03 Linear Colliders, Lepton Accelerators and New Acceleration Techniques

A09 Muon Accelerators and Neutrino Factories

Paper	Title	Page
WEOAPA03	MICE Overview - Physics Goals and Prospects	1870
	M. Yoshida Osaka University, Osaka
	Ionization cooling, a technique in which muon beam is passed through a series of absorbers and followed by RF-acceleration, is a proposed method for cooling muon beam, i.e., phase-space reduction. The international Muon Ionisation Cooling Experiment (MICE), which will construct and operate a realistic cooling channel and measure the beam cooling performance, is the first essential step towardsrealization of nutrino factories and eventually muon colliders based on intense muon sources. The MICE have got approved to be constructedin Rutherford Appleton Laboratory (RAL) and the fist beam commissioning is scheduled in 2007. The physics goal and future prospects of the MICE together with the beamline and the instruments which is now being built will be described.
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WEPLS001	Secondary Particle Production and Capture for Muon Accelerator Applications	2394
	S.J. Brooks CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
	Intense pulsed muon beams are required for projects such as the Neutrino Factory and Muon Collider. It is currently proposed to produce these from a high-Z target using a multi-megawatt proton driver. This paper examines the effect of proton energy on the yield and distribution of particles produced from tantalum and mercury, with further analysis using a tracking code to determine how these distributions will behave downstream, including a breakdown of loss mechanisms. Example 'muon front end' lattices are used from the UK Neutrino Factory design.
WEPLS002	Design and Expected Performance of the Muon Beamline for the Muon Ionisation Cooling Experiment	2397
	K. Tilley, D.J. Adams, P. Drumm CCLRC/RAL/ISIS, Chilton, Didcot, Oxon T.J. Roberts Muons, Inc, Batavia K.a. Walaron University of Glasgow, Glasgow
	It is proposed to install a Muon Ionisation Cooling Experiment (MICE) at the ISIS facility, at Rutherford Appleton Laboratory (RAL). This experiment will be the first demonstration of ionisation cooling as a means to reduce the large transverse emittance of the muon beam, produced during the early stages of a Neutrino Factory. In order to permit a realistic demonstration of cooling, a beam of muons must be produced, possessing particular qualities, notably in emittance and momenta. This paper describes the current design for the muon beamline, outlining issues particular to the needs of the MICE experiment, and discusses its expected performance.
WEPLS003	Simulation of MICE Using G4MICE	2400
	C.T. Rogers Imperial College of Science and Technology, Department of Physics, London R. Sandstrom DPNC, Genève
	In the Muon Ionisation Cooling Experiment (MICE), muons will be fired one by one through one or two cooling cells. The experiment will be used to optimise simulation of an ionisation cooling channel for a future Neutrino Factory. This is achieved by measuring the position of each muon in six-dimensional phase space and examining the behaviour of muons collected into bunches offline. The experiment will be run with a number of different input beams, magnet configurations, RF configurations and absorber types. We present the simulated detector and cooling performance of the MICE cooling channel using the G4MICE simulation code for a range of configurations. We detail the simulation of engineering, field and detector models and examine the implications for the cooling efficacy and measurement.
WEPLS005	The Target Drive for the MICE Experiment	2403
	C.N. Booth, L.C. Howlett, P.J. Smith Sheffield University, Sheffield N. Schofield University of Manchester, School of Electrical and Electronic Engineering, Manchester
	The MICE experiment requires a beam of low energy muons to test muon cooling. This beam will be derived parasitically from the ISIS accelerator. A novel target mechanism is being developed which will allow the insertion of a small titanium target into the proton beam halo on demand. The target must remain outside the beam envelope during acceleration, and then overtake the shrinking beam envelope to enter up to 5 mm into the beam during the last 2 ms before extraction. The technical specifications are demanding, requiring large accelerations and precise and reproducible location of the target each cycle. The mechanism must operate in a high radiation environment, and the moving parts must be compatible with the stringent requirements of the accelerator's vacuum system. A prototype linear electromagnetic drive has been built, and the performance is being measured and improved to meet the design specifications. Details of the drive, position readout and control systems will be presented, together with the performance achieved to date.
WEPLS006	Requirements for Accelerator-based Neutrino Facilities	2406
	A.P. Blondel DPNC, Genève
	Classification: 1-A18, 3-A09, 4-A15, 6-T03 (non exhaustive). The study of neutrino oscillations offers promises of great discoveries including leptonic CP violation. The experimental programs that are under discussion pose considerable challenges to accelerator builders. Extremely high intensities are needed for classical on- and off-axis pion decay beams; novel ideas such as beta-beams and muon decay beams have been invented and are being studied. The experiments to be performed require outstanding predictability and monitoring of the neutrino flux. The challenges will be reviewed and a list of requirements will be proposed.
WEPLS007	A Six-dimensional Muon Beam Cooling Experiment	2409
	R.P. Johnson, M. Alsharo'a, M.A.C. Cummings, M. Kuchnir, K. Paul, T.J. Roberts Muons, Inc, Batavia D.M. Kaplan Illinois Institute of Technology, Chicago, Illinois V.S. Kashikhin, V. Yarba, K. Yonehara Fermilab, Batavia, Illinois
	Ionization cooling, a method for shrinking the size of a particle beam, is an essential technique for the use of muons in future particle accelerators. Muon colliders and neutrino factories, examples of such future accelerators, depend on the development of robust and affordable ionization cooling technologies. A 6D cooling experiment has been proposed, incorporating a novel configuration of helical and solenoidal magnets in a prototype cooling channel. This Helical Cooling Channel (HCC) experiment is being designed with simulations and prototypes to provide an affordable and striking demonstration that 6D muon beam cooling is understood well enough to enable intense neutrino factories and high-luminosity muon colliders. Because of the large amount of expected beam cooling, helium instead of hydrogen can be used for the initial experiment, avoiding the safety complications of hydrogen. Cryostats are currently being developed using internal heat exchangers for simple, effective and safe hydrogen absorber systems to use in later cooling experiments and real cooling channels. The experimental design choices and corresponding numerical simulations are reviewed.
WEPLS009	Summary of the Low Emittance Muon Collider Workshop (February 6-10, 2006)	2412
	R.P. Johnson, K. Paul Muons, Inc, Batavia V. Yarba Fermilab, Batavia, Illinois
	The Low Emittance Muon Collider workshop, held at Fermilab February 6-10, 2006 focused on the development of high-luminosity muon colliders using extreme muon beam cooling, where many constraints on muon collider designs are alleviated with beams of smaller emittance and lower intensity. The workshop covered topics related to proton drivers, targetry, muon capture, bunching, cooling, cooling demonstration experiments, bunch recombination, muon acceleration, collider lattices, interaction-point design, site boundary radiation, and detector concepts for energy frontier and Higgs particle studies. Lower emittance allows for a reduction in the required muon current for a given luminosity and also allows high energy to be attained by recirculating the beam through high frequency ILC RF cavities. The highlights of the workshop and the prospects for such colliders will be discussed.
WEPLS010	20 - 50 GeV Muon Storage Rings for a Neutrino Factory	2415
	G. Rees CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon C. Johnstone Fermilab, Batavia, Illinois F. Meot CEA, Gif-sur-Yvette
	Muon decay ring studies are being undertaken as part of the International Scoping Study (ISS) for a Neutrino Factory. A racetrack and an isosceles triangle shaped ring are under design, initially for a muon energy of 20 GeV, but with an upgrade potential for 50 GeV. Both rings are designed with long straights to optimize directional muon decay. The neutrinos from the muon decays pass to one or two distant detectors; the racetrack ring has one very long production straight, aligned with one detector, while the triangular ring has two straights, each half as long, which can be aligned with two detectors. Lattice studies, injection, collimation, and RF system design for the large acceptance, high intensity rings are discussed and the performance of the two rings compared.
WEPLS011	General Design Considerations for a High-intensity Muon Storage Ring for a Neutrino Factory	2418
	C. Johnstone Fermilab, Batavia, Illinois F. Meot CEA, Gif-sur-Yvette G. Rees CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
	Muon decay ring design, shielding, and compatibility with potential neutrino detector sites are a critical part of the International Scoping Study (ISS) for a neutrino factory. Two rings are under development: a racetrack and an isosceles-triangle ring initially for muon energy of 20 GeV, but upgradable to 50 GeV. Neutrinos from the muon decays in specially designed production straights can be directed to one or two distant detectors; the racetrack ring has one very long production straight, aligned with one detector, while the triangular ring has two straights, each half as long, aligned with two detectors. An initial site survey of accelerators and distant detectors has been made, along with the required tilt angles from the horizontal will be discussed here. (Lattice studies, injection, collimation, and RF system design are covered in a separate contribution to these proceedings.) Heating and activation effects of beam loss in the chamber walls and components will also be presented.
WEPLS012	Use of Gas-filled Cavities in Muon Capture for a Muon Collider or Neutrino Factory	2421
	D.V. Neuffer Fermilab, Batavia, Illinois K. Paul Muons, Inc, Batavia
	Recent studies indicate that gas-filled cavities can provide high-gradient acceleration and simultaneous cooling for muons. In this paper we explore using these cavities in the front-end of the capture and cooling systems for muon colliders and neutrino factories. For a muon collider scenario we consider capturing the beam in a low-frequency cavity (~50 MHz) and cooling immediate after capture. For a neutrino factory, we consider capturing beam in high-frequency buckets and phase-energy rotating and cooling them using gas-filled rf cavities. Scenario variants are described and studied.
WEPLS016	Studies of a Gas-filled Helical Muon Beam Cooling Channel	2424
	R.P. Johnson, K. Paul, T.J. Roberts Muons, Inc, Batavia Y.S. Derbenev Jefferson Lab, Newport News, Virginia K. Yonehara Fermilab, Batavia, Illinois
	A helical cooling channel (HCC) can quickly reduce the six dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. The HCC is composed of solenoidal, helical dipole, and helical quadrupole magnetic fields to provide the focusing and dispersion needed for emittance exchange as the beam follows an equilibrium helical orbit through a continuous homogeneous absorber. We consider liquid helium and liquid hydrogen absorbers in HCC segments that alternate with RF accelerating sections and we also consider gaseous hydrogen absorber in pressurized RF cavities imbedded in HCC segments. In the case of liquid absorber, the possibility of using superconducting RF in low magnetic field regions between the HCC segments may provide a cost effective solution to the high repetition rate needed for an intense neutrino factory or high average luminosity muon collider. In the gaseous hydrogen absorber case, the pressurized RF cavities can be operated at low temperature to improve their efficiency for higher repetition rates. Numerical simulations are used to optimize and compare the liquid and gaseous HCC techniques.
WEPLS017	International Scoping Study of a Future Accelerator Neutrino Complex	2427
	M.S. Zisman LBNL, Berkeley, California
	The ISS, launched at NuFact05 to evaluate the physics case for a facility, along with options for the accelerator complex and detectors, is laying the foundations for a subsequent conceptual-design study. It is hosted by RAL and organized by the international community, with participants from Europe, Japan, and the U.S. Here we cover work of the Accelerator Group. For the 4 MW proton driver, we consider linacs, synchrotrons, and FFAG rings. For targets, issues of both liquid-metal and solid materials are examined. For beam conditioning (phase rotation, bunching, and ionization cooling), we evaluate schemes with and without cooling, the latter based on scaling FFAG rings. For acceleration, we examine scaling FFAGs and hybrid systems comprising linacs, dogbone RLAs, and non-scaling FFAGs. For the decay ring we consider racetrack and triangular shapes, the latter capable of simultaneously illuminating two different detectors at different baselines. Comparisons are made between various technical approaches to identify optimum design choices for the facility.
WEPLS018	Optics for Phase Ionization Cooling of Muon Beams	2430
	R.P. Johnson Muons, Inc, Batavia S.A. Bogacz, Y.S. Derbenev Jefferson Lab, Newport News, Virginia
	The realization of a muon collider requires a reduction of the 6D normalized emittance of an initially generated muon beam by a factor of more than 106. Analytical and simulation studies of 6D muon beam ionization cooling in a helical channel filled with pressurized gas or liquid hydrogen absorber indicate that a factor of 106 is possible. Further reduction of the normalized 4D transverse emittance by an additional two orders of magnitude is envisioned using Parametric-resonance Ionization Cooling (PIC). To realize the phase shrinkage effect in the parametric resonance method, one needs to design a focusing channel free of chromatic and spherical aberrations. We report results of our study of a concept of an aberration-free wiggler transport line with an alternating dispersion function. Resonant beam focusing at thin beryllium wedge absorber plates positioned near zero dispersion points then provides the predicted PIC effect.
WEPLS019	Parameters for Absorber-based Reverse Emittance Exchange of Muon Beams	2433
	R.P. Johnson Muons, Inc, Batavia Y.S. Derbenev Jefferson Lab, Newport News, Virginia
	The normalized longitudinal emittance of a muon beam after six-dimensional ionization cooling appears very small compared to the value that could be utilized or maintained after acceleration to muon collider energy. This circumstance offers the possibility for further reduction of the transverse emittance by introducing absorber-based reverse emittance exchange (REMEX) between longitudinal and transverse degrees of freedom before acceleration to high energy. REMEX follows Parametric-resonance Ionization Cooling and is accomplished in two stages. In the first stage the beam is stretched to fill the RF bucket at the initial cooling energy. In the second stage the beam is accelerated to about 2.5 GeV, where energy straggling begins to limit the absorber technique, and stretched again. The potential transverse emittance reduction and the intrinsic limitations of the REMEX technique have been analyzed earlier. In this report, we describe the required beam transport and RF parameters needed to achieve the maximum REMEX effect.
FRXAPA01	Neutrino Factories and Beta Beams	3616
	M.S. Zisman LBNL, Berkeley, California
	The presentation will review the various concepts of Neutrino Factories and Beta Beams and indicate the main challenges in terms of beam performance and technological developments. It will also present the world-wide organization to define and carry out the necessary R&D for component design, beam simulations of facility performance, and benchmarking of key subsystems via actual beam tests. Currently approved subsystem tests include the Muon Ionization Cooling Experiment (MICE), under construction at Rutherford Appleton Laboratory, and the Mercury Intense Target (MERIT) experiment, to be carried out at CERN. The major issues being examined by MICE and MERIT will be described as well as the plans and schedule to address them.
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