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MESA and its cavity cryomodule

MESA and its cavity cryomodule. M ainz E nergy recovering S uperconducting A ccelerator : A small superconducting accelerator for particle and nuclear physics Kurt Aulenbacher f or the MESA-Project-team. LHeC -workshop Chavannes-de- Bogis January21, 2014. Contents.

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MESA and its cavity cryomodule

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  1. MESA anditscavitycryomodule Mainz EnergyrecoveringSuperconductingAccelerator: A smallsuperconductingacceleratorforparticleandnuclearphysics Kurt Aulenbacher forthe MESA-Project-team LHeC-workshop Chavannes-de-Bogis January21, 2014 LHeC workshop

  2. Contents • Project objectives • R&D issues: Beamdynamics & Lattice • R&D issues: SRF LHeC workshop

  3. High power beam dump Experimental Hall Shaftbuilding MESA-Hall-1 MESA-Hall-2 Shielding MESA: Real estate conditions • No new buildings necessary • MAMI continues separately for • hadron structure exp. ~1GeV scale • MESA takes over “low energy” • experiments ~100MeV scale LHeC workshop

  4. PIT MESA: A Concept and its history 2ERL IN 1 2 3 • 3/2009 MAMI & beyond conference: idea of ERL-Project „MESA“ presented • 2011: MESA accelerator „stage-1“ becomesmajorpartof • proposalfor excellence cluster „PRISMA“, • P2 experimentimportantpartofproposalfor SFB1044 • 11/2011 SFB 1044 proposalaccepted • 1/2012 Evaluation of PRISMA proposal & startof SFB1044 • 6/2012 PRISMA Excellence clusteraccepted. • 12/2012 PRISMA clusterstarts, fundingperiodfiveyears SC PS RC DU to PV-experiment P2 LHeC workshop

  5. PIT MESAand its Research fields MESA‘smainobjectives Acceleratorphysics: Multiturn, superconducting ERL ParticlePhysics: Precision measurementoftheweakmixing angle (P2-experiment) New experimental techniquefornuclearandparticlephysics: The PIT - high luminosity/lowbackgroundatlowenergies 2ERL IN 1 2 3 MESA BEAM PARAMETERS: c.w. beam EB-mode: 150 mA, 200 MeV spin polarized beam (liquid Hydrogen target L~1039) ERL-mode: 10mA, 100 MeV unpolarized beam (Pseudo-Internal Hydrogen Gas target, PIT L~1035) SC PS RC DU Duringtheapplicationprocessitbecame evident, that not enoughfundingwouldbeavailabletorealizetheenvisaged Beam parameters – only a „stage-1“ was requested. to PV-experiment P2 LHeC workshop

  6. MESA-Beam-parameters in stages 1 (2) Additional demands occur due to main external experiment.... LHeC workshop

  7. EB-Experiment: “P2” 150 mA Beamcurrent, 60cm lq. H2, Beampol: 85%. 10000 h Data-taking (~13-15000 h Runtime) High accuracy polarization measurement (DP/P=0.5% !!) Extremely high demands on control of HC-fluctuations! • ~4000h/Year Runtime • Accelerator must be optimized for reliability& stability Good news: Very flat minimumof total errorallowstoreduce beam energyto ~150 MeV P2 is MESA-workhorse experiment LHeC workshop

  8. A possible accelerator layout From ERL Exp To ERL Exp • Vertical stacking “a la CEBAF” keeps transverse footprint small • compatibility with building. • Initial idea by Ralph Eichhorn • Vertical spreaders based on preliminary design for LHeC TF LHeC workshop

  9. A possible accelerator layout • Vertical stacking “a la CEBAF” keeps transverse footprint small • compatibility with building. • Initial idea by Ralph Eichhorn • Vertical spreaders based on preliminary design for LHeC TF LHeC workshop

  10. Turn 0 Turn 1 Turn 2 Turn 3 Turn 4 Turn 5 MESA-EB : 0-order Lattice • MAD-X calculation • (Half-)Turn 0: 5MeV • Turn 1: 30MeV • Turn 2: 55MeV • Turn 3: 80MeV • Turn 4: 105MeV • Turn 5: 130MeV

  11. MESA& experiments PV PIT • Size Based on 1300 MHz- „ ELBE“-type Modules • Sufficient for stage-1, but limited current • Length of acclerator can be extended by about 4 meters LHeC workshop

  12. Itshouldbepossibletoachievesuitablematchingfordecelleration (fromexitof turn5) EnergyRecovery: Beamline

  13. Turn 4 Turn 3 Turn 2 Turn 1 Zero-order in ERL-mode • Matchingthrough • experimental hall line • assumed

  14. Accelerator: R&D Issues Constraintsby Budget, Space and Schedule: Technology/Physicssolutions must becompatible! Technology: • Cryogenics • Cryomodule Physics: • Sources/Injector • BBU Instability • Rezirculator (Lattice) Design LHeC workshop

  15. Cryoplant-Constraint 200l /h, lq. Helium Available Power at 2K ≤100 Watt  DE>50MeV fromLinac would be unrealistic LHeC workshop

  16. Cryomodulesand BBU „Twoseater“ ELBE Cryomodule With 2*9cell „TESLA“ cavities J. Teichert et al. NIMA 557 (2006) 239 • “ELBE” –Modules are suitable for high gradient c.w. op. • Commercially available, no additional R&D • Costs & Delivery time are (to some extent) predictable • Limitation in Cryopower requires Q0=1010 at 14MeV/m • (achieved at DESY/FLASH in operation with TESLA cavity) MESA B. Auneet al. PRST/AB 3 092001 (2000) LHeC workshop

  17. Cryomodulesand BBU 9 cell ‘TESLA’ p-mode Cavity: Higher order modes (HOMs) with „bands“ ofEigenmodes e.g. TM11-like. BBU- Instabilityforbeamcurrent > IT In recirc. Linacs: Feedback-loop withinstabilitythreshold! (simplifiedformula!) General treatmentforERL‘s G.H. Hoffstaetter, I. Bazarov: PRSTAB 7 054401 (2004) LHeC workshop

  18. Cryomodulesund BBU • „High current“ – Recirculatorscallfor : • Strong HOM damping (TESLA-Cavitiesare not optimzed!) • Flexible Recirculationopticstoadjust T12 , T34 but probably also T56 • Conclusions/conflicts: • „Non-Tesla Cryomodule“ for MESA  But: compatiblewithbudget & schedule? • Second bulletcallsforindependentorbitrecirculation • But: Polytronrecirculator is more compact , better inherent stability. Initial-Plan: Use TESLA/Rossendorf Module („Stage-1“ with limited current) LHeC workshop

  19. Cryomodule alternative-1 Discussions with JLAB : Fabrication of one further „C-100“ cryomodule , identical To the ones used for CEBAF Energy doubling • JLAB „8-seater“ C-100 Cryomodule • at 1500 MHZ • + better HOM damping than TESLA • + several buildt and tested • + MESA energy doubling • possible with • investment in cryoplant • C100 Module too long • for exisiting shaft • Ongoing negociations for „C100/2“ • Current capability a few milliamp Source: JLAB LHeC workshop

  20. Cryomodule alternative-2 • Contactswith CERN LHC/LHeCgroup (O. Bruning, E. Jensen, M. Klein): • LHEC needscryomodulewithfrequencyas an integer multiple of LHC RF (40.079MHz) • (802 MHz is almost RF-frequency for SPS, the LHC injector) • CERN groupplanstobuild ERL testfacilitywith, e.g., 802 MHz cryomodule • Indications for a support of Testfacility+cryomodule project by CERN-management • (final decision end of September 13) • Common objectives, complementarycompetences, similartimescale: • This maybe a greatoppurtunity! E. Jensen, Talk atDaresburyLHeCmeeting January, 2013 LHeC workshop

  21. Conclusion • MESA is a low 100MeV- scale electron accelerator with external • beam-mode (EB) and ERL-mode 1MW beam power option • MESA is dedicated to electron scattering experiments: • Precision measurement of Weinberg angle (EB) and generic • experimentation technique Pseudo internal target -PIT – in ERL-mode • Three frequency options 800 MHZ (LHeC) 1300 MHz (ILC), • 1500 MHz (JLAB) • HOM damped cryomodule decisive component, tendering in 6/2014, • delivery expected end 2016 • Lattice and infrastructure will be also completed by end of 2016 • Commisioning of machine in 2017. - LHeC workshop

  22. Acknowledgments • MESA-Project-team: • I. Alexander, K. Aulenbacher, V. Bechthold, Ma.Dehn,Mo.Dehn, • J. Diefenbach, F. Fichtner, S. Friederich S. Heidrich, R. Heine, K.H. Kaiser, E. Kirsch, H.J.-Kreidel, Ch. Matejcek, F. Schlander, V.Schmitt, D. Simon • MESA issupportedby : • State ofRhinelandPalatinate • German universityexcellence initiative: • PRISMA-Cluster of excellence • German Science foundation (DFG): SFB 1044 • German Ministryofscience & ed. (BMBF ): • -PCHB- Consortium(Photocathodes for high brillancebeams) • -HOPE-Consortium (Hochbrillante Photoelektronenquellen) • WE ARE HIRING! • - ERL beam dynamics • Beam diagnostic, • vacuum and geodasics • Contact: • aulenbac@kph.uni-mainz.de LHeC workshop

  23. Thank you LHeC workshop

  24. Spares LHeC workshop

  25. Injector-Linac (ILAC) • Motivation for normal Conducting -ILAC: • Easy maintenance • Nocryogenicload, • Established design (based on MAMI-ILAC, Th. Weis, H. Euteneuer 1984) • Phase spaceshapingby „gradedbeta“ structure • ~100kW RF Power ( 50kW beam loading included) • T=5MeV, length: 11,5 m Dy100%< 2.3° DE/Erms=0.01% Detailed results published at IPAC 2013 (R. Heine et al.) LHeC workshop

  26. Beam-dynamics: Recirculator-Lattices LHeC workshop

  27. Beam-dynamics: Recirculator-Lattices „CEBAF“ inspired Design: Ralph Eichhorn • Advantage: • Identical horizontal deflectionsandmagnets • High symmetry • Problem: Vertikal stackingunderveryconstrainedlongorbitaxis • Large verticaldeflectionangles • Small spaceforcompensationquads. • Verticaldispersionprobablydifficulttocontrol Wepresentlyinvestigate also twotypesof „flat“ lattices LHeC workshop

  28. Horizontal lattices: “Conventional recirculator” „S-DALINAC“ inspired 105/155 105 155 105 105/205 55 205 105 Daniel Simon, Diplomathesis: Sketch of flat latticewith realisticdipoledimensions Lattice design is ongoing!! Second option for flat lattice: Polytron recirculator? LHeC workshop

  29. Asymmetric Polytron of second order (AP2) (A low budget lattice for up to 8 recirculations) „MAMI-C“ inspired Preliminary design by K.H. Kaiser Horizontallyfocusingsinguletts DE=25 MeV Injectionat 5MeV + transvere optics promising ! + order of magnitude less magnets /parameters compared to conventional recirculator - Very large turn by turn phase shifts must be compensated byshicanes in several (not all) turns. LHeC workshop

  30. AP2 –advantages wrt other lattices 155 105 105/205 105 205 55 105 • 50% reductionofcryoload • Significant reduction of invest for cryomodules • Much less space required • Energystability/stabilizationas in MAMI due to large R56, longbunchesallowed AP2 iskindof a temptation… LHeC workshop

  31. The AP2 –temptation: vade retro?! polytron ? Detail from: Hyronimus Bosch: Temptationof St. Anthony (15th century) LHeC workshop

  32. The AP2 –temptation: vade retro?! Possibledisadvantagesand/orshowstoppers • Fixed optics&largernumberofrecirculations •  (too) low BBU threshold? • Shicanesmandatory • Complexmagnetswithsmallbendingradius • (first turn critical) • 25 MeV req. 4 turn ERL (8mA in Linac at stage-1) ?? • Upgrade to 80mA (stage-2)???? LHeC workshop

  33. MESA-Collaborations • Collaborationbetween HZB & KPH • Consortiawithin BMBF: HOPE (High brillancesources) KPH/HZDR/HZB • and PCHB (Photocathodesfor high brillancebeams, manypartners) • Contactsrelatedto ERL problemswith: CERN/Daresbury/BNL/Daresbury •  CryomoduleCollaboration?? LHeC workshop

  34. MESA-Staffing MESA is PRISMA „Project E“. Project leaders: Kurt Aulenbacher & Frank Maas Black: PRISMA-personel/Blue: KPH-staff, Percentage: workfractiondevotedto MESA/Green: BMBF-personel (*) : Large reservoirof Master/diplomastudents! (**) Technician will beintegrated in TBV. • Acceleratorworkshop „TBB“ (6 workers&technicians): • Contributesstronglyto MESA infrastructure (has also tosupport MAMI anditsexperiments! ) • Electronics (TBE), mechanicalworkshops (TBM), vacuum&cryogenics (TBV): • Contributeto MESA withintheircapacities! (on average ~6 workers/techicians/engineers in eachunit) • Further MAMI staff (technicians, engineers, operators) are, as a rule, requiredfor MAMI operation, but maydeliversupportifcapacityallows. LHeC workshop

  35. Possible CERN/MAINZ/+X Collaboration Fabricationof a dedicated 802MHz cryomodule: Whatmaywecontribute? • Manpower (Post-Docs, PhDstudents) • Invest (same amountasforcommercialacquisition) • Infrastructure in HIM building(cleanroom, horizontal test stand/bunker) • But: Onlyvery limited numberofengineers, designers, etc…..! Fabricationof a dedicated 802 MHz cryomodule: Whereweneedsupportfromcollaborators • Cryomodule design • Resonator, HOM damping, etc design • Additional invest ??? • Project coordination, management, administration??? • ….. CERN/MESA Consultationstodefine a concrete plan „Whatittakestoachieve a newcryomodule“ will begin in thefirstweekof August. LHeC workshop F. Marhauser ,

  36. Horizontal lattices: Segment Magnet Recirculator 90 degree Segment • Segment- or „Polytron“- magnet: • Each Orbit entersandexitsatTHE SAME Pole edge • Orbit is SYMMETRIC around normal to pole edge: •  Deflection angle 2*pol faceinclination • Deflection angle isindependentofenergy • Veryconvenienttransv. Optics(Apart fromfringefields) • Dispersioncancelsafter eachtwodeflections • Circularorbitsachieved after N*2 Segments • N=1 Microtron (not suitablefor MESA) • N=2 Double sidedMicrotron (Twodispersionfreesections) • N=3 Hexatron E1 E2 S1 Pole face S2 Weinvestigate an AsymmetricPolytronofsecondorder (AP2) (Not: „singlesided DSM“) LHeC workshop

  37. “Low budget “ Lattice Alternative: Segment (Polytron-)Magnet Recirculator: Asymmetric Polytron of second order (AP2) Injectionat 5MeV Single Cryomodule DE=25MeV AP2-Coherence Condition: Distancebetweenadjacentorbits: 2nd non-dispersive straight First non-dispersive -LINAC-straight) „MAMI-C inspired“ 30 B~0.82 T 1. Rec. DO 105 4. Rec. 7. Rec. 180 205 2 m <2m <2m Design: K.H. Kaiser LHeC workshop

  38. Infrastructure issues Building& real estate Propriatoris „LBB“ 155 LBB= Landesbetrieb Liegenschaften und Bau Betreuung 105 55 • Buildinghasthickwallswhichhavetobecut/drilled (atapropriateplaces): • Buildingintegrety, fireprotectionby LBB & externalcompanies • Sufficientelectrical & cooling power isavailable, but machinecoolingwaterhydrauliclayout &temperaturestabilizationby LBB & externalcompanies, • Option formanagingotherinstallationworkby in housestaff, in particular: lq. Helium distribution/2K booster, Radiation ProtectionApplication LHeC workshop

  39. Horizontal Optics L2=70cm 2L1=960cm L2 Singulets in optisch gleichem Abstand F LHeC workshop

  40. VerticalOptics Norm. Emittanz:10mm*mrad*pi *1/3 Counter-field & gradient leadto strong longitudinal Phase shifts! LHeC workshop

  41. MESA Demonstrationsexperiment an MAMI: 100mA/855MeV auf 0.4% rad. length Tantal (2 WochenLaufzeit) (H. Merkel et al. PRL 106 251802 (2011)) Region interessantwg. (g-2)m Abweichung SuchenachdunklenPhotonen an MAMI/MESA “Bump-hunt” Experimentekönnen (MA’> 100MeV) sofortbegonnenwerden: MAMI/A-1 und JLAB/Aspect LHeC workshop

  42. PIT ERL/PIT: Einneues Regime bei E<1GeV Area:22*14m2 MESA-LAYOUT 10s beam envelope 2mm dia H2 beam in 2ERL IN Dublett Dublett 2 m long tube 1 2 3 Pump • Target dichteN=2*1018 atoms/cm-2 (3.2 mg/cm2, 5*10-8 X0) •  I0=10-2A: L= 1.2*1035cm-2s-1 • (mittlerer) Enereverlust (Ionisation): ~ 17eV •  RMS Streuwinkel (Vielfachstreuung): 10mrad • Single passStrahlverschlechterungistakzeptabel SC PS RC DU to PV-experiment LHeC workshop

  43. PIT MESA: Concept and its history 2ERL IN 1 2 3 SC PS BEAM PARAMETERS: 1.3 GHz c.w. EB-mode: 150 mA, 200 MeV polarized beam (liquid Hydrogen target L~1039) ERL-mode: 10mA, 100 MeV unpolarized beam (Pseudo-Internal Hydrogen Gas target, PIT L~1035) RC DU to PV-experiment LHeC workshop

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