Assertion: free electron | /r/HasProperty | formed into narrow convergent beam
Facets:
value: by an electric field
type: CAUSE
Source sentences:
text: They are then accelerated and formed into a narrow convergent beam by an electric field produced by three electrodes: the electron emitting strap, the cathode connected to the negative pole of the high (accelerating) voltage power supply (30 - 200 kV) and the positive high voltage electrode, the anode.