Pion Contamination Paper Phonecall, Wednesday 21st May, 10am BST¶

Discussion of pion contamination papers status and its requirements for publication.

Present: M. Bogomilov, P. Soler, K. Long, J. Nugent, D. Orestano, V. Blackmore

Actions¶

• V. Blackmore: Track paper's progress via the wiki's issue tracker
• K. Long: Locate engineering drawing showing the 'compound bend' (tilts) of D1/D2
• J. Nugent: Investigate source of small/narrow positron peaks in MC compared to data (statistics or missing physics process?)
• J. Nugent: Investigate effect of increased smearing on MC and the width of it's MIP peak
• J. Nugent/M. Bogomilov: Implement threshold cut that removes the peak at 0 on MC plot (slide 7)
• D. Rajaram: Comment on TOF calibration; geometry dependence, trigger offsets and calibration pixels
• J. Nugent: Investigate suppression of muon decays below a certain energy threshold in Geant/MAUS
• D. Orestano: Presentation of plots for paper at June CM
• V. Blackmore: Consult Orestano/Soler and Ed. Board re: suitable referees and provide a list to K. Long (after June CM, when MICE note is being drafted)

Minutes¶

• Status of the analysis:
  • Slides uploaded by J. Nugent, some of which was presented at the last analysis meeting
  • G4Beamline deck used to make MC is the 'official' version, and was validated with Step I data (see presentation at last CM). Simulates from the target to the upstream face of TOF0, then hands over to MAUS. Simulation in MAUS uses the KL digitiser provided by M. Bogomilov.
  • Analysis uses "(6, 200)" muon beam plus two pion calibration beams.
  • Some offset in time-of-flight between TOF0 and TOF1 is seen, could come from various sources (calibration, geometry and survey information, momentum distribution differences)
  • G4BL does include the different elevation of the beam line upstream of the DS, but does not include the compound bend. Upstream of D2, parameters are not (and there are no plans to yet) included in the configuration database, however, drawings do exist. Survey values used are those in MICE Note 216.
  • Time-of-flight offset is normalised to the positron peak, essentially rescaling by a constant factor giving the plots on slide 5. Small number of entries in those plots is a concern, may be statistics, but may be something else in the simulation.
  • Slide 7 is the end result: (left) data, (right) MC. Red and blue lines are calibration beams, where red corresponds to the muon template and blue the pion template. The pion template has a longer tail. Green represents the muon beams, to which we want to fit the templates. The right plot is MC that has been reconstructed and digitised.
  • Smearing in the MC needs to be tweaked, see how it effects the MIP peak (which is wider in data than MC)
  • Some discriminator effect causing peak at around 0 in MC plot -- investigate threshold cut in KL digitiser.
  • Geometry needs careful consideration, a few cm can make a large difference
  • Beam composition needs checking (i.e. relative amounts of muons and pions)
  • Requires understanding the level at which the simulation cuts on energy deposited in the KL (has a large effect on tails of distribution)
  • Need to talk to D. Rajaram about TOF calibration
  • Need to investigate suppression of muon decays below a certain energy value in MAUS (C. Rogers comments that there is a control variable for this)
  • Could use TOF2 (if a calibration for it exists for the runs used) to gain further insight on time-of-flight differences

• Timescale:
  • Time is required to converge on changes to KL digitisation
  • At June CM, present plots that have the content desired for the paper.
  • Write detailed MICE note, which is refereed.
  • Present draft paper at October CM