Chapter 4: Radiation Detectors - Scintillators

22 flashcards · Biology · by Kristóf Nagy

1. Scintillator detector

   A device that uses a scintillator to detect ionizing radiation by converting the emitted light into an electrical signal.34

2. Ionizing radiation

   Radiation that has enough energy to remove tightly bound electrons from atoms, creating ions.34

3. Scintillation

   The emission of visible light from a material when it absorbs ionizing radiation.34

4. Scintillator

   A material that exhibits scintillation.34

5. Organic scintillator

   A scintillator made of organic molecules.35

6. Inorganic scintillator

   A scintillator made of inorganic crystals.35

7. Band structure

   A model that describes the allowed energy levels for electrons in a solid.353637

8. Valence band

   The highest energy band in a solid that is occupied by electrons at absolute zero temperature.3536

9. Conduction band

   The lowest energy band in a solid that is unoccupied by electrons at absolute zero temperature.3536

10. Fermi energy

    The energy level at which there is a 50% probability of finding an electron at a given temperature.35

11. Activator

    An impurity added to an inorganic scintillator to enhance its light output and shift the emission wavelength to a more detectable range.3738

12. Photomultiplier tube (PMT)

    A vacuum tube that converts light into an electrical signal by using a photocathode to emit electrons and a series of dynodes to multiply the electrons.3839

13. Photodiode (PD)

    A semiconductor device that converts light into an electrical current.3840

14. Avalanche photodiode (APD)

    A photodiode that uses an internal gain mechanism to amplify the electrical signal produced by incident light.3841

15. Silicon photomultiplier (SiPM)

    A solid-state photodetector that operates in Geiger mode, producing a large electrical pulse for each detected photon.3842

16. Quantum efficiency (QE)

    The ratio of the number of emitted photoelectrons to the number of incident photons.39

17. Semiconductor

    A material with electrical conductivity between that of a conductor and an insulator.3643

18. Doping

    The intentional introduction of impurities into a semiconductor to modify its electrical properties.43

19. n-doping

    Doping a semiconductor with impurities that donate electrons to the conduction band.43

20. p-doping

    Doping a semiconductor with impurities that create holes in the valence band.41

21. p-n junction

    A boundary between p-type and n-type semiconductor materials, which creates a depletion region and a built-in electric field.41

22. Depletion region

    A region in a p-n junction where there are very few free charge carriers.41