UPDATE Matt King 12/05/2015 Recent work 2 Have been working with - PowerPoint PPT Presentation

1 MOEDAL SIMULATION UPDATE Matt King 12/05/2015

Recent work 2  Have been working with Rafal on geometry:  Fixing implementation of various pipes  Making full NTD array sensitive with per-sheet numbering  Continuing tests of high dE/dx functions at low beta  New exponential function 12/05/2015 Matthew King, IFIC

Low beta exp function 3  Mentioned in previous meetings how discrete shifts cause problems due to Geant4’s spline interpolation  => Add an exponentially decaying function to original dE/dx function  Easy to control curve properties using [0]=1 parameters [1]=0.1  Have set up to define [0,1] using a beta cut value  Peak at x=cut/2  Peak value y=10*y(cut)  Actual dE/dx peak will be slightly different due to addition to original (linear) dE/dx function 12/05/2015 Matthew King, IFIC

dE/dx functions (log(KE)) 4  The resulting dE /dx function for the normal curve, along with the “flat” and “ exp ” modifications are shown in Air and Aluminium (log(KE)) flat(0.01) exp(0.01) normal KE KE KE 12/05/2015 Matthew King, IFIC

dE/dx functions (beta) 5  Same functions, against linear beta flat(0.01) exp(0.01) normal beta beta beta 12/05/2015 Matthew King, IFIC

Effect on MMT acceptance 6  Slight shift towards higher kinetic energy normal exp(0.01) 12/05/2015 Matthew King, IFIC

Effect on MMT acceptance 7  Shift is not concentrated in any particular MMT area 12/05/2015 Matthew King, IFIC

Effect on stopping position 8  “Ripples” in stopping position seems to be prevented by the exp function  Somewhat lower stopping in back end of MMTs  As expected, monopoles travel a little less far  More distribution in Velo likely due to “drift” in low magnetic field  Turned beta-cut down to ~10e5, effect drift effects to come back in 12/05/2015 Matthew King, IFIC

Summary 9  Even a more extreme “bump” in the dE/dx distribution does not seem to massively effect MMT acceptance  Low beta approximation seems to be validated to within a minor uncertainty  No further plans to test other functions, move on to getting more ready for production 12/05/2015 Matthew King, IFIC