A direct sampling RF receiver for precise beam charge measurement*

We have developed and tested a direct-sampling RF receiver capable of measuring the amplitude of a 1497MHz sinusoidal beam signal in 0.5ms integration windows to within 8 parts-per-million ($10^{-5}$) relative uncertainty.  The receiver is intended for measuring signals from beam current monitoring cavities on the beamline of the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Laboratory.  The beam signal strength, frequency, and integration window are consistent with the thus far unmet requirements of the upcoming MOLLER experiment to measure the beam charge for different helicity states.