 The signal thus picked up by the anode is further amplified and processed to modulate a display screen and form an image as in SEM.Notably, in this design and the associated gaseous electron amplification, the product p·d is an independent parameter, so that there is a wide range of values of pressure and electrode geometry which can be described by the same characteristics.The consequence of this analysis is that the secondary electrons are possible to detect in a gaseous environment even at high pressures, depending on the engineering efficacy of any given instrument.