Difference between revisions of "JB Absolute theta"

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[[Production Analysis|go_back]]
 
[[Production Analysis|go_back]]
  
== Beam ==
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[[JB Absolute theta(oldmethod)]]
[[File:2Ncorr D20 ThetaAbs Legendre.png||750px]]
 
  
== MCNP-POLIMI ==
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=Analysis=
  
Below is an MCNP-POLIMI simulation of a cylindrical D20 target (axis length = 4"; dia. = 1.5") subject to a bremsstrahlung photon beam with an end point of 10.5MeV. The plot below shows the relative distribution of neutron direction cosines w.r.t. the incident photon beam. All neutrons are from the photodisintegration of D20 and the direction cosine is taken as neutrons exit the target geometry.
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After my first attempt at reconstructing the theta_abs distribution gave mediocre results, I decided to try again, but this time without integrating over experimental observables throught analysis, except for at the final step. To illustrate what I mean, see the histogram below:
  
[[File:MCNPD20Theta Abs 1.png|650px]]
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[[File:D2O3DHistogram.png|700px|thumb|center|alt=Large | Every singles event lies in a three dimensional space consisting of a PMT top and bottom time, and a specific detector. These observables can be recast as energy, vertical z position, and detector angle (54,78,102, ect). ]]
  
This plot is the same as above, except the neutron direction cosines are taken immediately after photodisintegration. If MCNP is correct here, than it suggests that the correlation of between asymmetry and neutron energy is a result of neutrons scattering within the target.
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The benefit of conducting the analysis in this 3D space, is that the neutrons correlated with the beam can be normalized to uncorrelated Cf252 neutrons detected in the same detector with similar positions and energies.
 
 
[[File:MCNPD20Theta Abs 2.png||650px]]
 

Latest revision as of 21:28, 22 November 2017

go_back

JB Absolute theta(oldmethod)

Analysis

After my first attempt at reconstructing the theta_abs distribution gave mediocre results, I decided to try again, but this time without integrating over experimental observables throught analysis, except for at the final step. To illustrate what I mean, see the histogram below:

Large
Every singles event lies in a three dimensional space consisting of a PMT top and bottom time, and a specific detector. These observables can be recast as energy, vertical z position, and detector angle (54,78,102, ect).

The benefit of conducting the analysis in this 3D space, is that the neutrons correlated with the beam can be normalized to uncorrelated Cf252 neutrons detected in the same detector with similar positions and energies.