Muon capture for the front end of a muon collider

We discuss the design of the muon capture front end for a \mu+-\mu- Collider. In the front end, a proton bunch on a target creates secondary pions that drift into a capture transport channel, decaying into muons. A sequence of rf cavities forms the resulting muon beams into strings of bunches of differing energies, aligns the bunches to (nearly) equal central energies, and initiates ionization cooling. The muons are then cooled and accelerated to high energy into a storage ring for high-energy high luminosity collisions. Our initial design is based on the somewhat similar front end of the International Design Study (IDS) neutrino factory.Comment: 3 pp. Particle Accelerator, 24th Conference (PAC'11) 28 Mar - 1 Apr 2011: New York, US

Design Concept for nu-STORM: An Initial Very Low-Energy Neutrino Factory

We present a design concept for a {nu} source from a STORage ring for Muons ({nu}STORM). In this initial design a high-intensity proton beam produces {approx}5 GeV pions that provide muons that are captured using 'stochastic injection' within a 3.6 GeV racetrack storage ring. In 'stochastic injection', the {approx}5 GeV pion beam is transported from the target into the storage ring, dispersion-matched into a long straight section. (Circulating and injection orbits are separated by momentum.) Decays within that straight section provide muons that are within the {approx}3.6 GeV/c ring momentum acceptance and are stored for the muon lifetime of {approx}1000 turns. Muon (and pion) decays in the long straight sections provide neutrino beams of precisely known flux and flavor that can be used for precision measurements of electron and muon neutrino interactions, and neutrino oscillations or disappearance at L/E = {approx}1m/MeV. The facility is described, and variations are discussed

Effect of subelement spacing in RRP Nb3Sn strands

The Restacked Rod Process (RRP) is the Nb{sub 3}Sn strand technology presently producing the largest critical current densities at 4.2 K and 12 T. However, when subject to plastic deformation, RRP subelements (SE) were found to merge into each other, creating larger filaments with a somewhat continuous barrier. In this case, the strand sees a larger effective filament size, d{sub eff}, and its instability can dramatically increase locally leading to cable quench. To reduce and possibly eliminate this effect, Oxford Instruments Superconducting Technology (OST) developed for FNAL a modified RRP strand design with larger Cu spacing between SE's arranged in a 60/61 array. Strand samples of this design with sizes from 0.7 to 1 mm were first evaluated for transport current properties. A comparison study was then performed between the regular 54/61 and the modified 60/61 design using 0.7 mm round and deformed strands. Finite element modeling of the deformed strands was also performed with ANSYS

The MANX muon cooling demonstration experiment

MANX is an experiment to prove that effective six-dimensional (6D) muon beam cooling can be achieved in a Helical Cooling Channel (HCC) using ionization-cooling with helical and solenoidal magnets in a novel configuration. The aim is to demonstrate that 6D muon beam cooling is understood well enough to plan intense neutrino factories and high-luminosity muon colliders. The experiment consists of the HCC magnet that envelops a liquid helium energy absorber, upstream and downstream instrumentation to measure the beam parameters before and after cooling, and emittance matching sections between the detectors and the HCC

Doped H(2)-Filled RF Cavities for Muon Beam Cooling

RF cavities pressurized with hydrogen gas may provide effective muon beam ionization cooling needed for muon colliders. Recent 805 MHz test cell studies reported below include the first use of SF{sub 6} dopant to reduce the effects of the electrons that will be produced by the ionization cooling process in hydrogen or helium. Measurements of maximum gradient in the Paschen region are compared to a simulation model for a 0.01% SF{sub 6} doping of hydrogen. The observed good agreement of the model with the measurements is a prerequisite to the investigation of other dopants

A Complete Scheme of Ionization Cooling for a Muon Collider

The conclusions of this report are: (1) New 1.5 TeV Collider lattice has more conservative IP parameters--(a) Luminosity 1 x 10{sup 34} achieved with bunch rep rate {approx}12 Hz but requires depth {approx}135 (m) to limit neutrino radiation, (b) Collider ring must be deep (eg 135 m of ILC) to control neutrino radiation, and (c) Proton driver ({approx}4 MW) is challenging; (2) Complete cooling scheme achieves required muon parameters--All components simulated (at some level) with realistic parameters, but much work remains; (3) Possible problem with rf breakdown in specified magnetic fields--Solutions with gas in cavities appear to work, and designs with open cell rf are promising; and (4) Lower cost acceleration possible using pulsed magnets in synchrotrons--Rings fit in Tevatron tunnel, and second ring uses hybrid of fixed and pulsed magnets

Use of Helical Transport Channels for Bunch Recombination

Cooling scenarios for a high-luminosity Muon Collider require bunch recombination for optimal luminosity. In this report we note that the tunable chronicity property of a helical transport channel (HTC) makes it a desirable component of a bunch recombiner. A large chronicity HTC is desirable for the bunch recombining transport, while more isochronous transport may be preferred for rf manipulations. Scenarios for bunch recombination are presented, with initial 1-D simulations, in order to set the stage for future 3-D simulation and optimization. HTC transports may enable a very compact bunch recombiner

Quasi-isochronous Muon Collection Channels

Intense muon beams have many potential applications, including neutrino factories and muon colliders. However, muons are produced as tertiary beams, resulting in diffuse phase space distributions. To make useful beams, the muons must be rapidly cooled before they decay. An idea conceived recently for the collection and cooling of muon beams, namely, the use of a Quasi-Isochronous Helical Channel (QIHC) to facilitate capture of muons into RF buckets, has been developed further. The resulting distribution could be cooled quickly and coalesced into a single bunch to optimize the luminosity of a muon collider. After a brief elaboration of the QIHC concept, recent developments are described

Helical channel design and technology for cooling of muon beams

Novel magnetic helical channel designs for capture and cooling of bright muon beams are being developed using numerical simulations based on new inventions such as helical solenoid (HS) magnets and hydrogen-pressurized RF (HPRF) cavities. We are close to the factor of a million six-dimensional phase space (6D) reduction needed for muon colliders. Recent experimental and simulation results are presented

A Helical Cooling Channel System for Muon Colliders

Abstract Not Provide