Deflection Sensitivity of Parallel-Wire Lines in Cathode-Ray Oscillographs

The deflection angle θ of a cathode-ray beam accelerated by a potential V is shown to be proportional to the linear charge density ρ transverse to the beam on the interior of the electrostatic deflection system, θ=ρ/2Vε0. The voltage deflection sensitivity depends on the plate-to-plate capacitance c per unit width, θ/E=c/2Vε0. This includes edge effects and permits a determination of the sensitivity from capacitance measurements or a simple graphical evaluation from the dimensions of the deflection system. The use of parallel-wire lines as a deflection system is suggested, and its deflection sensitivity evaluated. Such lines have low transit time error and are either easily tuned, or can be operated non-resonant with resistive termination.