Shielding hut for GEM electronics

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The main purpose of this study to determine the neutron-induced damage on electronics at the shielding hut for GEp.

Main drawings for the shielding hut are,

  • 12GEp_Elevation [1]
  • 12GEp_Iso [2]
  • 12GEp_Plan [3]

Few extra details from Alan Gavalya,

  • The green boxes are cast steel 52" x 52" x 26".
  • The distance between two green boxes are 96".
  • There are two steel plates between two green boxes (bottom-2.5" thick & front-7.5" thick). The bottom plate allows for the front plates to match the height of the green blocks for stacking the top plates.
  • And there is a steel plate (120" x 5" x 43") on the top (blue).

The drawings for the magnet support frame (by Alan) -[4]

The supporting frame and the shielding hut were added to the g4sbs/src/ - [5], See under MakeHCAL.

And this is how the shielding hut and supporting frame appear on the g4sbs - [6]. See page 3 & 4. Shielding hut.png

  • First, we wanted to compare the gamma yields with Pavel Degtiarenko's to cross-check the overall normalization.
    • These are the latest plots from Pavel's [7]. These simulations include exact GEp target configuration (40 cm Liquid H2 + Al walls).
    • And this is what we got by running our simulations [8]. Each slide shows the results from g4sbs (on top - when the hall is filled with Air (left) and Vacuum (right) and on the bottom - results from Pavel's when the hall is in vacuum.)

  • Next thing on the list is to calculate the energy deposited/dose/dose rate inside the shielding hut.
    • To do that, we defined a volume inside the hut and made it a sensitive detector.
    • And filled it with air (and water), and calculate the dose based on energy deposited on that volume.
<math>\text{Dose } (rad) = \sum \frac{\text{edep }(MeV)}{\text{Volume }(cm^2) \times \text{Density } (gcm^{-3}) \times 6.24\times 10^7 } </math>

where 6.24x10^7 is the conversion factor of MeV/g to rad.

  • Finally, we want to calculate the neutron-induced damage inside the shielding hut.
    • The effective damage to silicon detectors relative to 1 MeV neutron can be found at [9]. See figure 1.