| Paper |
Title |
Page |
| WEPP028 |
Flexible Momentum Compaction Return Arcs for RLAs
|
2578 |
| |
- D. Trbojevic
BNL, Upton, Long Island, New York
- S. A. Bogacz
Jefferson Lab, Newport News, Virginia
- R. P. Johnson
Muons, Inc, Batavia
- M. Popovic
Fermilab, Batavia, Illinois
|
|
| |
Neutrino Factories and Muon Colliders require rapid acceleration of short-lived muons to multi-GeV and TeV energies. A Recirculating Linear Accelerator (RLA) that uses a single Linac and teardrop return arcs can provide exceptionally fast and economical acceleration to the extent that the focusing range of the RLA quadrupoles allows each muon to pass several times through each high-gradient cavity and the cost of the return arcs is appropriate. Flexible Momentum Compaction (FMC) lattice designs for the teardrop return arcs provide sufficient momentum acceptance to allow multiple passes of each sign of muon in one string of magnets to improve cost-effectiveness.
|
|
| WEPP048 |
Recirculating Linear Muon Accelerator with Ramped Quadrupoles
|
2629 |
| |
- S. A. Bogacz
Jefferson Lab, Newport News, Virginia
- R. P. Johnson
Muons, Inc, Batavia
|
|
| |
Neutrino Factories and Muon Colliders require rapid acceleration of short-lived muons to multi-GeV and TeV energies. A Recirculating Linear Accelerator (RLA) that uses a single Linac and teardrop return arcs can provide exceptionally fast and economical acceleration to the extent that the focusing range of the RLA quadrupoles allows each muon to pass several times through each high-gradient cavity. A new concept of rapidly changing the strength of the RLA focusing quadrupoles as the muons gain energy is being developed to increase the number of passes that each muon will make in the RF cavities, leading to greater cost effectiveness. We are developing the optics and technical requirements for RLA designs, using RF cavities capable of simultaneous acceleration of both μ+ and μ- species, with pulsed Linac quadrupoles to allow the maximum number of passes.
Supported in part by DOE STTR grant DE-FG02-05ER86253
|
|
| WEPP108 |
The MICE Diffuser System
|
2761 |
| |
- M. Apollonio, J. H. Cobb, T. Handford, P. Lau, W. Lau, J. Tacon, M. Tacon, S. Q. Yang
OXFORDphysics, Oxford, Oxon
- M. Dawson
JAI, Oxford
|
|
| |
The MICE experiment at RAL will measure the performance of a cooling channel in a variety of configurations of momentum and initial emittance. Coverage in phase space relies on the MICE diffuser, a system with five different thickness lead degraders, remotely operated in a high magnetic field. Technical issues and degrader optimisation for beam matching are discussed.
|
|
| WEPP110 |
Design and Operational Experience of the MICE Target
|
2764 |
| |
- C. N. Booth, P. Hodgson, L. C. Howlett, M. T. Mohammad, R. Nicholson, 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 synchrotron. A novel target mechanism has been developed which allows the insertion of a small titanium target into the proton beam halo on demand. The target must remain outside of the beam envelope during acceleration, and then overtake the beam during the last 2ms before extraction. The technical specifications are demanding, and require large accelerations and precise and reproducible location of the target in each cycle. The mechanism must also operate in a high radiation environment, and the moving parts and materials must be compatible with the stringent requirements of operating in a working accelerator. The design, and the commissioning and operational experience using this system during the first operating periods in 2008 is described.
|
|
| WEPP111 |
Modeling Breakdown in RF Cavities Using Particle-in-cell (PIC) codes
|
2767 |
| |
- S. Mahalingam, J. R. Cary, P. Stoltz, S. A. Veitzer
Tech-X, Boulder, Colorado
|
|
| |
A main limitation on future accelerator projects is breakdown of metallic structures. We have developed computer models of the process of breakdown using Particle-In-Cell (PIC) codes which include: Fowler-Nordheim field emission due to large surface electric fields, impact ionization of neutral gas, ion-induced secondary electron emission, ion-induced sputtering of neutrals, the effects of applied magnetic fields, plasma radiation effects, and surface heating. Two computational tools have been used to self-consistently model the breakdown. These are- OOPIC Pro, a 2-Dimensional serial electromagnetic code with cylindrical coordinates, and
- VORPAL, a 3-Dimensional massively parallel electromagnetic code with cartesian grids.
We describe here the results of our numerical experiments including the effects of applied magnetic field strength and direction on the breakdown process, sensitivity of breakdown triggers on field emission parameters, and the potential to measure the onset of breakdown by examining impurity radiation. We show comparison with breakdown experiments performed at Fermilab and Argonne for copper structures being considered for a future muon collider project.
|
|
| WEPP116 |
Muon Decay Ring Study
|
2770 |
| |
- D. J. Kelliher, S. Machida, C. R. Prior, G. H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
- F. Meot
CEA, Gif-sur-Yvette
|
|
| |
Three different muon decay ring configurations are being considered for a neutrino factory. A racetrack design is the current ISS baseline (as it allows greater flexibility in the choice of detector sites) but triangular and bow-tie rings have advantages in neutrino production rates*. Using tracking code simulations, a study of the latter two designs is carried out. Since spin depolarisation measurements have been proposed for muon energy calibration**, spin tracking is included in this study. Dynamic aperture is important and is also calculated.
*International Scoping Study report, 2006.
**A Blondel et al. (editors), ECFA/CERN studies of a European Neutrino Factory Complex, CERN-2004-002 and EFCA/04/230, 13 April, 2004.
|
|
| WEPP119 |
The International Design Study for a Neutrino Factory
|
2773 |
| |
- C. R. Prior
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
- J. S. Berg
BNL, Upton, Long Island, New York
- M. Meddahi
CERN, Geneva
- Y. Mori
KURRI, Osaka
|
|
| |
The International Design Study (IDS) is the successor to the International Scoping Study (ISS), which identified a baseline scenario for a Neutrino Factory. IDS was launched in August 2007, with the aim of developing the baseline to the point where a full, technical design report can be written. The accelerator complex starts with a 4 MW proton driver operating at 50 Hz producing three to five, 1-2 ns bunches per pulse. The proton beam impacts on a liquid mercury jet target; pions are generated and are captured in a solenoid channel; they decay to muons which are phase rotated and formed into trains of interleaved bunches alternating in sign. The muon bunches then undergo ionisation cooling so as to be accepted by a linac, two dogbone recirculating linacs and finally an FFAG for acceleration to 25GeV. The muons are transferred to purpose-built storage rings, with long production straights, where they decay to neutrinos which are directed to detectors at distances of about 3000 km and 7500 km. IDS will be developing this baseline design, identifying its strengths and weaknesses, and progressing the whole towards a self-consistent scenario for the final technical design report stage.
|
|
| WEPP120 |
G4Beamline Particle Tracking in Matter-dominated Beam Lines
|
2776 |
| |
- T. J. Roberts, K. B. Beard
Muons, Inc, Batavia
- S. Ahmed, D. M. Kaplan, L. K. Spentzouris
Illinois Institute of Technology, Chicago, Illinois
- D. Huang
IIT, Chicago, Illinois
|
|
| |
Most computer programs that calculate the trajectories of particles in accelerators assume that the particles travel in an evacuated chamber. The development of muon beams, which are needed for future facilities such as muon colliders and neutrino factories, is limited by the lack of user-friendly numerical simulation codes that accurately calculate scattering and energy loss in matter. Geant4 is an internationally supported tracking toolkit that was developed to simulate particle interactions in large detectors for high energy physics experiments, and includes most of what is known about the interactions of particles and matter. Geant4 has been partially adapted in a program called G4beamline to develop muon beam line designs. We are continuing the development of G4beamline to enhance its graphical user-interface and add other features to the program to facilitate its use by a larger set of beam line and accelerator developers.
|
|
| WEPP121 |
Recirculating Ring for an Ionization Cooling Channel
|
2779 |
| |
- C. T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
|
|
| |
In a muon acceleration facility such as a Neutrino Factory or Muon Collider, the muons created from pion decay occupy a large volume of phase space. For a good capture efficiency this phase space should be reduced and this is typically achieved using ionisation cooling channels. These are quite expensive but the cost can be reduced by recirculating muons through the cooling hardware. Recirculating a high emittance beam typical of a Neutrino Factory is very challenging if it is to be achieved without significant losses. I describe latest attempts to design a high acceptance recirculator for a muon front end.
|
|
| WEPP122 |
Commissioning Status of the MICE Muon Beamline
|
2782 |
| |
- K. Tilley
STFC/RAL/ISIS, Chilton, Didcot, Oxon
|
|
| |
It is planned to install a Muon Ionisation Cooling Experiment (MICE) at the ISIS facility at Rutherford Appleton Laboratory. This experiment will be the first demonstration of ionisation cooling as a means to reduce the large transverse emittances expected in the early stages of a Neutrino Factory. A new muon beamline has been installed on ISIS, in order to supply muons of characteristic energy and emittance to the experiment. This paper gives an overview of the goals and design of the beamline, the detectors used to characterise the beam, and the techniques and results which have been obtained during its first operating periods in 2008.
K. Tilley on behalf of the MICE Collaboration.
|
|
| WEPP123 |
Isochronous Pion Decay Channel for Enhanced Muon Capture
|
2785 |
| |
- C. Y. Yoshikawa, C. M. Ankenbrandt, D. V. Neuffer, M. Popovic, K. Yonehara
Fermilab, Batavia, Illinois
- R. J. Abrams, M. A.C. Cummings, R. P. Johnson
Muons, Inc, Batavia
- Y. S. Derbenev
Jefferson Lab, Newport News, Virginia
|
|
| |
Intense muon beams have many potential applications, including neutrino factories and muon colliders. However, muons are produced in tertiary beams into a diffuse phase space. To make useful beams, the muons must be rapidly cooled before they decay. A promising new concept for the collection and cooling of muon beams is being investigated, namely, the use of a nearly Isochronous Helical Transport Channel (IHTC) to facilitate capture of muons into RF bunches. Such a distribution could be cooled quickly and coalesced into a single bunch to optimize the luminosity of a muon collider. We describe the IHTC and provide simulations demonstrating isochronicity, even in the absence of RF and absorber.
|
|
| THYG03 |
Ionization Cooling and Muon Colliders
|
2917 |
| |
- R. P. Johnson
Muons, Inc, Batavia
|
|
| |
Recent developments in the field of muon beam cooling are reviewed. A view of the impact of new cooling concepts on the overall design of muon colliders is included, as are the prospects for the experimental verification of the required muon beam cooling concepts and technology.
|
|
|
Slides
|
|