What occurs when a multi-focus image intensifier tube is operated in magnification mode?

When a multi-focus image intensifier tube is operated in magnification mode, greater voltage is applied to the electrostatic lenses. This adjustment is necessary to enhance image quality during magnification by focusing the electron beam more tightly. When the tube is switched to magnification mode, it uses a smaller input area of the image intensifier, which requires more precise control over the electron flow. By increasing the voltage, the electrostatic lenses can better direct the electrons toward the output phosphor, resulting in improved resolution and clarity of the image.

The process of increasing voltage also aids in compensating for the reduced input size to ensure that the electron multiplication remains effective, thereby maintaining brightness and detail in the magnified image. This technical requirement is crucial in achieving high-quality diagnostic images in radiographic procedures.