It was always my belief that the getter was simply a chemical impregnated ring that was heated from the outside of the tube after gas has been vacuumed; for the purpose of "burning off" of the remaining gas. Cathodes lose emission because the rare-earth electron-rich coating the cathode is covered with, eventually boils off and gets caught in the electron flow, so much like the "solar wind" until such time as the cathode has less electron-emitting capability, resulting in a lowered emission (weak tube). To this arguement, the getter had done its job at the factory when the tube was initially suctioned and sealed and has no further use after that time. Although the analogy of weakened cathode condition remains, both in tubes and neon bulbs. In the case of the electronic flash, it is possible that the capacitpr has lost some small part of capacity, triggering the neon tube to drop down slightly in starting voltage and relights as the capacitor is re-filled. The capacitor can be likened to a air tank or inner tube with a tiny pinhole in it.
Originally Posted by Gerald C Koch
Altogether said, the flickering of the neon tube can still be considered a negligible condition. No real harm done in flash power.
Last edited by Tom1956; 09-03-2013 at 12:37 AM. Click to view previous post history.