Chapter 6 CCD/CMOS Exam Questions Correctly Answered.

Chapter 6 CCD/CMOS Exam Questions Correctly Answered. 1. charge-coupled de- The oldest indirect conversion digital radiography systems used vices (CCDS) to acquire the digital image. 2. scintillation/ lenses or fiber 3. size/ light to electrical charge 4. analog-to-digital con- verter (ADC) 5. photosensitive recep- tor In a CCD system, x-ray photons interact with a material and the signal is transmitted by or optics to the CCD. During the transmission process, the lenses reduce the of the projected visible light image and transfer the image to one or more small capacitors that convert to . This charge is stored in a sequential pattern and released line by line and sent to an . A and electronics embedded into a substrate material in a silicon chip make up a CCD. 6. Incident light from a scintillator strikes the detector and electron/hole pairs are produced in the silicon. 7. light The number of electron/hole pairs is related to the amount of that is absorbed. 8. electrostatic forces The electrons are held by in the array until the charge is read out to from the image. 9. polysilicon layer, sili- con dioxide layer, sili- con substrate The chip is made up of a layer, layer, and a . 10. polysilicon The layer is coated with a photosensitive material and contains electronic gates. 11. silicon dioxide/ silicon substrate The layer is an insulator and the contains the charge storage area. 12. detector element (del) Each pixel or contains three electrodes that hold the electrons in a electrical potential wall. 13. voltage gates/ elec- trons 14. readout row/ "bucket brigade scheme" The dels are formed by that, at readout, are opened and closed like gates to allow the flow of . To collect the charge on the silicon chips, the voltage sign is changed on the electrodes within each del, moving the electrons by rows down the columns until the is reached. This is known as what? 15. amplifier Once the readout row is reached, the data are sent sequentially to the sense and are then digitized. 16. electrons There can be issues with overfill in the dels, which causes excessive to spill out of the del into an adjacent del. 17. "blooming" This is handled by building overflow drains into the array to reduce or prevent this " " ettect. 18. 5 cm x 5 cm Because of high cost of a CCD chip, it is not practical to manufacture CCD chips any larger than . 19. 2 to 4 cm Most chips range from to . 20. CCD The image has to be matched to the size of the , which implies that the image must be reduced in size. 21. scintillator, light collec- tion components, and noise 22. scintillator Reducing the image size involves several factors that contribute to the quality of the image including , , and . The type of and the way it is constr