The VUV Radiation Source Super-ACO

Super-ACO, the radiation source under construction at Orsay is described and the main features of the ring are presented. The Synchrotron Light Source Environment at Orsay Two former high energy physics storage rings are used at Orsay as dedicated synchrotron light sources. ACO is an electron ring, which is operated since 1965. Its maximum energy is 540 MeV. Output ports are installed in 4 bending magnets, and an optical klystron in a straight section 1.88 m long is used for free electron laser work. DCI is operated with positrons. At its maximum energy of 1.85 GeV, the beam emittance is 1.2×10-6 m.rad, and the critical wavelength 3.4 A°. The stored intensity at high energy is typically 250 mA, and the lifetime about 40 hours. A superconducting wiggler will be installed next winter, allowing to reach a critical wavelength of 1 A°. The new ring is meant to replace ACO. Super-ACO will have a better brilliance, a shorter critical wavelength, and six straight sections available for undulators. Positrons obtained from the existing Linac will be injected up to the maximum energy of the ring. Experience with DCI has proved the advantages of positrons versus electrons. There is no emittance growth, and lifetime is better and more reliable.