From: Francesco Cerutti (Francesco.Cerutti@cern.ch)
Date: Fri Aug 17 2007 - 16:51:09 CEST
Dear Yuanjie,
> (1)I use a negative decay time to score the neutron and gamma dose rate
> during irradiation, but FLUKA gives me the dose rate at the end of
> irradiation instead. I don't know why, are my following descriptions
> right?
>
> * 10days 5uA
> IRRPROFI 864000.0 3.12D+13
> RADDECAY 1.0 0.0 3.0 0.0 99999 0.0
> DCYTIMES 0.0 3600.0 28800.0 86400.0 604800.0 2592000.0
> DCYTIMES -1000.0
> USERWEIG 1.0
> DCYSCORE 7.0 EWT74Cn EWT74Cn USRBIN
> USRBIN 10.0 NEUTRON -40.0 100.0 100.0 0.5EWT74Cn
> USRBIN -100.0 -100.0 -0.5 100.0 100.0 10.0&
> DCYSCORE 7.0 EWT74Cp EWT74Cp USRBIN
> USRBIN 10.0 PHOTON -42.0 100.0 100.0 0.5EWT74Cp
> USRBIN -100.0 -100.0 -0.5 100.0 100.0 10.0&
your part of input looks fine. I think that the reason why the fluence
rate at -1000 s is equal to that at the irradiation end, is that you
already reached the saturation regime (where the decay rate of dominating
residual nuclei is equal to their production rate). If you look
at earlier times, e.g., -7d5 s, you will find lower values, i.e. build-up.
> (2)If the irradiation parameters and cooling times are not given, the
> gamma dose rate scored by usrbin includes radiation resulting from
> radioactive decay or not?
No, it doesn't. A USRBIN scoring not associated with any cooling time,
includes only the contribution of prompt radiation.
> (3) Is the result difference between 64bit PC and 32bit one?
In my tests I never saw differences, since FLUKA is always (also on 64bit
machines) compiled with the option -m32.
Cheers
Francesco
**************************************************
Francesco Cerutti
CERN-AB
CH-1211 Geneva 23
Switzerland
tel. ++41 22 7678962
fax ++41 22 7668854
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