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Energy loss true compared to measured

Energy loss in LH2. Red is MC, Black is reconstructed

Energy residuals upstream (black) and downstream (red)

Comparison of reconstructed momentum vs MC truth momentum. Black is upstream, Red is downstream

Present

Rhys Gardener
Celeste Pidcott
Chris Rogers
John Nugent
Rhys Gardener

Rhys Gardener

  • Trying to measure energy loss in the muon beam as they pass through the absorber
    • How much energy absorbed
    • Use trackers to make momentum measurement before and after the absorber
    • Subtract the two to get an energy loss measurement
    • Errors arise from:
      • Momentum resolution of the trackers
      • Systematic from energy loss in materials
        • Effects from materials not significant compared to momentum resolution; 2 MeV from material; take out the systematic by doing an absorber empty run
      • Knowledge of density of material; liquid Hydrogen density, Lithium Hydride density
  • Since collaboration meeting
    • Continuing toy analysis doing before the collaboration meeting; taking into account suggestions like off axis beam
    • Particles that lose more energy are reconstructed better; no correlation between transverse momentum and longitudinal momentum reconstruction
    • Start with momentum off centre, 1 % px
    • Normal emittances in x and y
    • Comparing momentum reconstructed in upstream and downstream tracker
  • Energy residuals upstream (black) and downstream (red)
    • Rhys to check why plots are not centred on 0

Celeste Pidcott

  • Looking at various sources of error; tracker misalignment, hoping for massive monte carlo from tracker group; simulated effect of Helium windows; appears to make a measurable effect; tracking through the fields is not quite working out, large momentum residuals tracking backwards from d/s TRP
    • Use Virtual plane to extract particle position at absorber
    • Used SciFi MonteCarlo hits at the scifi; Rogers suggests using Virtual planes

John Nugent

  • Nothing changed since Wednesday; attempting to merge toy remnant field model with CDB geometry, now tracking and looking at the beam distribution
    • Remnant field model done using toy solenoids with small currents to match Holger field map
  • Chasing up misalignment; got that installed and working at Glasgow

PlossvsMC.png - Energy loss in LH2. Red is MC, Black is reconstructed (8.55 KB) Gardener, Rhys, 24 July 2015 16:21

MC_Recon_Diff_both.png - Comparison of reconstructed momentum vs MC truth momentum. Black is upstream, Red is downstream (8.93 KB) Gardener, Rhys, 24 July 2015 16:21