Design and characterisation of the MICE beamline

1. Design and characterisation of the MICE beamline K. Walaron University of Glasgow K.Walaron IOP Warwick April 2006

2. Neutrino Factory physics (very quickly) • Neutrinos have mass and mix. • First conclusive evidence of physics beyond the standard model • Theta13, mass hierarchy and possibly leptonic CP violation needs investigated • Theta13  nu_e to nu_mu oscillation. Mass hierachy  change in osc. Prob. Between nu and nu bar (MSW) K.Walaron IOP Warwick April 2006

3. [ 900–1000 m below ground ] The Neutrino Factory To Soudan (500 m) Return leg • Proton Driver 4MW, 10^21 Muon Decays • Target and Pion Capture Huge power densities, 20 T solenoid • Phase Rotation & Cooling Reduce momentum spread/transverse emittance • Acceleration Linacs, RCL’s, FFAG to 8~50 GeV • Storage Triangular, Racetrack, dogbone etc To G Sasso (100 m) To Super-K (1000 m, projection) Return leg (vertical) 3 × FFAGs 3–8 GeV8–20 GeV20–50 GeV To Soudan 3 GeV linac Cooling Phase rot. Target To G Sasso ~10 GeV synch. + booster + linac To G Sasso K.Walaron IOP Warwick April 2006

4. Muon Cooling • Transverse emittance is defined as Where C is the 2N*2N matrix of covariances (Xi, Xj) with elements Cij = Covariance (XiXj) with Xi being an element of the 6D phase space vector (x, px, y, py, t, E) • The normalised transverse emittance measurement relevant to MICE is: • Physics requirement for MICE is a reduction of tranv. Norm. Emitt. by >10% +/- 0.1% for (140-240 MeV/c) muon beam K.Walaron IOP Warwick April 2006

5. MICE (just as quickly) • Emittance measurement carried out by SciFi trackers • 3 liquid H absorbers to reduce P • Pz component replaced by 8 RF cavities. 8MV/m K.Walaron IOP Warwick April 2006

6. Design requirements of the beamline • Muon purity. Pion/Muon momentum separation should be as large as possible • To provide a tuneable emittance muon beam to MICE • TOF0 to TOF1 minimum separation of 6.94m. Providing muon identification. K.Walaron IOP Warwick April 2006

7. General layout: MICE beamline K.Walaron IOP Warwick April 2006

8. Evolution of beamline • Initial design carried out using Transport and Turtle codes • New design modelled using Geant4 based program called G4Beamline. • Beamline evaluated: Detector rates, TOF separation, beam match, beam scraping etc. • If needs be back to the drawing board(Transport and Turtle) K.Walaron IOP Warwick April 2006

9. Example tune (AUG05, 240 MeV/c) • Show details from my AUG05 240 MeV/c tune. • Tune is based on a 200 MeV/c, 6pi mm mrad design with currents scaled • Not a final tune, changes have been made to the magnet/ detector positions within the hall since. Changes the magnetic lattice considerably. New tunes being developed as we speak. Q1-Q3 High Z diffuser Collimators Proton Absorber CKOV1 TOF0 D1 TOF0 D2 Q4 – Q6 Q6 – Q9 DecaySolenoid K.Walaron IOP Warwick April 2006

10. Sample X, Y beam profile K.Walaron IOP Warwick April 2006

11. Sigma x Lead diffuser Pre bend2 and absorber Post-TOF1 Collimator Pre-TOF1 TOF0 Q4 CKOV1 Q7 Q8 K.Walaron IOP Warwick April 2006

12. Sigma Y Lead diffuser Pre bend2 and absorber Post-TOF1 Collimator Pre-TOF1 TOF0 Q4 CKOV1 Q7 Q8 K.Walaron IOP Warwick April 2006

13. Transmission Lead diffuser Pre bend2 and absorber Post-TOF1 Collimator Pre-TOF1 TOF0 Q4 CKOV1 Q7 Q8 K.Walaron IOP Warwick April 2006

14. Ptot immediately downstream of lead diffuser K.Walaron IOP Warwick April 2006

15. 4D emittance Lead diffuser Pre bend2 and absorber Post-TOF1 Collimator Pre-TOF1 TOF0 Q4 CKOV1 Q5 Q6 Q7 Q8 K.Walaron IOP Warwick April 2006

16. Rates at beamline detectors • 100k Pi+ at target. • The rates for this tune assuming the tuned pion momentum and momentum spread of 500.42+/-17 MeV/c flat. • Rates are normalised to a MARS target simulation. • Assumptions made about target • Assumptions made about ISIS • ISIS target interaction big unknown for MICE K.Walaron IOP Warwick April 2006

17. Matching of beamline into MICE • Beamline automatic optimiser recently develloped • Uses minuit SIMPLEX engine to optimise quadrupole currents along muon matching section. • Matches to beta function inside first SciFi tracker • Will in time be adapted to include beam diffuser thickness K.Walaron IOP Warwick April 2006

18. K.Walaron IOP Warwick April 2006

19. Reduction of 45mm K.Walaron IOP Warwick April 2006

20. MICE target test • Beam conditions at target insertion point not well known both transversely and longitudinally (beam evolution over ~2ms) • Every rate ever quoted in beamline studies suffers from this. (Assumptions in transverse density/ how much of the beam we intercept). IMPORTANT, especially for TOF0. • LAHET, GEANT4 and LAHET target simulations all differ in pion yields (~ 20%) • Need to always be careful not to take too much of the beam and incur the wrath of ISIS. Correlate pion yield with beam loss • Aim to investigate this in a beam/target study in Summer 2006 K.Walaron IOP Warwick April 2006

21. Scintillator Scheme 5cm 20m from target • Need to measure particle yields as a function of target insertion • Momentum and flux depends on dip • Need to know numbers of pions/protons by counting and dE/dx in scintillator. Provide coincidence to reduce neutrons. Measure proton depleted rate. High Rate Ranges out low energy scattered protons K.Walaron IOP Warwick April 2006

22. Conclusion • On track to have on the floor a beamline that can be tuned to produce a selection of beams by end of this year • MICE then cools • Build a Neutrino Factory • Easy!!  K.Walaron IOP Warwick April 2006