DC2 Orbit and Background

1
DC2 Orbit and Background

• Toby Burnett
• University of Washington

• Orbit 55 days
• Pointing strategy scan rock!
• Background
• Model
• generation
• Interleave with signal
• Trigger
• Hardware
• Onboard filter
• Deadtime
• SAA
• Simulated trigger rate

2
The big picture
3
The Orbit

• Time references (UT)
• Mission start 0000 1-1-2001
• This simulation 0000 1-1-2008
• JD 2454466.5 MJD 54466
• MET 220838400
• Stoneking simulator
• launch from lat,lon(0,0) at -900 s.
• Altitude 561 km. (6939 km radius)
• Inclination 28.48? (Cape Canaveral latitude)
  (next DC maybe 25.3??)
• Recorded from t0 to t56 days in 30 s
  increments. 161250 entries

t0
theCape
launch
4
Why 55 days? Precession

• For the inclination, 55.2 period.
• Note initial azimuth is 0, an accident.

5
DC2 Backgrounds

• S. Ritz (at the IA workshop)
• Backgrounds are unbelievably unknown
• DC2 background model is about right

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Generate an event
current time
source model pseudo-background
generateposition, orientation
pointing history
select incomingparticle
yes
in SAA?
Earth location
no
signal
signal?
background
simulate
select eventreplace position info
Backgroundtuples
no
trigger?
yes
no
alive?
yes
generate output
output tuple
reconstruct