1. LICENCE AND COPYRIGHT
' The development of the GEF code has been supported by the European Union,
' EURATOM 6, Framework Program "European Facilities for Nuclear Data
' Measurements" (EFNUDAT), contract number FP6-036434, the Framework
' Program "European Research Infrastructure for Nuclear Data Applications"
' (ERINDA), contract number FP7-269499, and by the Nuclear Energy Agency of
' the OECD (from 2010 to 2016).
'
' The GEF code is free software: you can redistribute it and/or modify
' it under the terms of the GNU General Public License as published by
' the Free Software Foundation, either version 3 of the License, or
' (at your option) any later version.
'
' This program is distributed in the hope that it will be useful,
' but WITHOUT ANY WARRANTY; without even the implied warranty of
' MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
' GNU General Public License for more details.
'
' You should have received a copy of the GNU General Public License
' along with this program. If not, see .
' Copyright 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018:
' Dr. Karl-Heinz Schmidt, Rheinstraße 4, 64390 Erzhausen, Germany
' and
' Dr. Beatriz Jurado, Centre d'Etudes Nucleaires de Bordeaux-Gradignan,
' Chemin du Solarium, Le Haut Vigneau, BP 120, 33175 Gradignan, Cedex,
' France
2. NAME OF THE PROGRAM: GEF 2018/1.1
3. DESCRIPTION OF PROGRAM OR FUNCTION
GEF is a computer code for the simulation of the nuclear fission process.
The GEF code calculates pre-neutron and post-neutron fission-fragment nuclide
yields, angular-momentum distributions, isomeric yields, prompt-neutron yields
and prompt-neutron spectra, prompt-gamma spectra, and several other quantities
for a wide range of fissioning nuclei from mercury to seaborgium in
spontaneous fission and neutron-induced fission. Multi-chance fission (fission
after emission of neutrons) is included. For neutron-induced fission, the
pre-compound emission of neutrons is considered. Output is provided as tables
and as parameters of fission observables on an event-by-event basis.
Specific features of the GEF code:
- The mass division and the charge polarisation are calculated assuming a
statistical population of states in the fission valleys at freeze-out.
The freeze-out time considers the influence of fission dynamics and is not
the same for the different collective variables.
- The separability principle [1] governs the interplay of macroscopic and
microscopic effects.
- Five fission channels are considered. The strengths of the shells in the
fission valleys are identical for all fissioning systems. The mean positions
of the heavy fragments in the asymmetric fission channels are essentially
constant in atomic number, as suggested by experimental data [2].
- The stiffness of the macroscopic potential with respect to mass asymmetry
is deduced from the widths of measured mass distributions [3].
- The excitation-energy-sorting mechanism [4,5,6,7,11] determines the prompt
neutron yields and the odd-even effect in fission-fragment yields of even-Z
and odd-Z systems.
- Prompt neutron emission from the fragments is calculated with a Monte-Carlo
statistical code using level densities from empirical systematics [8] and
binding energies from mass tables with gamma competition included.
- Spectra and multiplicities of prompt gamma emission are provided.
Non-statistical gamma emission is calculated with a dedicated VMI model.
- Model uncertainties, covariances and correlation coefficients are
determined by a series of calculations with perturbed parameters.
Covariances and correlations of fission yields from two different systems
are available.
- Multi-chance fission is supported.
- Pre-compound emission of neutrons is considered for neutron-induced fission.
The official GEF websites are http://www.khs-erzhausen.de and
http://www.cenbg.in2p3.fr/GEF.
4. METHOD OF SOLUTION
The Monte-Carlo method is used.
Uncertainties are deduced from perturbed calculations.
5. TYPICAL RUNNING TIME
A typical calculation with 100 000 events takes about 5 seconds on one processor
of an Intel i7 CPU (2.80GHz). Calculations with perturbed parameters and
calculations at higher excitation energies, where multi-chance fission occurs,
require somwhat more time.
6. RELATED AND AUXILIARY PROGRAMS
The main routines are written in FreeBASIC (http://www.freebasic.net/). FeeBASIC
produces compiled binary code using the C run-time library. Graphics output is
based on the X11 library. A graphical user interface is provided for Windows [a],
written in JustBasic (http://www.justbasic.com/), which has a specific run-time
library. The Windows version of GEF runs also under WINE on LINUX.
7. REFERENCES
[1] Experimental evidence for the separability of compound-nucleus and fragment properties in fission,
K -H Schmidt, A Kelic, M V Ricciardi, Europh. Lett. 83 (2008) 32001
[2] Nuclear-fission studies with relativistic secondary beams: analysis of fission channels,
C. Boeckstiegel et al., Nucl. Phys. A 802 (2008) 12
[3] Shell effects in the symmetric-modal fission of pre-actinide nuclei,
S. I. Mulgin, K.-H. Schmidt, A. Grewe, S. V. Zhdanov, Nucl. Phys. A 640 (1998) 375
[4] Entropy-driven excitation-energy sorting in superfluid fission dynamics,
K.-H. Schmidt, B. Jurado, Phys. Rev. Lett. 104 (2010) 212501
[5] New insight into superfluid nuclear dynamics from the even-odd effect in fission,
K.-H. Schmidt, B. Jurado, arXiv:1007.0741v1 [nucl-th]
[6] Thermodynamics of nuclei in thermal contact,
K.-H. Schmidt, B. Jurado, Phys. Rev. C 82 (2011) 014607
[7] Final excitation energy of fission fragments,
K.-H. Schmidt, B. Jurado, Phys. Rev. C 83 (2011) 061601(R)
[8] Inconsistencies in the description of pairing effects in nuclear level densities,
K.-H. Schmidt, B. Jurado, Phys. Rev. C 86 (2012) 044322
[9] General description of fission observables,
K.-H. Schmidt, B. Jurado, Ch. Amouroux, JEFF-Report 24, NEA of OECD, 2014
[10] Revealing hidden regularities with a general approach to fission
K.-H. Schmidt, B. Jurado, Eur. Phys. J. A 51 (2015) 176
[11] Influence of complete energy sorting on the characteristics of the odd-even
effect in fission-fragment element distributions
B. Jurado, K.-H. Schmidt
J. Phys. G: Nucl. Part. Phys. 42 (2015) 055101
[12] General description of fission observables: GEF model code
K.-H. Schmidt, B. Jurado, C. Amouroux, C. Schmitt, Nucl. Data Sheets 131 (2016) 107
8. HARDWARE REQUIREMENTS
GEF can be compiled and installed under Windows [a] and Linux, using exactly
the same sources files. Specific executables are provided for the two systems.
GEF was tested on Windows [a] and Linux.
Memory < 250 MByte; Disc < 100 MByte, eventually more for event-wise output.
9. PROGRAMMING LANGUAGE(S) USED
Computer language
on Linux: FreeBASIC; on Windows [a]: FreeBASIC and JustBasic
10. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED
a) Windows [a] XP or newer
b) Any Linux distribution, 32-bit or 64-bit. Eventually, some additional
libraries need to be installed, see www.freebasic.net -> documentation
-> using the FreeBASIC compiler -> Installing FreeBASIC.
(It is recommended to use the 32-bit version of FreeBASIC on a 64-bit system
for better numerical stability. Please install the appropriate libraries!)
11. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS
Multi-chance fission is supported, except when a distribution of excitation
energies at fission is provided on input.
The results on neutron emission prior to fission and prompt-neutron emission
between saddle and scission, and from the fragments are given separately.
The sequence of the events in the list-mode output is sorted by energy at
fission in the case of multi-chance fission in order to save computing time.
An optional enhancement factor may be specified. A value >1 increases the
statistics of the Monte-Carlo calculation and hence reduces the statistical
uncertainties of the results. Default value is 1.E5 events. With this value,
the statistical uncertainties are already smaller than the model uncertainties
in most cases. Higher statistics may be useful to compare different systems, to
study systematic trends and to determine reliable covariances.
GEF provides all results event by event in a list-mode file on demand.
12. NAME AND ESTABLISHMENT OF AUTHORS
K.-H. Schmidt, Rheinstr. 4, 64390 Erzhausen, Germany
B. Jurado, CENBG, CNRS/IN2 P3, Chemin du Solarium B.P. 120, F-33175 Gradignan, France
13. MATERIAL AVAILABLE
FreeBASIC [c] source files. JustBasic [d] executable and run-time-library.
Executables for Windows [a] and Linux.
ReadMe file with technical instructions.
14. CATEGORIES
Nuclear fission
Keywords: Monte-Carlo method, event generator, macroscopic-microscopic model,
separability principle, energy sorting, statistical model,
pre-equilibrium emission, multi-chance fission, neutron evaporation,
prompt-gamma emission, uncertainties and covariance matrix of fission-fragment yields.
15. PRACTICAL HINTS
Please keep the sub-folder structure of GEF.zip. Subfolders that are
needed by the code for output are created automatically, if they do
not exist. GEF does not overwrite or delete the output files. Files
in the folders out, tmp, and dmp that are not needed any more should
be deleted explicitely.
"out" contains the main output as ASCII tables.
"ptb" contains full results of perturbed calculations (optional).
"tmp" contains more specific or internal information as ASCII tables.
"dmp" contains spectra in SATAN analyzer format.
"ctl" contains control files for multithreaded calculations.
On Windows [a]:
The file GEF.zip provides an executable of the main programm (GEF.exe)
and - in the subfolder GUI - a graphical user interface.
GEF is started by running "GEF.bat" (!) in a command window.
All user input must be entered by the GUI window!
If you want to apply any changes, use an IDE (e.g. FBIDE [b]) for editing
any of the source files (*.bas). Compile the main routine GEF.bas under
FreeBASIC [c]. The other files are automatically included in the compilation
process. (Compile by pressing the "compile" botton of FBIDE when GEF.bas is open.)
The GUI is written in JustBasic [d].
On Linux:
The file GEF.zip provides an executable (GEF) that runs directly in a
terminal by entering "./GEF". (Do not forget to set the file properties to
"execute as a programm".)
The GUI that is provided in the Windows version may also be used under Linux
by running the Windows version of GEF under Wine [e] without any loss of
performance.
If you want to make any changes to GEF, prepare an executable, using
an IDE (e.g. GEANY [f]) with the FreeBASIC [c] compiler. GEF.bas is the main
routine. The other files are automatically included in the compilation process.
Compile by pressing the "compile" botton of GEANY when GEF.bas is open or
by the command "fbc GEF.bas".
Remark: Installation of additional packages may be required. (See
http://www.freebasic.net/ -> Documentation -> User Manual ->
Using the FreeBASIC Compiler -> Installing FreeBASIC.)
E.g. the graphics output requires the installation of the X11 library.
If the graphics does not work, you may suppress it by commenting the line
( #Include Once "DCLPlotting.bas" ) in GEF.BAS.
Required input of GEF:
Z and A of fissioning nucleus or target
Excitation mode and excitation energy
Quantities available on output of GEF:
Contributions of fission chances
Relative yields of fission channels
Element-yield distribution*)
Isotonic-yield distribution (pre- and post-neutron)
Isobaric-yield distribution*)
Mass-chain yields (pre- and post-neutron)*)
Fragment angular-momentum distributions (for every nuclide)
Relative independent isomeric yields
Prompt-gamma spectrum
Prompt-neutron spectrum
Neutron-multiplicity distribution
Energies and directions of prompt neutrons (pre- and post-scission)
(Many more quantities are internally calculated and may be listed.)
*) Including uncertainties and covariances.
Advanced options:
- UNCERTAINTIES
Uncertainty analysis from calculations with perturbed parameters is available.
These calculations are also used to determine covariances and correlations
between different observables as required by the model. Covariances and
correlations between the fission yields of two different systems can also
be provided.
Due to the Monte-Carlo method, the calculated uncertainty, correlation and
covariance values fluctuate. There are two effects that contribute to these
fluctuations. These are the sampling of perturbed parameters from the
corresponding Gaussian distributions and the statistical flucuations of the
calculations with a specific parameter set. In order to keep the influences
of both effects at a similar level, both the number of perturbed parameter
sets (N_par) (sampled from the appropriate Gaussian distribution) and the
number of perturbed calculations (N_stat) with a specific parameter set
vary as a function of the total number (N_tot) of calculations, given as
input option. N_par is given by the following relation:
N_par = Int(sqr(N_tot / 1000)).
Table 1 gives on overview on these variations.
TABLE 1
N_tot Enhancement factor N_par N_stat
given on input
(Fenhance)
1.E5 1 10 10000
2.E5 2 14 14285
5.E5 5 22 22727
1.E6 10 31 32258
2.E6 20 44 45454
5.E6 50 70 71428
1.E7 100 100 100000
2.E7 200 141 141844
5.E7 500 223 224215
1.E8 1000 316 316455
2.E8 2000 447 447427
5.E8 5000 707 707214
1.E9 10000 1000 1000000
2.E9 20000 1414 1414427
5.E9 50000 2236 2236136
The calculations with the perturbed parameter values are only performed
to determine the uncertainties, correlations and covariances. The
nominal (most probable) values are calculated with the nominal
parameter values. Note that the calculations with the nominal parameter
values are performed with N_tot events.
The variation of the perturbed parameters (the width of the appropriate
Gaussian distribution, the perturbed parameter values are sampled from)
can be modified by a scaling parameter.
Values smaller than one are useful for avoiding the problem that the yields of
some nuclides become zero with some of the perturbed parameter sets, because
GEF will not provide covariances/correlations for these nuclei. For example,
a scaling factor of 0.5 may be used. Note that this leads to a reduction of the
calculated uncertainties by the same factor and a reduction of the variances
and covariances by a factor of 0.25. The correlations are not systematically
modified.
Another effect of the Monte-Carlo method of the GEF code is a noise of
fluctuations in the case of low statistics in the determined
covariance/correlation values. In particular covariances/correlations of
strongly correlated quantities (correlation coefficients close to one) are
reduced. This effect is particularly strong when covariances/correlations of
independent yields of two different systems are considered. It is also
aggravated when the variation of the perturbed parameters is reduced as
described above.
Both effects (lower yield threshold for calculated uncertainties/covariances/
correlations and reduction of covariances/correlations of strongly correlated
quantities) are reduced to the desired degree by performing the GEF calculation
with higher statistics (a larger number of fission events).
Note that also the uncertainties determined by GEF include the effect of the
statistical fluctuations in the case of insufficient statistics. In consequence,
the calculated uncertainties are increased. This effect can be investigated by
calculations with an increasing number of events. The influence of statistical
fluctuations becomes negligible, when the uncertainties given by GEF attain an
asymptotic value.
- ENERGY DISTRIBUTION
Instead of a single energy, also a distribution of excitation energies
above the ground-state at fission may be provided in a file.
The file name is fixed: Espectrum.in.
- Example: (energy, weight)
3.9 0.1
4.0 0.2
4.1 0.4
4.2 0.7
...
Each line gives an energy (in MeV) and a weight.
Energy steps of about 100 keV are recommended. The spectrum may be
un-normalized.
It is also possible to insert the rms compound-nucleus angular momentum as
the second row to the input data in Espectrum.in. (Zero angular momentum is
replaced by the ground-state spin of the compound nucleus.)
- Example: (energy, spin, weight)
3.9 9.8 0.1
4.0 10.1 0.2
4.1 10.4 0.4
4.2 10.9 0.7
...
The corresponding option is chosen by the GUI under Windows or by the
option "ES" under Linux. Note that GEF calculates only first-chance fission
for this option!
- INPUT LIST
GEF supports reading an input list from file. This option is chosen if
the file "file.in" is found.
Instructions:
When this option is used, at least two files must be provided.
The file "file.in" is created in the folder, where the exectable of GEF
is situated. It gives the names of the files with the specific information
of the cases to be processed. It is conventient to place those files in
the subfolder "\in". Detailed information is given below:
1. Create a file (for example in the subfolder "\in") with the following information:
First line: Statistical enhancement factor (default = 1 corresponds
to 10^5 events per system). A larger factor increases
the number of calculated events accordingly.
Second line: Energy value or list of energy values
For neutron-induced fission: List of energy values in ascending order.
For spontaneous fission: Energy value. (Only one value is allowed.)
Third line: Special options (optional)
Options(xxx,yyy,...)
Supported options are 'err' : perturbed-parameter calculations,
'ptb' : output of perturbed calculations,
'cor' : output of correlations,
'cov' : output of covariances,
'lmd' : list-mode output,
'neo' : even-odd staggering in Z and N
at scission suppressed.
In preparation: 'dparfac(value)' : factor to scale the
variation of perturbed parameters,
Following lines: Specification of the fissioning system.
(Z_CN, A_CN, kind of fission)
A range of consecutive isotopes can be specified in a shorter way:
(Z_CN, A_CN_first - A_CN_last, kind of fission)
If a second system is given, the correlations between the two systems
are calculated: (Z_CN, A_CN, Z_CN_2, A_CN_2, E_CN_2, kind of fission)
Options for the "kind of fission" are
"GS" for spontaneous fssion or fission from an excited compound nucleus,
"EB" for CN nucleus fission (The energy value is defined as the energy
above the outer fission barrier.) and
"EN" for neutron-induced fission.
- Example for spontaneous fission or fission from an excited compound nucleus:
10
0
94, 238-242, "GS"
98, 250, "GS"
' 98, 250, "GS"
98, 252, "GS"
END
99, 250, "GS"
99, 251, "GS"
In this example, the system 98, 250 is skipped due to the comment sign,
and the last two lines after the END line are disregarded.
...
- Example for neutron-induced fission with additional options:
2
0.0253E-6, 0.4, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
Options(err,cor)
92, 234-239, "EN"
...
A sequence of calculations is performed with the energies given
in the second line of the input file. This feature is supported for
the options "GS", "EN", and "EB".
(Correlations between two systems can only be calculated at a
single energy).
- Example for fission from a shape isomer:
(The isomers must be listed in the file NucProp.bas.)
100
0
94, 241, "IS1"
94, 242, "IS1"
...
- Example for correlations between two systems with additional options:
10
0.5
Options(err,ptb)
92, 236, 94, 240, 0.5, "EN"
2. Create the file "file.in", which contains the names of the input
files (one per line) in the folder, where the executable of GEF is
situated.. Again, single lines marked by a comment sign are
disregarded, and reading is stopped by an "END" line.
- Example
"\in\U238NF.in"
' "\in\CF252SF.in"
"\in\PU240SF.in"
In this example, only the files U238NF.in and PU240SF.in are treated.
CF252SF.in is skipped due to the comment sign.
- PARALLEL COMPUTING
GEF also supports running several processes in parallel, which calculate
the systems given in the input files (specified in "input.in") in parallel
in a coordinated way. This enables making efficient use of multi-processor
machines. Before starting a new sequence of calculations, the files
"\ctl\done.ctl", "\ctl\sync.ctl and "\ctl\thread.ctl" must be deleted.
You may also delete the complete "\ctl" folder.
After this, open a new command window (terminal) for each GEF process to
be started (Linux: "./GEF", Windows: "GEF.bat"), until you reach the limit
that is stored in the variable I_thread_max in GEF.bas.
Before lauching the next job, please wait, until the previous one started
the calculation!
Make sure that the value of I_thread_max has the right value for your system!
If necessary, change the value and recompile GEF.bas!
Multi-processing calculations are performed without graphics output.
- DELAYED PROCESSES (available in the full GEF version)
The full version of GEF calculates also the delayed processes after beta
decay: like beta-delayed neutron emission and cumulative yields. The decay
data from JEFF 3.1.1 are used. The output is found in the /out folder.
- ENDF FORMAT (available in the full GEF version)
Tables of independent and cumulative yields in ENDF format are written,
if the corresponding subroutines DCLbranching.bas, BRANCHINGS.bas,
DCLendf.bas, ENDF.bas, ENDF_tape_description.bas, and ENDF_EOT.bas
are included in the link process. This option is activated, if the line
#include once "DCLendf.bas" in GEF.bas is uncommented.
The nuclear-decay data used for the calculation of the cumulative yields
are listed in the file DCLendf.bas. The output is written to the subfolder
/ENDF. This folder is automatically created, if it does not exist.
Uncertainties are determined by calculations with perturbed parameters, taking
into account the covariances of the independent fission-fragment yields.
The cumulative nuclide yields, including isomeric yields, are also written in
plain ASCII to the output file in the /out folder. There is also a list of
delayed-neutron emitters.
It is recommended to use the option "input list from file" for these calculations
(see above), if they have to be done for a larger number of systems.
Random files of fission yields in ENDF format are produced, if the
corresponding input option is chosen. If the input list from file is used,
the variable B_Random_on must be set to one in GEF.bas:
Dim As UByte B_Random_on = 1 /' Write ENDF random files '/
and GEF.bas must be re-compiled.
16. DETERMINISTIC VERSION OF GEF AS A SUBROUTINE IN FREEBASIC AND FORTRAN.
A deterministic version of the GEF code provides pre-neutron fission-fragment
nuclide distributions and kinetic energies. It is written as a subroutine that
is called with a specific compound nucleus, its excitation energy and its
angular momentum on input. See the file "GEFSUB.pdf" for details.
[a] Windows is either a registered trademark or a trademark of Microsoft
Corporation in the United States and/or other countries.
[b] FBIDE is available from http://fbide.freebasic.net/ with no cost.
[c] FreeBASIC is available from http://www.freebasic.net/ with no cost.
[d] JustBasic is available from http://www.justbasic.com/ with no cost.
[e] Wine is a windows compatibility layer for Linux (http://www.winehq.org/)
[f] Geany is available from http://www.geany.org/ with no cost.
In case of problems, please contact schmidt-erzhausen at t-online.de .