Technical Challenges of future neutrino beams Mary Anne Cummings Northern Illinois University WIN ’03 Lake Geneva, Wisconsin

The current story..  Recent results from SNO and SuperK have convinced most of the HEP community that ’s oscillate, most likely among 3 known species  There exists now ongoing R & D in accelerator and experimental physics based on  beams, and the beams that can be extracted from them.  New machines can be developed in an incremental fashion, with a physics program for each step.  Proton drivers can provide intense conventional beams, and can provide an intense source of low energy  ’s (via  decay)  These  ’s must be cooled – an very active R & D program has sprung from developing this new technology.  As a proton driver is being constructed, work on collecting the  ’s and cooling them would be continued.  An intense source of cold muons could be immediately used for E and B dipole moments, muonium-antimuonium oscillations, rare decays…  As cooling and acceleration capability is developed, a storage ring could be the basis of the first neutrino factory.  Source of e ’s and v  ’s and their charged conjugates from  + an  - beams  During factory construction, further R & D on  acceleration can create a Higgs factory and higher energy muon colliders … using relatively compact collider rings

A bit of background  Concept of a muon collider: Tinlot (1960), Tikhonin (1968), Budker (1969), Skrinsky Neuffer (1979), Palmer (1995)  Muon Collider Collaboration  Many advantages over electron collider comes from the mass of a muon:   But, they decay, and luminosity becomes a challenge  Fast cooling technique – ionisation cooling – invented 1981: Skrinsky and Parkhomchuk  Another problem…….neutrino radiation!  Idea for a Neutrino Factory comes from seeking a use for beams produced a muon collider storage rings.. this turns out to be very positive! (S. Geer, 1997 FNAL workshop) Neutrino Factory! Enough neutrinos to be a problem …. must be enough to do physics - R. Edgecock

Muon Collaboration Now referred to as the Neutrino Factory and Muon Collider Collaboration –> 140 scientists –MC is sponsored by three national laboratories (BNL, FNAL, LBNL) Active Program: –Targetry –Cooling Simulations –RF Hardware –LH2 absorber Designs –High-field solenoids –Emmitance Exchange –Muon Acceleration –Neutrino Factory design studies I and II Experiments: –MUCOOL (FNAL) : Cooling channel component development: MTA completed! –MICE (Rutherford-Appleton) Muon cooling measurement: Approved! University Participation: –ICAR (Illinois Consortium for Accelerator Research) –Ph.D. and Masters students involvement –State of Illinois support to promote accelerator R & D

Not THAT ICAR… xx New Book by David M. Jacobs! New Book by David M. Jacobs! Thinking Clearly About UFO Abductions Video Interview with David Jacobs xxx Welcome to the ICAR Straight Talk About UFO Abductions The International Center for Abduction Research (ICAR) is an organization devoted to the dissemination of trustworthy information about UFO abductions. The ICAR will provide accurate information to therapists and lay individuals who are interested in abductions, and help cope with the myriad of problems that arise from the use of hypnosis and other memory collection procedures. David M. Jacobs is the Director of the ICAR and there is a small Board. A personal note from David M. Jacobs: I wrote most of the information on this website based on thirty-four years of UFO research and over twelve years of hypnotic regressions with abductees. I have tried to be as objective and as "agenda free" as possible, sticking close to the evidence that I have gathered over the course nearly 800 hypnotic regressions. However, there is no possibility that I have avoided error. The reader must be skeptical of what I say and what all others say in this difficult arena of abductions, hypnosis, popular culture, and cultural expectations. We are all amateurs doing our best to get to the truth knowing that objective reality may elude us.

Muon Collider R & D  Three stage scenario: Neutrino Factory Higgs Factory Muon Collider  5 different Neutrino Factory layouts: BNL CERN FNAL J-PARC RAL For example, at least 2 generations of colliders would fit on FNAL site… Technical Issues: 1.Proton driver 2.Target and Capture 3.Decay and Phase Rotation 4.Bunching and Cooling 5.Acceleration 6.Storage Ring BUT… Large PH init.  beam  rapid beam cooling Short lifetime  rapid acceleration Backgrounds: Muon colliders: compact design

Technical Staging and Physics Muon Collider Schematic Study II factory.. Possible Higgs factory..

JHF Superbeam Kobayashi Proton Beam Target Focusing Devices Decay Pipe Beam Dump  ,K,K  “Conventional” neutrino beam  Target Horns Decay Pipe Far Det. “Off-axis”

Proton Driver  Main requirements: 4 MW beam power, 1 ns bunch length,  50Hz  Two types : Linac (BNL type) RCS (FNAL type)  Range of energies: 2.2 to 50 GeV  BNL, FNAL parameters: R & D: HIPPI

Target Proposed rotating tantalum target ring Many challenges: enormous power density  lifetime problems pion capture Replace target between bunches: Liquid mercury jet or rotating solid target Stationary target: RAL CERN

Liquid Mercury Tests Tests with a proton beam at BNL. Proton power 16kW in 100ns Spot size 3.2 x 1.6 mm Hg jet - 1cm diameter; 3m/s 0.0ms0.5ms1.2ms1.4ms2.0ms3.0ms Dispersal velocity ~10m/s, delay ~40  s

Target Facility  Carbon or liquid mercury jet target  20 Tesla capture solenoid  Issues: 1.power dissipation, target durability 2.pion yield of solid & liquid target 3.performance of capture solenoid in a high radiation environment

Pion Capture 20T1.25T

Horn Capture Protons Current of 300 kA To decay channel  Hg target B  1/R B = 0

Phase Rotation & Bunching Beam after drift & adiabatic buncher – Beam is formed into string of ~ 200MHz bunches Beam after ~200MHz rf rotation; formed into string of equal-energy bunches; matched to cooling RF acceptance 1 B & R 2 R & B Alternative: 1.Rotation by induction Linac (E-field gradient on axis) into longer pulse, lower energy spread 2.Bunching by RF lattice (similar to cooling channel) into 200MHz

Ionization Cooling With transverse focussing (solenoid)  ~ beam envelope : Heating term (mult.scatt.) Cooling term  xx zz P1P1 P2P2    absorber accelerator absorber P1P1  Multiple scattering RF cavity The miracle of muons is that they can focus going through matter! Phase space equation: Liouville’s Theorem states that phase space is invariant.. need to remove energy to increase particle density… L R large  LH2

Transverse Cooling Channel Design  Shown here, a cooling cell with LH 2 Absorbers, RF cavities and Solenoid Magnet:  Issues: LH2 safety, windows strong but thin, RF cavities “benign”, structural intregrity in very large E and B fields Ignition source: very high E fields! Incendiary device (LH2) Quench site: very high B fields!

MuCool Research Current experiments at laboratories and universities.

LH2 Windows Photogrammetry: Non-contact measurement of strain by calculating displacement Photogrammetry ~1000 points Strain gages ~ 20 “points”

MuCool/ICAR research Current design and simulation programs at laboratories and universities.

Cooling channel RF cavities… Large E fields inside of large B fields! Large E field: cavity performance is determine by field emission from surface.

MTA LH2 Experiment Beamline: C. Johnstone

Mucool Test Area LH2 Setup Lab G magnet

MICE T.O.F. III Precise timing Electron ID Eliminate muons that decay Tracking devices: He filled TPC-GEM (similar to TESLA R&D) or sci-fi Measurement of momentum angles and position T.O.F. I & II Pion /muon ID precise timing 201 MHz RF cavities Liquid H2 absorbers or LiH ? SC Solenoids; Spectrometer, focus pair, compensation coil Muon Ionisation Cooling Experiment: Approved by RAL Technical Design Report in December

Muon Acceleration  Needs to be fast – muon lifetime  Needs to be a reasonable cost – not all linacs all the way  Baseline: Recirculating Linear Accelerators Other possibilities…… FFAGs & VRCS

FFAGs Fixed Field Alternating Gradient  magnets not ramped  Cheaper/faster RLAs/RCSs  Large momentum acceptance  Large transverse acceptance  less cooling required! Neutrino Factory Japanese staged physics program High Power Proton Driver –Muon g-2 Muon Factory (PRISM) –Muon LFV Muon Factory-II (PRISM-II) –Muon EDM Neutrino Factory –Based on 1 MW proton beam Neutrino Factory-II –Based on 4.4 MW proton beam Muon Collider

FFAG’s Proof Of Principle machine built and tested in Japan. 50keV to 500keV in 1ms. 150MeV FFAG under construction at KEK.

VRCS  Fastest existing RCS: ISIS at 50Hz  20ms  Proposal: accelerate in 37  s  4.6kHz  Do it 30 times a second  920m circumference for 4 to 20 GeV Combined function magnets 100 micron laminations of grain oriented silicon steel 18 magnets,  20T/m Eddy currents iron: 100MW  350kW Eddy currents cu : 170kW RF: 201MHz; 15MV/m Muons: 12 orbits, 83% survival

Parting Remarks  Neutrino oscillations: one of most important physics results  Many new experiments conceived  New beam neutrino facilities required: - Superbeams- - Neutrino Factory - Beta beams  All require extensive R&D  For Neutrino Factory: a thriving research program - proton driver - target - cooling (MuCool, MICE) - acceleration  Real Experiments are planned and approved