Time-dependent current-voltage relation in electron guns

Time-dependent current-voltage relation in electron guns

High Average Current Electron Guns for High-Power FELs

High average power FELs require high average current electron injectors capable of generating high quality, short duration electron bunches with a repetition rate equal to the frequency of the rf linac. In this paper we propose, analyze and simulate an rf-gated, gridded thermionic electron gun for use in high average power FELs. Thermionic cathodes can provide the necessary high current, have l...

Femtosecond Electron Guns for Ultrafast Electron Diffraction*

The photocathode radio-frequency (RF) gun is a powerful electron source to generate a high-brightness femtosecond electron beam with energies of 1~3 MeV. The RF gun based relativistic ultrafast electron diffraction (UED) is a promising new technique that has the potential to probe directly structural changes at the atomic scale with sub-100 fs temporal resolution. In this paper, we analyze the ...

Low Emittance Thermionic Electron Guns*

Methods for extra-low voltage transcranial direct current stimulation: current and time dependent impedance decreases.

OBJECTIVE Though tDCS is well tolerated, it is desirable to further limit the voltage applied for additional safety factors and optimized device design. We investigated the minimum voltage required for tDCS using 1.5 and 2.5mA. METHODS Impedance data has been collected prior to, during and after 18 tDCS sessions, using 1.5mA and 2.5mA tDCS currents and three different test current magnitudes....