SLAC, Menlo Park, California, USA
LBNL, Berkeley, California, USA
The Early Injector Commissioning program for LCLS-II aims to demonstrate CW electron beam production this year in the first two meters of the injector that includes the room-temperature 185.7 MHz single-cell gun and the 1.3 GHz two-cell buncher cavity. These cavities were designed and built by LBNL based on their experience with similar ones for their Advanced Photo-Injector Experiment (APEX) program. With the 258 nm laser system and Cs2Te cathodes, bunches of up to 300 pC are expected at rates as high as 1 MHz. The paper presents results from this program including the vacuum levels achieved, RF processing and field control experience, dark current measurements and laser and beam characterization.
SLAC, Menlo Park, California, USA
The main part of the SRF linac for the Linac Coherent Light Source II (LCLS-II) at SLAC National Accelerator Laboratory will consist of 35 cryomodules with superconducting RF cavities operating at 1.3 GHz. The cryomodules are assembled and tested at Fermi National Accelerator Laboratory and Thomas Jefferson National Accelerator Facility. Following the transport to SLAC, the cryomodules undergo several incoming inspection steps before ultimately being moved to the tunnel for installation in the linac. The RF part of the incoming inspection covers measurements of a number of parameters like cavity frequency spectrum, notch filter frequency of the higher order mode couplers and external quality factor Qext of the input coupler. The inspection results are compared to measurements at the partner labs prior to shipping and the nominal values in order to verify that the cryomodules have not been damaged during the transport and are ready for installation. We present an overview and analysis of the inspections for the cryomodules received to date.
