Neutrino Factory Accelerator R&D

1. Neutrino Factory Accelerator R&D F. Gerigk & C.R. Prior CCLRC Rutherford Appleton Laboratory

2. Work Programme 2003-7 • Proton Driver R&D • Muon Front End • Muon Acceleration and Storage • Financial situation - funding bids, FP6 etc.

3. Proton Driver R&D • 5 GeV, 50 Hz, 4 MW proto-type driver studied in reasonable detail. • Study of a more promising 15 GeV, 25 Hz, 4 MW design remain incomplete. • Accumulator and Compressor rings designed for CERN SPL scenario. No further work planned. • 30GeV, 8 Hz slow cycling synchrotron designed as possible replacement for CERN PS. • Current plans based on an upgrade to ISIS combining neutron and neutrino options. • A major theoretical study has been instigated into the electron cloud (e-p instability) problem.

4. Muon Studies • Pion decay/muon capture optimisation studies to be completed by September 2004 (Stephen Brooks) • Alternative muon cooling schemes to be studied in parallel (and complementary) to MICE (SJB/GHR); includes magnet development (Opera-3D) • Muon acceleration and storage • theoretical studies as part of ENG (under F.Meot) and independently at RAL

5. FP6 – HIPPI Proposals • Submitted April 2003 as JRA under ESGARD proposals to EC • Aimed primarily at improving existing infrastructure but will benefit R&D for future projects • Upgrades of proton injector at CERN to • increase the neutrino flux to Gran Sasso, • Increase the proton flux delivered to ISOLDE • Increase the proton flux for fixed target experiments • prepare for LHC luminosity upgrade. • Proton injector at GSI for anti-proton production • New linac for ISIS (also relevant to ESS)

6. HIPPI • HIPPI broken down into four work packages • Low energy, normal conducting, accelerating structures (DTL, H-DTL, SCL, CC-DTL) • Pulsed operation of superconducting RF structures (Elliptical/spoke cavities, RF couplers); includes R&D to determine lowest energy at which sc technology can be safely and economically used. • Fast beam chopping; CERN and RAL designs to be developed in parallel, with beam tests in 2007. • Beam dynamics, codes, diagnostics and collimation (study of beam halo, development of 3D simulation tools, design and construction of diagnostic tools to facilitate bench-marking of codes)

7. WP1: ISN-G (Jean-Marie De Conto) CEA-Saclay (P.E. Bernaudin) CERN (M. Vretenar) ISN-G (J-M. De Conto) RAL (F. Gerigk) University of Frankfurt (R. Tiede) WP2: CEA-Saclay (S. Chel) INFN Milan (C. Pagani) CEA-Saclay (B. Visentin) FZ Jülich (R. Toelle) ISN-G (J-M. De Conto) University of Frankfurt (H. Podlech) WP3: CERN (A. Lombardi) CERN (F. Casper) RAL (M. Clark-Gayther) WP4: GSI (I. Hofmann) CERN (A. Lombardi) CEA-Saclay (R. Duperrier) FZ Jülich (R. Toelle) GSI (L. Groening) INFN Milano (P. Pierini) ISN-G (J-M De Conto) RAL (C. Prior) University of Frankfurt (R. Tiede) HIPPI Organisational Structure Coordinators: R. Garoby (CERN), M. Vretenar (CERN)

9. Summary • Work ongoing towards construction of 280MHz RFQ and beam chopper for NF/ISIS linac (FP6, ISIS, ASTeC and other funding) • DTL design study (FG) and computer code development (CRP) included in FP6 • Design study for new ISIS synchrotron underway (FP6 bid April 2004?) • Theoretical and experimental work is in hand to explore electron cloud problem (GB) • Muon front end work continuing (GHR+SJB), to be extended to muon acceleration and storage • Preparations for possible Study III in hand

10. WP1: Normal Conducting Linac Accelerating Structures • Acceleration of the beam in a pulsed proton linac  Normal conducting structures (up to an energy ~150 MeV). • Upgrades of both proton injectors for CERN and GSI. (CERN high duty factor and high beam quality (no halo)) • CERN types of structures to be prototyped are DTL for the energy range from 3 to 40MeV, Coupled Cavity Drift Tube Linac (CCDTL) for 40 to 100 MeV and Side Coupled Linac (SCL) above 100 MeV. • Design, construction and high power test of prototypes • validate technological choices and codes • select the economical optimum. • H-mode structures for GSI linac over full range of energies. • Low power model (to be built and measured) • High power 350 MHz CH cavity prototype (test stand at GSI or at CERN) • DTL design for new ISIS linac

11. WP2: Super Conducting Linac Accelerating Structures • Aim is to determine the lowest energy at which superconducting cavities can be operated safely and economically. [At low energy, sc technology is less efficient and Lorentz detuning of cavities is severe.] • Input power couplers to be tested up to 1 MW (forward peak power) for reliability issues under frequency-dependent effects such as multipactoring and outgassing • Test: • existing vertical cryostats at low power • existing horizontal cryostats at full power (fully equipped cavities). This will necessitate development of a high RF power source and its modulator. • Low beta sc cavities are under consideration as accelerating structures at the end of the CERN and GSI injector upgrades and could then be the first full-sized components of a future higher energy upgrade.

12. WP3 : High Speed Beam Chopper • Loss-free ring injection and fast ring extraction are made possible by creating a gap in the train of linac micro-bunches. • The beam chopper, positioned in the low energy stages of the linac, after the RFQ, is deflects bunches to collector plates. • Deflecting field has to rise in the gap between bunches, usually 2 ns (at ~300MHz) • Two different approaches are proposed by CERN and RAL • At RAL, a powerful “slow” pulser drives one set of deflecting structures, and a less powerful “fast” pulser drives the second set (integrated beam dump) • At CERN, both deflecting structures are driven by similar drivers, and the beam dump is localised. • Prototypes of the meander line structures, the drivers and the beam dumps will be designed, built and tested with beam. • Based on the experimental results, conclusions will be drawn for the optimum technological solution in any future superconducting high energy linac.

13. WP4 : Beam dynamics, codes, diagnostics and collimation • Continuous development of simulation tools needed to match improving cavity technology (e.g. low beta super conducting cavities). • Increased computing power opens avenues for end-to-end beam transport simulation including errors (structures and beam errors). • The project aims to develop: • analytical and numerical tools for the analysis of beam dynamics • models for beam halo generation in high intensity proton linacs • beam instrumentation to characterise beam profile over a large dynamic range and test the above-mentioned tools, especially in the longitudinal plane. • Includes exchange and bench-marking of existing codes by comparison with experiments at low energies (~3 MeV). • A time resolve beam profile monitor and of an instrument for beam halo measurement at 3 MeV will be designed, built and tested.

15. 180 MeV H- Linac Collimation Momentum Ramping Injection 2 bunches of 2.5 1013 protons Two 1.2 GeV, 50 Hz Rapid Cycling Synchrotrons 4 bunches of 2.5 1013 protons Two 5 GeV, 25 Hz Rapid Cycling Synchrotrons 5GeV, 50 Hz Proton Driver

16. 15GeV, 25 Hz Proton Driver 3 bunches

17. RAL Muon Cooling Ring A=absorbers S,S1=solenoids