Package janus.format.endf.data.weighting comprised of classes that implement weighting functions. These functions represent the weighting of a cross-section by a flux. This cross-section is imported from FILE 3 in ENDF format. The corresponding weighting grid is selected by the user.
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The flux given by the user may be of four types:
· constant at a given value.
· given in a text file in the form of a list of (x,y) pairs that are to be linearly interpolated.
· corresponding to the flux of a pressurized water reactor (PWR). This flux is defined on three energy ranges by three functions. There are constraints of continuity at the boundaries of the energy ranges.
· in a generalized form. In this form there are four functions defined on four energy ranges. There are also constraints of continuity at the boundaries of the energy ranges for this case.
The third case is a specific case of the fourth in which the last energy range is non-existent.
The weighting grid is one of two types:
· having a regular step in a logarithmic scale with a number of groups per decade. The number of groups are defined by the user.
· being defined by the user. In this case, a file is given containing the boundaries of each range used for integration.
Class ENDF_Spectrumand its subclasses implement the types of flux used for calculating weighted cross-sections. These classes are all subclasses of Function and ComputableFunction. Once the Function object describing the flux is derived, it is assigned to the field functionin an ENDF_SpectrumData object. The ENDF_SpectrumData and ENDF_WeightedCrossSectionobjects are both DataLeaf instantiations. Their parent is an ENDF_WeightedDataNodeor DataNode object. This DataNode object is then assigned to a DataBlockobject. These relationships are illustrated in Figure 3-1.
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Figure 3-1. Illustration of tree structure for weighting data with the tree levels appearing on the left