ALICE2011: Statistical Model Code System to Calculate Particle Spectra from HMS Precompound Nucleus Decay
Lawrence Livermore National Laboratory, Livermore, California,
Institut f. Reaktorsicherheit, Forschungszentrum Karlsruhe, FRG,
Los Alamos National Laboratory, Los Alamos, New Mexico,
Institute of Applied Physics,Academy of Sciences, Chisinau, Moldova
Institute of Physics and Power Engineering, Obninsk, Russia.
Fortran; PC and Mac (P00550PCX8603).
The HMS-Alice (Hybrid Monte-Carlo Simulation) codes began evolution from the Alice code in 1985 with the development of the Monte Carlo precompound model. This new release designated HMS-ALICE2011 uses the HMS precompound decay model, the Weisskopf- Ewing evaporation model (with optional s-wave approximation) and Bohr-Wheeler fission models. Treatment of angular distributions uses the linear momentum conservation model of Chadwick and Oblozinskyall with multiple particle emission cascades to estimate single- and double-differential emission spectra and product yields of nuclear reactions induced by probes from photons to heavy ions. Initial excitations up to 1 GeV should be tolerated, but a range of 0.2-250 MeV is advised as pion production channels have not been programmed into the physics. Product yields include A, Z of fission products. An option exists to give output of exclusive particle emission spectra of up to multiplicity 3. This version of ALICE gives the option (parm=512) to override the A=12 default mass number as the mass at or below which Fermi decay is implemented. This version also differs from earlier versions in allowing isotopic targets to be used except for incident heavy ions (A>1). It contains cluster exit channels on demand, precompound and compound (use PARM=128). An ENDF output for 1,2,3 n,p,alpha out reactions is an option. The logic used could be extended to include other clusters and to higher multiplicities if needed. Earlier versions permitted setting of coincident detector ‘gates’ to predict spectra such as might be measured in an experiment with multiple detectors.
5. METHOD OF SOLUTION
The models listed above are evaluated using Monte-Carlo methods with an energy histogram for emission spectra/residual excitations where the mesh size is an input option. The angular distributions are based on the linear momentum conservation model of Chadwick and Oblozinsky. Natural isotopic targets may be specified. Cluster exit channels are an option.
HMS-Alice2011 has been written for ease of use via an interactive interrogating screen default input option, which offers master user choice or author defaults of calculation details/methods (e.g. level densities, energy mesh, output types, etc.). It outputs useable input files to hard drive which may be used, or edited and used by option to bypass the interactive input process.
Sample problems ran in approximately 15 seconds. Time depends on the number of Monte-Carlo events per incident energy, number of incident energies, and excitation energies.
ALICE2011 runs on PC or Mac and consumes approximately 12MB of disk space.
The code runs on PC under Windows or Linux and on Mac computers. A Fortran 95 compiler is required on all systems. This package has no executables in the package distribution.
10.a included in documentation:
M. Blann, A. Y. Konobeev, W. B. Wilson, and S. G. Mashnik, “Manual for Code Alice Version July 7, 2008,” (July 27, 2008).
M. Blann, W. G. Wilson, S. G. Mashnik, and A. Y. Konobeev, “Summary of Capabilities of Monte-Carlo HMSALICE Code Post-1996,” (September 17, 2008).
M. Blann and A. Y. Konobeev, “Precompound Cluster Decay in HMSAlice,” (September 22, 2008).
10.b special acknowledgement
A. V. Ignatyuk, V. P. Lunev, and Yu. N. Shubin from the Institute of Physics and Power Engineering, Obninsk.
The package is transmitted on a CD-R in a WinZIP file, which contains the documents referenced above, source code, and example problems.
October 2009, July 2010, December 2010, September 2011.
KEYWORDS: NUCLEAR MODELS; WORKSTATION; MICROCOMPUTER