Glass tube with glass fiber, vacuum tube, inside he is to prevent the accelerated electron does not come out of the gas or particle collision with to reduce friction between the electrons with the air themselves.
The glass tube is made of glass Pirates won. Inside the tube is a vacuum in order to prevent the accelerated electrons collide with the particles out of gas. Or to reduce the friction between the electrons and air.
Glass tube glass Pyrex. Inside the tube is a vacuum to prevent electrons to accelerate out not collide with particles of the gas. Or to reduce the friction between the electron and the air itself.