Proton Driver Research Articles

Physics at an Upgraded Fermilab Proton Driver

In 2004 the Fermilab Long Range Planning Committee identified a new high intensity Proton Driver as an attractive option for the future, primarily motivated by the recent exciting developments in neutrino physics. Over the last few months a physics study has developed the physics case for the Fermilab Proton Driver. The potential physics opportunities are discussed.

Atomic physics with a relativistic H− beam

A study is currently under way at the Fermi National Accelerator Laboratory for a superconducting linear accelerator that will accelerate H− ions to 8 GeV. This Proton Driver beam is intended to be injected, stripped down to protons, into the 120 GeV Main Injector for the mass production of neutrinos aimed at a neutrino detector (MINOS) in a mine shaft in Soudan, Minnesota, USA, for the study of neutrino oscillations. The highly relativistic kinematics of the one- and two-electron atomic systems (H0 and H−) that could be produced by this accelerator present unique research opportunities in atomic physics for the study of fundamental questions. Finally we shall discuss the effects of black-body radiation on high-energy H− beams.

Neutrino Factory R&D in Europe

This paper will review the R&D towards a Neutrino Factory being performed in Europe, with particular emphasis given to work done since NuFact'03. Topics covered include improvements to funding in Europe, the CERN Feasibility Study and R&D on the proton driver, target, pion collection, muon front-end and muon acceleration.

Physics at an Upgraded Proton Driver at Fermilab

The accelerator-based particle physics program in the US is entering a period of transition. This is particularly true at Fermilab which for more than two decades has been the home of the Tevatron Proton-Antiproton Collider, the World's highest energy hadron collider. In a few years time the energy frontier will move to the LHC at CERN. Hence, if an accelerator-based program is to survive at Fermilab, it must evolve. Fermilab is fortunate in that, in addition to hosting the Tevatron Collider, the laboratory also hosts the US accelerator-based neutrino program. The recent discovery that neutrino flavors oscillate has opened a new exciting world for us to explore, and has created an opportunity for the Fermilab accelerator complex to continue to address the cutting-edge questions of particle physics beyond the Tevatron Collider era. The presently foreseen neutrino oscillation experiments at Fermilab (MiniBooNE [1] and MINOS [2]) will enable the laboratory to begin contributing to the Global oscillation physics program in the near future, and will help us better understand the basic parameters describing the oscillations. However, this is only a first step. To be able to pin down all of the oscillation parameters, and hopefully make new discoveries along the way,more » we will need high statistics experiments, which will require a very intense neutrino beam, and one or more very massive detectors. In particular we will require new MW-scale primary proton beams and perhaps ultimately a Neutrino Factory [3]. Plans to upgrade the Fermilab Proton Driver are presently being developed [4]. The upgrade project would replace the Fermilab Booster with a new 8 GeV accelerator with 0.5-2 MW beam power, a factor of 15-60 more than the current Booster. It would also make the modifications needed to the Fermilab Main Injector (MI) to upgrade it to simultaneously provide 120 GeV beams of 2 MW. This would enable a factor of 5-10 increase in neutrino beam intensities at the MI, while also supporting a vigorous 8 GeV fixed-target program. In addition, a Proton Driver might also serve as a stepping-stone to future accelerators, both as an R&D test bed and as an injector, with connections to the Linear Collider, Neutrino Factories, and a VLHC. Hence, although neutrino physics would provide the main thrust for the science program at an upgraded Fermilab proton source, the new facility would also offer exciting opportunities for other fixed-target particle physics (kaons, muons, neutrons, antiprotons, etc.) and a path towards new accelerators in the future.« less

Plans for a Proton Driver at Fermilab

During the last several years, stunning experimental results have established that neutrinos have nonzero masses and substantial mixing. The Standard Model must be extended to accommodate neutrino mass terms. The observation that neutrino masses and mass splittings are all many orders of magnitude smaller than those of any of the other fundamental fermions suggests radically new physics, perhaps originating at the GUT or Planck Scale, or perhaps the existence of new spatial dimensions. In some sense we know that the Standard Model is broken, but we don't know how it is broken. Whatever the origin of the observed neutrino masses and mixing, it is likely to require a profound extension to our picture of the physical world. The first steps in understanding this revolutionary new physics are to pin down the measurable parameters and to address the next round of basic questions: (1) Are there only three neutrino flavors, or do light, sterile neutrinos exist? (2) If there are only three generations, there is one angle ({theta}{sub 13}) in the mixing matrix that is unmeasured. How large is it? (3) Which of the two possible orderings of the neutrino mass eigenstates applies? (4) If {theta}{sub 13} is large enough onemore » it may be possible to measure the quantum-mechanical phase {delta}. If {theta}{sub 13} and {delta} are non-zero there will be CP violation in the lepton sector. These questions can be addressed by accelerator based neutrino oscillation experiments. The answers will guide our understanding of what lies beyond the Standard Model, and whether the new physics provides an explanation for the baryon asymmetry of the Universe (via leptogenesis), or provides deep insight into the connection between quark and lepton properties (via Grand Unified Theories), or perhaps leads to an understanding of one of the most profound questions in physics: Why are there three generations of quarks and leptons? The answers may well further challenge our picture of the physical world, and will certainly have important implications for our understanding of cosmology and the evolution of the early Universe. The current Fermilab Program is an important part of the world-wide accelerator based effort to explore and understand the physics of neutrino oscillations. By early 2005, with both MINOS and MiniBooNE taking data, Fermilab will be able to answer some of the most pressing first-round questions raised by the discovery that neutrinos have mass. Fermilab's high-intensity neutrino beams are derived from 8- and 120-GeV proton beams. MiniBooNE is currently taking data using 8 GeV Protons from the Booster. The 120 GeV NuMI beam will start to operate in early 2005 using a 0.25 MW proton beam power from the Main Injector. Future neutrino programs will build on these existing facilities. New short and long baseline experiments have been proposed. There are proposals to increase the available number of protons at 8 and 120 GeV with the goal of addressing the full range of questions presented by neutrino oscillations. Key to that vision is a new intense proton source that usually is referred to as the Proton Driver.« less

High Intensity Muon Beams

The development of high power (multi- mw ) proton drivers opens up the potential for very high intensity muon beams, particularly at low energy. These beams are essential for a wide range of physics topics, from the fundamental properties of the muon (like the g − 2 experiments) to the use of slow muons in condensed matter physics and perhaps the life sciences for muon spin resonance studies.

Physics at an Upgraded Proton Driver

A new 2 MW proton machine, known as the “proton driver”, is being considered for Fermilab. It would play a key role in advancing accelerator-based neutrino physics. A workshop was organized in October 2004 at Fermilab to explore this physics case, as well as other physics that could be performed with this machine.

Future hadron physics facilities at Fermilab

Fermilab's hadron physics research continues in all its accelerator-based programs. These efforts will be identified, and the optimization of the Fermilab schedules for physics will be described. In addition to the immediate plans, the Fermilab Long Range Plan will be cited, and the status and potential role of a new proton source, the Proton Driver, will be described.

Neutrino oscillation studies with laser-driven beam dump facilities

A new mechanism is suggested for efficient proton acceleration in the GeV energy range; applications to non-conventional high intensity proton drivers and, hence, to low-energy (10–200 MeV) neutrino sources are discussed. In particular, we investigate possible uses of these sources to explore subdominant ν ¯ μ → ν ¯ e oscillations at the atmospheric scale and their CP conjugate. We emphasize the opportunity to develop these facilities in conjunction with projects for inertial confined nuclear fusion and neutron spallation sources.

JHF synchrotron as a proton driver

Japan Hadron Facility (JHF) was approved last year and we are expecting the first beam in five years. We will describe the design and status of the synchrotrons.

Muon front-end chicane and acceleration

A muon front-end system is described which includes an initial pion to muon decay channel, a reverse phase slip bending chicane and a 190–400 MeV, 88 MHz muon linac. A chicane is preferred to a phase rotation system as it leads to a more linear acceleration of the muons in a shielded, 88 MHz linac. The design proposed is compatible with the linac-compressor ring option for the proton driver of the CERN neutrino factory scheme.

Lattices for 8 and 30 GeV proton drivers

Lattices for 8 and 30 GeV proton drivers are described. The former is for a potential upgrade of the ISIS facility at RAL, and the latter for a possible neutrino factory driver in the ISR tunnel at CERN.

Neutrino Factory design based on FFAG

An overview of a neutrino factory design in Japan is presented. Our design goal is to obtain 1×10 20 muon decays per straight section per year with the muon energy of 20 GeV/c . It will be about four times more if the proton driver is upgraded. Upgrade path to higher muon energy is also considered.

Technical design aspects of Feasibility Study-II

Feasibility Study-II examined a high-performance Neutrino Factory providing 1×10 20 neutrinos per year aimed at a long-baseline detector. The Study was sponsored jointly by BNL and the Neutrino Factory and Muon Collider Collaboration and is based on a 1 MW proton driver operating at 24 GeV , i.e., an upgraded version of the AGS accelerator. Compared with the earlier FNAL-sponsored study (Feasibility Study-I), there is a sixfold improvement in performance. Here we describe details of the implementation of Study-II concepts and discuss their efficacy. Alternative approaches that will be pursued in follow-on R&D activities are also described briefly.

Proton driver optimization fornew-generation neutrino superbeams to search for sub-leadingνµ→νe oscillations(θ13 angle)

In this paper, we perform a systematic study of particleproduction and neutrino yields for different incident protonenergies Ep and baselines L, with the aim of optimizing theparameters of a neutrino beam for the investigation ofθ13-driven neutrino oscillations in the Δm2range allowed by Superkamiokande results. We study the neutrinoenergy spectra in the `relevant' region of the first maximum ofthe oscillation at a given baseline L. We find that to eachbaseline L corresponds an `optimal' proton energy Ep whichminimizes the required integrated proton intensity needed toobserve a fixed number of oscillated events. In addition, we findthat the neutrino event rate in the relevant region scalesapproximately linearly with the proton energy. Hence, baselinesL and proton energies Ep can be adjusted and the performancefor neutrino oscillation searches will remain approximatelyunchanged provided that the product of the proton energy times thenumber of protons on target remains constant. We apply these ideasto the specific cases of 2.2, 4.4, 20, 50 and 400 GeV protons. Wesimulate focusing systems that are designed to best capture thesecondary pions of the `optimal' energy. We compute the expectedsensitivities to sin 22θ13 for the variousconfigurations by assuming the existence of new-generationaccelerators able to deliver integrated proton intensities ontarget times the proton energy of the order of \U0001d4aa(5×1023) GeV×pot/year.

Online isotope separation at ISAC with a 10 μA proton driver beam

After initial operation using a 1 μA proton driver beam for radioactive ion beam production, the ISAC facility at TRIUMF has progressed to operating at higher proton beam intensities, in the range of 10 μA p +. ISOL targets designed for 1 μA p + levels have been successfully operated for extended periods at the higher beam intensities, with only minor modification. Thin niobium foil targets with reduced volume were employed to maximize the release of short lived Rb product nuclides. Production yields were measured by depositing the beam on a movable tape in a collection station with both beta- and gamma-counting capabilities for product identification. The yield per μA p + of 75Rb ( t 1/2∼19 s) was observed to increase in a nonlinear manner with increasing proton current on target.

A 40–80 MHz system for phase rotation and cooling

In this note a scheme for the collection, phase rotation and cooling of muons for a neutrino factory is reported. The scheme is sufficiently generic to be site independent also if some particular choices are influenced by the CERN design. The system discussed in this note is worked on as a possible alternative to the induction linac scheme. The results presented assume the following overall set-up: the proton driver is constituted by a 2.2GeV superconducting linac followed by an accumulator and compressor ring; the muon re-circulator and decay ring are assumed as described in PJK scenario.

Collective effects and final bunch rotation in a 2.2 GeV–44 MHz proton accumulator–compressor for a neutrino factory

This paper is a review of the collective effects and the final bunch rotation in the CERN scenario of a 4MW proton driver for a neutrino factory.

Proton drivers for neutrino factories: The CERN approach

The paper describes the CERN approach for a proton driver for a Neutrino Factory. Two main layouts are presented: the so-called CERN Reference Scenario, based on a 2.2GeV linac and an alternative one, based on a 30GeV synchrotron. Both produce bunches of 1ns (r.m.s.) and a beam power of 4MW.

Superconducting linac for a proton driver

A proton driver using a superconducting linac has the potential to provide beam with flexible characteristics at powers exceeding 4 MW. Efficient use of the input mains power is also an expected feature of such a system. The requirements specific to a neutrino factory which were listed at “NuFact’99” are summarized, and the basic design of such a linac-based proton driver is given. Subjects of further studies are outlined.