DC2 IRF Status • Meeting agenda, references at: http://confluence.slac.stanford.edu/display/DC2/060203 • Deadlines • Feb 10: finish parameterization definitions (functional forms, bins) • Feb 13: finish implementation • Feb 17: Verification • Feb 20: Final report • Event Classes - finalized to be A and B as proposed by Julie • DC2Cuts.C now in DataChallenge package, under cvs control. • Effective area - Jean • Dispersion – Riccardo • PSF – Toby (new stuff)
The calibration data – updated with new low energy • Photon response from “allgamma” • Version v7r3p4, with reprocess to update CTB variables • (4000-2)*50 K generated events into 6 m2: • uniformly in log(E) from 18 MeV to 180 GeV (4 decades) • uniform in cos() from -1 to 0 (upper LAT hemisphere) • (2000-1)*5 K generated 1.25 <log(E) < 3.75. (1.5 decades) • Factor of 40/3 more for E<562 MeV • Background • Version v7r3p5, also CTB updated, and filtered with CTBGAM>0 • 18675 seconds of live time, distributed uniformly over 3 days of the DC2 orbit new
PSF - Jean class A class B front back
Dispersion, cont • Parameterization of energy and angle in progress – needs more data at low energy, has not use the new run • Class B – big problem!
Class B: what to do with it • Substantial low energy tail in dispersion • These events will not be fit properly! • Is it worth it? I think not! But if we include them, we have to treat the analysis properly: the effective area for analyses that depend on the energy must be reduced ? good energy
PSF (Toby) • Revise scaling function so that 68% containment is ~1 for class A.
PSF, cont class A back • Since the fit is restricted to ~10 68% radii, there is a potential normalization issue, if the predicted tail is different from the measured one. • The largest class A deviation is at right • class A front fits are all within 0.1% overestimate: 0.5% underestimate: 1.6%
Addendum: new class B Riccardo suggested to modify the class B definition by requiring CTBGoodEnergyProb>0.3 for all events. Here are the resulting acceptances. The blue points are those for which the measured energy is >60% of the actual.