1 / 10

Paul Jacks 05/06/06 NMT1002 Prof Marshel

Paul Jacks 05/06/06 NMT1002 Prof Marshel. Gas Filled Radiation Detectors. What you should learn about the equipment you are using . How it works. How to operate it. How to perform maintenance and quality control. How to repair it. . Gas Filled Used for non-imaging applications

adriana
Télécharger la présentation

Paul Jacks 05/06/06 NMT1002 Prof Marshel

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Paul Jacks05/06/06NMT1002Prof Marshel Gas Filled Radiation Detectors

  2. What you should learn about the equipment you are using • How it works. • How to operate it. • How to perform maintenance and quality control. • How to repair it.

  3. Gas Filled Used for non-imaging applications Three types used in nuclear medicine Ionization Chambers Proportional Counters Geiger-Mueller Detectors Scintillation Used in nuclear medicine for radiation detection when imaging is being performed Radiation DetectorsGas Filled vs. Scintillation

  4. Ionization • When an atom becomes ionized, it forms a pair of ions that are oppositely charged. This is called an ion pair. • The ion pair consists of a positively charged atom and negatively charged electron • Radiation causes ionization

  5. Neg Neg Neg Ionization Neg

  6. Construction • Gas filled detectors contain Helium, Argon, Neon, or Hydrogen • At one end of the chamber is a positive anode, at the other end is a negative cathode. Power Source Alarm Anode Cathode Measurement Gas

  7. Ionization Chamber • 100-400V • Radiation causes ionization • Electrons are attracted to positive anode • Positive ions are attracted to negative cathode • Ion pairs pulled apart and a current forms • Current is measured and determines how much radiation is deposited in chamber

  8. Proportional Counter • Similar to Ionization chamber • Higher Voltage 400-800V • Ions gain kinetic energy and “bump” into gas molecules causing them to become ionized in a chain reaction. • More ions form than in an ionization chamber, but measurement of current is proportional to amount of energy deposited from radiation.

  9. Geiger-Mueller Counter • Higher Voltage 1000-1500V • Even small amount of radiation sets off a chain reaction of ionization from the ions bumping into gas molecules with tremendous kinetic energy. • Works like a yes/no detector since even small amounts of radiation cause large current.

  10. Application • Ionization chamber and proportional counters can be used to measure activity of a dose to be given to patient • Geiger-Mueller Detectors can be used to survey the lab for radiation in unknown places.

More Related