Contents of this memo

1
Contents of this memo
In the original report (vrvs_2003-09-01.ppt),
straight-track-charged-events are reproduced well
whereas bent track events and neutral ones showed
some discrepancy, indicating that 2ndary models
need to be modified. Referring to papers of
Balloon measurements, new proton/e-/e/muon/gamma
2ndary models are constructed and proposed here.
Updated TKR hit distributions and the number of
tracks distributions are also presented.
pp. 2-6 New models pp. 7-10 Updated TKR hit
distribution pp. 11-12 Updated the number of
reconstructed tracks distribution
2
New model(1) muon
new models
original model(mu-)
Reference Boezio et al. 2000, Phys. Rev. D 62,
032007-
3
New model (2) proton
original model

• new models
• downward
• upward keep the original model

Dont care about vertical line at 4GeV! (This is
due to a bug in root.)

• Reference
• Alcaratz et al. 2000, Phys. Let. B 472, 215
• Abe et al. 2003, Phys. Let. B. 564, 8
• Verma 1967, JGR 72, 915
• Pennypacker et al. 1973, JGR 78, 1515

4
New model (3) gamma 2ndary
Angular distribution (left) and energy spectrum
(right). Original model is shown in black line
and the new in red.
Due to bug in root. Please ignore
5
New model (4) e-/e
new model
Please ignore this
original model

• Reference
• Alcaratz et al. 2000, Phys. Letters B 484, 10
• Barwick et al. 1998, JGR 103, 4817
• Verma 1967, JGR 72, 915
• Israel 1969, JGR 74, 4701

6
And more

• Take an attenuation by air into account. Assuming
  density of air above detector to be 4g/cm2 and
  Nuclear collision length 60g/cm2, use the
  attenuation factor (for proton and alpha primary)
  as below.
• Exp(-1./15cos(tehta)) for cos(theta)gt0.2
• Exp(-1./150.2) for cos(theta)0.2
• Reduce primary proton flux by 10

7
TKR hit distribution (1)
Hit rate of each layer for charged events.
new model
original model
data
muon
gamma
e-/e
alpha
proton
8
TKR hit distribution (2)
Hit rate of each layer for neutral events.
new model
original model
gamma upward
gamma downward
9
TKR hit distribution (3)
Hit rate of each layer for charged events, where
the primary track (the track the reconstruction
program gives back first) is straight.
new model
original model
10
TKR hit distribution (4)
Hit rate of each layer for charged events, where
the primary track (the track the reconstruction
program gives back first) is bent.
new model
original model
11
of reconstructed tracks (1)
original model
new model
Charged events
original model
new model
Neutral events
12
of reconstructed tracks (2)
original model
new model
Charged events The first tracks is straight
new model
original model
Charged events The first track is bent