Superbeams with SPL at CERN SPL Superconducting Proton

Superbeams with SPL at CERN SPL = Superconducting Proton Linac A concept for modern high intensity proton beams at CERN based on a high-energy Superconducting Linear Accelerator 1. Introduction 2. SPL principle and characteristics 3. On-going R&D 4. Staging 5. Summary and Conclusion M. Vretenar for the SPL W. G. 1 NBI 2002 - 18/03/2002

From Neutrino Factory to Neutrino Superbeam Neutrino CERN baseline scenario for a Superbeam neutrino from SPLFactory nmfrom m fromppdecay, collected, cooled, energy accelerated 250 Me. V and circulated in a decay ring Optimal baseline for far detector Optimal » 130 kmbaseline 2000 -3000 km M. Vretenar for the SPL W. G. 2 NBI 2002 - 18/03/2002

Other Applications of the Proton Driver u Approved physics experiments n n n u CERN Neutrinos to Gran Sasso (CNGS): increased flux (~ ´ 2) Anti-proton Decelerator: increased flux Neutrons Time Of Flight (TOF) experiments: increased flux ISOLDE: increased flux, higher duty factor, multiple energies. . . LHC: faster filling time, increased operational margin. . . Future potential users n n n “Conventional” neutrino beam from the SPL “super-beam” Second generation ISOLDE facility (“EURISOL” -like) LHC performance upgrade beyond ultimate… M. Vretenar for the SPL W. G. 3 NBI 2002 - 18/03/2002

The Team Work going on since 1999… Neutrino Factory Working Group (http: //nfwg. home. cern. ch/nfwg/nufactwg. html) Superconducting Proton Linac Working Group (http: //cern. web. cern. ch/CERN/Divisions/PS/SPL_SG/) Proton Driver Rings Working Group (http: //hos. home. cern. ch/hos/Nufact. WG/Pdrwg. htm) Target Study Team M. Vretenar for the SPL W. G. 4 NBI 2002 - 18/03/2002

The SPL Working Group REFERENCE : Conceptual Design of the SPL, a High Power Superconducting Proton Linac at CERN Ed. M. Vretenar, CERN 2000 -012 M. Vretenar for the SPL W. G. 5 NBI 2002 - 18/03/2002

The Superconducting Proton Linac: Main Principles In line with modern High Power Proton Accelerator projects (SNS, JKJ, …) Re-use of the LEP RF equipment (SC cavities, cryostats, klystrons, waveguides, circulators, etc. ) The LEP klystron Storage of the LEP cavities in the ISR tunnel M. Vretenar for the SPL W. G. 6 NBI 2002 - 18/03/2002

The Superconducting Proton Linac: Design (1) H- source, 25 m. A 14% duty cycle Fast chopper (2 ns transition time) RF system: • freq. : 352 MHz • amplifiers: tetrodes and LEP klystrons M. Vretenar for the SPL W. G. Cell Coupled Drift Tube Linac new SC cavities: b=0. 52, 0. 7, 0. 8 5 -cell b 0. 8 cavities replacing 4 -cell b 1 cavities in the LEP cryostat 7 2. 2 Ge. V energy: • direct injection into PS • threshold for p production NBI 2002 - 18/03/2002

The SPL: Design (2) 54 cryostats, 32 directly from LEP, the others reconstructed M. Vretenar for the SPL W. G. 51 LEP-type klystrons (44 used in LEP) 8 NBI 2002 - 18/03/2002

SPL Beam Specifications M. Vretenar for the SPL W. G. 9 NBI 2002 - 18/03/2002

The Accumulator – Compressor Scheme Two Rings in the ISR Tunnel Accumulator: 3. 3 ms burst of 144 bunches at 44 MHz Compressor: Bunch length reduced to 3 ns M. Vretenar for the SPL W. G. 10 NBI 2002 - 18/03/2002

Characteristics of the beam sent to the target M. Vretenar for the SPL W. G. 11 NBI 2002 - 18/03/2002

Layout on the CERN site M. Vretenar for the SPL W. G. 12 NBI 2002 - 18/03/2002

Cross section M. Vretenar for the SPL W. G. 13 NBI 2002 - 18/03/2002

SPL R&D Topics 1. 2. 3. 4. 5. 6. Minimise beam loss to avoid activation of the machine (loss<1 W/m) Beam Dynamics studies, optimise layout and beam optics Chopper structure to create a time distribution in the beam that minimises losses in the accumulator Travelling wave deflector with rise time <2 ns Efficient room-temperature section (W<120 Me. V) CCDTL concept Development of SC cavities for b<1 Sputtering techniques Pulsing of LEP klystrons Built for CW, operated at 50 Hz, 14% duty Pulsing of SC cavities and effects of vibrations on beam quality Low power (feedback), high power (phase and amplitude modulators) and active (piezos) compensation techniques M. Vretenar for the SPL W. G. 14 NBI 2002 - 18/03/2002

SPL R&D – Low Energy Chopper structure 3 D view of a coupled cavity drift tube module (CCDTL) Scaled model (1 GHz) in test -Full performance prototype tested -Driver amplifier in development Collaboration on RFQs with CEA-IN 2 P 3 (IPHI) and INFN Legnaro M. Vretenar for the SPL W. G. 352 MHz test place prepared (planned tests of CEA-built DTL structures in 2002) 15 NBI 2002 - 18/03/2002

SPL R&D – Low Beta SC Cavities CERN technique of Nb/Cu sputtering for b=0. 7, b=0. 8 cavities (352 MHz): ð excellent thermal and mechanical stability ð (very important for pulsed systems) ð lower material cost, large apertures, released ð tolerances, 4. 5 K operation with Q = 109 The b=0. 7 4 -cell prototype Bulk Nb or mixed technique for b=0. 52 (one 100 k. W tetrode per cavity) M. Vretenar for the SPL W. G. 16 NBI 2002 - 18/03/2002

SPL R&D – Pulsing of LEP Klystrons RF output power (800 k. W max. ) Mod anode driver 5 ms/div 14/05/2001 - H. Frischholz 1 ms/div Þ LEP power supplies and klystrons are capable to operate in pulsed mode after minor modifications M. Vretenar for the SPL W. G. 17 NBI 2002 - 18/03/2002

SPL R&D – RF power distribution & field regulation in the SC cavities Effect on field regulation Effect on the beam Þ unsolved problem ! Needs work (high power ph. &ampl. modulators, piezos, …) Þ similar difficulties are likely in the muon accelerators! M. Vretenar for the SPL W. G. 18 NBI 2002 - 18/03/2002

Staging u Test of a 3 Me. V H- injector n u 120 Me. V H- linac in the PS South Hall n n n u In collaboration with CEA-IN 2 P 3 exploiting the IPHI set-up Goal: increase beam intensity for CNGS and improve characteristics of all proton beams (LHC, ISOLDE…) Under study: detailed design report with cost estimate in 2003 Needs new resources (collaborations, manpower, money) Full SPL M. Vretenar for the SPL W. G. 19 NBI 2002 - 18/03/2002

The SPL Front-end (120 Me. V) in the PS South Hall (intermediate proton intensity increase) To the PSB Beam dump PS H- source LEIR Þ Increased brightness for LHC, ´ 1. 8 the flux to CNGS & ISOLDE, … (with upgrades to the PSB, PS & SPS) Þvery cost-effective facility: hall and infrastructure available in the PS all the RF is recuperated from LEP shielding is done with LEP dipoles! M. Vretenar for the SPL W. G. 20 NBI 2002 - 18/03/2002

The 120 Me. V Linac 75 m (100 m available in PS South Hall) M. Vretenar for the SPL W. G. 21 NBI 2002 - 18/03/2002

Summary and Conclusion u The SPL design is improving, R&D is going on u Work in progress on most items, based on collaborations u A staged approach is proposed u Feedback (and support !) is needed from potential users M. Vretenar for the SPL W. G. 22 NBI 2002 - 18/03/2002