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), and by the Nuclear Energy Agency of the OECD. ' ' 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: ' 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 2012/2.1 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 polonium to seaborgium in spontaneous fission and neutron-induced fission. The result refers to first-chance fission. 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. - Four 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] determines the prompt neutron yields and the odd-even effect in fission-fragment yields of even-Z and odd-Z systems. - Neutron evaporation is calculated with a Monte-Carlo statistical code using level densities from empirical systematics and binding energies with theoretical shell effects with gamma competition included. 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). 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. 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. 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. The author tested GEF on Windows [a] and linux. Memory < 50 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. Eventually, some additional packages need to be installed, e.g. X11 developer tools. 11. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS GEF covers only first-chance fission (before evaporation of neutrons). 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, neutron evaporation. 15. PRACTICAL HINTS 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. 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".) If you want to make any changes to GEF, prepare an executable, using an IDE (e.g. GEANY [e]) with the FreeBASIC [c] compiler. GEF.BAS is the main routine. The other files are automatically included in the compilation process. Remark: 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 "Plotting.bas" ) in GEF.BAS. Required input of GEF: Z and A of fissioning nucleus Excitation mode and excitation energy Quantities available on output of GEF: Relative yields of fission channels Element-yield distribution Isotonic-yield distribution (pre- and post-neutron) 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 (Many more quantities are internally calculated and may be listed.) Advanced options: GEF supports reading an input list from file. This option is chosen if the file "file.in" is found. Instructions: 1. Create a file with the following information: First line: Statistical enhancement factor (default = 1). A larger factor increases the number of calculated events accordingly. Following lines: Specification of the fissioning system. (Z_CN, A_CN, kind of fission, energy) Example for spontaneous fission: 10 98, 250, "GS", 0 98, 252, "GS", 0 ... Example for neutron-induced fission: 2 92, 234, "EN", 0.0253E-6 92, 236, "EN", 0.0253E-6 Example for fission from a shape isomer: (The isomers must be listed in the file NucProp.bas.) 100 94, 241, "IS1", 0 94, 242, "IS1", 0 ... In the case of neutron-induced fission, a sequence of energies is calculated. This sequence is specified in the code. Only the lowest energy (in MeV) is given in the input file. 2. Create the file "file.in", which only contains the name of the input file in the first line. (At the moment, only one input file is allowed at a time.) GEF also supports starting several processes in parallel, which calculate the systems given in the input file in parallel in a coordinated way. This enables making efficient use of modern multiprocessor machines. Before starting a new sequence of calculations, the files "done.ctl" and "thread.ctl" must be deleted. [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] Geany is available from http://www.geany.org/ with no cost. In case of problems, please contact schmidt-erzhausen at t-online.de .