… Oscilloscopes, spectrum analysers and other instruments and apparatus for measuring or checking electrical quantities, … alpha, beta, gamma, X-ray, cosmic or other ionising radiations. …
Explanatory notes
… spectrum analysers and other instruments and apparatus for measuring or checking electrical quantities, … The ions formed when a radiation enters the chamber are attracted to the electrodes, and the resulting changes in … usually consisting of a loop of taut wire with mirrors attached, moves in the field of an electro‑magnet. The …