Commissioning of a Locally Isochronous Lattice at ALS

With the advance of the ultra-fast science, manipulating electron beam at the sub-micron and nanometer scale has been actively pursued. A special lattice of the ALS storage ring was conceived to study the sub-micron longitudinal structure of the beam. It contains sections that are isochronous to the first order. Due to the practical constraints of the accelerator, sextupoles have to be off and the dispersion at the injection point is close to 60 cm, which make commissioning a highly nontrivial task. After a few months of tuning, we have been able to store at 40 mA of beam at the lifetime of 1 hour. After a brief introduction to the motivation of the experiment and the design of the lattice, the process and more detailed results of the commissioning will be presented. Future plan will also be discussed.