Setting up a source of zero kinetic energy electrons

An option for starting particles from an electrode with zero energy.

The required data are similar to those required for the thermionic cathode, where the initial kinetic energy can also be made zero. The present option is provided because it avoids the extra computations involved with a cathode and with space charge. (However if the initial energy is required to be non-zero the cathode option in CPO3DS should be used with a non-random initial distribution of energies and directions.)

The initial ray information is put into the output data file in a form suitable for re-use in an input data file as 'individual rays', if the print level is 'most' or 'all' (search for 'Initial ray information'). But note that the initial energies at the initial positions do not take any account of potentials due to any space-charges that might exist.

If the particles are accelerated to high energies it might be necessary to use the same precautions as when using a cathode with an anode at high voltage

For users who are editing or constructing an 'input data file' without the use of the data-builder -that is, pre-processor:

But Manual editing is certainly not recommended -it is a relic from the time when the databuilder was not available All users are strongly encouraged to use the databuilder, which always gives the correct formats and which has many options for which the formats are not described or easily deduced.

CPO2D:

Typical data, from the end of test2d11.dat, for non-space-charge use:

zero initial kinetic energy

10 0. number of segments, current density

i 0. 0.'i' for 'inside', and (r,z) of reference point

0.005 starting distance from electrode

n calculate space-charges?

1 1 symmetries of rays in r (or x) and z planes

CPO2DS:

Typical data, from the end of test2d11.dat, for space-charge use:

zero initial kinetic energy

10 6.391number of segments, current density

i 0. 0.'i' for 'inside', and (r,z) of reference point

0.005 starting distance from electrode

Y calculate space-charges?

0.02 distance parameter for space-charges

repeat of previous rays

1.0 = factor to multiply ORIGINAL currents

repeat of previous rays

1.0 = factor to multiply ORIGINAL currents

finish of space-charge iterations

CPO3D:

Typical data, from the end of test3d11.dat, for non-space-charge use:

zero initial kinetic energy

12 0. number of segments, current density

i 0. 0. 0. 'i' for 'inside, and xyz of reference point

0.005 distance from electrode for starting rays

n calculate space-charges?

1 1 1 1 symmetries of rays in yz, zx, xy and x=y planes

CPO3DS:

Typical data,, from the end of test3d11.dat, for space-charge use:

zero initial kinetic energy

12 6.391 number of segments, current density

i 0. 0. 0. 'i' for 'inside, and xyz of reference point

0.005 distance from electrode for starting rays

Y calculate space-charges? -

0.01 distance parameter for space-charges

repeat of previous rays*****************************

1.00 = factor to multiply ORIGINAL currents

repeat of previous rays*****************************

1.00 = factor to multiply ORIGINAL currents

finish of space-charge iterations***************************

.