As part of meeting the requirements of the CNSC, applicants must have an available survey meter at any site of the licensed radioactive activity. A survey meter can also be used for emergency events involving the portable gauges, including crushing or other physical damage. The applicant may satisfy the requirements by having a calibrated survey meter at the site of licensed activity within two hours of notification that it is needed. The applicant may have a contract with a service provider who can provide a calibrated survey meter. A copy of the contract must be provided to the service provider for the proposed period of the license.

The radiation survey meter is an essential piece of equipment for doing radiation surveys, or in the case of an accident or emergency. The term “survey meter” encompasses a broad category of devices, from the simple to the very complex. These devices are designed to measure gamma radiation, and since that is the primary concern with portable gauges, is quite practical for our needs. There are survey meters that are capable of measuring other forms of radiation. An example would be the M200. It measures alpha, beta, gamma, and x-rays. The law requires organizations who use survey meters to perform an annual instrument calibration check to ensure that they operate accurately.

A simple survey meter employs a Geiger-Muller tube. As ionizing radiation enters the GM tube, it ionizes the gas within the tube creating ion pairs. The negative ions are attracted to the anode, and the positive ions are attracted to the cathode. Whenever a particle makes contact, a brief circuit, or “count” occurs. In a survey meter, these counts are converted to Absorbed Dose units. In the gauges, this count information is analyzed against the current calibration curve and displayed as density.