description of fission observables. Released December 4, 2020.
Last update January 4, 2021.
Short characterisation of
Compared to GEF 2020/1.1, the description of asymmetric fission in the
pre-actinides has been revised. The carefully measured energy
dependence of the
mass yields in 205Bi(p,f) [Swinton-Bland et al., Phys. Rev. C 102
(2020) 054611] is better reproduced by a reduction of the macroscopic
binding energy on the asymmetric fission path. Other systems in the
pre-actinides are less well described, in particular at low excitation
Note that the parameters of GEF 2020/1.2 might still slightly be modified.
The mass distribution of 235U(nth,f) from GEF-2019/1.1
comparison with the JEFF 3.3 evalution (black symbols with error
bars). The calculated contributions from different
fission channels are traced in green. 10 million events have been
An extended version of GEF-2020/1.2that
includes delayed processes (output of delayed-neutron multiplicities,
delayed-neutron emitters, cumulative fission-fragment yields in ENDF
format) is available on demand. It provides
option for producing random files of fission-fragment yields in ENDF
are happy about any feed-back (mail to
schmidt-erzhausen<at>t_online.de). This helps to correct
to improve the quality of the model and to better respond to the needs
and preferences of the users.
Use of the GEF code is subject to the GNU GENERAL PUBLIC LICENSE
agreement that you find here: <License>.
Stand-alone version (Monte-Carlo method)
stand-alone version of the GEF code is written in FreeBASIC (a). The
FreeBASIC compiler produces binary code from the same source on Windows
(b) and on Linux. The executable uses the C library.
version, a GUI is provided, written in JustBasic (c). The Windows
version runs also on Linux with Wine (d). The Windows version
runs also on OS X (e)
with Wine (d).
a) FreeBASIC is available from http://www.freebasic.net/
b) Windows is either a registered trademark or a trademark of Microsoft
Corporation in the United States and/or other countries.
c) JustBasic is available from http://www.justbasic.com/ with no cost.
d) Wine is a windows compatibility layer for Linux and Mac OS X
e) OS X is a trademark of Apple Inc., registered in the U.S. and other
Quick start on Windows:
- Download the binaries
(that includes some additional files).
- Start GEF.bat
- Fill in the input mask of the graphical user interface and
- Output is written to file \out\...
Quick start on Linux:
- Download the binaries.
- Make sure that the binary file GEF is executable.
- Enter ./GEF
in a command
- Answer the input dialogue.
- Output is written to file
of the graphical
For Windows and Linux
(Technical information, list of relevant publications)
24, part I
(Comprehensive documentation of the GEF model.)
24, part II
(Technical information on the GEF code.)
Source (for Windows and Linux)
Input files for extended input options
Distribution of entrance energies (example)
List of input parameters (example)
for more detailed information.
Data tables in XML-assisted format (example)
List-mode file (example)
(short sample of most complete event list)
Raw data for the multi-variate distribution of fission-fragment yields
from calculations with perturbed parameters (example)
for more detailed information.
may consider using the Windows version of GEF on Linux with Wine in
order to profit from the more comfortable input handling offered by the
graphical user interface. This option may also solve problems of
missing libraries under Linux.
Subroutine (Folding method)
The subroutine aims for being used
in combination with other nuclear-reaction codes. For a given
fissioning nucleus with excitation energy E* and angular
it calculates complete distributions of a number of fission observables
before emission of prompt neutrons and prompt gamma radiation with the
Technical description of the subroutine