ebisim.beams module

This module contains tools for computing characteristic quantities of electron beams typically found in an electron beam ion source / trap.

class ebisim.beams.ElectronBeam(cur, b_d, r_d, b_c, r_c, t_c)[source]

Bases: object

This class contains logic that allows estimating the space charge corrected energy of an electron beam and the resulting energy spread

Parameters

  • cur (float) – <A> Electron beam current.

  • b_d (float) – <T> Magnetic flux density in the centre (drift tubes) of the EBIS.

  • r_d (float) – <m> Drift tube radius.

  • b_c (float) – <T> Magentic flux density on the cathode surface

  • r_c (float) – <m> Cathode radius.

  • t_c (float) – <K> Cathode temperature.

characteristic_potential(e_kin)[source]

Returns the characteristic potential due to spacecharge

Parameters

e_kin (float) – <eV> Electron kinetic energy.

Returns

float – <V> Characteristic potential.

herrmann_radius(e_kin)[source]

Returns the Hermann radius of an electron beam with the given machine parameters

Parameters

e_kin (float) – <eV> Electron kinetic energy.

Returns

float – <m> Hermann radius.

space_charge_correction(e_kin, r=0)[source]

Returns the space charge correction at a given radius r, current and electron beam energy This is done by iteratively computing the spacecharge correction and the hermann radius until the realtive change in space charge correction is < 1e-6.

Parameters

  • e_kin (float) – <eV> Electron kinetic energy.

  • r (float, optional) – Distance from the axis at which to evaluate the correction, by default 0.

Returns

float – <V> Space charge correction.

Raises

ValueError – If r is larger than the drift tube radius.

property current

Current of the electron beam.