D11.2.1: DAΦNE IR design for the upgraded KLOE detector

For the WP11 ANAC (Assessment of Novel Accelerator Concepts ) Task 2 a new Interaction Region (IR) has been designed and built at the Italian electron-positron Φ-Factory DAΦNE, with the aim to increase the luminosity for the KLOE-2 detector run in 2011-2013. The IR is based on a new collision scheme called Crab-Waist developed at Frascati by P. Raimondi, and already tested at DAΦNE in 2009 with a compact experimental apparatus for nuclear physics, with an improvement of about a factor of 3 on the peak luminosity. The main issue of this R&D activity has been finding the theoretical and technical solutions necessary to make the Crab-Waist compatible with a large experimental detector. Crab-Waist collisions are based on strong focusing, large Piwinski angle and Crab-Waist compensation of the synchro-betatron resonances by means of two sextupoles installed at proper phase advance with respect to the Interaction Point (IP). Integrating the high luminosity collision scheme with the KLOE-2 detector introduces new challenges in terms of IR layout and optics, beam acceptance, coupling correction, lifetime and backgrounds, as well as collective effects which are increased due to the small beam sizes.