The RCS Driver Option H Schnauer for HIP

The RCS Driver Option H. Schönauer for HIP WG 9. 04. 2003 u Motivation u Basic Spec’s and Requirements u Layout u Challenges u Some Details u Cost Estimate

Motivation: N. B. When the neutrino boom started, the SPL was already there… q Ø Some Assumptions and Beliefs : Production requires higher p energies Ø Low Rep rate ~10 Hz: Favorable for muon acceleration (RFC duty cycle), muon collider, possibly for cooling rings Short bunches 1 ns rms can be made (almost) naturally Synchrotrons are less expensive than linacs Ø Ø q q Injector for SPS > t , replacing CPS 2. 2 Ge. V/50 Hz / 0. 44 MW Booster (150 k. W in parasite for !)

Specifications for Proton Driver from Nu. Fact (and CERN)

Perspective on Earlier Nu. Fact. Scenarios of 4 MW Beam Power

P 08/03/2000 Perspective on Scenarios H. O. S. 5

RCS Driver Layout Main Ring Cycle

Specific Challenges of the RCS’s • • • RF capture during injection into booster accelerating bucket: no time for truly adiabatic capture critical voltage program, cf. Slide “Quasi -adiabatic capture in RCS” Some capture loss may be inevitable higher injection energies unfavorable High t–Lattices with dispersion-free SS are difficult. Additional constraint on 1 coeff. near transition; To be met together with zero-chromaticity and large dynamic aperture Very large RF voltages required; Little SS space for RFC’s in dispersion-free regions

Specific Challenges and. Problems of the 30 Ge. V RCS, cont’d. • • Enormous stored energy in the large magnets: 300 k. J in each of the 64 main dipoles of the NF 952 lattice. Consequence: Very expensive resonant PS or even more expensive IGBT groups Long holding time on flat bottom of main synchr. coupled bunch instabilities All resonators need to be damped; difficult for HOM in accelerating cavities; 30 Ge. V adiabatic compression: Low fsy =140 Hz at end of cycle. Nevertheless natural bunch length of 1 ns rms is achieved. High Q resonators up to 200 MHz may cause loss. Tight Impedance budget: Z/jn <2 ohms critical Large shielded ceramic chambers or alternatives

180 Me. V H- Linac from RAL

2. 2 Ge. V Booster

30 Ge. V / 8 Hz Main Ring

2. 2 Ge. V Booster Lattice (Stretched Austron RCS Lattice)

2. 2 Ge. V Booster Approximate Lattice

Quasi-Adiabatic Trapping into a Rapidly Cycling Synchrotron at 150 Me. V (0. 5 MW/50 Hz AUSTRON III) Early Trapping: RF Voltage limited to preserve capture efficiency RF Voltage increase can begin only after 1/4 rotation ! A careful tracking study is always necessary to achieve loss-less capture at least in simulation !

Driver Lattice NF 952 Yuri Senichev 2000

Hybrid Lattice GHR 30 Ge. V Grahame Rees 2002

NF 952 Lattice: 1 bare= 0. 047 1 (0)= -0. 026 1 (-6)=0. 0006 (=Chromaticity)

GHR 30 Ge. V Lattice: 1 bare= 0. 042 1 (0) = 0. 014 (=Chromaticity)

W. PIRKL'S DESIGN for RF CAVITY 10 MHZ for the 30 Gev / 8 Hz RCS

A 2 nd harmonic has been added to the sinusoidal magnet cycle to smooth the motion and the forces on the tuning vibrator.

Availability of dispersion-free long straight sections in the 30 Ge. V Lattices

The SPL + 30 Ge. V RCS Scenario SPL + RCS Scenario

Cost Estimate (RAL) of 180 Me. V Linac for RCS Scenarios

Cost Estimate of 2. 2 Ge. V / 50 Hz Booster for the CERN RCS scenarios

Cost Estimate of 25 -30 Ge. V / 8 Hz Drivers for the CERN RCS scenario

Partial Cost Estimate of PDAC Rings Sources (acknowledged) : Magnets M. Sassowsky Power Supplies H. Ullrich Vacuum P. Strubin RF Injection, Extraction Beam Diag. Collimators R. Garoby Scaled from ESS Study (1996)

COMPARISON Reference Scenario SPL+ PDAC Rings vs. Alternative RCS’s

Summary: • • No Conclusions … Full PDAC and full RCS Driver Costs appear comparable ~ 400 - 500 MCHF RCS 1 st stage: For ~200 MCHF one can get a 0. 5 MW / 2. 2 Ge. V / 50 Hz proton Source = 3 present ISIS, in reach of today’s technology • 30 Ge. V Machine requires major hardware developments: High-Gradient RFC’s in the 10 MHZ range for small frequency swing, Cost-effective large Power Converters, resonant or IGBT etc. , vacuum chambers

Appendix: Cost Estimate and Power Requirements of RCS Main Magnets