MICE ANALYSIS WORKSHOP 4 September 2008 @ RAL Goals: • Discuss what ‘Analysis’ means for MICE • Different from other PP experiments – engineering.
Download ReportTranscript MICE ANALYSIS WORKSHOP 4 September 2008 @ RAL Goals: • Discuss what ‘Analysis’ means for MICE • Different from other PP experiments – engineering.
MICE ANALYSIS WORKSHOP 4 September 2008 @ RAL Goals: • Discuss what ‘Analysis’ means for MICE • Different from other PP experiments – engineering matters • Bring people up to speed / pass on folklore – Don’t reinvent the wheel! • Identify tasks & priorities • Have new ideas • How to connect with Nufact IDS (& Mu cooling in general) Welcome to people new to MICE Hope for lots of discussion / use of blackboard 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 1/20 Rough Agenda 10.00 10.05 10.30 11.00 Organisation – C. Rogers Introduction & Overview – J. Cobb Emittance – C. Rogers Amplitude – M. Apollonio 11.30 Coffee (R1 cafeteria) 12.00 What degrades Cooling Channel performance? – J.Cobb / All 12.30 Discussion 13.00 Lunch (R22 restaurant) 14.00 What we learn from Step III – M. Apollonio 14.30 Use of TOFs for Beam measurement & RF phasing – M. Rayner 15.00 Discussion 15.30 Tea (R1 cafeteria) 16.00 Compilation of task list – J. Cobb / All 16.30 Wrap up; bringing MICE experience to Neutrino Factory – C. Rogers / All Hope for informal discussions 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 2/20 OUTLINE 1. 2. 3. 4. 5. 6. 7. Definitions Introduction to Ionisation Cooling Introduction to MICE The Physics of MICE Analysis ‘philosophy’ – as I see it Analysis Tools What has / hasn’t been done 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 3/20 SOME DEFINITIONS Particle in beam oscillates around reference trajectory: x x At sin( z ) z A = Amplitude – property of particle t = Beta[tron] function – property of lattice (magnet system) Acceptance = largest amplitude particle accepted by a machine Emittance e = mean amplitude of particles in a beam / 4 t = e / s q2 (at a focus) Normalised Emittance: en = ge = sxspx / moc [Length] (at a focus) Normalised emittance conserved 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 4/20 COOLING: Generalities Particles (in a beam) are distributed in 6D phase space px Particle density = f(x, y, t, px, py, E) f can be described by a ‘temperature’ x Higher temperature ‘larger’ beam lower density Liouville’s theorem: Phase space density in vicinity of particle is conserved in Hamiltonian system, df/dt = 0 Cooling: violate Liouville’s theorem = increase phase space density = decrease normalised emittance Shape may change with time but area conserved Muon lifetime conventional cooling, e.g. stochastic, too slow Ionisation cooling Phase space usually factorised into transverse & longitudinal f = ft(x,y,px,py) x fl(t,E) = ft(At) x fl(Al) if well behaved 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 5/20 IONISATION COOLING Bethe-Bloch dE dX ---------------------------------------------- Absorber • • ERF RF Cavities Pass muons through absorbers dE/dX reduces pt and pl RF replaces pl beam cooled; scattering heats d e n e n dE 2 dz E dX • • t 0.014 GeV 2 3 Em X 0 2 Transverse emittance decreases exponentially ~ 200 MeV/c is about optimum 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 6/20 HOW MUCH COOLING NEEDED FOR NF? Coloured histogram is scraping in one 5.5m section only Amplitude distribution en = 20 (p) mm Acceptance = 30mm Depends on acceptance of final accelerators Move high amplitude muons into acceptance Need enough cooling to get useful gain in number of muons 2 – 3 x emittance reduction if acceptance ~30mm (FFAGs) Stop and reaccelerate muons ~once en ~ 5 – 7 mm 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 7/20 MICE Section of FS2 Cooling Channel + Emittance measurements + PID Dual Goals: • Design, build, commission & operate realistic section of cooling channel • Measure performance in variety of operating modes & beam conditions • i.e. demonstrate that a cooling channel can be built to specification required for a NF & that it works • Both equally important for NF or Muon Collider • Feedback to design of NF 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 8/20 UNDERLYING PHYSICS OF MICE • Maxwell’s Equations – Well known • Lorentz Force – F = q (E + v B) • Energy Loss & Multiple Scattering – Understood for many years – Distributions important but not easy to calculate – Implementation in simulations suspect • Will eventually need attention • ‘Magnetics’ possibly biggest engineering challenge – Forces / superconductors / alignment / shields.... 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 9/20 ANALYSIS PHILOSOPHY SOURCE = Beam + Upstream Tracker & PID COOLING SECTION DETECTOR = Downstream Tracker & PID • Cooling section must be built to NF specification • Particle detectors confirm performance • Results must be unambiguous – i.e. expect (say) 10% cooling; observe 10% cooling – minimal corrections – ideally none – Treat cooling section as black box (except RF phasing) • MICE Analysis is everything that is not anything else! – Design & Specification as well as Data Analysis 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 10/20 But that’s not all • MICE is a D.E.Y. (do everything yourself ) exp’t – Including • ISIS beam on target (recent addition) • Beamline optimisation – Only a few people working • Detector reconstruction & calibration – Detector people should contribute • PID algorithms – Some development by R. Sandstroem • Field mapping (Spectrometers) • Error fields from Hall shielding (current concern) – All ‘Analysis’ • Fast (quasi real-time) reconstruction & analysis required for feedback to tune channel – many ‘modes’ 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 11/20 EXPECTED PERFORMANCE OF MICE Change in emittance: De / e = Dp/p )( 1-e0/e ) Dp ~ 5% in each absorber 15% cooling for large ein Emittance Single particle experiment Measure amplitude distributions Demonstrate cooling Measure transmission 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 Amplitude Before & After 12/20 MICE STEPS MICE assembled in steps PHASE I I & II characterise beam III control systematics PHASE II IV demonstrate cooling V cooling + re-acceleration VI full lattice section Also ‘Step III.1’ with LiH absorber between spectrometers Cooling – but no re-acceleration 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 13/20 ‘MODES’ & ‘CASES’ • Foreseen to run in ‘modes’ (aka ‘cases’) with different optics: – ‘Flip’, ‘Non-flip’, ‘Solenoid’ • Magnetic field flips sign at absorbers 3, 1 or 0 times • Investigate build up of canonical angular momentum – Cases described in TRD & MICE notes; not all possible at 240 MeV/c Momenta of 140, 170, 200, 240 MeV/c ; several beta-functions • Baseline is 200 MeV/c Flip mode • Also with input beams of 3, 6 and 10 mm emittance – Defined by diffuser & software selection • Also Full (with absorbers) & Empty (no absorber) – Measure scraping / systematics • Also selection of solid (& liquid) absorbers • 3 x 4 x several x 3 x 2 x a few = Many x 72 ‘tunes’ ! • Need fast feedback from analysis to optimise 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 14/20 ANALYSIS TOOLS G4MICE C++ Reconstruction Full simulation of cooling channel & detectors Fancy graphics Analysis GUI(s) ‘Living code’ Not fast but ‘Gridified’ Hard for non experts! Will be used for analysis Official MICE S/ware ICOOL F77 ‘Truth’ Physics simulations: Tracking, muon decay, dE/dX + scattering (6 models) Analysis routines, esp. ecalc9 based on MuCOOL 71‘Bible’ Accelerator physics code maintained at BNL Fast Used for MICE design Used for NF FS2,A,B G4BL C++ Beamline MICE simulation T. Roberts, Muons Inc. Transport Turtle ? Beamline design Matrix & tracking codes Standard beam transport codes Ad-hoc F77 code for magnetic fields & optics; some Excel… Comsol, Superfish, OPERA3D for fields, shields and so on 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 15/20 What has/hasn’t been done – 1 COOLING CHANNEL Optics Simulation Step I Step II Optimise for TOF & KL Step III Y ICOOL & G4MICE Step III.1 Y ICOOL & G4MICE Specified LiH Abs Step IV Y Step V Y Step VI Y Production solenoids Ongoing G4MICE / ICOOL Comparison (M.R.) F & C Coils will change ICOOL Some G4MICE F & C Coils will change Need ICOOL / G4MICE comp. Need slightly different optics for Full / Empty channels (DE in half absorber) All simulations use idealised Gaussian beams injected in upstream spectrometer Need simulations with beam starting upstream of Ckovs & TOF0, especially for Steps V & VI to prove RF phasing from TOF times 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 16/20 What has/hasn’t been done – 2 ALIGNMENT – effect on emittance, transmission & measurement BEAM Spectrometer 1 Y (Documented ?) Few mm, mr FCs & CCs Y (MICE notes) 1mm, 1mr Channel Spectrometer 2 Ongoing (D.F.) Few mm, mr ? SPECTROMETER MAPPING Will happen soon(ish) Needs acceptance criterion ERROR FIELDS from shields on Hall Current worry walls + stray iron Needs simulation 1% flatness for tracker ?? Volunteer ?? Need general field quality specification 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 17/20 What has/hasn’t been done – 3 BEAM Emittance Matrix 140, 200, 240 MeV/c x 3, 6, 10mm Diffuser thicknesses MICE note Beam element settings Only 200 MeV Need slightly different beams for Full / Empty channels (DE in half absorber) BEAM CHARACTERISATION Momentum measurement w. TOFs Demonstrated – Needs MICE note (MR) Emittance measurement w. TOFs Being studied – G4MICE (M.R.) Emittance measurement with Tracker Beam not contained in Trckr! PID How much really required? Useful? Need Step I study RF Phasing Use of TOFs for RF phasing of s 06 November 2015 Essential but not demonstrated! Needs study; full simulation with beam J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 18/20 A lot to do even before analysing real (cooling) data • Reconstruction & PID – Calibration, efficiencies &c. • Mustn’t get hung up on details • Needs someone to take ownership • Beam – Emittance matrix, tuning.... – Interface with G4MICE • Need consistent description at least as far back as TOF0 » The most important coupling is Timing RF phase • Experiment – Simulate realistic beam into MICE V or VI (see above) • Prove we can do experiment – Continue to understand specs. whilst in design/build phase – ad-hoc code for magnetics, matching, -functions • Make user-friendly & document – will be needed many times whilst running 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 19/20 THE END 06 November 2015 J.H. Cobb Oxford / JAI MICE Analysis workshop RAL 4 Sep 2008 20/20