Engineering topics
Brachmann, A
Publications and source records attributed to Brachmann, A.
High-brightness Electron Beam Evolution Following Laser-based Cleaning of a Photocathode
Abstract Not Provided
High-brightness Electron Beam Evolution in Time Following Laser-based Cleaning of the LCLS Cathode
Abstract Not Provided
RF Gun Photocathode Research at SLAC
LCLS is presently operating with a third copper photocathode in the original rf gun, with a quantum efficiency (QE) of {approx}1 x 10{sup -4} and projected emittance {gamma}{var_epsilon}{sub x,y} = 0.45 {micro}m at 250 pC bunch charge. The spare LCLS gun is installed in the SLAC Accelerator Structure Test Area (ASTA), fully processed to high rf power. As part of a wider photocathode R and D program, a UV laser system and additional gun diagnostics are being installed at ASTA to measure QE, QE lifetime, and electron beam emittance under a variety of operating conditions. The near-term goals are to test and verify the spare photocathode production/installation sequence, including transfer from the final holding chamber to the rf gun. Mid- and longer-term goals include development of a rigorous understanding of plasma and laser-assisted surface conditioning and investigation of new, high-QE photocathode materials. In parallel, an x-ray photoemission spectroscopy station is nearing completion, to analyze Cu photocathode surface chemistry. In this paper we review the status and anticipated operating parameters of ASTA and the spectroscopy test chamber.
ILC Polarized Electron Source Design and R&D Program
The R and D program for the ILC electron focuses on three areas. These are the source drive laser system, the electron gun and photo cathodes necessary to produce a highly polarized electron beam. Currently, the laser system and photo cathode development take place at SLAC's 'ILC Injector Test facility', which is an integrated lab (laser and gun) that allows the production of the electron beam and is equipped with a set of diagnostics, necessary to characterize the source performance. Development of the ILC electron gun takes place at Jefferson Lab, where advanced concepts and technologies for HV DC electron guns for polarized beams are being developed. The goal is to combine both efforts at one facility to demonstrate an electron beam with ILC specifications, which are electron beam charge and polarization as well as the cathode's lifetime. The source parameters are summarized in Table 1. The current schematic design of the ILC central complex is depicted in Figure 1. The electron and positron sources are located and laid out approximately symmetric on either side of the damping rings.