1. PSI, Zurich February 29 – March 2 2016 Session classification : Accelerator Concepts Tuesday, March 1, 2016 Introduction Vyacheslav Yakovlev Fermilab, USA

2. Outline: Proton Drivers: - GeV-energy range - MW-power range - Applications: neutrinos, muons, neutrons, ADS. Types of accelerators for proton drivers: - Cyclotrons and Fixed-Field Alternating Gradient accelerators (FFAG); - Rapid Cycle Synchrotrons (RCS); - High intensity pulsed linear accelerators; - CW Superconducting RF linear accelerators. Why electrical efficiency is critical: - Capital cost - Operational cost - Reliability 3/1/2016Vyacheslav Yakovlev. Session classification : Accelerator Concepts. Introduction 2

3. Outline: Efficiency drivers: - RF source efficiency; - Acceleration Efficiency; - Magnet system; - Cooling and/or refrigeration system; - Auxiliary systems; - Other The goal of the session: - Efficiency drivers for different types of the proton drivers - Wall-plug efficiency limits for the MW-range proton driver - The ways of the efficiency improvement - New technologies should be developed for this. 3/1/2016Vyacheslav Yakovlev. Session classification : Accelerator Concepts. Introduction 3

4. Types of accelerators for proton drivers: Cyclotrons – J.K. Grillenberger 3/1/2016Vyacheslav Yakovlev. Session classification : Accelerator Concepts. Introduction 4

5. Types of accelerators for proton drivers: Cyclotrons – J.K. Grillenberger 3/1/2016Vyacheslav Yakovlev. Session classification : Accelerator Concepts. Introduction 5

6. Types of accelerators for proton drivers: FFAG – Sh. Machida 3/1/2016Vyacheslav Yakovlev. Session classification : Accelerator Concepts. Introduction 6 What is Fixed-Field Alternating Gradient accelerator (FFAG)? Proposed in 1950s. o ~10 years development at MURA. o Rebirth in 2000. o EMMA at Daresbury in 2012. Similar to cyclotrons. o DC magnet. o Orbit spirals out. Similar to synchrotrons. o Alternating gradient (AG) focusing makes o small beam size. o Orbit excursion from injection to extraction is minimized. o Transverse tune is constant. o Pulsed mode operation with single turn extraction. o Energy can be more than 1 GeV. Chandrasekhar Bohr 400 keV radial sector 180 keV spiral sector

7. Types of accelerators for proton drivers: FFAG – Sh. Machida 3/1/2016Vyacheslav Yakovlev. Session classification : Accelerator Concepts. Introduction 7 High average beam power by high repetition rate (~ 100 Hz). o Neutron user either shares the high repetition pulses with multiple targets or obtains the whole with lower repetition after beam stacking in a FFAG. o Muon and other users may accept ~100 Hz pulses. Staged beam power up with a proper RF installation scenario. o Repetition rate and beam intensity are controlled by RF, not the lattice magnets. o Adding RF cavities in line with 1) user request, 2) target readiness, 3) beam loss handling, etc. Low operation cost due to superconducting (superferric) or permanent magnets. o Keep the field strength moderate (~2 T) so that accelerator size is not smaller than RCS. o Cryo-cooler operation is the goal.

8. Types of accelerators for proton drivers: Pulsed linacs – S-H. Kim 3/1/2016Vyacheslav Yakovlev. Session classification : Accelerator Concepts. Introduction 8 High Energy Physics –PIP-II (FNAL): H- Linac –SPL (CERN): H- Linac Neutron Source –Long pulse Linac: ESS (ESS), H+ –Short pulse Linac (H-) + Rapid Cycling Synchrotron: ISIS, J-PARC (JAEA), CSNS Linac (H-) + Accumulator Ring: SNS (ORNL), PSI (LANL) PIP II (project): Linac output : 16 kW at 800 MeV; 20Hz, 2mA (macro pulse), 0.55 ms (upgrade: 1.6 MW CW) SPL (project): Low Power Superconducting Proton (H-) Linac (LPSPL) Linac output: 190 kW at 4GeV 2Hz, 20 mA (macro pulse average), 1.2 ms, length: 460 m Superconducting Proton (H-) Linac (SPL) Linac output: 4 MW at 5 GeV 50 Hz, 40 mA (macro pulse average), 0.4 ms, length: 535 m

9. Types of accelerators for proton drivers: Pulsed linacs – S-H. Kim 3/1/2016Vyacheslav Yakovlev. Session classification : Accelerator Concepts. Introduction 9 ESS (under construction) –Linac output: 5 MW at 2 GeV 14 Hz, 62.5 mA (macro pulse average), 2.86 ms –Transition Energy between warm and cold linac: 90 MeV J-PARK (in operation) Linac (all warm linac) Output: ~135 kW at 400 MeV 25 Hz, 26.5 mA (macro pulse average), 0.5 ms 1 MW at 3 GeV after RCS (average current 333 uA)

10. Types of accelerators for proton drivers: Pulsed linacs – S-H. Kim 3/1/2016Vyacheslav Yakovlev. Session classification : Accelerator Concepts. Introduction 10

11. Types of accelerators for proton drivers: RCS - Masahito Yoshii 3/1/2016Vyacheslav Yakovlev. Session classification : Accelerator Concepts. Introduction 11

12. Types of accelerators for proton drivers: RCS - Masahito Yoshii 3/1/2016Vyacheslav Yakovlev. Session classification : Accelerator Concepts. Introduction 12

13. Session Schedule: 3/1/2016Vyacheslav Yakovlev. Session classification : Accelerator Concepts. Introduction 13