Neutrino Factory Muon Beam Production Studies

1. m Neutrino Factory Muon Beam Production Studies Stephen Brooks JAI Advisory Board, February 2006

2. 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 Brooks JAI Advisory Board, February 2006

3. Thesis Title • “Muon Capture and Cooling Schemes for the Neutrino Factory” • So far I’ve concentrated on muon capture Stephen Brooks JAI Advisory Board, February 2006

4. Problem • The neutrino factory is (at least) a tertiary beam facility: p+»on target  p±  m± »  n,ne,m • Efficient capture of the pions as they decay to muons is a critical step • Resultant beam must obey constraints longitudinally (DE, bunch length) and transversely (emittance < acceptance) Stephen Brooks JAI Advisory Board, February 2006

5. 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 Brooks JAI Advisory Board, February 2006

6. UKNF Muon “Front End” RF phase rotation (reduces energy spread) Solenoidal decay channel Target: difficult engineering challenge in itself, covered by UKNF WP2 Stephen Brooks JAI Advisory Board, February 2006

7. Target Simulations Pions • 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 Protons 1cm Cylinder of material 20cm for Ta … 66cm for C Stephen Brooks JAI Advisory Board, February 2006

8. Target Results Stephen Brooks JAI Advisory Board, February 2006

9. Particle Tracking Features • Starts with MARS15 output • Cannot use paraxial approximation, so 3D • Nonlinear dynamics e.g. spherical aberration • (Somewhat) realistic geometry, obstructions • Includes p±  m± and muon, kaon decays • Supports lattice optimisation ranges • Novel multi-parameter approach • Genetic algorithm Stephen Brooks JAI Advisory Board, February 2006

10. 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 Brooks JAI Advisory Board, February 2006

11. Optimisation Network • Internet-based computer grid being used • 20 million simulations run, 100s of users • Several lattice-ranges submitted Stephen Brooks JAI Advisory Board, February 2006

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 Brooks JAI Advisory Board, February 2006

13. Stephen Brooks JAI Advisory Board, February 2006

14. Alternative Design Chicane phase rotation decreases the bunch length Over 80% caught in linac bucket Stephen Brooks JAI Advisory Board, February 2006