Screen Wire Simulations (3-16-00)

Some simulations were run to see if the model would predict a 15% difference in screen transmission between +10 and -10V. The model shows that there is significant deflection of paths that pass near the wires but the number that actually hit the wire changes by less than 1%. In both cases the deflection is likely to scatter more into the walls.

This simulation should over estimate this effect considerably. It only used parallel wires in one direction. The actual screen is a grid with wires in both directions. This would make the leakage field between wires much smaller.

This model does show that electrons of slightly lower energy than the screen voltage can pass through. This effect could partially account for the 1V offset seen in gun energy. This model shows that about 50% can get past the screen at 0.5eV below the screen voltage but most paths are badly deflected and probably would not reach the anode.