Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Welcome ! Professor Bob Cywinski Dean of the Graduate School and Special Adviser (Research) to the VC IIAA

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA £140m turnover £300m benefit to the local economy Over 2,800 staff on payroll 24,000 students studying more than 400 degrees An international University –Students from over 130 countries –Delivering courses in China, Hong Kong, India and Singapore The University of Huddersfield

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Top 10 for Teaching Excellence (The Sunday Times) Top 10 for Student Satisfaction (NSS and ISB) Top 10 for Employability (DELI) Top 10 for Financial Sustainability Top 10 of “Green” Universities Top 10 for quality of buildings (category A) Doubled research income and PG recruitment Outstanding Employer status Human Resources (HR) Excellence in Research Award, bestowed by the European Commission THES Entrepreneurial University of the Year (2012) Two Queen’s awards (2013) Guardian University Award Winner (2013) THES University of the Year (2014) The University of Huddersfield

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA The University of Huddersfield

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA The International Institute for Accelerator Applications

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Future Muon Sources Professor Bob Cywinski Dean of the Graduate School Special Advisor (Research) International Institute for Accelerator Applications University of Huddersfield

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Future (Surface) Muon Sources Professor Bob Cywinski Dean of the Graduate School Special Advisor (Research) International Institute for Accelerator Applications University of Huddersfield

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Physics Magnetism Superconductivity Surfaces Fundamental physics Materials Polymers Semiconductors Hydrogen in metals Chemistry Molecular dynamics Oxides Muonium Biology Proteins Currently there are muon beam users world-wide, with 255 signed-up members of the International Society for MuSR Spectroscopy (ISMS) Surface muons for MuSR spectroscopy

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Muon facilities world-wide TRIUMF Continuous Beams ISIS Pulsed (50Hz) Beams PSI Continuous Beams JPARC Pulsed (25Hz) Beams

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Question: What do muon beam users want ? Answer: Orders of magnitude more muon intensity and smaller muon beam dimensions Why? At current positron count-rates (up to 40kHz) a typical spectrum from a typical sample (of a few cm 2 ) will take ~30min to collect with reasonable statistics At all existing facilities, muon production is a sub-optimal compromise determined through consultation with other users of the proton drivers (symbiotic, parasitic, or complimentary?) What do we need? Parametric studies (as functions of temperature, magnetic field, pressure and/or sample concentration) can take days Studies of small (mm 2 ) samples (eg single crystals) can take even longer Low energy muon studies of surface phenomena can take weeks

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Designing the future Cost Stand alone facilities or shared accelerator beams? The Accelerator Linac, synchrotron, cyclotron, FFAG ? Energy, current, frequency ? Protons or other particles ? Pion production target Material (graphite, beryllium, nickel, composite..) Geometry, volume, size Beam conditioning Collection geometry, beam optics, cryogenic cooling, pulse shaping

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA 4.1 MeV   = 26 ns Pion production

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Pion production Single pion production (threshold 280MeV) Double pion production (threshold 600MeV)

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Proton Energy ? Surprisingly our simulations show that higher energy protons do not necessarily produce more (surface) muons A peak in muon production rate is observed just below 500 MeV Increasing energy produces more pions in the forward direction and well outside the momentum range likely to be used by a decay beam

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Proton Energy ? Surface muon production normalised to proton energy Surface muon production normalised to number of interacting protons

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA T w (ns) Relative µSR asymmetry Transverse field, mT Pulsed or CW operation? The finite proton pulse width (eg 80ns at ISIS) limits the dynamic response of a µSR spectrometer at a pulsed source. There are no such limitations in CW Synchrotron operation at 50Hz (eg ISIS) is inefficient for MuSR – it provides a measuring window of 20ms whilst only 20µs (ie 10τ m ) is needed (duty cycle =0.1%) At a pulsed source the positron count rate (~40kHz at ISIS) is limited only by detector deadtime effects. Significant increases in countrate can therefore be achieved by increasing source intensity

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA At a CW source only one muon can be allowed in the sample at a time. Long time beam-borne backgrounds are generally significantly higher than at a pulsed source (but can be reduced by the Muons on Request technique) Muons on request (MORE) at PSI Conventional muon spectrometers at PSI and TRIUMF already count at 25-40KHz. This is the maximum rate possible with CW operation and is governed by the muon lifetime. However significant increases in muon beam intensity are important for small samples and LE muons Pulsed or CW operation?

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Pion production targets should produce a high yield of pions and muons Pion production rates are approximately independent of atomic number, although the production of other particles (neutrons, gammas) increases with Z. Low-Z materials minimize proton scattering Particle/target interactions should generate little heat and targets should dissipate heat easily Monolithic targets are not necessarily the best design – surface to volume ratio should be maximised, whilst the target size should be kept small PHYSICAL REVIEW SPECIAL TOPICS - ACCELERATORS AND BEAMS 17, (2014 – Bungau et al) Production targets

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Possibilities Gains in muon beam intensities can be made at existing facilities by improving target geometry and composition, and muon collection but: (i) proton energies, repetition rate and current are fixed (ii) the fraction of protons taken by the pion production target, although negotiable, is also fixed (eg 4% at ISIS) The greatest gains necessitate construction of a fully stand-alone facility: (i) Proton energy ~ MeV, current 0.5-1mA (ii) Optimal target geometry, thickness and material (Additionally an optimised pulsed muon source should have a repetition rate approaching 10kHz and a pulse width of ~30ns) A dedicated proton driver unconstrained by parasitic uses of the proton beam will enable precise tailoring of beam/target assemblies, allowing smaller proton/muon beams, and more efficient pion/muon collection and will also facilitate the implementation of multiple muon production targets. x10

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA The way forward? IIAA ESS 5MW

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA The way forward? The foundation stone for the 1.7b€ European Spallation Source has just been laid after more than 25 years of design, redesign and political campaigning by 5000 European neutron beam users There is much we can learn from the ESS (and SNS and J-Parc) campaigns We need to build a strong science case, emphasising “impact” and the roles that muons can play in the “Grand Challenges” We need to engage the wider muon community (fundamental physics, imaging, etc) It may also be beneficial to engage with Fermilab and Brookhaven National Laboratory. Both have recently held workshops which have focussing upon muon production and MuSR facilities

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Session 1: Muon production and accelerator technologies Session 2: Specialised beams Session 4: Update and outlook from the Facilities Session 3: Condensed matter µSR / New Techniques Session 5: Novel applications of muons Future Muon Sources 2015

Future Muon Sources, University of Huddersfield, 12/13 January 2015 IIAA Thank You!