2 ISIS Accelerators H ion source (17 kV) 665 kV H RFQ 70 MeV H linac 800 MeV protonsynchrotronExtracted protonbeam linesThe accelerator produces apulsed beam of 800 MeV(84% speed of light) protonsat 50 Hz, average beam currentis 230 A (2.9× 1013 ppp) therefore184 kW on target (148 kW to TS-1 at 40 pps, 36 kW to TS-2 at 10 pps).
3 ISIS Upgrades Present operations for two target stations Operational Intensities: 220 – 230 μA (185 kW)Experimental Intensities of 31013 ppp (equiv. 240 μA)DHRF operating well: High Intensity & Low LossNow looking at overall high intensity optimisationStudy ISIS upgrade scenarios0) Linac and TS1 refurbishment1) Linac upgrade leading to ~0.5 MW operations on TS12) ~3.3 GeV booster synchrotron: MW Target3) 800 MeV direct injections to booster synchrotron: 2 – 5 MW Target4) Upgrade 3) + long pulse mode option
4 ISIS MW Upgrade Scenarios 1) Replace ISIS linac witha new ≈ 180 MeV linac(≈ 0.5MW)2) Based on a ≈ 3.3 GeV RCS fed by bucket-to-bucket transfer from ISIS 800 MeV synchrotron (1MW, perhaps more)3) RCS design also accommodates multi-turn charge exchange injection to facilitate a further upgrade path where the RCS is fed directly from an 800 MeV linac (2 – 5 MW)
6 Power / Benefit / Cost Neutrons £ + Risk Power Upgraded TS1 TS2 Existing TS1Power
7 ISIS Upgrades, Developments and R&D Work We have on-going research and studies todevelop and fully exploit the machinemap out the best development routesdefine principle upgradesundertake basic R&D into physics of high intensity beamsMain focus presently ~180 MeV Injector Upgradesummarised in the following pagesholistic optimisation including targets, neutronics, … “at the user”Next stepsExploring the possibilities for optimistic & less optimistic funding scenariosMapping out the best options for a 1-2 MW short pulse neutron sourceDevelopment and research on present machine
8 ISIS Injection Upgrade New 180 MeV LinacISIS Injection Upgrade70 MeV LinacA New 180 MeV InjectorUpdate old linacIncrease beam power ~0.5 MWAdvantagesReduces Space Charge (factor 2.6)Chopped, Optimised Injection & TrappingChallengesInjection straightActivation (180 MeV)Space charge, beam stability, ....MICE800 MeV SynchrotronTS1TS2
9 ISIS Injection Upgrade Ring Physics Study Snapshots of the work: challenges of getting 0.5 MW in the ISIS RingInjectionLongitudinal DynamicsInjection Straight ModellingInjection StraightAnalytical WorkSimulation ResultsTest DistributionEvolution of bunchFoil temperaturesInjected distributions in (x,x’),(y,y’),(,dE)RF BucketVariation of key parametersTransverse & Full Cycle 3D DynamicsOther Essentials: Activation, DiagnosticsPredicted Space Charge LimitSingle particle tune shift distributions at 0.5 MWActivation vs EnergyActivation MeasurementsCoherent Tune Shift and ResonanceElectron Cloud MonitorStrip-line Monitor/KickerAccelerated distributions in (x,x’),(y,y’),(,dE)
15 Capacity upgrade scenarios “Traditional” 3-stage MW upgrade scenario could be extended so 3.2 GeV RCS includes multiple extraction straights (or switchyard in EPB), with or without 800 MeV linac.Stacked rings (as at CERN PSB) could be implemented as part of AC magnet replacement programme. Would require increased linac performance, but otherwise it is an engineering challenge to minimise off time during installation rather than an accelerator physics challenge, and would be a very predictable upgrade.
16 One synchrotron with several extraction straights? Target station #1Target station #2“Efficient” footprintMaximises total number of neutron beam linesFlexibleEasy extraction of proton beams of different energies, intensities and repetition rates to suit wide range of neutron experimentsLinacSynchrotronWould need to drive trim quads. and steerers differently for different energies and intensities, but trim quads. and steerers are pulsed anyway, and so changing trim magnet current profiles from acceleration cycle to acceleration cycle should raise no fundamental complications.Target station #4Target station #3
17 Ring High Intensity Beam Studies on ISIS Some of our R&D StudiesHalf-integer intensity limit in proton ringsUsing the ISIS ring to study halo formationNew simulation code: Set 3DiModel losses, benchmark on ISISSimulationSimulationMeasurement(Y,Y)Y profileY profileHigher order loss effects and imagesInvestigating complex loss mechanismsHead-tail instabilityKey for high intensity proton ringsImage driven resonanceVertical dipole motion along bunch on successive turnsVertical difference signal(along bunch, many turns)Loss vs Q measurementSamples along bunchTurn
18 Necessary Hardware R&D High power front end (FETS)RF SystemsStripping FoilsDiagnosticsTargetsKickersetc.To realise ISIS upgrades and generic high power proton driver development, common hardware R&D will be necessary in key areas:In the neutron factory context SNS and J-PARC are currently dealing withmany of these issues during facility commissioning and we have a watchingbrief for all of theseActive programmes in some specific areas