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Proton driver front end test stand Plans and organisation for 2004–05 David Findlay ISIS Accelerator Division. STVLTVS EST QVI ACCELERATORIBVS CVRANDIS VICTVM QVAERIT. Why a front end test stand? Prove key elements of high power proton accelerators
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Proton driver front end test standPlans and organisation for 2004–05 David FindlayISIS Accelerator Division STVLTVS EST QVI ACCELERATORIBVS CVRANDIS VICTVM QVAERIT
Why a front end test stand? • Prove key elements of high power proton accelerators • Applications Generic Spallation neutron sources Neutrino factories Transmutation machines Tritium generators Energy amplifiers Training / Young people / Real hardware Specific ISIS upgrades UKNF UK academic accelerator community
ISIS • World’s leading spallation neutron source • Natural wish to stay at or near front • Upgrade strategies important • CCLRC funding through ASTeC • UK Neutrino Factory • Strong drive from UKNF community • PPARC support for proton driver R&D • Synergies with possible ISIS upgrades • UK academic community • Imperial-CCLRC joint appointment • Extend university accelerator centres to protons
What’s in a front end? • Ion source, LEBT, RFQ and beam chopper • Why does it matter? • Where beam quality set for entire machine • What has to be tested? • New, high performance ion sources, RFQs and beam choppers • ISIS 0.16/0.24 MW RunningSNS 1 MW Running soon • JPARC 1 MW Running soon • ISIS 1, 2, 5 MW Plans • UKNF 4 MW — a big step! Plans
Proton driver front end test stand at RAL • ISIS Accelerator Division CCLRC/ASTeC • Imperial College PPARC • Warwick University PPARC • CCLRC/ASTeC ~£500k per year • PPARC ~£500k over three years • + 1¾x½ SY/year EU (HPRI-CT-2001-50021) (~£30k/year) • + 3 x¾ SY/year EU (HIPPI/CARE/ESGARD) (~£50k/year) • £2–2½M total
Relationship with CERN test stand • Formal cooperation through HIPPI • Meeting last week at CERN • Spreading bets on beam chopper • But different • CERN test stand for Linac4 then SPL • Proton / H– ion sources • RAL test stand more generic • Differences reflect organisation’s missions
Ion source 60 mA2 ms RFQ Bunch + accel-erate Chopper Switch in 2 ns for~0.1 ms LEBT Match ion source to RFQ Beam stop Diagnostics Transverse emittancesEnergy & energy spectrumBunch widthHalo Or RFQ - chopper - RFQ ?
H– ion source — Development requiredBased on ISIS H– ion source LEBT — Revision of new ISIS LEBT sufficient RFQ — Base on ISIS & ESS 4-rod RFQsISIS RFQ designed for 10% RF duty factor cf. ISIS 2%Most expensive item: ~1 MW RF driver Beam chopper — Development requiredBased on ESS conceptNot necessarily ESS frequency (280 MHz) But need ion source, LEBT and RFQ to test beam chopper
H– ion source R&D programme — for future high power proton accelerators (e.g. for future spallation neutron sources) — × ~10 output required Important milestone passed Successful thermal modelling of world leading ISIS ion source — extraction of surface temperatures Excellent agreement between calculated and measured thermocouple temperatures Anode 600°C Cathode 200°C Ab initio calc. Meas. °C °C Anode t/c 456 400 – 600 Cathode t/c 501 440 - 530 Body t/c 416 390 - 460 1 inch
Beam chopper R&D programme — specialised hardware — fast, high voltage pulser specified and procured >1 kV rise in <2 ns
At end of three years, i.e. by March 2007, expect to have • Dedicated area (in R8 (probably)) • Lead shed (shield against RFQ X-rays) • Support structure / Stands • Operational ~60 mA ion source available • LEBT assembled • Design for RFQ • Specification for RF driver • Proven electrical design for beam chopper • Design for quadrupoles and cavities for chopper • Specification of diagnostics
19 5 m 6½ 7½ 1½ 12 7 6½ 2 R8, existing test stand area Total area 166 m²
Also have hardware available for subsequent three years • Area in R8 is well provided • Space, electricity, water, air, crane, loading bay, on ISIS controls circuit, …
2004–2007 Overall scheme, design, infrastructure, specifications, some hardware £2–2½M 2007–2010 Complete scheme £5M more — but would have world-class facility [End]
RAL beam chopper design • Robust design with explicit provision for high power beam collection Slow transmission line 0 1 0 1 Up to 100 µs Lumped line — thermally hardened 2 ns 8 ns
1145 mm Beam Fast switch Slow switch Buncher cavity Buncher cavity Close-coupled chopper module