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.
Design of a target able to withstand a high intensity beam such as those planned for a Neutrino Factory and Muon Collider requires integration of particle yield optimisation with engineering ...feasibility studies. This article reports a basic thermo-mechanical analysis of cylinders of common engineering materials irradiated by an 8GeV proton beam (Neutrino Factory beam energy) of varying sigma. Beam induced peak temperature jump, a typical temperature distribution, peak energy density, peak quasi-static Von Mises stresses and material yield strengths are reported here as a reference guide for target design.
This paper reports results from an experiment exposing the hot isostatic pressed tantalum cladding of a tungsten spallation target sample to a 34 m/s water jet. The unpolished tantalum surface was ...placed under the jet for 4.5 months with a view to quantifying pitting and erosion. Micrographs and laser profilometry records of the sample surface taken before and after the experiment are reported here.
The experiment described in this paper is the first study of the response of a static tungsten powder sample to an impinging high energy proton beam pulse. The experiment was carried out at the ...HiRadMat facility at CERN. Observations include high speed videos of a proton beam induced perturbation of the powder sample as well as data from a laser Doppler vibrometer measuring the oscillations of the powder container. A comparison with a previous analogous experiment which studied a proton beam interaction with mercury is made.
A tungsten powder jet is a potential candidate technology for a particle production target in a future high power (i.e. Multi-MW) particle accelerator based facility, such as a so-called conventional ...neutrino Super Beam, a proposed Neutrino Factory, or a future neutron source. To test the viability of producing a suitable powder jet a few simple experiments were performed using standard pneumatic conveying equipment and the encouraging results are presented.
This paper describes some preliminary studies of the production of a horizontal jet of powdered tungsten undertaken to investigate the viability of such a jet for use as a beam target in a high power particle accelerator (The Neutrino Factory Project).
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Unstable tungsten powder jet leaving a 20
mm ID cylindrical nozzle
This paper reports the results from single-pulse experiments of a440GeV/cproton beam interacting with granular tungsten samples in both vacuum and helium environments. Remote high-speed photography ...and laser Doppler vibrometry were used to observe the effect of the beam on the sample grains. The majority of the results were derived from a trough containing∼45μmdiameter spheres (not compacted) reset between experiments to maintain the same initial conditions. Experiments were also carried out on other open and contained samples for the purposes of comparison both with the45μmgrain results and with a previous experiment carried out with sub-250μm mixed crystalline tungsten powder in helium Phys. Rev. ST Accel. Beams 17, 101005 (2014). The experiments demonstrate that a greater dynamic response is produced in a vacuum than in a helium environment and in smaller grains compared with larger grains. The examination of the dynamics of the grains after a beam impact leads to the hypothesis that the grain response is primarily the result of a charge interaction of the proton beam with the granular medium.
The Long Baseline Neutrino Facility (LBNF, formerly the Long Baseline Neutrino Experiment) is under design as a next generation neutrino oscillation experiment, with primary objectives to search for ...CP violation in the leptonic sector, to determine the neutrino mass hierarchy and to provide a precise measurement of θ23 . The facility will generate a neutrino beam at Fermilab by the interaction of a proton beam with a target material. At the ultimate anticipated proton beam power of 2.3 MW the target material must dissipate a heat load of between 10 and 25 kW depending on the target size. This paper presents a target concept based on an array of spheres and compares it to a cylindrical monolithic target such as that which currently operates at the T2K facility. Simulation results show that the proposed technology offers efficient cooling and lower stresses whilst delivering a neutrino production comparable with that of a conventional solid cylindrical target.
Fluidized tungsten powder has been proposed as a potential target technology for particle accelerator applications with very high power highly focused pulsed beams. This has motivated a series of ...experiments carried out at the HiRadMat facility at CERN to study the response of a tungsten powder sample to an impinging high energy proton beam pulse. The main observation was that of beam induced lifting of the powder sample which was recorded by high speed video. In this paper we consider three mechanisms to explain the observed powder lift including aerodynamic, thermal expansion and induced charge effects. Simulations of the aerodynamic effect revealed that this could not explain the magnitude of the observed eruptions especially during tests carried out with the powder in a vacuum. Thermal expansion of tungsten particles giving rise to the eruption seems implausible due to the propensity for the powder to absorb perturbations. We show that the observations can be explained by a Coulombic eruption of the tungsten particles. The high energy beam leaves a pattern of charge distributed in the poorly conducting powder sample, which creates an electric field that consequently results in a force acting on the individual charged particles. We calculate the charge deposited, the electric field and the resulting acceleration and show that this is a plausible mechanism for causing the observed eruptions. We believe the response of a granular conductive sample to an incident proton beam has not previously been explained.
We present a new design study of the neutrino Super Beam based on the Superconducting Proton Linac at CERN. This beam is aimed at megaton mass physics, a large water Cherenkov detector, proposed for ...the Laboratoire Souterrain de Modane in France, with a baseline of 130 km. The aim of this proposed facility is to study CP violation in the neutrino sector. In the study reported here, we have developed the conceptual design of the neutrino beam, especially the target and the magnetic focusing device. Indeed, this beam presents several unprecedented challenges, related to the high primary proton beam power (4 MW), the high repetition rate (50 Hz), and the low kinetic energy of the protons (4.5 GeV). The design is completed by a study of all the main components of the system, starting from the transport system to guide the beam to the target up to the beam dump. This is the first complete study of a neutrino beam based on a pebble-bed target capable of standing the large heat deposition of MW class proton beams.
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