What material is used in the input phosphor of modern image intensifier tubes?

The input phosphor of modern image intensifier tubes is made from cesium iodide. This material is chosen for its high efficiency in converting x-rays into visible light, which is crucial for the performance of the image intensifier. Cesium iodide crystals have a unique structure that allows for superior resolution and a higher light output compared to other materials. The use of cesium iodide contributes to the enhanced image quality, ensuring that the details captured during fluoroscopy are clear and precise.

In modern applications, the effectiveness of cesium iodide is particularly significant when comparing it to older materials. For instance, while sodium iodide can also act as a phosphor, it does not provide the same level of resolution. Calcium tungstate has been used historically, but it offers lower efficiency and produces less light compared to cesium iodide. Zinc cadmium sulfide, although historically important in certain applications, is less commonly utilized in the latest image intensifier designs because of issues related to luminescence and stability. Therefore, cesium iodide is the material of choice in modern imaging technology, providing optimal performance in fluoroscopy.