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Scintillators

Scintillators. Crystal and Liquid. Objectives. To differentiate between the crystal and liquid scintillators. To discuss the application of the liquid scintillator in the carbon 14 urea breath test. Scintillators: How they work. Base on band theory.

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Scintillators

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  1. Scintillators Crystal and Liquid

  2. Objectives • To differentiate between the crystal and liquid scintillators. • To discuss the application of the liquid scintillator in the carbon 14 urea breath test.

  3. Scintillators:How they work • Base on band theory. • The substance fluoresces or emits light when it interacts with a photon. • Use photomultiplier tube to convert the light energy into electrical pulses.

  4. Crystal scintillators • Sodium Iodide crystal activated in Thallium, NaI(Tl), used to enhance scintillation . • Na(Tl) are used in gamma ray detection (Gamma camera) and CsI(Na) crystals are used for x-ray detection. • Photomultiplier tubes attached to crystal

  5. NaI Gamma Camera Crystal

  6. Liquid scintillators • Used for detection of β-radiation. • A sample is dissolved in a scintillator solvent • Most common solvent used is benzene due to its scintillating properties. • The photomultiplier tubes are set outside the liquid sample.

  7. Liquid ScintillationApplications • Most application common is the Carbon 14 breath test • Non invasive procedure to detect the presence of Helicobacter pylori bacteria in the stomach and rule out gastritis. • Performed in 30 minutes.

  8. Carbon 14 Urea Breath Test • The patient swallows a urea capsule of 1 mCi. • After 10 minutes a breath sample is collected. • The breath sample is mixed with scintillation cocktail and analyzed

  9. Carbon 14 urea Breath Test

  10. Conclusion • The crystal and liquid scintillators work by the same principle of the scintillation of substances when interacting with incident radiation. • The vary in the type of scintillating material used and where the PM tubes are located. • Each has specific applications.

  11. Questions • Most common type of scintillator crystal? • NaI (Tl)

  12. The Carbon 14 urea breath test takes several hours to perform. (True or False). • False- takes 30 minutes.

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