Measurement of Q-Weak Detector Sensitivities

The Q-Weak experiment at Jefferson Laboratory will provide a 4{\%} measurement of the proton's weak charge (Q$^{p}_{w})$ using parity-violating electron scattering from a liquid Hydrogen target. The scattering rates into the detectors depend significantly on five electron beam parameters at the target: transverse position x and y, angle x' and y', and incident energy, E. Small helicity-correlated variations in these parameters produce false asymmetries which are enhanced by various broken symmetries in the apparatus. While great care is being taken to suppress or eliminate helicity-correlated changes in beam parameters at the polarized source, we will measure the detector sensitivities (dA$_{f}$/dx$_{i}$ (i=1..5)) for first order offline correction of beam false asymmetries. To directly measure the detector sensitivities, we will modulate the beam in (x,x',y,y') using pairs of electromagnets, and in E using an SRF cavity. We estimate a 10{\%} measurement of the 5 beam sensitivities will be possible each day using only 1{\%} of our total beam time. I will discuss simulations of predicted detector sensitivities, as well as our group's work on the design and implementation of a robust beam modulation system.