Difference between revisions of "D2O photodisintegration simulation"
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| − | == | + | ==(\gamma,n) reaction cross sections for different elements== |
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[[File:X_section_compare.gif | 550 px]] [[File:Pb208_gn_xsection.jpg | 550 px]] | [[File:X_section_compare.gif | 550 px]] [[File:Pb208_gn_xsection.jpg | 550 px]] | ||
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| + | ==Neutron spectra separation== | ||
Neutron yield (<math>4\pi</math>) from <math>D_2O</math> (90%<math>D_2</math> concentration) in reaction <math>O16(\gamma,n)O15</math> is presented below. Initially <math>5\cdot 10^7</math> brem photons with 25 MeV end-point energy were thrown on the target. 410 neutrons initially produced got absorbed in the target (E=0MeV) and 2509 neutrons will likely escape the target. Figure in blue on the left is the total energy spectrum of neutrons created in reaction <math>O16(\gamma,n)O15</math>. Figure in blue on the right is the neutron energy spectrum with energy cut applied. | Neutron yield (<math>4\pi</math>) from <math>D_2O</math> (90%<math>D_2</math> concentration) in reaction <math>O16(\gamma,n)O15</math> is presented below. Initially <math>5\cdot 10^7</math> brem photons with 25 MeV end-point energy were thrown on the target. 410 neutrons initially produced got absorbed in the target (E=0MeV) and 2509 neutrons will likely escape the target. Figure in blue on the left is the total energy spectrum of neutrons created in reaction <math>O16(\gamma,n)O15</math>. Figure in blue on the right is the neutron energy spectrum with energy cut applied. | ||
Revision as of 13:56, 11 April 2011
(\gamma,n) reaction cross sections for different elements
The result of GEANT4 simulation of neutron photoproduction on deuterium and oxygen-16 is presented below:
Neutron spectra separation
Neutron yield () from (90% concentration) in reaction is presented below. Initially brem photons with 25 MeV end-point energy were thrown on the target. 410 neutrons initially produced got absorbed in the target (E=0MeV) and 2509 neutrons will likely escape the target. Figure in blue on the left is the total energy spectrum of neutrons created in reaction . Figure in blue on the right is the neutron energy spectrum with energy cut applied.
Neutron yield () from (90% concentration) in reaction is presented below. Initially brem photons with 25 MeV end-point energy were thrown on the target. 857 neutrons initially produced got absorbed in the target (E=0MeV) and 16799 neutrons will likely escape the target. Figure in black on the left is the total energy spectrum of neutrons created in reaction . Figure in blue on the right is the neutron energy spectrum with energy cut applied.
So, if we apply the energy cut in neutron spectrum which is a sum of neutrons coming from and reactions at (0MeV)<E<=5MeV, then the ratio of "unpolarized" neutrons from and "polarized" neutrons from will be . In the same time we will loose of the "good" high energy neutrons produced in reaction. Binning is the same for all the plots above.
I will verify if those spectra and all the ratios are the same in the case where we use the geometrical constrains applied by the detectors placement.