive X-ray inspections find internal chipping and scratching without disassembling objects by irradiating X-rays and detecting differences in the amounts X-rays transmitted through object.
3. Terbium-doped gadolinium oxysulfide is a phosphor that absorbs X-rays and emits them in the form of visible light and is universally used.
4. Afterglow is the luminescence after X-ray irradiation stops. It is the decay time, which is how long it takes for luminance to reach 1/e (Napier number) after X-ray irradiation stops. The afterglow (afterglow luminance divided by initial luminance) after a certain time is used as an indicator.
5. Praseodymium-doped gadolinium oxysulfide is a phosphor that absorbs X-rays and emits light at a different wavelength, resulting in a shorter afterglow than terbium-doped gadolinium oxysulfide.
6. Initial brightness results from using Toray equipment to measure in-house products 400 micrometers thick at a tube voltage of 70 kilovolts, with no additional filter. Relative values are benchmarked against the conventional technology’s initial luminance of 100%.
7. After measuring initial luminance with in-house equipment, Toray obtained luminance values 50 days after irradiation with a cumulative 1.1 MGy of X-rays at 60 kilovolts. The difference between the initial luminance of 100% and relative value is shown.