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Updated some documentation.

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amandalund 2018-07-05 15:32:33 -05:00
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docs/source/methods/photon_physics.rst
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@ -16,7 +16,10 @@ de-excitation of these atoms can result in the emission of electrons and
photons. Electrons themselves also can produce photons by means of
bremsstrahlung radiation.
------------------------------
-------------------
Photon Interactions
-------------------
Coherent (Rayleigh) Scattering
------------------------------
@ -56,7 +59,7 @@ accounts for `anomalous scattering`_ which can occur near absorption edges. In a
Monte Carlo simulation, when coherent scattering occurs, we only need to sample
the scattering angle using the differential cross section in :eq:`coherent-xs`
since the energy of the photon does not change. In OpenMC, anomalous scattering
is ignored such that differential cross section comes
is ignored such that differential cross section becomes
.. math::
:label: coherent-xs-openmc
@ -147,7 +150,6 @@ section. The complete algorithm is as follows:
6. If :math:`\xi_2 < (1 + \mu^2)/2`, accept :math:`\mu`. Otherwise, repeat the
sampling at step 3.
-------------------------------
Incoherent (Compton) Scattering
-------------------------------
@ -207,24 +209,49 @@ the form factor. As in other codes, `Kahn's rejection method`_ is used for
from step 1.
Doppler Energy Broadening
-------------------------
+++++++++++++++++++++++++
LA-UR-04-0487_ and LA-UR-04-0488_
--------------------
Photoelectric Effect
--------------------
Pair Production
---------------
-------------------
Secondary Processes
-------------------
New photons may be produced in secondary processes related to the main photon
interactions discussed above. A Compton-scattered photon transfers a portion of
its energy to the kinetic energy of the recoil electron, which in turn may lose
the energy as bremsstrahlung radiation. The vacancy left in the shell by the
ejected electron is filled through atomic relaxation, creating a shower of
electrons and fluorescence photons. Similarly, the vacancy left by the electron
emitted in the photoelectric effect is filled through atomic relaxation. Pair
production generates an electron and a positron, both of which can emit
bremsstrahlung radiation before the positron eventually collides with an
electron, resulting in annihilation of the pair and the creation of two
additional photons.
Atomic Relaxation
-----------------
---------------
Pair Production
---------------
---------------------------
Thick-target Bremsstrahlung
---------------------------
Electron-Positron Annihilation
------------------------------
Bremsstrahlung
--------------
Thick-Target Bremsstrahlung Approximation
+++++++++++++++++++++++++++++++++++++++++
.. _Koblinger: http://www.tandfonline.com/doi/abs/10.13182/NSE75-A26646