Neutrino Factories and Muon Ionization Cooling Channels D. Errede HETEP University of Illinois 17 March, 2003

2 Why build a Neutrino Factory? (Physics, of course) What does a Neutrino Factory look like? In particular, what is an ionization cooling channel? What has the University of Illinois been doing with respect to a cooling channel?

17 March,

4 The Physics of Neutrinos Neutrino masses (pattern of the all fermion masses) Neutrino oscillation parameters (fill in the CKM matrix for leptons) CP Violating processes in the Lepton Sector (origin of baryon-antibaryon asymmetry in our universe?) GUTS: relating properties of quarks and leptons Is there a grand unified scheme?

17 March,

6 The Physics of Neutrinos Standard form for Mixing Matrix connecting weak and mass eigenstates        are the 4 real parameters that describe the mixing…  0 implies CP violation. (phase between 0 and 2 

17 March, The Physics of Neutrinos Connect two weak eigenstates with the evolution operator – involves Hamiltonian H 0 Use two assumptions: m1 < m2 << m3 and dM 2 = dm 2 atm = dm 2 32 ~ dm 2 31 we get And something similar but more complicated for 

17 March, The Physics of Neutrinos The sign of  m 2 : solar neutrinos Matter effects : MSW (Mikheev, Smirnov, Wolfenstein) e interacts with electrons in matter through the charged current interaction. This adds a term to the evolution operator. There is a resonance in matter near a = 1 for typical values of sin 2 2  ( ) “a” depends on N e, G F, E,  m 2.  =  12,  13

17 March, The resonance applies to neutrinos for positive dm 2 and antineutrinos for negative  m 2. Thus we can get the mass hierarchy m m m1 OR m m m3 The Physics of Neutrinos

17 March, The Physics of Neutrinos 3 Plausible Sets of Values J - Jarlskog factor a measure of CP violatioin

17 March, J = c 12 c 13 2 c 23 s 12 s 13 s 23 sin  Jarlskog J-factor a measure of CP violation CP Operation: C( e L ) = e L P( e L ) = e R CP Violating Process: For example: in vacuum … The Physics of Neutrinos : CP VIOLATION

17 March, The Physics of Neutrinos CP Violating Processes in the Lepton Sector Why is this interesting/fun/exciting? A possible explanation for Baryogenesis. (So far CP violating processes in the b quark sector are insufficient to explain baryogenesis) A SCENARIO Heavy Neutral Leptons: Majorana neutrinos through see-saw mechanism produces a light neutrino pair and a heavy neutrino pair. N e- H+ or e+ H- (both massless particles because this is occuring before EW symmetry breaking).

17 March, The Physics of Neutrinos N e- H+ or e+ H- CP Violating processes provides excess of e +,  ,  + over e -,  ,  - before EW phase transition. Andrei Sakharov says we also need non-equilibrium conditions so that these processes are not driven to equalize the numbers. Standard Model nonperturbative processes violate B, L, but conserve B-L. Churns lepton+’s into baryon material. Thank you Boris Kayser

17 March, The Physics of Neutrinos CP Violation in the Lepton Sector What would this have to do with CP violating processes in the low mass neutrino sector? We don’t know, but certainly CP violation in leptons at low mass makes CP violation in leptonic interactions at high mass scales more plausible. GUTs: one can also imagine unifying quarks and lepton such that their CKM matrices are also related. We won’t understand this until all the parameters are measured.

17 March, Neutrino Factory 1.High intensity beam on target to produce particles (  ’s) for a secondary beam. - Proton Driver + Target 2.Collects  ’s, allow them to decay into muons, spread bunch (large  E) and then perform phase rotation – Drifts + Induction Linacs 3.Reduce energy (and emittance) between induction linacs – Minicooling 4. Adiabatically change from one lattice to the next lattice – Matching Sections 5.Divide long bunch (~100 m) into short bunches that cooling section can handle - Buncher

17 March, Neutrino Factory 6.Reduce beam emittance – Cooling Channels 7.Accelerate to energy and emittance size that the next recirculating accelerators can handle - Linac 8.Accelerate from 2.8 GeV to 20 GeV – Recirculating Linear Accelerators (RLA’s) 9.Circulate muons and let some decay on production straight – Muon Storage Ring 10.Make measurements on neutrino interactions – Near and Far Detectors

17 March,

17 March, Neutrino Factory: Proton Driver Based on Feasibility Study 2 version of a neutrino factory…hence set at Brookhaven Natl Lab AGS proton driver uses existing ring, bypasses existing booster and introduces 3 new superconducting linacs.

17 March, Neutrino Factory: AGS Proton Driver Parameters Total beam power (MW)1 Beam Energy (GeV)24 Average beam current (  A) 42 Cycle time (ms)400 Number of protons per fill1 x Average circulating current6 No. of bunches per fill6 No. of protons per bunch1.7 x Time between extracted bunches (ms)20 Bunch length at extraction, rms (ns)3 Peak bunch current (A)400 Total bunch area (eV-sec)5 Bunch emittance, rms (eV-sec)0.3 Momentum spread, rms0.005

17 March, AGS Proton Driver Layout To target station High Intensity Source plus RFQ 116 MeV Drift Tube Linac (first sections of 200 MeV Linac) Superconducting Linacs 400 MeV 800 MeV 1.2 GeV Booster AGS 1.2 GeV 24 GeV 0.4 s cycle time (2.5 Hz) 6 bunches

17 March, Neutrino Factory: Superconducting Linacs Period Cryo-Modules Insertion at room temp C D AB cavity A B Topology of a Period C D Configuration of the cavities within the cryo-modules

17 March, Injection turns360 Repetition rate (Hz)2.5 Pulse length (ms)1.08 Chopping rate (%)65 Linac average/peak current (mA) 20/30 Momentum spread+/ Norm. 95% emittance (  m rad) 12 RF Voltage (kV)450 Bunch length (ns)85 Longitudinal emittance (eV-s)1.2 Momentum spread+/ Norm. 95% emittance (  m rad) 100 AGS Injection Parameters

17 March, AGS Proton Driver AGS : Harmonic bunches Bunch pattern for using harmonic 24 to create 6 bunches

17 March, Neutrino Factory : Target Energy on target 24 GeV, baseline beam power 1 MW, Pion momentum distribution peaks at 250 MeV, = 150 MeV  large angles coming off target…. Capture with 20 Tesla solenoid (r = 7.5cm, p Tmax = 225 MeV). Actually a horn which “tapers” to 1.25 T (r= 30cm, p Tmax = 67.5 MeV) (A horn converts transverse momentum into longitudinal momentum.) Target: High Z  maximize yield of  /p Goal of muon per year ( 10 7 seconds) decaying in detector direction, 50 kT, 1800 km away.

17 March, Neutrino Factory : Target Z

17 March, Neutrino Factory : Target Liquid Hg jet target chosen for maximum yield. Need to handle 1 – 4 MW beams. Want v jet = 30m/s to resupply Hg. Tests achieved 2.5 m/s to date. ( 30m/s only resupplies mercury before next bunch on average – 6 x 2.5 Hz = 15/sec )

17 March, Target R&D for MW-Scale Proton Beams Carbon Target tested at AGS (24 GeV, 5E12 ppp, 100ns) –Probably OK for 1.5 MW beam … limitation: target evaporation Target ideas for 4 MW: Water cooled Ta Spheres (P. Sievers), rotating band (B. King), conducting target, Front-runner = Hg jet 13 Tesla CERN/Grenoble Liquid Hg jet tests in 13 T solenoid – Field damps surface tension waves 0 Tesla BNL E951: Hg Jet in AGS beam – Jet (2.5 m/s) quickly re-establishes itself. Will test in 20T solenoid in future. t = ms 2 ms 7 ms 18 ms 27

17 March, Neutrino Factory : Drifts and Induction Linacs Beam has large energy spread. Drift allows beam to spread out to a long bunch length. Induction linacs accerlate late muons (lower energy) and decelerate early muons (higher energy).

17 March, Neutrino Factory : Drifts and Induction Linacs

17 March, Neutrino Factory : Drifts and Induction Linacs

17 March, Neutrino Factory : Drifts and Induction Linacs

17 March, Neutrino Factory : Drifts and Induction Linacs

17 March,

17 March, Neutrino Factory : Drifts and Induction Linacs

17 March, Neutrino Factory : Minicooling in Drifts and Induction Linacs

17 March, Neutrino Factory : Buncher and Cooling Channel In order to fit muon beam into cooling lattice the Buncher separates the ~100m long trail of muons into rf buckets. The cooling channel (P nominal = 200 MeV) then reduces the transverse emittance to a level acceptable for acceleration to 20 GeV.

17 March, Momentum-time distributions through the buncher

17 March, Neutrino Factory : Buncher and Cooling Channel

17 March, Momentum-time distributions through the buncher

17 March,

17 March, Neutrino Factory : Cooling Channel Lattice Cell

17 March, Neutrino Factory : Cooling Channel

17 March, Neutrino Factory : Cooling Channel

17 March, Neutrino Factory : Cooling Channel

17 March, Neutrino Factory : Cooling Channel

17 March, Neutrino Factory : Cooling Channel

17 March, Neutrino Factory : Cooling Channel

17 March, Neutrino Factory : Cooling Channel

17 March, Absorber : Forced Flow Design

17 March, Approximate Equation Transverse Emittance in a step ds along the particle’s orbit: First term is the Ionization Energy Loss (Cooling) Term Second term is the Multiple Scattering (Heating) term

17 March, Absorber Aluminum Window Pressure/Burst Testing

17 March, MUCOOL: UIUC Absorber Instrumentation Project Zach Conway Mike Haney Debbie Errede

17 March, MUCOOL RF R&D High Power 805 MHz Test Facility 12 MW klystron Linac-type modulator & controls X-Ray cavern 5T two-coil SC Solenoid Dark-current & X-Ray instrumentation Need high gradient cavities in multi-Tesla solenoid field Concept 1 – open cell cavity with high surface field Concept 2 – pillbox cavity - close aperture with thin conducting foil 805 MHz Cavity built & tested ®Surface fields 53 MV/m achieved ®Large dark currents observed ®Breakdown damage at highest gradients ®Lots of ideas for improvement 805 MHz Cavity built & being tested 53

17 March, Neutrino Factory : Cooling Channel

17 March, Construction of FODO Quad Cooling Cell 1/2 1/2 abs F rf D rf F rf D abs COOLING CELL PHYSICAL PARAMETERS: Quad Length0.6 m Quad bore0.6 m Poletip Field~1 T Interquad space m Absorber length0.35 m * RF cavity length m* Total cooling cell length4 m *The absorber and the rf cavity can be made longer if allowed to extend into the ends of the magnets. Or, more rf can be added by inserting another FODO cell between absorbers In this design For applications further upstream at larger emittances, this channel can support a 0.8 m bore, 0.8 m long quadrupole with no intervening drift without matching to the channel described here.

17 March, MOVIE Quad cooling movie / Kyoko Makino GSview - View – fit window – full screen – page down - escape Quad Cooling Beam Dynamics Group UIUC – Debbie Errede, Kyoko Makino, Kevin Paul MSU – Martin Berz FERMILAB – Carol Johnstone, A. Van Ginneken

17 March, Recirculating Linear Accelerators (RLAs)

17 March, Recirculating Linear Accelerators (RLAs) : Preaccelerator

17 March, Recirculating Linear Accelerators (RLAs) : Preaccelerator

17 March, Recirculating Linear Accelerators (RLAs) : Preaccelerator

17 March, Recirculating Linear Accelerators (RLAs) : Preaccelerator

17 March, Recirculating Linear Accelerators (RLAs) : Preaccelerator

17 March, Recirculating Linear Accelerators (RLAs) : Preaccelerator

17 March, Recirculating Linear Accelerators (RLAs) : Injection Chicane from Linac to RLA

17 March, Recirculating Linear Accelerators (RLAs) : Arcs

17 March, Recirculating Linear Accelerators (RLAs) : Arcs

17 March,

17 March, Recirculating Linear Accelerators (RLAs)

17 March, Recirculating Linear Accelerators (RLAs)

17 March, Muon Storage Ring Maximize number of muon on production straight f s = L s /C Minimize length of arcs Real Estate is an important issue here. Larger energy decreases angular beam spread (1/  ) allowing more neutrinos on “target” = detector

17 March,

17 March, Real Estate is an important issue here! : ARCS

17 March, COSY : Kyoko Makino (UIUC), Martin Berz (MSU) Tracking performed on a single arc cell.

17 March, COSY : Kyoko Makino (UIUC), Martin Berz (MSU)

Same Lattice with End Fields added

17 March,

17 March, Conclusions Neutrino physics is fascinating, beautiful and accessible. A Muon Collaboration exists that has done two feasibility studies on neutrino factory designs and R&D on targetry, absorbers, 800 (200) MHz NCRF cavities, solenoid magnets, and constructing a test area off of the Fermilab 400 MeV/c proton linac. Design studies for Ring Coolers, FFAG machines, Emittance Exchange are ongoing. Alternative technologies pursued at CERN and in Japan. Future plans include the construction of a cooling channel lattice cell to be tested in a low intensity muon beam at Rutherford Labs near Oxford, England.