An electron DC gun capable for producing very low emittance beam is now under evaluation of beam qualities at Laboratory of Nuclear Science, Tohoku University. The DC gun employs a high voltage of 50 kV to extract electrons, which is suitable to drive Smith-Purcell backward wave oscillator free electron laser (BWO FEL) . From a result of numerical simulation using a 3-D finite deference time domain (FDTD) method , the BWO FEL oscillation at the terahertz wavelength region maybe achieved by using the electron beam with an emittance lower than 1 n mm mrad. Average power is expected to be more than 100 W/mm2. In addition to which a very small cathode of LaB6single crystal is employed for the gun , the geometrical structure is optimized to produce the lower emittance beam. A numerical calculation of the electro-static model for the DC gun to solve equilibrated beam envelope predicts a normalized beam emittance of 0.3 n mm mrad will be possible for the beam current of a couple of hundreds mA. Particularly by applying additional bias voltage between the cathode and the wehnelt, the transverse distribution of electrons is possibly becoming to be an ideal Kapchinskij-Vladimirskij (K-V) beam , so that the space charge effect will be minimized.
|Number of pages
|Published - 2007
|29th International Free Electron Laser Conference, FEL 2007 - Novosibirsk, Russian Federation
Duration: 2007 Aug 26 → 2007 Aug 31
|29th International Free Electron Laser Conference, FEL 2007
|07/8/26 → 07/8/31