1 / 51

Muon Colliders

Learn about the compact and cost-effective muon colliders, their unique capabilities, and challenges in achieving high luminosities and reducing phase space for groundbreaking physics research. Discover the innovative ionization cooling techniques, target facility design, and promising results from the MuCool project. Join us on this journey into the future of high-energy physics with muon colliders.

hughc
Download Presentation

Muon Colliders

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. m- m+ Muon Colliders Steve Geer SLAC/LBNL November, 2009 1

  2. Physics Landscape Steve Geer SLAC/LBNL November, 2009 2

  3. Decision Tree 0.5 TeV e+e- 3 TeV e+e- 3-4 TeV m+m- Pierre Oddone Steve Geer SLAC/LBNL November, 2009 3

  4. Muon Collider Motivation • If we can build a multi-TeVmuon collider it’s an attractive option because muons don’t radiate as readily as electrons (mm / me ~ 207): - COMPACT Fits on laboratory site - MULTI-PASS ACCELERATION Cost Effective (e.g. 10 passes → factor 10 less linac) - MULTIPASS COLLISIONS IN A RING (~1000 turns) Relaxed emittance requirements & hence tolerances- NARROW ENERGY SPREAD Precision scans - TWO DETECTORS (2 IPs)-DTbunch ~ 10 ms … (e.g. 4 TeV collider) Lots of time for readout Backgrounds don’t pile up -(mm/me)2= ~40000 Enhanced s-channel rates for Higgs-like particles COST PHYSICS Steve Geer SLAC/LBNL November, 2009 4

  5. Muon Colliders are Compact 3 TeV 0.5 TeV 4 TeV Steve Geer SLAC/LBNL November, 2009 5

  6. Narrow Energy Spread Shiltsev Beamstrahlung in anye+e- collider E/E  2 Steve Geer SLAC/LBNL November, 2009 6

  7. Challenges ● Muons are born within a large phase space (p→mn) - To obtain luminosities O(1034) cm-2s-1, need to reduce initial phase space by O(106) ● Muons Decay (t0 = 2ms) - Everything must be done fast→ need ionization cooling - Must deal with decay electrons - Above ~3 TeV, must be careful about decay neutrinos ! Steve Geer SLAC/LBNL November, 2009 7

  8. Muon Collider Schematic √s = 3 TeV Circumference = 4.5kmL = 3×1034 cm-2s-1m/bunch = 2x1012 s(p)/p = 0.1% b* = 5mm Rep Rate = 12Hz Proton source: Upgraded PROJECT X (4 MW, 2±1 ns long bunches) 1021 muons per year that fit within the acceptance of an accelerator Steve Geer SLAC/LBNL November, 2009 8

  9. Target Facility Design • A 4MW target station design study was part of “Neutrino Factory Study 1” in 2000 ORNL/TM2001/124 • Facility studied was 49m long = target hall & decay channel, shielding, solenoids, remote handling & target systems. • Target: liquid Hg jet inside 20T solenoid, identified as one of the main Neutrino Factory challenges requiring proof-of-principle demonstration. • Beam dump = liquid Hg pool. Some design studies started. V. Graves, ORNL T. Davonne, RAL 4MW Target Station Design Proton Hg Beam Dump Steve Geer SLAC/LBNL November, 2009 9

  10. MERcury Intense Target Experiment (MERIT) • Proof-of-principle demonstration of a liquid Hg jet target in high-field solenoid ran at CERN PS in Fall 2007. • Successfully demonstrated a 20m/s liquid Hg jet injected into a 15T solenoid, & hit with a suitably intense beam (115 KJ / pulse !). • Results suggest this technology OK for beam powers up to 8MW with rep. rate of 70Hz ! 1 cm Hg jet in a 15T solenoid Measured disruption length = 28 cm Steve Geer SLAC/LBNL November, 2009 10

  11. Front-End Specifications p±→mn m/p within reference acceptance = 0.085 at end of cooler → » 1.5 1021 μ/year Steve Geer SLAC/LBNL November, 2009 11

  12. Front-End Simulation Results Neuffer Steve Geer SLAC/LBNL November, 2009 12

  13. Ionization Cooling • Must cool fast (before muons decay) • Muons lose energy by in material (dE/dx). Re-accelerate in longitudinal direction reduce transverse phase space (emittance). Coulomb scattering heats beam  low Zabsorber. Hydrogen is best, but LiH also OK for the early part of the cooling channel. Cooling Heating Steve Geer SLAC/LBNL November, 2009 13

  14. MuCool • Developing & bench testingcooling channel components • MuCool Test Area at end of FNAL linac is a unique facility: • -Liquid H2 handling • -RF power at 805 MHz • -RF power at 201 MHz • -5T solenoid (805 MHz fits in bore) • -Beam from linac (soon) New beamline MTA 42cm ÆBe RF window Liq. H2 absorber Steve Geer SLAC/LBNL November, 2009 14

  15. RF in Magnetic Field: 805 MHz Results • When vac. copper cavities operate in multi Tesla co-axial mag. field, the maximum operating gradient is reduced. • Data reproducible & seem to follow universal curve. • Possible solutions: • -special surfaces (e.g. beryllium) • -Surface treatment (e.g. ALD) • - Magnetic insulation • Effect is not seen in cavities filled with high pressure hydrogen gas (Johnson & Derbenev) – possible solution (but needs to be tested in a beam – coming soon) >2X Reduction @ required field Peak Magnetic Field in T at the Window Steve Geer SLAC/LBNL November, 2009 15

  16. Instrumentation m Ionization Cooling Instrumentation MICE GOALS: Build a section of cooling channel capable of giving the desired performance for a Neutrino Factory & test in a muon beam. Measure performance in various modes of operation. • Beam Line Complete • First Beam 3/08 • Running now • PID Installed • CKOV • TOF • EM Cal • First Spectrometer • Spring 2010  Multi-stage expt.  First stage being installed at purpose-built muon beam at RAL (first beam to hall March 2008).  10% cooling measured to ±1%. Anticipate completed ~2011/12 Spectrometer Solenoid being assembled Steve Geer SLAC/LBNL November, 2009 16

  17. 6D Cooling Palmer • MC designs require the muon beam to be cooled by ~ O(106) in 6D • Ionization cooling reduces transverse (4D) phase space. • To also cool longitudinal phase space (6D) must mix degrees of freedom as the cooling proceeds • This can be accomplished with solenoid coils arranged in a helix, or with solenoid coils tilted. Alexhin & Fernow Steve Geer SLAC/LBNL November, 2009 17

  18. 6D Cooling Channel Scheme Palmer Steve Geer SLAC/LBNL November, 2009 18

  19. 6D Cooling Channel Development REQUIRES BEYOND STATE OF ART TECHNOLOGY → Ongoing R&D Detailed Simulations for candidate 6D cooling schemes Helical Cooling Channel- Muons Inc. FOFO Snake - Alexhin Magnet develop-ment for 6D cooling channels HCC magnet4 coil test Steve Geer SLAC/LBNL November, 2009 19

  20. Final Cooling • When the emittance is very small, to continue cooling we need very high field solenoids (to continue winning against scattering) • For fields up to ~50T, the final luminosity is ~ prop-ortional to the solenoid field at the end of the channel. • For higher fields we no longer expect to continue to win (limited by beam-beam tune shift). Steve Geer SLAC/LBNL November, 2009 20

  21. The Promise of HTS Steve Geer SLAC/LBNL November, 2009 21

  22. HTS Solenoid R&D NHMFL test coil LBL Test Coil FNAL test cable. Test degradation of Jc in the cabling process Steve Geer SLAC/LBNL November, 2009 22

  23. Acceleration ● Early Acceleration (to 25 GeV ?) could be the same as NF. Needs study. ●Main Acceleration – Attractive Candidates - RLAs (extension of NF accel. scheme ?) - Rapid cycling synchrotron – needs magnet R&D - Fast ramping RLA ●Options need study → particle tracking, collective effects, cavity loading, ... 1.0 Accelerating muons from 3 GeV to 2 TeV Bogacz 0.8 0.6 MUON SURVIVAL FRACTION 0.4 Example: TESLA cavities: Real estate gradient ~31 MV/m → 97% survival 0.2 0.1 1 2 5 10 20 50 AVERAGE GRADIENT (MV/m) Steve Geer SLAC/LBNL November, 2009 23

  24. Collider Ring • Muons circulate for ~1000 turns in the ring • Need high field dipoles operating in decay back-grounds → R&D • First lattice designs exist  New ideas → conceptual designs for various options  Comparison of different schemes, choice of the baseline  Detailed lattice design with tuning and correction “knobs”  Dynamic aperture studies with magnet nonlinearities, misalignments and their correction  Transient beam-beam effect compensation  Coherent instabilities analysis WE ARE HERE DESIGN PROCESS Steve Geer SLAC/LBNL November, 2009 24

  25. Neutrino Radiation • With L ~ E2 → • OK at √s = 1 TeV • OK at √s = 3 TeV if D = 200m • Above 3 TeV need to pay attention (wobble beam, lower b*, higher Bring , … ) Steve Geer SLAC/LBNL November, 2009 25

  26. Background from Muon Decay m-→ e-nenm 2  2 TeV Collider • 2 x 1012 muons/bunch • 2 x 105 decays/m • Electron decay angles O(10) mrad • Mean electron energy = 700 GeV Number of Decays As the decay electrons respond to the fields of the final focus system they lose 20% of their energy by radiating on average 500 synchrotron photons with a mean energy of ~500 MeV … & are then swept out of the beampipe. Mean energy= 700 GeV 0 500 1000 1500 2000 Electron Energy (GeV) Steve Geer SLAC/LBNL November, 2009 26

  27. Detector Backgrounds • Muon Collider detector backgrounds were studied actively ~10 years ago (1996-1997). The most detailed work was done for a 22 TeV Collider → s=4 TeV. • Since muons decay (t2TeV=42ms), there is a large background from the decay electrons which must be shielded. • The electron decay angles are O(10) microradians – they typically stay inside the beampipe for about 6m. Hence decay electrons born within a few meters of the IP are benign. • Shielding strategy: sweep the electrons born further than ~6m from the IP into ~6m of shielding. Steve Geer SLAC/LBNL November, 2009 27

  28. Background Simulations • Shielding design group & final focus design group worked closely together & iterated • Used two simulation codes (MARS & GEANT), which gave consistent results • Shielding design & simulation work done by two experts (Mokhov & Stumer) in great detail, & involved several person-years of effort. Steve Geer SLAC/LBNL November, 2009 28

  29. Final Focus Setup  Fate of electrons born in the 130m long straight section: 62% interactupstream of shielding, 30% interact in early part of shielding, 2% interact in last part, 10% pass through IP without interacting. Steve Geer SLAC/LBNL November, 2009 29

  30. IP Region Steve Geer SLAC/LBNL November, 2009 30

  31. More Shielding Details r=4cm Designed so that, viewed from the IP, the inner shielding surfaces are not directly visible. Z=4m Steve Geer SLAC/LBNL November, 2009 31

  32. MARS GEANT N. Mokhov I. Stumer 4 TeV Collider Backgrounds Results from Summer 1996 Background calculations & shielding optimization was performed using(independently) MARS & GEANT codes … the two calculations were inbroad agreement with each other (although the designs were different in detail). Steve Geer SLAC/LBNL November, 2009 32

  33. Particles/cm2 from one bunch with 2  1012 muons (2 TeV) 4 TeV Collider Backgrounds GEANT (I. Stumer) Results from LBL Workshop, Spring 1997 Steve Geer SLAC/LBNL November, 2009 33

  34. Occupancies in 300x300 mm2 Pixels TOTAL CHARGED Steve Geer SLAC/LBNL November, 2009 34

  35. Vertex Detector Hit Density  Consider a layer of Silicon at a radius of 10 cm: GEANT Results (I. Stumer) for radial particle fuxes per crossing: 750 photons/cm2 2.3 hits/cm2 110 neutrons/cm2 0.1 hits/cm2 1.3 charged tracks/cm2 1.3 hits/cm2 TOTAL 3.7 hits/cm2 •  0.4% occupancy in 300x300 mm2 pixels MARS predictions for radiation dose at 10 cm for a 2x2 TeV Collider comparable to at LHC with L=1034 cm-2s-1 • At 5cm radius: 13.2 hits/cm2 1.3% occupancy • For comparison with CLIC (later) … at r = 3cm hit density about ×2 higher than at 5cm → ~20 hits/cm2→ 0.2 hits/mm2 Steve Geer SLAC/LBNL November, 2009 35

  36. Pixel Micro-Telescope Idea S. Geer, J. Chapman: FERMILAB-Conf-96-375 Photon & neutron fluxes in inner tracker large but mean energies O(MeV) & radial fluxes ~ longitudinal fluxes ( isotropic)Clock 2 layers out at variable clock speed (tomaintain pointing) &take coincidence. Blind to soft photon hits& tracks that don’t come from IP Steve Geer SLAC/LBNL November, 2009 36

  37. Pixel Micro-Telescope Simulation - 1 Steve Geer SLAC/LBNL November, 2009 37

  38. Pixel Micro-Telescope Simulation - 2 Steve Geer SLAC/LBNL November, 2009 38

  39. TPC V. Tchernatine •  Exploit 10ms between crossings •  Large neutron flux – gas must not contain hydrogen: 90% Ne + 10% CF4 • Vdrift = 9.4 cm/ms with E = 1500 V/cm. Ion buildup DE/E = 0.7%  Cut on pulse height removes photon & neutron induced recoils Steve Geer SLAC/LBNL November, 2009 39

  40. Electromagnetic: Consider calorimeter at r=120 cm, 25 r.l. deep, 4m long,22 cm2 cells:  GEANT  400 photons/crossing with <Eg> ~1 MeV  <ETower>~400 MeV  sE ~ (2<ng>) <Eg> = 30 MeV  For a shower occupying 4 towers: <E> = 1.6 GeV and sE = 60 MeV Hadronic: Consider calorimeter at r=150 cm, 2.5m deep (~10l), covering30-150 degrees, 55 cm2 cells:  <ETower> ~ 400 MeV  sE ~ (2<ng>) <Eg> = O(100 MeV) Calorimeter Backgrounds These estimates were made summer 1996, before further improvements tofinal focus + shielding reduced backgrounds by an order of magnitude … so guess background fluctuations reduced by 3 compared with above. Steve Geer SLAC/LBNL November, 2009 40

  41. Bethe-Heitler Muons (gZ  Zm+m-) Special concern: hard interactions (catastrophic brem.) of energetic muons travelling ~parallel to the beam, produced by BH pair production. Believe that this back-ground can be mitigated using arrival-times, pushing calorimeter to larger radius, & spike removal by pattern recognition … but this needs to be simulated Steve Geer SLAC/LBNL November, 2009 41

  42. Comparison with CLIC • We are not yet in a position to make an apples-to-apples comparison with CLIC, but ….. FROM CLIC Machine-Detector interface studies: hits/mm2/bunch train NOT AN APPLES-to-APPLES COMPARISON … BUT … Background hit densities appear to be similar to MC … so there may be many detector design issues in common between the 2 machines CLIC Note: CLIC shielding cone= 7o c.f. 20o for MC (but we hope to improve on this) 30mm O(1) hit/mm2/bunch train  Steve Geer SLAC/LBNL November, 2009 42

  43. MC R&D – The Next Step • In the last few years MC-specific R&D has been pursued in the U.S. by Neutrino Factory & Muon Collider Collaboration (NFMCC) & Muon Collider Task Force (MCTF) • Last December the NFMCC+MCTF community submitted to DOE a proposal for the next 5 years of R&D, requesting a greatly enhanced activity, aimed at proving MC feasibility on a timescale relevant for future decisions about multi-TeV lepton colliders. Steve Geer SLAC/LBNL November, 2009 43

  44. NFMCC/MCTF Joint 5-Year Plan • ● Deliverables in ~5 years: • Muon Collider Design Feasibility Report • - Hardware R&D results → technology choice • Cost estimate • Also contributions to the IDS-NF RDR • ● Will address key R&D issues, including • Maximum RF gradients in magnetic field • - Magnet designs for cooling, acceltn, collider • - 6D cooling section prototype & bench test • - Full start-to-end simulations based on technologies in hand, or achievable with a specified R&D program • ● Funding increase needed to ~20M$/yr • (about 3x present level); total cost 90M$ Steve Geer SLAC/LBNL November, 2009 44

  45. R&D – Ongoing NFMCC/MCTF HISTORY & FUTUREPROPOSAL Steve Geer SLAC/LBNL November, 2009 45

  46. Anticipated Progress NOW5 YEARS Key component models Steve Geer SLAC/LBNL November, 2009 46

  47. Aspirational Bigger Picture Steve Geer SLAC/LBNL November, 2009 47

  48. Muon Collider R&D: A National Program Steve Geer SLAC/LBNL November, 2009 48

  49. Final Remarks • Steady progress on the Front-End develop-ment for Muon Colliders- Cooling channel design concepts - NF R&D (IDS-NF, MERIT, MICE, … ) • The time has come to ramp up the Muon Collider specific R&D → a National Program • There are many challenges to be overcome- RF in magnetic fields & 6D Cooling Channel - Cost effective acceleration scheme - Collider Ring - Detector/Backgrounds optimization • The incentive to meet these challenges is great → “5 Year Plan” → Design Feasibility Study Steve Geer SLAC/LBNL November, 2009 49

  50. Illustrative Staging Scenario 4MW multi-GeVProton Source 4 GeVNF a Accumulation &Rebunching 3 25 GeV NF b 4 Steve Geer CERN Neutrino Workshop October 1-3, 2009 50

More Related