2009.10.12 Jason EEMC geometry: effects of adding layers

Effect of added layers in Jason geometry file (ecalgeo.g23)

Monte-Carlo setup:

  • One photon per event
  • EEMC only geometry with LOW_EM option
  • Throw particles flat in eta (1.08, 2.0), phi (0, 2pi), and pt (6-10 GeV)
  • Using A2Emaker to get reconstructed Tower/SMD energy
    (no EEMC SlowSimulator in chain)
  • Vertex z=0
  • ~50K/per particle type
  • Non-zero energy: 3 sigma above pedestal

Cuts for shower shapes:
Single particle kinematic cuts: pt=7-8GeV, eta=1.2-1.4
All shapes are normalized to 1 at peak (central strip)

Added layer definition from Jason file:

  • EXPS is the plastic spacer in the shower maximum section
  • EBLS is the layer of material on the back of the SMD planes
  • EFLS is the layer of material on the front of the SMD planes

Some comments:

  1. Figs. 1-2 show that I can reproduce
    sampling fraction and shower shapes
    which I see with geometry file from CVS
    if I disable all three added layers in Jason geometry file
    (this assumes/shows that G10 layer have tiny effect).
    This a good starting point, since it indicate that
    all other (cosmetic) code modifications
    are most probably done correctly and has no
    effect on simulated detector response.
  2. Fig. 3 shows effect of each added layer
    (plastic spacers and layers in front/back of SMD)
    on the sampling fraction and 2x1/3x3 energy profile:

    • Each layer contributes more or less equally to the sampling fraction.
    • Energy profile (E2x1 / E3x3) does not affected by the added layers
  3. Fig. 4 shows effect of each added layer on the shower shapes:
    • Back SMD layer does not contribute much (as expected).
    • Front and spacers introduce equal amount of "shape narrowing".
  4. Figs. 5-6 show pre-shower sorted shower shapes
    and comparison with eta-meson shapes.

No layers and G10 removed

Figure 1: Sampling fraction vs. thrown energy

Figure 2: Shower shapes

Adding new laters (spacer, front, back)

Figure 3: Sampling fraction vs. thrown energy (left), 2x1/3x3 energy ratio (right)
See legend for details

Figure 4: Shower shapes. See legend for details

Shower shapes sorted by pre-shower energy

Pre-shower bins:

  1. Ep1 = 0, Ep2 = 0 (no energy in both EEMC pre-shower layers)
  2. Ep1 = 0, Ep2 > 0
  3. 0 < Ep1 < 4 MeV
  4. 4 < Ep1 < 10 MeV
  5. Ep1 > 10 MeV
  6. All pre-shower bins combined

Ep1/Ep2 is the energy deposited in the 1st/2nd EEMC pre-shower layer.
For a single particle MC it is a sum over
all pre-shower tiles in the EEMC with energy of 3 sigma above pedestal.
For eta-meson from pp2006 data the sum is over 3x3 tower patch

Figure 5: Shower shapes (left) and their ratio (right)

Figure 6: Shower shape ratios