MEASUREMENT OF EMITTANCE AND OTHER OPTICS QUANTITIES V. Blackmore MICE Optics Review 14 th January, /22

Depends on material Depends on magnetic lattice Depends on upstream beam line (mostly diffuser) Depends on particle species  backgrounds! Multiple scattering Ionisation Cooling Measure a change in emittance PHYSICS GOALS 02/22

THE MICE MUON BEAMLINE 03/22

The MICE Muon Beamline during Step I EMR 04/22

STEP I CHARACTERISATION 1 DOI: /epjc/s /epjc/s /22

MEASURING EMITTANCE IN MICE 06/19 06/22

MEASURING EMITTANCE Run 7469, selected (x, Px) distribution at TKU plane 1 07/22

RUN 7469 Conventional Magnet Current (A) D D DS Q Q Q Q Q Q Q Q Q Superconducting Coil Current (A) SSU-E2249 SSU-C278 SSU-E1234 SSU-M20.0 SSU-M10.0 FCU-upstream0.0 FCU-downstream0.0 SSD-M10.0 SSD-M20.0 SSD-E10.0 SSD-C0.0 SSD-E20.0 Taken on Oct 7 th 2015, from 15:39 to 16:48 (3, 200) mu+ optics Only 3 (of 5) coils powered in SSU Expect non-uniform field across tracker (will return to this!) ISIS at 700MeV (not 800MeV) 08/22

SELECTION CRITERIA Only use particles that satisfy all of the following: 1.Have a spacepoint (hit) in TOF0 2.Have a spacepoint (hit) in TOF1 3.Have a spacepoint (hit) in all 5 tracker planes 4.Have a time-of-flight from TOF0  TOF1 between 27 and 40ns 5.Have a good track fit The downstream tracker is ignored, as is TOF2/KL/EMR for the moment. PID selection can and will be improved. 14’392 particles to “have fun” with! 09/22

SANITY CHECKS ~1m PRY Upstream tracker (plane 5) 10/22

SANITY CHECKS Measurement at…Mean P (MeV) TOF0  TOF1 Pattern Recognition (TKU)194.2 Kalman fit (TKU) Expected P at TKU plane 5~189 Run 7469, |P| distribution at TKU plane 5 11/22

CONSISTENCY CHECKS Run 7469, Pt distribution at TKU plane 5 12/22

CONSISTENCY CHECKS Run 7469, Pz distribution at TKU plane 5 13/22

CALCULATING THE COVARIANCE MATRIX xyPxPy x y Px Py At tracker plane 1 (reference plane): From 14’392 particles: Comment: beam is not rotationally symmetric 14/22 Note difference from report. Data has since been reprocessed with improved track fit quality estimates

CALCULATING THE COVARIANCE MATRIX 15/22

CALCULATING THE COVARIANCE MATRIX Sample A Sample B o Measure covariance matrix of Sample A at plane 5 o Measure covariance matrix of Sample B at plane 1 (reference plane) o Compare… Beam direction Plane 1 (reference plane) Plane 5 16/22

CALCULATING THE COVARIANCE MATRIX Sample A Sample B Beam direction Plane 1 (reference plane) Plane 5 z (mm) A B o Reduces sample size to ~7’000 particles/sample o Large emittance change across tracker volume implies work still to be done… 17/22

SOURCES OF UNCERTAINTY o Kalman track fit (currently) assumes a 4T uniform field o With E1-C-E2 coils powered at full current, and others at 0, field is not flat across tracker o PRY enhances field strength o MC studies in progress to assess fully o Can estimate effect from pattern recognition o Not a perfect estimate, as field variation will also affect circle radii… Field calculated assuming warm coil dimensions and no PRY 18/22

SOURCES OF UNCERTAINTY Plane 5 (Sample A) Plane 5 (Sample A) 19/22

Plane 5 (Sample A) SOURCES OF UNCERTAINTY Plane 1Plane 5 Plane 1 (Sample B) NB: Emittance here is calculated using pattern recognition estimates, not Kalman track fit estimates as on previous slide Currently assume this Field calculated assuming warm coil dimensions and no PRY 20/22

SOURCES OF UNCERTAINTY o The degree to which the following affect the emittance measurement are under investigation: o Field non-uniformity – Kalman track fit can account for this o Field scale (i.e. PRY enhancement) o Improved coil geometry from field map data o Pions and electrons mis-identified as muons o Independent measurement of emittance using Step I method (TOF0  TOF1) can be used to cross-check measurement at tracker, by evolving ellipse back through SSU field to TOF1. 21/22

SUMMARY Run 7469, phase space distribution at TKU plane 1 22/22