Status of Low Emittance Tuning at CesrTA

We report on the status of emittance tuning techniques at the CESR Test Accelerator (CesrTA). The CesrTA experimental program requires that we operate in a variety of machine lattices, each with the smallest possible emittance. We utilize high-bandwidth BPM electronics for fast, precision measurements of orbit, betatron phase, transverse coupling, and dispersion. Analysis of the data and implementation of corrections are completed in a few minutes. An xray beam size monitor (xBSM) capable of bunch-by-bunch, turn-by-turn measurements provides a real time check on the effectiveness of the procedure. The procedure typically yields an emittance less than 20pm at 2.1GeV in 1-2 iterations. We have achieved 6pm vertical emittance with adjustment of closed coupling/vertical dispersion bumps, betatron tunes, and modification of beta functions at the xBSM source point.