The Operational Check consists of a 21oz (600g) sample of granite gravel, enclosed in a container that may be sealed by closing two ball valves and end caps.

Granite generally contains trace amounts of both uranium and thorium that has been in the rock since it was formed, millions if not billions of years ago. Therefore all the progeny of both the uranium and thorium decay chains are fully supported and in full equilibrium down to ²²⁶Ra and ²²⁴Ra.

The Operational Check therefore constitutes a rock-steady emitter of both radon and thoron. It is possible to take advantage of that property to check the performance of a RAD7.

Operational Check Physical Specifications