DC2 IRF Status

1
DC2 IRF Status

• Meeting agenda, references at http//confluence.s
  lac.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)

2
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 ltlog(E) lt 3.75. (1.5
  decades)
• Factor of 40/3 more for Elt562 MeV
• Background
• Version v7r3p5, also CTB updated, and filtered
  with CTBGAMgt0
• 18675 seconds of live time, distributed uniformly
  over 3 days of the DC2 orbit

new
3
PSF - Jean
class A
class B
front
back
4
Dispersion - Riccardo
5
Dispersion better function
6
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!

7
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
8
PSF (Toby)

• Revise scaling function so that 68 containment
  is 1 for class A.

9
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
10
Addendum new class B
Riccardo suggested to modify the class B
definition by requiring CTBGoodEnergyProbgt0.3 for
all events. Here are the resulting
acceptances. The blue points are those for which
the measured energy is gt60 of the actual.