Transcript ppt
Gamma-ray Large Area Space Telescope Understanding SVAC CalMip Variables Monica Pepe Stefano Germani INFN Perugia Instrument Analysis Meeting December 16, 2005 SVAC Instrument Analysis Meeting, December 16, 2005 Outlook • Aim of the work: – First look to the new CalMip variables in the SVAC ntuple • Consistency check (Monica) • Direction and Correlation with tracks (Stefano) • Data: – Surface Muons 1M Montecarlo • SVAC Ntuple /nfs/farm/g/glast/u11/InstrumentAnalysis/MC/EngineeringModelv5r0703p3/LAT_Surface_Muons/surface_muons_1M_svac.root Stefano Germani & Monica Pepe 2 SVAC Instrument Analysis Meeting, December 16, 2005 CalMipNum All Events TkrNumTracks=1 Events CalMipNum CalMipNum CalMipNum Event Fraction 0 42.9 % 1 52.4 % 2 4.6 % 3 0.03 % 4 8E-6 Stefano Germani & Monica Pepe Why zero Mips? Why more than one Mip? 3 SVAC Instrument Analysis Meeting, December 16, 2005 Why 1 Track and 0 Mip (I) ? 1 Track and 0 Mip Tkr1NumHits 1 Track and 1 Mip Tkr1NumHits The Track may not reach the CAL as seen in next slides Stefano Germani & Monica Pepe 4 SVAC Instrument Analysis Meeting, December 16, 2005 Why 1 Track and 0 Mip (II) ? Tkr1EndPos 0 Mip Tkr1EndPos Tkr1EndPos 1 Mip No Mip found if track ends on LAT edge Stefano Germani & Monica Pepe 5 SVAC Instrument Analysis Meeting, December 16, 2005 Why 1 Track and 0 Mip (III) ? Tkr1 Extrapolation to Cal: 0 Mip Tkr1 Extrapolation to Cal: 1 Mip Tkr1 Extrapolation at CAL entry No Mip found if track extrapolation do not enter in CAL Stefano Germani & Monica Pepe 6 SVAC Instrument Analysis Meeting, December 16, 2005 Why 1 Track and >1 Mip ? The two Mip segments belong to the same TRUE Mip (separated along Z: if Mip1 is at High Z Mip2 is at Low Z) CalMip2Pos(X) vs CalMip1Pos(X) mm CalMip2Pos(Z) vs CalMip1Pos(Z) mm mm CalMip2Pos(Y) vs CalMip1Pos(Y) mm mm mm Stefano Germani & Monica Pepe Mip Finder algorithm can find several Mip Track segments due to CAL segmentation and position resolution (Thanks Fred!) 7 SVAC Instrument Analysis Meeting, December 16, 2005 MIP Energy CalMip1Ecor CalMip1Ecor is the mean vertical-equivalent energy averaging path length corrected energy on layer basis CalMip1Erm is the total energy in a cylinder of 1 Moliere radius (35 mm in CsI) MeV CalMip1Erm vs Mip Track Length MeV CalMip1Erm MeV Stefano Germani & Monica Pepe 8 mm SVAC Instrument Analysis Meeting, December 16, 2005 Conclusions • CalMip Ntuple – variables seems to be correctly filled • Mip Finder – behaves as expected when the muon track reaches the CAL – Multiple Mips associated to the same track are actually segments of the same MIP • Would it be necessary to improve the algorithm in order to take into account these topologies? Stefano Germani & Monica Pepe 9