Re: USRYIELD card normalization

From: Francesco Cerutti <>
Date: Mon, 3 Nov 2008 16:37:20 +0100

Dear Ercan,

according to your (meaningful) choice for WHAT(6) of the continuation
card, USRYIELD is giving d2N/dx1dx2, as yourself wrote in the card
comment. x1 is LET, expressed in keV/(micrometer g/cm3), as in your
plot label. x2 is ion energy (GeV in one case and GeV/n in the other).
So your y label is wrong: we are not dealing with fluence, but just with a
LET spectrum given in counts/[GeV keV/(micrometer g/cm3)] per primary in
the first case and in counts/[GeV/n keV/(micrometer g/cm3)] per primary in
the second one. Since your kinetic energy intervals are 0.8 GeV and 0.02
GeV/n wide, respectively (both choices are correct), your two curves
are supposed to differ by a factor of 40. Let us multiply them by 0.8 GeV
and 0.02 GeV/n, respectively, and give the two (identical) LET spectra in
counts/[keV/(micrometer g/cm3)] per primary.

With respect to your usreou.f implementation, note that LET values are
indeed gotten, for particles crossing a given boundary, as unrestricted
stopping power in any material you wish (specified again in WHAT(6) of the
USRYIELD continuation card - as you did - provided that it is assigned to
some region). In principle this is not the energy lost up to that boundary
divided by the travelled path (the stopping power depends on energy).



Francesco Cerutti
CH-1211 Geneva 23
tel. ++41 22 7678962
fax ++41 22 7668854
Received on Tue Nov 04 2008 - 09:10:35 CET

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