1. The document discusses potential future upgrades to the ISIS accelerator at Rutherford Appleton Laboratory, including increasing beam power up to 5 MW through higher proton beam energies and currents. 2. It also explores using RAL facilities for a potential neutrino factory or projects like MICE, which requires an intense proton source for pion production. 3. Developing the necessary accelerator technology and training young scientists are seen as important challenges for these large projects.

1. FELIX QVI POTVIT RERVM COGNOSCERE CAVSAS Some future accelerator scenarios at RAL David Findlay Accelerator Division ISIS Department Rutherford Appleton Laboratory

4. ISIS upgrades not necessarily accelerator upgrades

5. Source strength × Reliability × Instrumentation × Innovation × Investment × Support facilities × Support staff × Cost effectiveness × User community 10 × 1 × 1 × 1 × 1 × 1 × 1 × 1 × 1 2 × 1 × 1.26 × 1.26 × 1.26 × 1.26 × 1.26 × 1.26 × 1.26 1 × 1 × 1.39 × 1.39 × 1.39 × 1.39 × 1.39 × 1.39 × 1.39

8. ISIS at present

9. Second Target Station upgrade No power upgrade, but 18 more instruments (7 on Day 1)

10. ISIS at present

11. New ~180 MeV linac ½ MW upgrade — extra power by increasing current Present 70 MeV linac

15. Higher injection energy  space charge forces less of a problem Should be able to inject and accelerate higher currents ~300 µA at 70 MeV (with 2RF upgrade) ~600 µA at 180 MeV? 800 MeV × 600 µA = 480 kW ≈ 0.5 MW Need detailed beam dynamics calculations to confirm — ASTeC Intense Beams Group

16. Proton beam Individual proton in beam Space charge forces

19. Beam loss Why chopper? Ion source Linac Ring Bunching Also to minimise RF transients and control beam intensity

20. No beam loss Ion source Linac Ring Bunching With chopper — gaps in beam

21. Chopper performance required DC accelerator RF accelerator ns – µs spacing ESS: 280 MHz, bunch spacing 3.57 ns Switch between bunches Partially chopped bunches a problem! Tune shifts! Good Bad On Off

23. Close-coupled chopper module 1145 mm Slow switch Fast switch Beam Buncher cavity Buncher cavity

24. 1 MW upgrade Extra power by increasing energy

25. Transmutation and energy production with high power accelerators, G. P. Lawrence, Los Alamos National Laboratory, http://epaper.kek.jp/p95/ARTICLES/FPD/FPD03.PDF Proton range in tungsten target from integrating stopping power

27. 1 MW upgrade 800 MeV synch. TS1 TS2 3 GeV synch. TS3 (+ 8 GeV) µ

28. Circumference of 3 GeV synchrotron = 3 × circumference of 800 MeV synchrotron 800 MeV 26 m radius 2 – 3 µC per bunch 3 GeV 78 m radius Can “fit in” three times as much charge

37. 2½ & 5 MW upgrades

38. 2½ and/or 5 MW upgrades

39. 2½ MW upgrade TS3 µ 180 MeV linac 2 × 1.2 GeV synchrotrons 39 m radius 1 × 3 GeV synchrotron 78 m radius 50 pps

40. Circumference of 3 GeV synchrotron = 2 × circumference of 1.2 GeV synchrotron 3 GeV 78 m radius 1.2 GeV 39 m radius 1.2 GeV 39 m radius

41. 5 MW upgrade TS3 µ 180 MeV linac 2 × 1.2 GeV synchrotrons 39 m radius 2 × 6 GeV synchrotron 78 m radius 2 × 25 pps

43. Want intense beam of neutrinos — but can’t accelerate neutrinos (no charge) Can get neutrinos from muons If muons decay in flight, neutrinos tend to go in direction of muons   So get intense beams of neutrinos by accelerating intense beam of muons — but no natural source of muons

46. p + A Z  n,  , … (pion production)    +  (pion  muon + neutrino)   e +  +  (muon  electron + 2 × neutrinos) KARMEN experiment at ISIS Electron anti-neutrinos not produced by ISIS, so their appearance would be evidence for neutrino oscillations and thus evidence for neutrino mass  ’ s in all directions — KARMEN close to target

47. Muon Storage Ring High current H – source Cooling Muon Acceleration ‘ near’ detector (1000–3000km) ‘ far’ detector (5000–8000km) ‘ local’ detector Proton Driver Target Capture

48. UK Neutrino Factory

50. FNAL BNL CERN GSI CEA INFN JHF DUBNA RAL? Neutrino experiment

52. Protons  pions  muons http://puhep1.princeton.edu/mumu/target/targettrans15.pdf

53. Muons produced with large energy and angular spreads — pretty ghastly source for an accelerator “ Phase rotation” in energy-time phase space to selectively speed up slow muons — several different schemes, all need RF “ Cooling” to reduce transverse motion but not longitudinal motion — reduce longitud. and transv. energy in absorber — put back longitud. only — MICE experiment at RAL

54. Particle with transverse momentum After losing energy in absorber After acceleration in RF cavity Muon Ionisation Cooling Experiment

56. 50 GeV muon recirculating superconducting linac ISIS synchrotron