ELECTRONS AND CAVITATION IN LIQUID-HELIUM

We describe a number of experiments in which the effect of electrons o n cavitation is studied. Electrons in liquid helium become trapped in a bubble from which the liquid is almost completely excluded. By apply ing a negative pressure to the helium, we are able to make these bubbl es explode. We have measured the variation of this pressure with tempe rature and the results are in very good agreement with theoretical exp ectations. At low temperatures the electron bubbles become attached to vortices. The circulation of the liquid around the electron bubble le ads to a reduction in the magnitude of thr negative pressure required to explode the bubble, and we have been able to measure this reduction .