1. Angular resolution: Critical for source morphology
Typical TeV
beam size
Chandra
SN 1006
Angular resolution: Critical for source morphology
J. Hiraga ASCA/Chandra
RXJ 1713

2. Angular resolution limit
perp. to B
E-1/2

3. Angular resolution how many photons are needed?
limited by
photon stat.
100 GeV
limited by
shower fluct.
1 TeV
Relative to
PMT efficiency

4. Resolution required for photon parameters
adding NSB:
modest effect
Photon direction Photon position
1 TeV
1 TeV
10 m
dish
20 m
dish
H.E.S.S.

5. Background rejection: Protons Scatter of (true) emission points
1 TeV g
2 TeV p
sx [m] sy
[m] sy
[m]
sx [m]
100 GeV g
200 GeV p
Rejection: ~ 10-2
Rejection: few 10-4
similar rejection obtained from fit (but low statistics)

6. Electron background Try to track primary electron: Simulations: 1 TeV
count all photons approaching
reconstructed shower axis
within 10 m above h=17 km
Simulations:
1 TeV
ephoton = 1%
with NSB g e
e ~ 30%
preliminary