Empirically determined response matrices for on-line orbit and energy correction at Thomas Jefferson National Accelerator Facility

Thomas Jefferson National Accelerator Facility (Jefferson Lab) uses digital feedback loops (less than 1 Hz update rate) to correct drifts in the Continuous Electron Beam Accelerator Facility´s (CEBAF) electron beam orbit and energy. Previous incarnations of these loops used response matrices that were computed by a numerical model of the machine. Jefferson Lab is transitioning this feedback system to use empirically determined response matrices whereby the software introduces small orbit or energy deviations using the loop´s actuators and measures the system response with the loop´s sensors. This method is in routine use for orbit correction. This paper describes the problem that both software lock systems are designed to address. A brief discussion of the design and operational experience of the numerical model based orbit and energy lock software system follows. Next, the empirical orbit lock system is described. Finally, future plans for an empirical energy lock system are presented