Dear Fluka experts

I am getting some unexpected results when increasing the pressure of a fixed volume of Nitrogen gas.

I am interested in the amount of activation generated in the nitrogen gas. However, when I increase the pressure from 1bar to 10bar (a factor of 10 density increase - 0.0011g/cc to 0.011g/cc) I get a factor of 100 increase in the total activity.

I have tried with and without the MAT-PROP card and set the pressure to 10 bar although this seems to make little difference to the results.

I have attached my input file although this includes lots of other details as I was previously using it to look at the foils separating the gas.

Thanks,

Mike

He_10atm.inp (31.2 KB)

He_10atm.flair (46.2 KB)

Table of results below

Pressure | 1bar | 10bar |
---|---|---|

Decay time | 1 sec | 1 sec |

Window gap | 1.34E+06 | 2.35E+08 |

Gap 1 | 1.28E+06 | 2.42E+08 |

Gap 2 | 1.59E+06 | 2.53E+08 |

Gap 3 | 1.73E+06 | 2.65E+08 |

Gap 4 | 2.28E+06 | 2.81E+08 |

Gap 5 | 2.90E+06 | 2.98E+08 |

Gap 6 | 3.50E+06 | 3.11E+08 |

Gap 7 | 4.77E+06 | 3.35E+08 |

Gap 8 | 5.07E+06 | 3.48E+08 |

Gap 9 | 4.25E+06 | 3.64E+08 |

Gap 10 | 2.94E+06 | 3.23E+08 |

Gap 11 | 2.22E+06 | 2.44E+08 |

Gap 12 | 2.03E+06 | 1.93E+08 |

Gap 13 | 1.97E+06 | 1.96E+08 |

Gap 14 | 5.03E+06 | 4.23E+08 |

TOTAL (Bq) | 4.29E+07 | 4.31E+09 |

TOTAL (MBq) | 42.88 | 4310.77 |