1. MANX and Muon collider progress Katsuya Yonehara Fermi National Accelerator Lab yonehara@fnal.gov DPF2006, Honolulu, Hawai’i October 30 th, 2006

2. Outline Physics in muon colliders Design muon collider MANX experiment Future prospects Summary

3. Physics in muon collider Higgs factory –Large cross section in an s-channel scalar Higgs  (      H 0 )/  (e + e -  H 0 ) = (m  /m e ) 2 = 40,000 New particle search –SUSY –Particles beyond LHC region 1.5 ~ 5 TeV CoM energy Another interesting physics, see C. M. Ankenbrandt et al, PRSTAB 2, 081001 (1999)

4. Design muon collider  Proton driver 8 GeV Power=1.1 MW  Capture 0.15  /proton  Cooling section  transverse (mm): 20  0.0025  longitudinal (mm): 400  20  Low Energy RLA Injection energy = 2.5 GeV  High Energy RLA Injection energy = 30 GeV Final energy = 750 GeV  Low Emittance Muon Collider Revolution freq = 132 kHz bunch intensity = 10 11 N of bunches = 10  = 0.06 beta star = 5 mm Average luminosity = 3 10 34 /cm 2 /s rep rate = 65 Hz  p/p = 1 % R. P. Johnson et al, “Letter of Intent for Fermilab”, http://www.muonsinc.com/tiki-download_wiki_attachment.php?attId=36 See M. Popovic’s presentation

5. Difficulties in muon acceleration Relatively heavy particle –200 times heavier than electron mass No synchrotron radiation Produced in a vast phase space  Short life time  –2.2  s in a rest frame Ionization cooling is one of the most effective methods to cool a muon beam.  transverse = 20 mm  longitudinal = 400 mm The required beam phase space for muon colliders is  transverse = 2  m  longitudinal = 20 mm

6. Each particle loses momentum by ionizing a low-Z absorber. Only the longitudinal momentum is restored by RF cavities. The angular divergence is reduced until limited by multiple scattering. Successive applications of this principle with clever variations. Leads to smaller emittances for high Luminosity with fewer muons. Cool a muon phase space only in the transverse direction. Principle of Ionization Cooling

7. Ionization Cooling is only transverse. To get 6D cooling, emittance exchange between transverse and longitudinal coordinates is needed. Continuous Energy Absorber for Emittance Exchange and 6d Cooling

8. HCC with continuous absorber HP GH2 filled high grad cavity + Dispersive devise for emittance exchange RF breakdown study in a high Pressurizing GH2 filled 800 MHz pillbox cavity (P. Hanlet et al, EPAC06) Continuous Gaseous H2 works 1.Suppression of rf breakdown 2.Ionization cooling material Helical cooling channel with continuous absorber

9. Particle motion in helical cooling channel Blue: Beam envelope Red: Reference orbit Magnet Center Repulsive force Attractive force Both terms should be opposite sign. Combined function magnet Solenoid Helical dipole Helical quadrupole Dispersion Focusing Y.S. Derbenev and R.P. Johnson, PRSTAB 8, 041002 (2005) Energy loss should be compensated by a bunch of rf cavities.

10. Emittance in series of HCC 6D cooling factor in the series of HCC is ~50,000. Muon collider is required the cooling factor 10 6. Recent muon scattering experiment in low Z material (MUSCAT, hep-ex:0512005) shows the conventional multiple scattering angle is overestimated. This is predicted by U. Fano (PR93,117,1954) and A. Tollestrup (MuNote0176). The new scattering model will improve the cooling factor 3~4. K. Yonehara, EPAC06

11. Extra cooling & Reverse emittance exchange Parametric ionization cooling channel Reverse emittance exchange Extra cooling by using 50 Tesla solenoid Y.S. Derbenev et al., COOL05, EPAC06 S. Kahn et al., EPAC06 Y.S. Derbenev et al., COOL05, EPAC06 K.B. Beard et al., PAC05

12. Muon collider And Nutrino factory eXperiment (MANX) 6-D cooling demo experiment –Proof exceptional 6-D cooling in helical magnet Make helical cooling magnet –Many challenges Magnet design Spectrometer Window Cryostat

13. Collaborators Fermilab Muons, Inc. Jlab IIT BNL

14. Tips for demo channel design Use liquid helium (LHe) as absorber –No big safety issue –Thin windows at both ends of channel No RF cavity inside HCC –Save R&D time & money Momentum dependent (z-dependent) field map –Initial P = 0.3 GeV/c: Final P = 0.15 ~ 0.18 GeV/c –Maximum field is less than 6 T. K. Yonehara et al., COOL05

15. Make realistic fields in TOSCA Snake type MANX Consists of 4 layers of helix dipole to produce tapered fields. Maximum field is ~7 T (coil diameter: 1.0 m) Hard to adjust the field configuration Slinky type MANX Consists of 73 single coils (no tilt). Maximum field is ~5 T (coil diameter: 0.5 m) Flexible field configuration V. Kashikhin et al. MCTFM 7/31/06 at fermilab Large bore channel Small bore channel

16. Emittance evolutions in 6DMANX by using a flat beam Tran/longi cooling factors are ~1.5, respectively. 6D cooling factor is 3.8. Average transmission efficiency is 50 % by using a flat beam.

17. Simulation test with matching Upstream matching It transforms a coaxial beam into a helical one. transverse momentum kick displacement 2mm Thick Al Windows HCC Helical solenoid coil

18.  x =  y = 40.0 mm  x’ =  y’ = 0.2  p = 20 MeV/c run09060160  x =  y = 60.0 mm  x’ =  y’ = 0.2  p = 20 MeV/c run09060170  x =  y = 80.0 mm  x’ =  y’ = 0.2  p = 20 MeV/c run09060180  x =  y = 40.0 mm  x’ =  y’ = 0.2  p = 40 MeV/c run09060190  x =  y = 80.0 mm  x’ =  y’ = 0.1  p = 40 MeV/c run09060200  x =  y = 40.0 mm  x’ =  y’ = 0.1  p = 40 MeV/c run09060210 Equal cooling scheme with various parameters Cooling factor is 250 ~ 300 %. Transmission efficiency is 20 ~ 40 %. All cooling decrements are quite same.

19. Future prospects (Budget plan) Current budget status is “green”. We submitted a proposal of a MANX magnet design to the DOE AARD project with fermilab. We will submit a proposal for a MANX experiment to fermilab. We try to keep our status by proposing the DOE SBIR projects.

20. Summary We innovated a novel muon beam cooling channel by using a helical magnet with a continuous GH2 absorber. We observed an exceptional cooling performance in the simulation. We propose a cooling demo experiment. We are looking for more collaborators. All references can be found on http://www.muonsinc.com