Very intense neutrino beams and large neutrino detectors will be needed in order to enable the discovery of CP violation in the leptonic sector. We propose to use the proton linac of the European Spallation Source currently under construction in Lund, Sweden to deliver, in parallel with the spallation neutron production, a very intense, cost effective and high performance neutrino beam. The baseline program for the European Spallation Source linac is that it will be fully operational at 5 MW average power by 2022, producing 2 GeV 2.86 ms long proton pulses at a rate of 14 Hz. Our proposal is to upgrade the linac to 10 MW average power and 28 Hz, producing 14 pulses/s for neutron production and 14 pulses/s for neutrino production. Furthermore, because of the high current required in the pulsed neutrino horn, the length of the pulses used for neutrino production needs to be compressed to a few µs with the aid of an accumulator ring. A long baseline experiment using this Super Beam and a megaton underground Water Cherenkov detector located in existing mines 300-600 km from Lund will make it possible to discover leptonic CP violation at 5 σ significance level in up to 50% of the leptonic Dirac CP-violating phase range. This experiment could also determine the neutrino mass hierarchy at a significance level of more than 3 σ if this issue will not already have been settled by other experiments by then. The mass hierarchy performance could be increased by combining the neutrino beam results with those obtained from atmospheric neutrinos detected by the same large volume detector. This detector will also be used to measure the proton lifetime, detect cosmological neutrinos and neutrinos from supernova explosions. Results on the sensitivity to leptonic CP violation and the neutrino mass hierarchy are presented.
The ESS Design: Accelerator 6The ESS Design: Target 66The ESS Design: Controls 93The ESS Design: Conventional Facilities 109Physica ScriptaPhys. Scr. 93 (2018) 014001 (121pp) https://doi.org/10. 1088/1402-4896/aa9bff This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercialNoDerivs 3.0 licence. Content from this work may be used under the terms of the Creative Commons Attribution-NonCommercialNoDerivs 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Neutron scattering is a well-developed and extensively used means to get access to fundamental properties of biological matter as well as of physical materials. Until the end of the twentieth century that was mainly practiced with-and limited in performance by-the continuous flux of neutrons from ageing nuclear reactors (e.g. the Institut Laue-Langevin (ILL), the flagship of neutron research in Europe and in the world) [1]). Looking forward to the following two decades, an OECD report published in 1998 diagnosed the foreseeable decrease of the number of operational facilities [2] and the need to progress in performance. Considering the high scientific interest and the increasing importance of the subject for society at large, the report concluded by strongly recommending the construction of next generation neutron sources in America, Europe and Asia. Pulsed spallation neutron sources (SNS) using a proton beam power exceeding 1 MW were specifically mentioned as the most interesting high performance facilities in the future landscape of neutron laboratories.The USA was the first country to follow this advice by building the SNS in the Oak Ridge National Laboratory (ORNL) which started in 2006 [3, 4]. Japan followed in 2009 with the Japan Proton Accelerator Research Centre (J-PARC) in Tokai [5,6]. In Europe, the subject was part of a concerted effort to further develop the European world-leading largescale research infrastructures suite. In 2003, the European Strategy Forum for Research Infrastructures (ESFRI), set up by the Research Ministries of the Member States and associated countries, concluded that a 5 MW long-pulse, single target station layout with nominally 22 'public' instruments was the optimum technical reference design for an European Spallation Source (ESS) that would meet the needs of the European science community in the second quarter of the century [7].Six years later, in 2009, it materialised in a real project with the adoption of the site of Lund (Sweden). A preconstruction phase followed until the end of 2013 during which the design was finalised [8]. Construction then started with the first neutron beams planned to be available in 2019, and the ESS facility to be operational at full performance in 2025.2 Description 2.1 Principle and specifics. The high level parameters of ESS are shown in table 1. As at SNS and J-PARC, neutrons at ESS are produced by spallation, when the 2 GeV protons hit the meta...
The LHC is currently operating with a proton energy of 4 TeV and à functions at the ATLAS and CMS interaction points of 0.6 m. This is close to the design value at 7 TeV (à ¼ 0:55 m) and represented a challenge for various aspects of the machine operation. In particular, a huge effort was put into the optics commissioning and an unprecedented peak beating of around 7% was achieved in a high energy hadron collider.
An AC dipole is a magnet which produces a sinusoidally oscillating dipole field and excites coherent transverse beam oscillations in a synchrotron. By observing this driven coherent oscillation, the linear optical parameters can be directly measured at locations of the beam position monitors. The driven oscillations induced by an AC dipole will generate a phase space ellipse which differs from that of free oscillations. If not properly accounted for, this difference can lead to misinterpretations of the actual optical parameters, for instance, 6% or more in the cases of the Tevatron, RHIC, or LHC. This paper shows that the effect of an AC dipole on the observed linear optics is identical to that of a thin lens quadrupole. By introducing a new amplitude function to describe this new phase space ellipse, the motion produced by an AC dipole becomes easier to interpret. The introduction of this new amplitude function also helps measurements of the normal Courant-Snyder parameters based on beam position data taken under the influence of an AC dipole. This new parametrization of driven oscillations is presented and is used to interpret data taken in the FNAL Tevatron using an AC dipole.
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