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The RAL Front End Test Stand David Findlay for Alan Letchford Accelerator Division, ISIS Department Rutherford Appleton Laboratory HIPPI-05, Cosener’s House, Abingdon, 28–30 September 2005. RAL Front End Test Stand (FETS)
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The RAL Front End Test Stand David Findlay for Alan Letchford Accelerator Division, ISIS Department Rutherford Appleton Laboratory HIPPI-05, Cosener’s House, Abingdon, 28–30 September 2005
RAL Front End Test Stand (FETS) • Part of CCLRC’s generic R&D programme on high power proton accelerators • Specifically, demonstration of some key technologies for the front ends of • Spallation neutron sources • Neutrino factories • Waste transmuters • Tritium production • Energy amplifier
FETS is a collaborative effort amongst • CCLRC RAL ISIS • CCLRC ASTeC Intense Beams Group • Dept. Physics, Imperial College, London • Dept. Physics, University of Warwick Promotion of accelerator science in UK universities
FETS collaborators • John Back, Giulia Bellodi,Mike Clarke-Gayther, Dan Faircloth, Graham Gosling, Stephen Jolly,Ajit Kurup, Alan Letchford,Eddie McCarron, Ben Pine,Dan Ciprian Plostinar, Jürgen Pozimski, Peter Savage, Mark Whitehead,Trevor Wood
FETS funding • CCLRC, through ASTeC • ISIS and ASTeC staff + hardware • PPARC, through ASTeC • UK university staff • CCLRC, through Infrastructure Fund • Reconfiguration of test stand area • EU, through HIPPI programme
RFQ Chopper • FETS main components: • High brightness H— ion source • Magnetic LEBT • High current, high duty factor RFQ • Very high speed beam chopper • Comprehensive diagnostics RFQ Chopper
FETS specification • 60 mA H—, 2 ms, 50 pps • 75 keV 3-solenoid LEBT • 3 MeV, 324 MHz RFQ • 2 ns chopping • Comprehensive diagnostics • Test stand in practice
H— surface Penning ion source • 35 mA, 200 µs (ISIS) 60–70 mA, 1–2 ms • Increase largely achieved • Separate Penning field • Thermal modelling • Electromagnetic modelling • Extensive experimental work on dedicated ion source development rig
3-solenoid magnetic LEBT • Design proceeding well • Beam chopper • [Other talks]
RFQ — 3 MeV, 324 MHz • Ready availability of Toshiba E3740A 3 MW pulsed klystron (J-PARC) • Electromagnetic DTL quadrupoles
RFQ beam dynamics at 324 MHz encouraging • 3 MeV, 4 metre design • 95% transmission, 80 kV electrode voltage • Low voltage design 4-rod type possible • 4-rod and 4-vane designs being investigated
Diagnostics • Full suite of diagnostics to maximise the experimental capabilities • Beam currents • Emittances • Energy spectra (magnetic + gas scattering spectrometers) • Non-destructive laser/optical • Residual gas ion spectroscopy
Possible beam halo monitor? • Activate scandium annulus? • 45Sc(p,n)45Ti • Ethresh 2.8 MeV, 45Ti t½ 3 hours, 85% β+ decay Low background 2.5 mA mean, 10—5 halo, 100 seconds → 30 Bq Sc melts 1540°C
Radiation shielding • 60 mA, 2 ms, 50 pps, 3 MeV into copper • 2–3×1010 neutrons/second • ~100 mSv/hour at 1 metre Say lose 3% ~1 mSv/hour at 2 metres ~1 metre concrete ~1 µSv/hour C (graphite) or Al(-Si alloy) for beam dump? C: 13C(p,n) threshold 3.00 MeV (13C (1.1%)); 10-minute 13N from 12C (p,γ) Al-Si: (p,n) > 5 MeV; no activity from (p,γ)
Conclusions • RAL Front End Test Stand will make an important contribution to HPPA R&D • Good progress from RAL/ISIS, ASTeC, Warwick and Imperial • Builds on experience gained with ISIS RFQpre-injector upgrade • First LEBT beam anticipated for 2006