A metal tube that directs the X-rays to the specified size.

X-ray imaging requires the use of harmful ionizing radiation to image structures inside the body.  An x-ray image intensifier, shown in Figure 1, allows high-quality imaging with very low radiation exposure to the patient.Figure 1  Schematic of an x-ray image intensifierThe x-ray image intensifier amplifies the imaging signal by approximately 300,000 times.  The intensifier converts the image data from x-ray photons to visible light, then to electrons, and back to visible light.  At each conversion stage, the signal is amplified up to 1,000 times.The x-ray image intensifier consists of a vacuum chamber that contains an input phosphor, a photocathode, focusing electrodes (not shown in Figure 1), an anode, and an output phosphor.  The anode voltage is 25 kV higher than the photocathode, generating a strong electric field in the vacuum.  The input phosphor converts x-ray photons into visible light, which then ejects electrons from the photocathode.  Even with an anode voltage of 25 kV, no current will flow through the vacuum unless electrons are ejected from the photocathode.  Ejected electrons are accelerated toward the anode and focused onto the output phosphor.  At the output phosphor, the electrons are converted back into visible light, allowing image data to be recorded with a camera or video system.  (Note:  Use c = 3 × 108 m/s in a vacuum, if needed.)Question 30Is the vacuum chamber in an x-ray image intensifier an electrical insulator?A.Yes, because only electrons ejected from the photocathode can travel through the vacuum chamberB.Yes, because no electrons can travel through the vacuum chamberC.No, because electrons can travel through the vacuum chamber even without x-rays at the input phosphorD.No, because electrons in the vacuum chamber are not exposed to a voltage difference

describe the uses of x-rays in dentistry

Through the movement of electron, energy is produced, in the case of X-ray production what form of energy does an x-ray tube produced?

Cathode rays

What are canal rays?