Using Sensors to Detect Radiation

This article was updated on the 6th May 2019.

Ionizing radiation is invisible to the naked eye. When it interacts with matter several events can take place, including the emission of charged particles and photons. These events can be used to detect radiation and calculate particle flux intensity.​

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Basic Principle

Ionizing radiation can be detected using the following methods:

• Geiger counter - A device consisting of a Geiger Müller tube filled with an inert gas. When a high voltage is applied to the gas-filled tube and radiation passes through, the gas becomes ionized and the charged gaseous ions move to the cathode and anode. This results in an electrical current that can be measured and used to work out the number of ionization events caused by the radiation.
   
• Scintillation counter – A solid, liquid or gaseous material that produces short bursts of light when it interacts with ionizing radiation. The photons produced in the scintillation burst can be detected using a photomultiplier tube, which also amplifies the current produced by ionization events to levels that can be recorded.
   
• Particle track devices – A device able to visualise the path of ionizing particles. An example of such a device is a cloud chamber which reveals the path of an ionizing particle as condensation traces in air supersatured with water. The curvature of the path can be used to calculate the charge and momentum of the particles.
   
• Neutron REM meter – A device consisting of a proportional counter tube filled with helium-3 or boron trifluoride gas. These capture any incoming neutrons and emit charged particles that subsequently ionize the gas. Charged ions are formed which move due to an applied voltage and can then be measured.

References

• Principles of Radiation Detection – IIT Bombay
• Radiation Detection – Georgia State University