Submicron emittance and ultra small beam size measurements at ATF

This paper covers improvements to a photoinjector that lead to the realization and measurement of submicron normalized emittance for a 0.5 nC electron beam at the Brookhaven Accelerator Test Facility. A fitting procedure utilizing beam size measurements from multiple beam profile monitors along the transport line was used instead of more traditional techniques. Such a small emittance beam in combination with a tight focusing scheme allowed us to achieve 10 μm RMS beam sizes at 60 MeV. The behavior and limitations of different BPM screens is compared for such beams.