How's the electrons of the accelerated electron beam enter the bubble chamber that contains the liquid hydrogen? Wouldn't the high intensity of the electron beam cause a massive explosion and destroy the bubble chamber that has an outer wall of at least quarter inch of steel!! I think hydrogen is highly flammable and an high energy electron beam could maybe cut through steel? The cloud chamber's, that is the predesisor of the bubble chamber, particles are produced by a radioactive isotope that is inserted into the cloud chamber but the bubble chamber that is an offspring of the cloud chamber must somehow let the electrons into the bubble chamber to create the ionization tracks that are used to justify the existence of the subatomic particles and particle physics. Maybe someone could ask the honorable Higgs but don't give him a heart attack since he's such a nice guy and extremely funny.