Photogun

In the 100 kV DC electron gun voltages up to 100 kV can be applied across a diode consisting of a flat copper cathode and a copper anode with a hole, which are separated by 1 cm. The high voltage is applied through a very compact HV feedthrough. At 100 kV this results in a DC electric field of 12 MV/m on the cathode surface. Ultrashort electron bunches can be generated by photoemission with 266 nm femtosecond laser pulses, the 3rd harmonic of the 800 nm Ti-sapphire wavelength. The electron bunches are typically created by front illumination of a bulk copper cathode through the hole in the anode, using the laser incoupler component, but back illumination is also possible by using a glass cathode on which a thin (10-20 nm) layer of copper, silver or gold has been deposited. Using front illumination of a bulk copper cathode, a 1 μJ 266 nm laser pulse is sufficient to generate a 1 pC electron bunch. Directly on the exit of the 100 kV DC electron gun a magnetic solenoid lens is mounted to collimate the electron bunch, which undergoes a strong Coulomb expansion at typical bunch charges (0.01-1 pC).The 100 kV DC Electron Gun is the source of ultrashort electron bunches in our Crystallography system. The photogun includes the 100 kV supply necessary for operating the gun. For more information please consult the specification sheet or contact us.

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