1 β - beams : R & D challenges in FP 7

As a quite novel concept for producing pure flavour neutrino beams, the beta-beam project presents several R&D challenges requiring careful studies. In the centre of these, the production of radioactive ion beams of beta-decaying nuclides of intensities orders of magnitudes higher than achieved so far has triggered various investigations. This article focuses on the production and beam preparation issues of such intense radioactive ion beams for beta-beams. Among the different scenarios for next generation neutrino beam facilities, beta-beams make use of intense post-accelerated radioactive ion beams for producing pure electron neutrino and antineutrino beams [1]. For such a project to meet the sensitivity requirements for the θ 13 mixing angle and CP violating phase determination, fluxes of 1.10 18 ν and 3.10 18 were generally assumed [2], in first approximation independant of the isotopes that are considered. The isotopes that were proposed so far are 6 He and 18 Ne [1,3], and more recently 8 Li and 8 B with an original production method making use of ionization cooling mechanism in a ring [4,5]. For each of these isotopes, general considerations will be made concerning the production, transport, ionization methods and efficiencies. Issues concerning the collimation of such intense ion beams in the storage ring used for neutrino beam generation were introduced during the time of the conference and will be reported in a future paper [6]. Other R&D challenges related to the acceleration techniques, radioprotection and multi-ionization are presented in separated contributions to this conference [7,8] as well as a possible alternative production technique for 6 He and 8 Li [9].