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SLAC’s SLC polarized Electron Source. A. Brachmann. History. Polarized e- from GaAs at SLAC since 1978 strained GaAs at SLAC after 1991/92 (Pol. > 80%) Besides SLC, many fixed target experiments, Last: E158
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SLAC’s SLC polarized Electron Source A. Brachmann SuperB Project Workshop
History • Polarized e- from GaAs at SLAC since 1978 • strained GaAs at SLAC after 1991/92 (Pol. > 80%) • Besides SLC, many fixed target experiments, • Last: E158 • Polarized source has been used for PEPII to produce a beam during fixed target program period • Occasionally, during the PEPII (only) program the polarized source served as a backup for the T-Gun • Gun maintenance until the end of PEPII • One operating gun remains at the ‘Gun Test Lab’ SuperB Project Workshop
Polarized source layout (CID injector) SuperB Project Workshop
CID Injector schematic SuperB Project Workshop
The most important slide SuperB Project Workshop
Beam Parameters SuperB Project Workshop
Photocathode for polarized electrons GaAs/GaAsP strained layer superlattice QE ~ 0.3 – 0.5 % Pol. ~ 85 % Lifetime (between Cesiation several days) SuperB Project Workshop
Drive Laser System SuperB Project Workshop
Source Status • CID Gun non operational since 2007 • CID Laser system not maintained since 2007 • Systems still complete, no ‘scavenging’ so far • Recovery at SLAC or elsewhere? • Possible with some effort • Several months of work • Laser system is okay • New cathode probably necessary • Expertise is maintained by GTF / CTS activities (ILC/CLIC source work) • GTL is a 1:1 copy of CID injector • Gun and Laser system SuperB Project Workshop
Thank you We can do a tour … SuperB Project Workshop