The Geiger Muller sensor is used to monitor Alpha, Beta and Gamma radiation.

The GM sensor consists of the Geiger Muller adapter, a Geiger Muller Counter (GM tube with built-in integral high tension power supply) and a steel rod for fixing to a suitable holding device.

No additional power supply is required.

This updated version of the Geiger Muller sensor has 2 new ranges (counts per 10 seconds and counts per minute) and an improved counting algorithm. The sensor now has 5 ranges compared to 3 in the previous version.

Applications

Physics:

• Radioactive half life decay curves e.g. Protactinium
• Effect of distance from a source on count rate
• Activity of different radioactive sources
• Radioactive penetration through different materials placed between the source and GM tube
• Environmental Science:
• Background radiation
• Locating radiation hot spots due to mineral deposits
• Increased radiation in enclosed spaces due to Radon production and retention
   

Use the Counts per one second, ten seconds or one minute ranges for investigations to determine half life and absorption of radiation by different materials.

Use Open Count to measure a total accumulated count e.g. background count. Use the button on the sensor housing to reset a count to zero.

Pulse Output - Each radioactive particle will generate one voltage pulse. The occurrence of the pulse is recorded to show the randomness of atomic decay. This range requires fast data capture.

The GM sensor does not require an external power source as it derives power from the EasySense unit. A yellow LED power indicator shows that an operating voltage is supplied to the Counter, and a buzzer emits an audible signal for each radioactive pulse that is recorded.

Technical specification for the GM tube window:

• Thickness: 1.5 to 2.0 mg/cm2
• Useful diameter: 9.14 mm
• Material: Mica
• Gas filling: Neon, Argon, and Halogen

The GM tube's window is made of a thin sheet of mica, which is a fragile material, easily damaged. To protect this window the tube is fitted with a protective cap that should be left on except when measuring Alpha radiation.

Measurement procedure: Radioactive sources used in schools are usually weak, but care must be taken in handling them. An authorised person must be in attendance. Ensure all local rules and recommendations made in any relevant Safety Data Sheets are complied with. Prepare a risk assessment before the experiment or activity is carried out.