Anyone proficient in the use of e/m Apparatus??

Question

I am conducting an electron charge -to-mass ratio experiment... Would like to know if anyone is particularly good at using this apparatus and if so I have a troubleshooting question.

A few of the beam "SWIRL" when the experiment is on. Now I know that there is a feature that allows the beam to BEND towrd one of the Helmholtz coils ( to demonstrate the effect of magnetic field on the beam). But i think this problem is different.

It swirls (sometimes more than once) and he current k**b does not have much effect. This does not happen with all just a few. Wondering if this is a problem of worn tubes or is it the apparatus .... what am i doing wrong (i set them all up the same way, others work).

Can someone assist?? That would be greatly appreciated.

Answer 1

Your bulb needs to be rotated.  In a magnetic  field, charged particles follow a helixical path.  If you have the bulb rotated to the proper orientation, the magnetic fields will basically balance one another and not allow any translational motion of the electrons.