From: Stefan Roesler (sroesler@mail.cern.ch)
Date: Wed Sep 20 2006 - 12:14:50 CEST
Hello Nisy,
A few comments:
1) Fluences were never multiplied with conversion factors due to a
misalignment in the input, e.g.
USRTRACK 1.0 8.0 -23. 34.14137.1669 1. AMB74-P34
USRTRACK 0.0 0.0 &
The SDUM must always start in column 71, otherwise my dose conversion
factor folding would not know which set to use and return fluence
instead..
2) Your beam energy is set at 2MeV. In principle it should always be
higher than the highest energy set in source, i.e. 20MeV. I don't know if
results will be really different in case of low-energy neutrons, but at
least output files are not identical if I switch from 2MeV to 20MeV in the
beam card. Also you upper energy limit of the Usrtrack scoring is affected
for particles other than neutrons, e.g. in the output-file
for 2MeV
linear energy binning from 0.0000E+00 to 6.1337E-02 GeV, 1
bins ( 6.1337E-02 GeV
wide)
for 20MeV
linear energy binning from 0.0000E+00 to 1.9489E-01 GeV, 1
bins ( 1.9489E-01 GeV
wide)
3) I think you would like to score photons in detectors AMB74-P12 and
following, but what you score is indeed neutrons, e.g.
USRTRACK 1.0 8.0 23. 12.14137.1669 1. AMB74-P12
USRTRACK 0.0 0.0 &
Greetings
Stefan
On Tue, 19 Sep 2006, Nisy Ipe wrote:
> Hello all,
>
> I have a simple neutron problem - a 252Cf source inside a tunnel with
> concrete walls but no roof. The californium source has a dose rate
> profile and so a source routine was written (attached). Ambient dose
> equivalent for all particles, neutrons and photons were scored at
> various locations using USRTRACK and compiling with ustsuw.f. Input and
> results are attached. The results (calif. dose) read p/cmq/pr but I
> think in my case this would be pSv/n? Multiplying the mass by 2.4 E12
> n/g of 252Cf and the results by the number of neutrons, I obtained the
> ambient dose equivalents at various locations.
>
> If I do a simple calculation of dose transmitted through the concrete
> wall I get results which are 6 x higher tthan the FLUKA results. So I
> think I am doing something wrong but can't figure it out. Could the
> experts please help?
>
> Thanks and Regards,
>
> Nisy
>
-- ___________________________________ Stefan Roesler CERN, SC/RP CH-1211 Geneva 23 Switzerland Phone: +41-22-7679891 Fax: +41-22-7669639 E-mail: Stefan.Roesler@cern.ch
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