UMG31-FC

Prepared by: Marcel Reginatto, PTB Marcel.Reginatto@ptb.de
Contents The programs MXD_FC31, GRV_FC31 and IQU_FC31.................................................. 3 Instructions for running MXD_FC31 and GRV_FC31...................................................... 6 Input files for MXD_FC31 and GRV_FC31.................................................................... 13 Output files generated by MXD_FC31 and GRV_FC31 ................................................. 21 Instructions for running IQU_FC31................................................................................. 23 Input files for IQU_FC31................................................................................................. 27 Output files generated by IQU_FC31 .............................................................................. 33 Appendix 1: The MXD_FC31 and IQU_FC31 algorithms .............................................. 34 Appendix 2: The GRV_FC31 algorithm .......................................................................... 41 Appendix 3: Some remarks on the use of diagonal and block diagonal covariance matrices to describe uncertainty in the default spectrum.................................................. 42 References........................................................................................................................ 49
********************************************************************** * * * Copyright Notice for U_M_G * * * * The programs in the UMG package were prepared by employees of the * * Physikalisch-Technische Bundesanstalt (PTB). All rights in the * * programs are reserved by the PTB. Neither the German Government * * nor the PTB makes any warranty, express or implied, or assumes * * any liability or responsibility for the use of this software. * * * **********************************************************************
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*********************************************** *** *** *** U_M_G version 3.1 *** *** *** *** Unfolding with Maxed and Gravel *** *** *** *********************************************** Release date: 5 - August - 2002
The authors: -----------Marcel Reginatto, Marcel.Reginatto@ptb.de Burkhard Wiegel, Burkhard.Wiegel@ptb.de Andreas Zimbal, Andreas.Zimbal@ptb.de Physikalisch-Technische Bundesanstalt (PTB) Section 6.42, "Neutron Dosimetry" Bundesallee 100 38116 Braunschweig GERMANY
MXD_FC31 was written specifically for the unfolding of Bonner sphere data, but it can be adapted for use with other types of “few-channel” data. It differs from the original version of MAXED (1) in the following ways: (1) It can be can run either interactively or using a control file. (2) The main algorithm has been modified slightly. A new constraint (see Appendix 1, equation 2.A) has been added to the set of conditions under which the relative entropy is maximized. (3) The algorithm used for searching for the maximum of the entropy has been modified slightly, and now the temperature parameter used by the simulated annealing algorithm
Note: ----The original version of MAXED was developed by Marcel Reginatto and Paul Goldhagen, EML The HEPRO package, including PlofW and PlotaW was developed by Manfred Matzke, PTB
The "few-channel" unfolding programs in the UMG package: MXD_FC31 and IQU_FC31, and GRV_FC31 (UMG package, version 3.1 - release date: August 5, 2002)
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can be set in almost all cases to 1.0 (in the original version of MAXED it depended somewhat on the input data). (4) The format of the input and output files has been modified, to allow the user to run the program as part of the HEPRO package(9). (5) It generates an additional output file, with extension “.par”, which is used by the program IQU_FC31. (6) A new “ Requested final chi-squared per degree of freedom ” parameter allows the user to pre-define the final chi-squared per degree of freedom of the solution (in the original version of MAXED it was set equal to 1). (7) The SAND-II option has been elis MXD_FC31, GRV_FC31 and IQU_FC31
The purpose of this report is to provide clear and concise instructions for running the “fewchannel” unfolding programs MXD_FC31 (a modification of MAXED) and GRV_FC31 (a modification of SAND-II) and the integral quantities, sensitivity analysis and uncertainty propagation program IQU_FC31. Therefore, we include only a brief account of the mathematical basis of these programs (see Appendices 1 and 2), and very little discussion regarding their conceptual basis. These issues are, however, of great importance and we strongly encourage the user to become familiar with the basic ideas that these programs are based on before attempting to run them. For a discussion of the approach used in MXD_FC31, see previous publications on MAXED(1-3) as well as more general references on the application of the maximum entropy principle to problems of data analysis (4,5). For a discussion of the approach used in GRV_FC31, see the original SAND-II report(6) as well as more general references on unfolding methods(7,8).