From: Joseph Comfort (Joseph.Comfort@asu.edu)
Date: Thu Apr 05 2007 - 02:49:25 CEST
Thank you for the suggestions about the kinks in my neutron spectum. To
remind you, I am looking at neutrons produced by a 30-GeV beam on a Ni
target, about 5 cm thick.
I reanalyzed the data in terms of neutron kinetic energy, and
specifically applied the binning of the 72 neutron groups, up to 19.6
MeV. Above that energy, I used bins that are 20-MeV wide, cut off at
about 6 GeV. All of the bins were put into a single array for plotting.
The attached figure shows the results. The upper portion shows the raw
yields per bin vs. bin #. The first 72 bins are the neutrons below 19.6
MeV. For the lower fignure, I rescaled the number of events in each bin
so as to reflect bins of equal width (20 MeV). Then I multiplied those
numbers by the mean kinetic energy of the bin. I think this is close to
your 'lethargy' quantity. There is a kink at bin 72 (19.6 MeV), and a
second one near bin 90 (about 400 MeV). The yields between these bins
are well above the neighbors, and have an unexpected distribution.
I want to be able to parameterize an algorithm for generating the
spectrum, and the kinks will make that difficult. Should I just lop off
the extra neutrons between 20-400 MeV, and fit a smooth distribution?
-- Joseph Comfort Phone: (480)-965-6377 Department of Physics & Astronomy Dept.: (480)-965-3561 Arizona State University Fax: (480)-965-7954 Tempe, AZ 85287-1504 Email: Joseph.Comfort@asu.edu
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