What part of the image intensifier accelerates the electrons?

The focusing lens and anode play a crucial role in the operation of an image intensifier by accelerating and directing the electrons generated by the photocathode. When x-rays strike the input phosphor, it emits light photons. These photons then strike the photocathode, causing it to release electrons in a process known as photoemission.

Once the electrons are emitted, they are drawn towards the anode, which is positively charged. The focusing lens helps to direct these electrons toward the output phosphor in a more focused beam, thereby enhancing the efficiency of the image intensification process. By creating a strong electric field, the anode accelerates the electrons as they travel through the vacuum of the image intensifier, ultimately resulting in a brighter output image when these electrons finally strike the output phosphor.

This process is essential for improving image quality in fluoroscopy, as the accelerated and focused electrons contribute to a higher intensity of light emitted from the output phosphor, facilitating better visualization of the anatomical structures being examined.