Burt, Graeme and Dexter, Amos and Wildner, E. (2014) Design of a neutrino source based on beta beams. Physical Review Special Topics: Accelerators and Beams (17): 071002. ISSN 1098-4402
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Abstract
"Beta Beams" produce collimated pure electron (anti-) neutrino beams by accelerating beta active ions to high energies and having them decay in a race track shaped storage ring of 7 km circumference, the Decay Ring. EUROnu Beta Beams are based on CERN infrastructures and existing machines. Using existing machines may be an advantage for the cost evaluation, however, this choice is also constraining the Beta Beams. The isotope pair of choice for the Beta Beam is 6He and 18Ne. However before the EUROnu studies one of the needed isotopes, 18Ne, could not be produced in rates that satisfy the needs for physics reach of the Beta Beam. Therefore, studies of alternative beta emitters, 8Li and 8B, with properties interesting for a Beta Beam have been proposed and have been studied within EUROnu. These alternative isotopes could be produced by using a small storage ring, in which the beam traverses a target, creating the 8Li and 8B isotopes. This Production Ring, the injection Linac and the target system have been evaluated. Measurements of the cross-section of the reactions to produce the Beta Beam isotopes show interesting results. A device to collect the produced isotopes from the target has been developed and tested. However, the obtained rates of the 8Li and 8B, using the Production Ring for production of 8Li and 8B, is not yet, according to simulations, giving the rates of isotopes that would be needed. Therefore, a new method of producing the 18Ne isotope has been developed and tested giving good production rates. The baseline presented for the Beta Beam is therefore now to use the 6He and 18Ne isotopes for neutrino production. A 60 GHz ECRIS prototype, the first in the world, was developed and tested with contributions from EUROnu. The Beta Beam has to take into account the modifications of the injectors planned in view of LHC-upgrades. The Decay Ring lattices for the 8Li and 8B have been developed, the lattice for 6He and 18Ne has been optimized also to ensure the high intensity ion beam stability.