Does glass stop electrostatic fields?

[Opcom]

Stupidest of science questions here.

The drawing is of a vacuum tube in which an electron beam is coming at the observer  - perpendicular to the page. Like a beam from the electron gun in a CRT.

There are aluminum foil electrodes - same as a sort of deflection plates -on the outside of the tubing of either common glass or borosilicate.

Am I correct in assuming that deflection will not occur to the beam because the glass insulates the space inside the vacuum tube from the external charge placed on the plates?

If it makes a difference, the voltage applied could be DC to maybe 5MHz.

[K8DI]

Electric field strength is influenced by the medium, be it vacuum, air, mica, glass.  None of these BLOCK electric fields.  Conductors have a far greater effect.  The beam will deflect.

Think about this in a few instances…metal plates next to tubes for neutralization pickup..A capacitor, which is an electric field energy storage device….

Ed

[Opcom]

The old warnings about mercury vapor rectifiers and RF fields now comes to mind. Indeed!

[DMOD]

Stupidest of science questions here.

The drawing is of a vacuum tube in which an electron beam is coming at the observer  - perpendicular to the page. Like a beam from the electron gun in a CRT.

There are aluminum foil electrodes - same as a sort of deflection plates -on the outside of the tubing of either common glass or borosilicate.

Am I correct in assuming that deflection will not occur to the beam because the glass insulates the space inside the vacuum tube from the external charge placed on the plates?

If it makes a difference, the voltage applied could be DC to maybe 5MHz.

The beam will deflect in the -X, +X direction as the external potential is varied with respect to magnitude and polarity. The electron beam will deflect to the +X direction with the potential shown.

Since glass is a dielectric, the static field will be distorted somewhat.

Phil - AC0OB

[Opcom]

Stupidest of science questions here.

The drawing is of a vacuum tube in which an electron beam is coming at the observer  - perpendicular to the page. Like a beam from the electron gun in a CRT.

There are aluminum foil electrodes - same as a sort of deflection plates -on the outside of the tubing of either common glass or borosilicate.

Am I correct in assuming that deflection will not occur to the beam because the glass insulates the space inside the vacuum tube from the external charge placed on the plates?

If it makes a difference, the voltage applied could be DC to maybe 5MHz.

The beam will deflect in the -X, +X direction as the external potential is varied with respect to magnitude and polarity. The electron beam will deflect to the +X direction with the potential shown.

Since glass is a dielectric, the static field will be distorted somewhat.

Phil - AC0OB

I was thinking about that. The result would be more or less unpredictable from a straight experimental position without a simple way to simulate ot FEA it. Also the beam cross section  could easily become distorted.

Best filed under 'thought experiments', but the use of an oscilloscope CRT too near the RF tank of a large transmitter could be a problem without some shielding.
--Patrick/opcom