What Does 'Gain of the Detection System' Mean in Particle Detection?

[pivoxa15]

In the context of detectors of gamma rays, electrons etc. Does the term 'gain of the detection system' mean the ratio of the number of registered counts per bombardment from radioactive source?

 

[Astronuc]

If heard 'gain' used in the context of signal strength of each interaction. In older electronics, stronger individual pulses did have an influence on detector efficiency because the electronics could not distinguish a low energy interaction following a higher energy interaction.

See if this discussion is useful -
http://www.nucsafe.com/Technology/gamma_interactions_and_spectroscopy.htm

What textbook is one using?