FENDL/C-2.0 CHARGED PARTICLE SUBLIBRARY
(PROCESSED)
Description of contents and format
The files TDFA.DAT and TDFB.DAT begin with the list of
physical constants, and properties (nuclear masses, Q-value, etc.)
of particles participating in the reaction (sections (2)-(4)).
In section (5) there is a tabulation of values (in b-cm/s)
vs. temperature (kT, in MeV). The last column in that tabulation
(labeled "EXTR") is the average total incoming energy (in MeV) at each
temperature, given by /.
The next part of the file gives tabulations of the Maxwellian-averaged
spectrum in the laboratory system for each of the outgoing particles,
as a function of temperature. The temperatures in this part of the file
do not have to be same as those given in the tabulation.
Section (6) lists values at which the spectrum was "cut" in order to
determine the energies at which the spectrum is tabulated (given as
fractions of the maximum value). Since each cut projects on two energies,
in addition to the maximum, there are 2*N+1 energies tabulated for N cuts
(labeled "SPECTRUM LEVELS").
Line (7) gives (for each temperature) the outgoing-particle number and
number of laboratory energies at which spectrum is tabulated. "AREA" is
the numerical energy integral of the spectrum (should be unity),
scaled by the value of at that temperature "SIGVB".
The spectrum follows in section (8). For each outgoing-particle
energy (MeV in laboratory) its "SPECTRUM" (in 1/MeV) is tabulated,
as given by the expression:
= sqrt(2)/pi M'^(3/2)/sqrt(m1 m2 m3 m4)
int_0^infty {de/(kT)^2 e sigma(e)/sqrt(e+Q)
[exp(-J1) - exp(-J2]}.
Here
J1/2 = e/(kT) + M'/(M m3 kT) [sqrt(M'E) +/-
sqrt(m4(e+Q))]^2,
and M = m1+m2, M' = m3+m4.
This expression was first derived by Talley and Hale in their contribution
to the 1988 Mito Nuclear Data Conference [Ref. 1].
The final column in this tabulation, labeled "INTEGRAL" gives the partial
integral of the spectrum from E=0 to the tabulated energy for energies up to
maximum of the spectrum. For energies above the maximum, the definition
switches to the partial integral from E=infty to the tabulated value, so
that those contributions are negative. These partial integrals correspond
to unit normalization of the spectrum over all energies, as mentioned
above. Sections (7) and (8) are repeated for all outgoing particles at each
temperature in the spectrum grid.
The following comments apply only to the 1-H-3(d,n)2-He-4 data
file. A temperature grid has been chosen for the
tabulation that is linear in log(kT), giving (the same) 10 points
per decade in the tabulated range 10^(-4) to 1 MeV. The spectra are
tabulated at every second one of these temperatures, making their grid a
subset of the grid.
The "SPECTRUM LEVELS" (cuts) in the tabulation are only approximate,
since this prescription has not been used to establish the outgoing-particle
energy grid. The grid is chosen to be linear in sqrt(E), with 5 points on
either side of the energy of the spectral maximum.
The quantities "AREA" and "INTEGRAL" were computed analytically between
the tabulated energies, using the functional form
= A sqrt(E) exp[-(sqrt(E) - B)^2/C]
to give 3-point interpolation in each interval, and also to extrapolate
above and below the range of the tables. The accuracy obtained for these
integrals indicates that this functional form is suitable for interpolating
and extrapolating table entries for the spectra.
References:
1) T.L. Talley, G.M. Hale, Proceedings of the International
Conference on Nuclear Data for Science and Technology, Mito,
Japan, May/June 1988, pp. 299-302.