12. Glossary

Barémage; Gauging, Strapping

Evaluation (or "gauging") of the volume of a tank, reservoir or cistern, especially when legally required, for example in commercial transactions (governed by legal metrology).

Soft" and "hard" photons

A distinction is made between hard and soft photons (generally X-rays) according to their energy, the former being greater than around 5 to 10 keV (wavelength less than 0.1-0.2 nm). Unlike hard photons, soft photons are easily absorbed by millimetre-thick solid matter.

Bulk density

Apparent density or, more precisely, apparent density without compaction, often incorrectly referred to as "bulk density", is a quantity used mainly with substances in granulated form, in the food industry, in soil science for soil description, or in building...