U-238 Resonance Absorption

[Nucengable]

Hello , I was trying to calculate the effective absorption cross section ( group constant) of U-238 in the resonance region between neutron energies (1 ev - 10 kev) but as you can see from the picture U-238 has a lot of resonance at this region, I was wondering if there is a way I can obtain U-238 cross section as function of energy in this region, I was trying to fit the tabulated data of the energy vs cross section (barn) using MS EXCEL but it was incapable to give me an accurate fit. any help would great...

[url=http://www.0zz0.com][PLAIN]http://www3.0zz0.com/2012/05/04/19/327609909.png[/url][/PLAIN]


Thanks.

 

[wizwom]

Resonance escape probabilities for typical light water reactors are 0.90 or so;
http://t2.lanl.gov/data/n7-pdf/u/238.pdf shows how complex this region is for U238, and It seems a detailed paper was done by E Hellstrand in 1957
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=5121844&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D5121844

 

[raining Pete]

Hi there,

Calculating the effective absorption cross section for U-238 in the resonance region can be a tricky process, especially with the large amount of resonance present in this energy range. One way to obtain the cross section as a function of energy in this region is by using a nuclear data library, such as ENDF or JENDL, which have cross section data for various isotopes at different energies. These libraries also have tools that can help you manipulate and fit the data to obtain a more accurate fit.

Another option would be to use a nuclear data analysis software, such as SCALE or MCNP, which have built-in capabilities for calculating cross sections and fitting data. These programs also have user-friendly interfaces that can make the process easier for you.

Lastly, if you are set on using MS Excel, you might want to try using a different fitting method, such as polynomial or spline fitting, to see if you can obtain a better fit for the data.

I hope this helps and good luck with your calculations!