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

MOEDAL SIMULATION UPDATE

Matt King

12/05/2015

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Recent work

 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

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Low beta exp function

 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 parameters

 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

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[0]=1 [1]=0.1

dE/dx functions (log(KE))

 The resulting dE/dx function for the normal curve, along with the “flat”

and “exp” modifications are shown in Air and Aluminium (log(KE))

12/05/2015 Matthew King, IFIC

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normal flat(0.01) exp(0.01) KE KE KE

dE/dx functions (beta)

 Same functions, against linear beta 12/05/2015 Matthew King, IFIC

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normal flat(0.01) exp(0.01) beta beta beta

Effect on MMT acceptance

 Slight shift towards higher kinetic energy 12/05/2015 Matthew King, IFIC

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normal exp(0.01)

Effect on MMT acceptance

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

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Effect on stopping position

 “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

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Summary

 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

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