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The Low Energy Relativistic Heavy Ion Collider (RHIC) electron Cooler (LEReC) is designed to deliver a 1.6 MeV to 2.6 MeV electron beam, with rms dp/p less than 5e-4. The superconducting radiofrequency (SRF) Booster Cavity is the major accelerating component in LEReC. It is a 0.4 cell cavity operating at 2 K, providing a maximum energy gain of 2.2 MeV. It is modified from an experimental Energy Recovery Linac (ERL) photocathode gun, and thus has fundamental power couplers (FPCs), pickup (PU) couplers (field probes) and HOM coupler close to each other on the same side of the cavity. Direct capacitive coupling between the FPC and PU, called the crosstalk effect, combined with microphonic detuning, can induce closed loop voltage fluctuations that exceed the total energy spread requirement of LEReC. The crosstalk effect in this cavity is modelled, simulated, and measured, and a correction method is proposed and demonstrated to suppress the voltage fluctuation so that energy spread requirement can be met. [ABSTRACT FROM AUTHOR]

Abstract: The DC–SC photoinjector is a compact electron gun integrating a DC pierce gun with a 1.3GHz 1+1/2 cell superconducting cavity. A test facility of the DC–SC photoinjector had been installed in Peking University and beam-loading tests at 4.4K have been finished. To date the gradient of 6MV/m has been achieved. The maximum energy gain is 1.1MeV at 4.4K. With average beam current of 270μA, the measured rms emittance is about 5mmmrad at the beam energy of 500keV. In this paper some of the experimental results are summarized. [Copyright &y& Elsevier]