Re: Role of DCYTIMES in finding time evolution of dose eq rate

From: Mina Nozar <nozarm_at_triumf.ca>
Date: Tue, 24 Jul 2012 10:37:11 -0700

Dear Francesco,

Thank you for your reply.

On 12-07-24 06:07 AM, Francesco Cerutti wrote:
> Dear Mina
> let me reaffirm some fundamental beliefs:

> i. putting in a card a wrong (misspelled) name of a region leads the run to abort. Putting in RESNUCLE a name of a wrong
> (not desired) region has no effect on other detectors. (I understand that you did not mean the opposite, but it's just
> to prevent any misinterpretation of your message).

By "wrong" I meant not a misspelling of a region's name but the name of another defined region in the input file. In
this case, FLUKA runs without any issues. I was studying six different targets (so six different FLUKA setups, one for
each), each containing a set of regions. I was scoring activities for same ramp-up and cooling times in each case for
six regions making up the target. These regions were: Tgt (target material), Ta (Tantalum), Cu (Cupper), 6061 (an
Aluminium alloy), AlN (Aluminium Nitride), and SSN (stainless steel). When comparing activities 3 years after EOB with
assay results, we noticed a large discrepancy for Na-22 activities. When I looked closer, I found out that I had
mistakenly assigned Tgt as the region for 6061 and Na-22 is largely produced from 6061 and AlN. In the second set of
runs, I corrected this and saw that Na-22 levels were higher. At the same time, I re-checked the dose rates as a
function of the same ramp-up and cooling times, expecting to get the same results as before but results were lower.
This was puzzling and set off a set of investigation.

> ii. residual dose values at a given cooling time depend on the irradiation profile and on the selected cooling time, and
> not on other cooling times.

This is what I would have expected as well.

> Now, in your two cases (Ta26_Wrong and Ta26), you have always 13 cooling times, with identical subsequences #1-2 and
> #5-13, whereas #3[Ta26_Wrong]=#4[Ta26]. So, for negative and zero cooling times (up to #5 included) your results look
> perfectly consistent (and your table is wrong, since a "*" is put on the wrong row - 2 instead of 4 - and you compare in
> rows 3-4 values referring to different cooling times).

Yes, this is true. I have corrected the placement of the *.

> As for the discrepancies at positive cooling times, would you be so kind as to send the two input files in order to
> investigate them?
> Ciao
> Francesco

Yes, I will in a second. This has been bothering me since I systematically eliminated all other differences in the two
input files (PART-THRES, EMF-BIAS, scaling transport threshold cut in the RADDECAY card, slight error in the original
geometry, even different versions of FLUKA).

Thank you again,
Mina
Received on Tue Jul 24 2012 - 22:41:41 CEST

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