Trigger Meeting

RAL CR10, 23rd January 2015

Alan Bross
Ed Overton
Durga Rajaram
Victoria Blackmore
Chris Rogers
David Adey

Victoria Blackmore, data rate analysis

Victoria presented the data rate analysis which she performed

  • Study done using old settings, from G4MICE day
  • Sought to answer how long would we need to run for to get 100k muons at TRP?
  • Use MR analysis, amalgamation of data sets, look at number of muons at TOF1 and Mark Rayner reconstructed tracks
  • 800k total TOF1 triggers
    • 40 triggers per spill on average
    • PID -> 564000 muons based on TOF1 timing cut 26.5 - 40 ns; all same beamline settings, "200 MeV/c", table 8.3 in Rayner thesis
    • On average 1 V ms from spreadsheet, 50/128 Hz, guess limit was 2 V ms, we are at 4 MV ms at 50/64
      • Expect we get a factor 2 more per dip, factor 2 more for double dip
      • Take a Gaussian selection in pz of 10,0000 muons, mean 200 MeV/c, rms 10 MeV/c = 27% of beam; rms 20 MeV/c = 51 % of beam
      • Made Iris 1.4 radiation lengths; tracked the 10,000 muons through TRP, took a 4*6 mm amplitude matched ellipse, gives 9209 -> 4258 muons

ACTION (Rogers/physics group): Set the desired number of good muons/what are the aims/scope?
ACTION (Pasternak/beamline integration): Generate optimised beamlines
ACTION (Rogers/physics group): Redo analysis with optimised beamline
ACTION (Rogers/physics group): Redo analysis with softer transverse cut
ACTION (Rogers/physics group): Check momentum spread/momentum cut effects (what happens to the beam if we make a bigger momentum spread)
ACTION (Rogers/physics group): Look at TOF2 trigger effect on analysis
ACTION (Rogers/phyics group): Determine effect of increased dip depth in ISIS

ACTION (Bross/tracker): Investigate dropping tracker ADC information
ACTION (Karadzhov/DAQ): What are implications for hardware/running of TOF2 trigger

  • Ed Overton suggested after the meeting (with some Rogers hacking):
    • We take forward going muons;
    • We make a TOF0-1 trigger to reject pions;
    • We collimate on muons at the centre of D2;
  • Overall effect is (maybe) to have a pencil muon beam, with smaller momentum spread; muon rate from pion beam may be better than muon rate from muon beam, so we still have a reasonable rate after collimation
    ACTION (Rogers/physics group): Look at that as well
Date of Next Meeting
  • Guess February 12th