2014 Dose Data from the Fixed Point Surveillance Network

The Fixed Point Surveillance (FPS) network monitors public radiation dose due to radioactive materials in the atmosphere. The FPS network is used primarily to measure the external dose from three noble gases in particular; Argon-41, Xenon-133 and Xenon-135, as well as the total combined external dose from all sources, measured as Total Air KERMA.

For all of the tables on this page, the following definitions apply:

nGy (nanoGray)

A Gray (Gy) is a standard unit of measurement for radiation dose, defined as 1 Joule of energy deposited per kilogram of matter. A nanoGray (nGy) is 1×10-6 milliSieverts (mSv) and it is a much more common unit of measure for these types of very low doses.

KERMA (Kinetic Energy Released in Matter)

In this case the 'Total Air KERMA' refers to the radiation dose from all external gamma sources, not just from the three noble gases Argon-41, Xenon-133 and Xenon-135. This includes natural background radiation as well, such as from mineral deposits in the ground or radon gas in the air.

(hyphen)

The system has a limit on the amount of low-level radiation it can reliably detect and use to calculate a monthly dose and the hyphens represent any data which falls below this detection limit. The minimum detectable dose for the three noble gases being monitored are:

• 6 nGy/month for Argon-41
• 3 nGy/month for Xenon-133
• 3 nGy/month for Xenon-135

These detection limits are well below the acceptable public dose limit of 1 mSv/year as published by the Canadian Nuclear Safety Commission in their Radiation Protection Regulations.

(x)

The dose data for this month was not collected due to a problem with the equipment or data transfer.