FF 2014-11-26¶

Meeting on Wednesday 26th November, at RAL. We will be in room R66 G.06 (the room used for the hall meeting).

Time	Title	Presenter	File
10:00	Step IV Data Taking and Papers	Chris Rogers	Preparing_for_Step_IV_Data.pdf
10:20	Track Reconstruction Resolution at Step IV	David Adey	Adey_Tracker_AnalysisWorkshop_141126.pdf
10:40	Track Reconstruction Resolution at Step IV	Melissa Uchida	Tracker_Alignment_analysis_26_11_14.pdf
11:00	Particle ID at Step IV	Celeste Pidcott	PIDatStepIV.pdf
11:20	Measurement of Magnetic Alignment	Chris Rogers	Measuring_Magnet_Alignment.pdf
11:40	Discussion	All
13:00	Lunch	All
13:30	Hall Meeting (for those that are interested)	All
14:30	Field Mapping Status	Victoria Blackmore	slides (pdf, NB gifs won't animate)
14:50	Quality of Transported Beam	Chris Hunt	beam_transport_quality.pdf
15:10	Online Analysis tools	Chris Rogers	online_analysis_tool.pdf
15:30	Offline Analysis tool	Chris Hunt	offline_analysis_tool.pdf
15:50	Batch processing and physics block challenge	Ryan Bayes	Simulations.pdf
16:10	Discussion	All

The atmosphere is intended to be ad-hoc - so don't consider this such a rigid structure.

Phone Details¶

Where possible we will use the regular MICE phone bridge (which has free phone numbers).

Between 15:00 and 16:00 the MAUS crew will take over. We can divert to this number

We can use this number if there are any other interruptions/conflicts.

Briefing¶

• Step IV Data Taking, Proposed Papers - Chris Rogers
  • Best plot prize?
• Track reconstruction at Step IV David Adey, Melissa Uchida
  • What will be the resolution in x,y,px,py,pz?
  • What measurements are required to demonstrate this resolution? Do we talk about e.g. matching between upstream and downstream tracker here?
  • job list...
• Particle ID at Step IV Celeste Pidcott
  • What will be the efficiency and purity of beam PID?
  • How do we demonstrate this efficiency/purity? Fight upstream and downstream? Select at D2 for measurement?
  • job list...
• Measurement of Magnetic Alignment Chris Rogers
  • Field mapping status and "dead reckoning" procedure Victoria Blackmore
  • How do we measure the magnetic alignment? What magnet settings? Any issues e.g. hysteresis, long term stability, current dependent alignment? Chris Rogers, Chris Hunt
  • job list...
• Quality of transported beam Chris Hunt
  • Beam selection procedure Chris Rogers
  • What beam parameters do we want to measure?
  • Resolutions on measured parameters?
  • job list...
• Support
  • Online analysis tool Chris Rogers
  • Offline analysis tool Chris Hunt
  • Batch processing status Ryan Bayes
  • Beamline settings Jaroslaw Pasternak

If time:

• Skeleton outline of "First observation of normalised emittance reduction" paper Chris Rogers

Remember aim is to get a list of measurements/plots and a "job list"; first pass on the data required to support this paper.

Notes¶

It was a very useful and provocative meeting. Rogers notes:

Summary of Actions¶

These are general actions, they are general and hence mostly on Rogers... specific actions are contained in the subheadings as "Job List" (and I think folks mostly know what they are doing).

• ACTION (Pasternak/Rogers): determine magnetic settings routine - do we imagine "equivalent coil"? Implement iron in MAUS? Run everything through OPERA?
• ACTION (Pasternak/Rogers): determine standard magnetic settings for commissioning e.g. magnet currents for 420 mm beta in solenoid mode
• ACTION (Pasternak/Rogers): determine standard beamline settings
• ACTION (Dobbs/Rogers): specify MAUS implementation of "estimate of the error on the field as a function of position" in detail and implement
• ACTION (Someone): would like to know how well the bobbin on which the coils are wound is aligned to the SS bores
• ACTION (Rogers): arrange a "magnet bolting down meeting" to determine how Physics group does the handover of the magnet axes and how the installation will work
• ACTION (Rogers): Need to consider how we staff the "accelerator physics" during running
• ACTION (Rogers): Xboa specification document
• ACTION (Rogers): Bring in Dobbs MAUS analysis framework to xboa?
• ACTION (Rogers/delegate): need an accelerator physics helper for the analysis of existing batch simulations

General Comments¶

• We need full current settings, including effect of iron. We need some mechanism (responsible person) to generate such field maps on a case-by-case basis; presumably need access to Opera
  • ACTION (Rogers/Pasternak): determine magnetic settings routine - do we imagine "equivalent coil"? Implement iron in MAUS? Run everything through OPERA?
  • ACTION (Rogers/Pasternak): determine standard magnetic settings for commissioning e.g. magnet currents for 420 mm beta in solenoid mode
• We need an estimate of the error on the field as a function of position. Feature request that this should be available from the field API (presumably MAUS)
  • ACTION (Dobbs/Rogers): specify this in detail and implement

Step IV Data Taking and Papers - Chris Rogers¶

Consider adding subsections:

• Confirmation of input beams, discuss diffuser design and beam matching through the diffuser
• Energy loss in windows (probably as subsection of "quality of transported beams")

Tracker - David Adey¶

• Look at hit efficiency, reconstruction efficiency; this can be done more or less internally to the tracker
  • Note that detector + reconstruction efficiency needs to be added to the "track reconstruction at Step IV" as a measurement; mainly a concern downstream, but we should report upstream also.
• Look at position residual by comparing track position with view hit
• No algorithm to understand momentum residual
  • Suggested compare upstream and downstream trackers (relies on good understanding of the fields)
• No beam settings or requirements proposed
  • Suggest high emittance beam to check large r fibres, use LED where stats are low
  • Low pz spread can be advantageous; select in TOF
• Job list
  • Fix Kalman fit
  • Look at dependency on Bz, presumably using "standard" alignment tolerances 1 mm 1 mrad on the bobbin (all coils)
  • If required, add non-axial Bz to reconstruction routines (requires new calculation of propagator matrix, may be significant refit

Global - Melissa Uchida¶

• Discussion on how we align trackers
• Trackers installed by;
  • Taking a vector which is normal to the plane made by the survey pillars
  • Aligning this vector to the centre of the magnet bore opening (beam pipe)
  • Projecting the vector down the beam pipe to the tracker
  • ACTION: would like to know how well the bobbin on which the coils are wound is aligned to the bore
• Propose job list:
  • Back of envelope calculations
  • Massive MC job - some discussion as to how "massive" this should be
  • Data analysis
  • Magnetic scan to determine magnetic axis
    • Ill-defined for me (Rogers) what this means
• Missing:
  • Alignment of TOFs
  • Alignment to KL/EMR
  • (Alignment to Ckov)

PID - Celeste Pidcott¶

• Propose varying D1 to obtain beams with different admixtures of pions, muons and clearly separated pion peaks
  • Use D2 to select the appropriate momentum band
  • Use the mixed pion/muon log likelihood and tracker vs TOF PID variable
  • Figure out e.g. how many pions are misidentified as muons
• Propose using upstream vs downstream
  • Check PID upstream == PID downstream
  • Where particles have decayed, check that number of decays matches the particle lifetime

Field Mapping - Victoria Blackmore¶

• Have a calculation of the field map in FC1 ( 0.0022 radian tilt in x, etc); some cross-checks still needed
• Now FC2, SSU, SSD should be easy, right?
• ACTION (Rogers): arrange a "magnet bolting down meeting" to determine how Physics group does the handover of the magnet axes and how the installation will work

Measuring Magnet Alignment¶

• Use beam based alignment technique
• To get measurable displacements, need to change magnet currents by 10% or more
• Settings
  • Mainly go with low emittance setting and watch beam centroid move
  • High emittance setting for transfer matrix changes - but looks hard
  • Scan around "nominal setting" which corresponds to some baseline optics
  • Scan around "optimal setting" designed to give biggest kick per coil
  • Check for non-linearity in the coils
  • Hysteresis check - flip polarity?
  • Check for reproducibility; daily reference settings
• Job list
  • Figure out analytical behaviour
  • Figure out analysis routine, compare with "laptop study"
  • Run batch MC with "standard" misalignment set
  • Consider modelling non-linearities etc

Quality of Transported Beam¶

• Chris Hunt had lots of things on his slides
• Need to descope - focus on
  1. Kalman fit
  2. Measuring beam optics functions and emittances (with errors); and transmission
• Beam optics measurements will be with empty lH2 absorbers
• Job list
  • Determine errorss on measured parameters
  • Look at source of errors
  • MC of "standard" setting

Online Analysis Tool - Chris Rogers¶

• Specification for online analysis tool
  • In addition to slides; we DO want beam selection routines; we DO want non-axial stuff; we DO NOT want undecays
• Wish to support Rogers and Blackmore routines
  • If one doesn't work out, we fall back to the other
  • Request Rogers routines to have the "sliders" approach - fast turnaround etc
  • Request Rogers routines to fix the geometry
• No decision as to primary routine
• ACTION (Rogers): Need to consider how we staff the "accelerator physics"
  • Do we want an on-call system... or something

Offline Analysis Tool - Chris Hunt¶

• Agreed that we continue to use xboa
• Agreed that it should continue to be a 3rd party library in MAUS
• Request that the C++ part should be enhanced
• ACTION (Rogers): Specification document; think about resource requirements, do we do an event loop or hold everything in memory, etc
• ACTION (Rogers): Bring in Dobbs framework
• ACTION (Rogers/Dobbs): Run analysis validation as part of the batch reco (and MC?)

Simulation - Ryan Bayes¶

• Ryan outlined the simulation status
• ACTION (Rogers/delegate): need an accelerator physics helper for the analysis of existing simulations
• Ryan requested priorities
  1. Commissioning/alignment (as per this meeting)
  2. First observation of normalised emittance reduction using MICE
  3. Everything else (priorities TBD)