Gabriele Cosmo
52 lines
2.6 KiB
Plaintext
52 lines
2.6 KiB
Plaintext
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This README file provides instructions for reading the radioactive decay
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schemes in the files zXX.aYYY found in the directory RadioactiveDecay5.0
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(most recent version). This directory, as well as previous versions, is
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available from the Geant4 download page
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http://cern.ch/geant4/support/download.shtml
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under the Data files heading. In order to use the radioactive decay module
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correctly, you must download and unpack the above directory in your local
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area, and set the environment variable
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G4RADIOACTIVEDATA
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to point to it.
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**************************************************************************
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In each of the files, lines beginning with '#' are comments.
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Lines beginning with a 'P' are headers, indicating metastable states of the
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nucleus which may be parent nuclei for further decays. The first number is
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the excitation energy in keV, followed by a character representing the floating
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level. If this is "-", the level is assumed to be fixed. If it is
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+X, +Y, +Z, +W, +U or +V, the level is floating, or undetermined. The number
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following this is the half life in seconds. Indented lines under the 'P' lines
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are decay modes for that excitation. There are two types of records here,
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distinguished by the number of columns.
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If there are four columns only, this is a header describing the total strength
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of each type of decay from this level. The first column is the decay mode,
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the second column is always zero, the third column indicates whether the level
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is floating or not, as mentioned above, and the fourth column is the total
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branching ratio going through this mode, as a fraction of unity. Therefore,
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the fourth column of all the 4-column records under a given 'P' line should sum
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to 1.0.
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If there are five columns, this is a record which describes a subset of the
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decay type, specific to a given lower level in the daughter species. The
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first column is the decay type, the second and third columns are the excitation
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level (keV) of the daughter reached after the decay and its floating level
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indicator, and the fourth column is the branching ratio as a percentage
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(! note... not a fraction of unity) of the total branching ratio which came
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from the 4-column record for this decay.
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In the case of beta- or beta+ decay, there will often be a sixth column
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describing the "forbiddenness" of the particular decay channel. This is
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indicated by the tags firstForbidden, secondForbidden, thirdForbidden,
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uniqueFirstForbidden, uniqueSecondForbidden, uniqueThirdForbidden, which
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determine the shape of the beta spectrum.
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**************************************************************************
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