Plotting Neutron Cross Section Data from ENDF

[Gordon Haverland]

On Fri, 16 Aug 2019 14:49:31 +0000 (UTC)
Djones9976 via texhax <texhax at tug.org> wrote:

> I am using pstricks to plot neutron cross section data obtained
> Brookhaven National Laboratory Nuclear Data files (NNDC ENDF), but I
> am having trouble when plotting cross section data for different
> reactions on the same graph.  I have to use listplot() with X and Y
> axes specific to each plot because the X axis is not incremented the
> same for each graph.  If anyone has worked this problem before and
> worked out a solution, I would appreciate hearing about it.

> Thank you in advance. D. W. Jones

I don't think I ever paid attention to the energy axis, and it has been
a few years since I worked on nuclear things.  Big chunks of the data
should be close to continuous, and then there should be resonances in
places (approximately delta functions).

Akima splines do get used in situations such as specific heat, and seem
to handle the discontinuity of the transition okay.  It nay be that de
Boor (Practical Guide to Splines) has a data set (or a reference to a
data set).  I had almost finished a fairly complete Akima toolkit for
myself, when the disk crashed.  And I've never been able to recover one
of the references (someone (probably male) in the University of
California system) had come up with some extensions, I think he was
interested in aircraft wings.  I think it was a master's degree thesis.

I think I was adding how to do Not-a-Knot end conditions when the crash
happened.


Anyway, I was thinking you model the "smooth" parts and interpolate to
a set of energies (X coordinates), and then somehow add in the
resonances where they occur.

Gord