OBNINSK.readme
Level density parameters for the generalized superfluid models
(Provided by A. V. Ignatyuk, 28 October 1997)
Contents
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The file contains the level density parameters for the Generalized Superfluid
Model (extension of the Barden-Cooper-Schiefer model). The parameters are
obtained by fitting the corresponding formulas both to neutron resonance
spacings and to cumulative numbers of low-lying levels evaluated by the
Obninsk group. The Generalized Superfluid Model takes into account beside
the shell and superfluid effects also the collective enhancement of the
nuclear level density.
Format
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FORMAT(I4,A3,I4,F5.1,F7.3,2(F8.3),12F.2,F8.3,I4) is used for data.
Each row includes the following data:
Z : Atomic number of compound nucleus,
Sym : Element symbol of compound nucleus,
A : Mass number of compound nucleus,
Io : Spin of the ground state for target nucleus,
Bn : Neutron binding energy of compound nucleus in MeV ,
a : Level density parameter of the Fermi gas formula in 1/MeV,
del : Effective shift of the excitation energy in MeV,
Do : Average resonance spacing in eV,
Uo : Excitation energy corresponding to the estimated number of
low-lying levels in MeV,
No : Cumulative number of low-lying levels below Uo .
Utility code
------------
Code for the level density calculations in the framework of the Generalized
Superfluid Model is given in the file OBNINSK_BCS.FOR. This file should be
found in the subdirectory [.OTHER_FILES]. The code can be run on a PC with
the following command:
OBNINSK_BCS.EXE < BCS.INP > BCS.OUT
Input data, BCS.INP, are written in the FORMAT(2X,2(F5.1,1X),8(F7.3,1X))
and include the following values:
Z : Atomic number of compound nucleus,
A : Mass number of compound nucleus,
AAS : Asymptotic value of the level density parameter in 1/MeV, which
is usually close to a-as=.073*A +.115 A**.6666,
D0 : Energy gap parameter in MeV, which is approximately equal to
12/A**.3333,
D1 : Effective shift of the excitation energy in MeV,
OM : Energy of quadrupole vibrations in MeV, which defines the vibrational
enhancement of the nuclear level density,
BET : Parameter of quadrupole deformation that defines the rotational
enhancement of the nuclear level density,
USTEP and UMAX : Energy interval and maximal excitation energy in MeV,
for which the level density calculations will be done
BCS.OUT repeats the input data + the following information:
the excitation energy, LOG-10 of the state and level densities, the spin
cutoff parameter, the temperature of excited nucleus, the coefficients of
vibrational and rotational enhancement of the level density. An example of
BCS.OUT is given below:
28.0 56.0 4.640 -7.210 1.600 .300 .850 .000 .500 10.000
ENERGIES LOG.STATES & LEVELS SIGMA2 TEMPER QVIBR QROT
.500 1.171 .129 1.279 .725 6.253 1.000
1.000 2.147 .862 2.078 .844 9.289 1.000
1.500 2.935 1.497 2.825 .968 13.320 1.000
2.000 3.404 1.869 3.430 1.109 18.515 1.000
2.500 3.798 2.188 3.987 1.222 22.508 1.000
3.000 4.143 2.471 4.511 1.316 25.217 1.000
3.500 4.456 2.731 5.012 1.398 26.820 1.000
4.000 4.747 2.976 5.495 1.469 27.565 1.000
4.500 5.023 3.212 5.961 1.534 27.686 1.000
5.000 5.290 3.441 6.415 1.592 27.374 1.000
5.500 5.549 3.667 6.857 1.645 26.774 1.000
6.000 5.802 3.890 7.289 1.694 25.992 1.000
6.500 6.052 4.112 7.711 1.739 25.104 1.000
7.000 6.299 4.332 8.125 1.782 24.162 1.000
7.500 6.542 4.552 8.531 1.823 23.202 1.000
8.000 6.784 4.770 8.929 1.861 22.248 1.000
8.500 7.024 4.989 9.320 1.898 21.316 1.000
9.000 7.262 5.206 9.704 1.932 20.416 1.000
9.500 7.498 5.424 10.082 1.966 19.554 1.000
10.000 7.733 5.640 10.454 1.998 18.734 1.000
Stop - Program terminated.