1. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /1 Machine R&D towards a Neutrino Factory with focus on a Muon Ionization Cooling Experiment Alessandra Tonazzo Università Roma Tre and INFN Sez. Roma III

2. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /2 Towards a Neutrino Factory: the challenges Target and collection –High  + and  - yield –Sustain high power –Capture as many produced pions as possible Muon cooling –Reduce  +/  - phase space to capture as many muons as possible in an accelerator Muon acceleration –Has to be fast, because muons are short-lived !

3. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /3 Target and collection Achieve intense muon beam by maximizing production of  + and  - Soft pion production –E910 measurements available –HARP cross-section results awaited! (talk by J.J.Gomez-Cadenaz tomorrow) High Z material Sustain high power (4 MW) –Solid target is not adequate Optimize pion capture Neutrino Factory Targetry concept: Hg jet continuous flow target Pion focusing magnetic system –EU: horn –US: 20T SC solenoid

4. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /4 Pion collection 2.2 GeV 4 MW Protons Current of 300 kA  B  1/R B = 0 The CERN magnetic horn for pion collection Prototype built at CERN

5. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /5 Hg jet target Continuous flow free Hg jet –Tilted w.r.t. incoming proton beam direction –Intense solenoidal B field to capture low p t pions Key issues: –To what extent will the jet disperse due to rapid energy deposition by intense proton pulse ? –To what extent will magnetic forces perturb the flow of the jet into the magnet and affect the possible dispersal of the jet by the beam ?

6. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /6 Target: Hg jet tests E951 1 cm v=2.5 cm/s 24 GeV 4 TP p beam No B field CERN/Grenoble 4 mm v=12 m/s No p beam 0,10,20T B field Hg jet dispersal properties : proportional to beam intensity velocities ~½ times that of “confined thimble” target largely transverse to the jet axis delayed 40 ms The Hg jet is stabilized by the 20 T B field Minimal jet deflection for 100 mrad angle of entry Jet velocity reduced upon entry to B field

7. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /7 Participating Institutions 1)RAL 2)CERN 3)KEK 4)BNL 5)ORNL 6)Princeton University Proposal to test a 10m/s Hg Jet in a 15T Solenoid with an Intense Proton Beam Target & collection Installation and commissioning at CERN by April 2006

8. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /8 Reduction of  emittance Reduction of  emittance The muon beam emittance must be reduced for injection into the acceleration system Energy spread ► phase rotation Transverse emittance ► cooling Accelerato Accelerator acceptance R  10 cm, x’  0.05 rad rescaled @ 200 MeV  and  after focalization

9. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /9 Muon ionization cooling principle reality (simplified) Never realized in practice ! A realistic prototype should be built and proven to be adequate to the Neutrino Factory requirements. reduce p t and p l increase p l heating Stochastic cooling is too slow. Frictional cooling is only for  +. A novel method for  + and  - is needed: ionization cooling

10. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /10 Muon Ionization Cooling Experiment Aims: Show that it is possible to design, build and operate a section of cooling channel capable of giving the desired performances for a Neutrino Factory Place it in a muon beam and measure its performances in a variety of operating modes, thereby investigating the limits and practicality of cooling Proposal submitted to RAL on Jan.10 2003 Approval “strongly recommended” by Review Panel (May 20, 2003) Scientific approval from CCLRC chief executive (Oct 24, 2003)

11. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /11 MICE goals  Build a section of cooling channel long enough to provide measurable cooling (10% reduction of transverse emittance) and short enough to be affordable and flexible  Measure: 1) transverse emittance reduction with 0.1% precision 2) transmittance of the channel ►Delicate integration of accelerator and particle detector physics ! ►Never done before ! Difficulty: standard emittance measurement barely reach the required precision Solution: Single particle measurement –Measure track parameters before/after cooling channels –Reject non-muon background (undecayed  s, electrons from  s) The advantages: –Separate measurement of transmittance and emittance variation –A precision on (  T in -  T out ) <10 -3 can be achieved The challenge: –The measurement should not affect the cooling

12. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /12 MICE setup: cooling + diagnostics

13. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /13 MICE cooling channel High gradient reacceleration –10% reduction of muon emittance for 200 MeV muons requires ~20MV RF Challenge: integration of these elements in the most compact and economic way 3 Liquid Hydrogen absorbers 8 cavities 201MHz RFs, 8MV/m 5T SC solenoids Minimize heating term: Absorber with large X 0 SC solenoid focusing for small  T

14. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /14 RF module (Berkeley, Los Alamos, JLAB, CERN, RAL) MICE cooling channel R&D LH 2 window (IIT, NIU, ICAR) First cavity has been assembled Be window to minimize thickness The challenge: Thin windows + safety regulations

15. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /15 MICE cooling channel Beam properties Quantities to be measured Curves for 23 MV, 3 full absorbers, particles on crest cooling effect at nominal input emittance ~10% Equilibrium emittance

16. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /16 MICE: Emittance measurement Each spectrometer measures 6 parameters per particle x y t x’ = dx/dz = P x /P z y’ = dy/dz = P y /P z t’ = dt/dz =E/P z Evaluate emittance with: Compare  in with  out Simulation of a muon traversing MICE Determines, for an ensemble (sample) of N particles, the moments: Averages etc… Second moments: variance(x)  x 2 = 2 > etc… covariance(x)  xy = > Covariance matrix M

17. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /17 Spectrometer: requirements and errors Measurements 10% emittance reduction measured to 1%  absolute errors <0.1% Resolution on all measured parameters better than 10% Statistical 10 5 muons   (  T in -  T out ) < 10 -3 (in ~ 1 hr) Systematic Description of apparatus Systematic differences between in/out spectrometers Transport: wrong particles with different kinematics will spoil the measurements –Muon in … muon out   /  and  /e rejection at < 1% level Robustness against harsh environment –Noise from RF cavities –Background –Intense magnetic fields

18. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /18 MICE Tracker Alternative option: TPC with GEM readout (TPG) Baseline option: Scintillating fiber tracker 5 planes of Sci-Fi With double layer. 0.35 X 0 per layer The prototype

19. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /19 MICE Tracker performance A typical cosmic ray event Measured and expected efficiencies Point resolution ~440  m Light yield

20. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /20 MICE: Particle ID Upstream: –TOF hodoscopes with 10m path, 70 ps resolution –Cherenkov   /  separation at better than 1% at 300 MeV/c Downstream:  0.5% of  s decay in flight: need electron rejection at 10 -3 to avoid bias on emittance reduction measurement –TOF hodoscope –Aerogel Cherenkov (n=1.02, blind to  s) –Calorimeter for MIP vs E.M. Shower Ckov Cal

21. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /21 MICE at RAL Hall has been emptied and preparation to host the experiment begun

22. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /22  - STEP I: spring 2006 STEP II: summer 2006 STEP III: winter 2007 STEP IV: spring 2007 STEP V: fall 2007 STEP VI: 2008 MICE installation phases 2006 2007 2008 Subject to availability of funds… ……………

23. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /23 Muon acceleration Previous accelerator scheme: LINAC + Recirculating Linear Accelerator (RLA) –Very costly: need high RF gradient to limit losses from muon decay Proposed solution: use Fixed Field Alternating Gradient (FFAG) accelerator –Repetition rate can be raised >10 times faster than in ordinary synchrotrons New US Scheme Japan Scheme

24. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /24 Muon acceleration: FFAG Latest ideas in US have lead to the invention of a new type of FFAG (“non-scaling FFAG”) –interesting for more than just Neutrino Factories –may require a demonstration experiment (plans are developing) R&D in Europe is just starting  Perhaps the different concepts are merging to produce something better ?? Much progress in Japan with the development and demonstration of large acceptance FFAG accelerators

25. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /25 Why we are optimistic/enthusiastic – US perspective: Note: In the Study 2 design roughly ¾ of the cost came from these 3 roughly equally expensive sub-systems. New design has similar performance to Study 2 performance but keeps both  + and  - ! (S.Geer - CERN MW ws April 2004) Good hope for improvement in performance and reduction of cost! We are working towards a “World Design Study” with an emphasis on cost reduction

26. Neutrino2004 - Paris, June 14-19 2004A.Tonazzo – Machine R&D towards a Neutrino Factory /26 Summary and outlook The construction of a Neutrino Factory poses several stimulating challenges Target and collection –Magnetic horn prototype built at CERN –Complete target test experiment proposed and approved Muon cooling –International Muon Ionization Cooling Experiment at RAL Acceleration –The FFAG solution is progressing both in Japan and in the US Enthusiastic R&D is ongoing, and a lot has already been accomplished