Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9844901 | Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | 2005 | 5 Pages |
Abstract
The design of the electron gun for generating a low-emittance beam is presented. This gun employs a diode for generating the beam and a 1.6-cell RF cavity for accelerating up to relativistic energies. The goal of this gun is to generate a beam of â1nC and 100 A peak current with a normalized rms transverse emittance of below 1Ïμm. In the diode region, pulsed voltage with a pulse duration of â1ns and voltage of 2 MV is applied to the 2-mm-gap between cathode and anode, generating a field gradient of â1GV/m. The combination of the high-field diode and the RF cavity can reduce space charge effects on emittance to a greater extent than an RF gun and solenoid field system. A Cs-Te was selected to match the requirement of a photocathode with high quantum efficiency (QE) since the laser power available to us at KEK-ATF gives â5μJ/pulse at a UV wavelength of 266 nm. A diamond is used for the substrate to allow UV light to be injected from the back of the cathode. To estimate the generated beam emittance, a simulation was performed using the general particle tracer (GPT) code. Details of the design and simulations are presented.
Keywords
Related Topics
Physical Sciences and Engineering
Physics and Astronomy
Instrumentation
Authors
K. Hasegawa, H. Hayano,