Changes between Version 10 and Version 11 of GuarDyan_PhysModel


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Timestamp:
Feb 13, 2018, 3:49:31 PM (6 years ago)
Author:
dieda
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  • GuarDyan_PhysModel

    v10 v11  
    77Free path sampling follows the Woodcock (delta-tracking) scheme with energy dependent majorant sampling cross section. The selection of isotope and interaction type happens in the analog way except for choosing between scattering and fission events.
    88
    9 We consider reactions with the following MT numbers: 2, 5, 11, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 28, 29, 30, 32, 33, 34, 35, 36, 37, 38, 41, 44, 45, 51-90, 101. After choosing the reaction, the determination of the new energy and angle of the neutron depends on the given ACE law (ACE Laws 3, 4, 7, 9, 11, 44, 61 or 66 ). S($\alpha$, $\beta$) treatment and handling unresolved resonances are not yet included in the physics modeling.
     9We consider reactions with the following MT numbers: 2, 5, 11, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 28, 29, 30, 32, 33, 34, 35, 36, 37, 38, 41, 44, 45, 51-90, 101. After choosing the reaction, the determination of the new energy and angle of the neutron depends on the given ACE law (ACE Laws 3, 4, 7, 9, 11, 44, 61 or 66 ). S($\alpha$, $\beta$) treatment and handling unresolved resonances are also included in the physics modeling.
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    1111== Verification
    … …  
    4949  $corr=\frac{\sum_{N}^{i=1}\left ( x_{i}-\overline{x} \right )\left ( y_{i}-\overline{y} \right )}{\sqrt{\sum_{N}^{i=1}\left ( x_{i}-\overline{x} \right )^{2}}\sqrt{\sum_{N}^{i=1}\left ( y_{i}-\overline{y} \right )^{2}}}$
    5050
     51 Table I. shows the correlation of the number of a certain ACE law sampling with the $\chi$^2^ values for different neutron starting energies. Near zero correlation coefficients indicate no correlation, near 1 or -1 strong linear correlation. 
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     53Elastic scattering appears always with near zero coefficients with consistently negative sign. At 10-8 MeV and 18MeV the correlation is greater but still negative; we may interpret this as elastic scattering contributing to better match of results. ACE Law 3 (inelastic level scattering), ACE Law 4 (continuous tabular distribution) and ACE Law 61 (correlated energy and angle distribution) show a clearly nonzero and  often positive correlation indicating that the GPU implementation differ from MCNP. All three of these sampling processes happen with high energy neutrons, for low starting neutron energies the interactions happen after fission has occurred. Number of sampled interactions with these laws shows that without fissile material present, none of these sampling processes are called.
     54
     55||||    10-8 MeV||      10-6 MeV||      10-3 MeV||      1MeV    ||18Mev||
     56||Elastic scattering||  -0.21372        ||-0.01053      ||-0.05259      ||-0.07189||    -0.26171||
     57||ACE Law 3     ||0.4743        ||0.43175       ||0.41582       ||-0.05454||    -0.15467||
     58||ACE Law 4     ||0.30463       ||0.32031       ||0.67385       ||0.45868       ||0.17577||
     59||ACE Law 7     ||-0.00399      ||-0.00405      ||0.01045       ||-0.00808      ||-0.00166||
     60||ACE Law 9     ||-0.00872      ||-0.00649      ||0.01524       ||-0.00716      ||0.03139||
     61||ACE Law 11    ||-0.01198      ||0.00382       ||0.05435       ||0.00464       ||0.00769||
     62||ACE law 44    ||0.00206       ||-0.00254      ||0.04434       ||0.14184       ||-0.03327||
     63||law61 ||0.31364       ||0.21316       ||0.50553       ||-0.00556||-0.09562||
     64||law66 ||-- || --      ||--||  --||    -0.00607 ||
     65
     66**Table I. Correlation of $\chi$^2^  values with number of sampling of a certain ACE law**
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