Geant4 Cross Reference |
1 2 This README file provides instructions for reading the radioactive decay 3 schemes in the files zXX.aYYY found in the directory RadioactiveDecay3.2 4 (most recent version). This directory, as well as previous versions, is 5 available from the Geant4 download page 6 7 http://geant4.web.cern.ch/geant4/support/download.shtml 8 9 under the Data files heading. In order to use the radioactive decay module 10 correctly, you must download and unpack the above directory in your local 11 area, and set the environment variable 12 13 G4RADIOACTIVEDATA 14 15 to point to it. 16 17 ************************************************************************** 18 In each of the files, lines beginning with either a 'W' or a '#' are 19 comments. 20 21 Lines beginning with a 'P' are headers, each of which describes a level of 22 the nucleus. The first number is the excitation energy in keV, the second 23 is the half life in seconds. Indented lines under the 'P' lines are decay 24 modes for that excitation. There are two type of records here, 25 distinguished by the number of columns. 26 27 If there are 3 columns only, this is a header which describes all decays of 28 that type from this level. The first column is the decay mode, the second 29 column is zero, and the third column in the branching ratio to this mode, 30 as a fraction of unity. Therefore, the third columns of all the 3-column 31 records under a given 'P' line should sum to 1.0. 32 33 If there are four columns, this is a record which describes a subset of the 34 decay type, specific to a given lower level in the daughter species. The 35 first column is the decay type, the second column is the excitation level 36 of the daughter (in keV), and the third column is the branching ratio as a 37 percentage (! note... not a fraction of unity) of the total branching ratio 38 which came from the 3-column record for this decay.