Upload
allen-shaw
View
214
Download
0
Embed Size (px)
Citation preview
Stephen BrooksJAI Advisory Board, February 2006
1 of 12
Neutrino Factory Muon Beam Production Studies
Stephen BrooksJAI Advisory Board, February 2006
2 of 12
Confusing Acronyms• I am a DPhil student1 with Oxford Particle
Physics and part of the JAI• I actually work at RAL (a site of CCLRC) in the
ASTeC Intense Beams Group• Nationally, my research contributes to the UKNF
project2 (funded by PPARC)– Specifically, WP1: Conceptual Design3
• Internationally, this year it contributes to the NF Scoping Study (ISS)4
– Specifically, the accelerator study group5
[1] Supervisor: John Cobb, Oxford PP[2] Project leader: Ken Long, Imperial College[3] WP manager: Chris Prior, ASTeC IB Group, RAL[4] Project leader: Peter Dornan, Imperial College[5] Group coordinator: Mike Zisman, LBNL
Stephen BrooksJAI Advisory Board, February 2006
3 of 12
Thesis Title
• “Muon Capture and Cooling Schemes for the Neutrino Factory”
• So far I’ve concentrated on muon capture
Stephen BrooksJAI Advisory Board, February 2006
4 of 12
Problem
• The neutrino factory is (at least) a tertiary beam facility:
p+ » on target ± ± » ,e,
• Efficient capture of the pions as they decay to muons is a critical step
• Resultant beam must obey constraints longitudinally (E, bunch length) and transversely (emittance < acceptance)
Stephen BrooksJAI Advisory Board, February 2006
5 of 12
Research Activity (so far)
• Simulations of pion production in target– Optimal proton energy (or energies)– Target material choice
• Tracking of particles up to cooling– Finding the most efficient capture system
• Comparison, optimisation of schemes
– Also defining what we want from the target
• Cooling modelling preparation
Stephen BrooksJAI Advisory Board, February 2006
6 of 12
UKNF Muon “Front End”
Solenoidal decay channelRF phase rotation(reduces energy spread)
Target: difficult engineering challenge in itself, covered by UKNF WP2
Stephen BrooksJAI Advisory Board, February 2006
7 of 12
Target Simulations
• Particle production setup:
• Used MARS15 code• Scanned possible proton energies• Four materials studied so far
– Ta (solid), Hg (liquid jet), C (granular?), Cu
NF International Scoping Study (ISS); also GEANT4 benchmarking by K. Walaron
20cm for Ta … 66cm for C
1cmCylinder of material
Protons
Pions
Stephen BrooksJAI Advisory Board, February 2006
8 of 12
Target Results"PR2.2" Probability Grid Yield (MARS15)
0
0.005
0.01
0.015
0.02
0.025
0.1 1 10 100 1000
Proton Energy (GeV)
Par
ticl
es p
er p
.GeV
Tantalum piplus
Tantalum piminus
Mercury piplus
Mercury piminus
Carbon piplus
Carbon piminus
Copper piplus
Copper piminus
Stephen BrooksJAI Advisory Board, February 2006
9 of 12
Particle Tracking Features
• Starts with MARS15 output
• Cannot use paraxial approximation, so 3D– Nonlinear dynamics e.g. spherical aberration– (Somewhat) realistic geometry, obstructions
• Includes ± ± and muon, kaon decays
• Supports lattice optimisation ranges– Novel multi-parameter approach– Genetic algorithm
Stephen BrooksJAI Advisory Board, February 2006
10 of 12
Simulation
• Challenge: high emittance of target pions– Here they come from a 20cm tantalum rod
Evolution of pions from 2.2GeV proton beam on tantalum rod target
Stephen BrooksJAI Advisory Board, February 2006
11 of 12
Optimisation Network
• Internet-based computer grid being used– 20 million simulations run, 100s of users– Several lattice-ranges submitted
Stephen BrooksJAI Advisory Board, February 2006
12 of 12
Muon Cooling
G.H. Rees at RAL conceptually designed a “cooling dogbone” lattice– Future use for tracking/optimising code– Will compare with John Cobb using ICOOL
• Must include ‘energy absorbers’ (material)• At Oxford, the ELMS study has computed
the real muon cross-sections needed– I’ve studied how to integrate this with my code– Wade Allison, Simon Holmes’ speciality (next!)
Stephen BrooksJAI Advisory Board, February 2006
13 of 12
Stephen BrooksJAI Advisory Board, February 2006
14 of 12
Alternative Design
Over 80% caught in linac bucket
Chicane phase rotation decreases the bunch length