Re: [fluka-discuss]: heavy ion dose scoring

From: Sunil C <csunil11_at_gmail.com>
Date: Mon, 8 Dec 2014 09:47:46 +0530

Dear Roxana

If you mean to score neutron (or photon) dose from heavy ion reactions,
then FLUKA has the capability to do so. If you intend to score the dose
equivalent due to (the exposure to) heavy ions, then FLUKA will do what you
quoted from the manual, simply because there are no fluence to dose
conversion coefficients available for heavy ions. For a list of available
dose conversion coefficients, please see http://www.fluka.org/DoseCoeff/.
However, the energy deposition (and thus the absorbed dose) due to heavy
ions can be scored. Dose equivalent can then be obtained using a radiation
weighting factor (Wr). ICRP publication number 103 recommends 20 as Wr for
alpha particles, fission fragments and heavy ions.
Best regards
Sunil

On Thu, Dec 4, 2014 at 7:38 PM, Roxana-georgiana Rata U1179323 <
Roxana.Rata_at_hud.ac.uk> wrote:

> Dear Sunil,
>
> Thank you for your help. Indeed, at this stage I am interested to obtain
> the prompt neutron dose, to see if we need a roof above the machine.
> Right now, I am running the simulations as you suggested me.
> Thank you for you useful advices.
> I have another questions. I will have to make the same scenario, but for
> other ions like O, Ne, He, Ar, Xe. DOSEEQ can be used for heavy ions?
> Because in the manual I found that :
> Dose conversion coefficients exist only for some particle types: hadrons,
> muons, photons, electrons/positrons. For all other particle types, zero
> factor will be returned. This is particularly
> important for heavy ions where zero factor will be scored
>
> Regards,
>
> Roxana
> ------------------------------
> *From:* Sunil C [csunil11_at_gmail.com]
> *Sent:* Thursday, December 04, 2014 5:16 AM
> *To:* Roxana-georgiana Rata U1179323
> *Cc:* fluka-discuss_at_fluka.org
> *Subject:* Re: [fluka-discuss]: heavy ion dose scoring
>
> Dear Roxana
>
> Your input is good, except I notice that you have an irradiation profile
> card which does not help just by itself. If you are interested in scoring a
> time profile result (such as induced activity or residual dose rates ), you
> must use raddecay, dcyscore and dcytimes and associate your scoring cards
> with the dcytimes cards.But I presume this is not what you want since you
> are looking for the prompt neutron dose (for shielding purposes, I gather)
> and your irradiation profile card was meant to obtain the neutron dose rate
> for a given beam current since you mention the beam loss number in it.
>
> I suggest removing the irradiation profile card, run simulations and
> obtain the dose results in pSv/primary. You can then convert it for your
> loss scenario. This also has an advantage that, if the beam loss scenarios
> are changed (a distinct possibility in the nascent stage of accelerator
> radiation shielding calculations), this number (or dose rate per unit beam
> current) alone is sufficient to calculate the new dose rates,shielded or
> not, as the dose rates scale linearly with the beam loss (beam current).
> Thus, obtain psv/ion, multiply it by the primaries per second (2.5e7
> ions/s in your case) and multiply by 3600 (s/h) to get pSv/h.Factor in the
> 1e-3 and you have microSv/h for your beam loss number.
>
> With flair, you can modify the usrbin results by multiplying with the
> (above) factor so that you obtain plots with units in microsv/h (instead of
> pSv/primary), and it should look like the one you had attached in one of
> your mails. Here, I attach a plot obtained with your input with 5e4
> primaries, in units of pSv/p (with some juggling in the range of values
> plotted) but without the irradiation profile card. The pattern is evidently
> similar to the other plot.
>
> I can also see that your stainless steel composition looks a tad
> incomplete. For the purpose of neutron production, it should be OK to use
> just a few element composition (and you have listed the major ones) but in
> case you also would like to calculate the induced activity or residual dose
> rate at a later stage, it is better to use a composition that is accurate
> upto the trace levels. Stainless steel can be a nasty object from the
> induced activity point of view.
>
> FLUKA very well reproduces the neutron and photon doses from heavy ion
> interactions at the energy domain you are working. I have compared such
> results with experimental results and found it to be excellent.
>
> Hope it helps!
>
> Cheers
> Sunil
>
>
> On Fri, Nov 28, 2014 at 4:38 PM, Roxana-georgiana Rata U1179323 <
> Roxana.Rata_at_hud.ac.uk> wrote:
>
>>
>> Dear FLUKA experts,
>>
>> I have to simulate a 250 MeV carbon beam hitting a stainless steel pipe
>> and to measure the neutron dose equivalent.
>> I created my input, my simulation is running perfectly but it seems that
>> the neutron dose is to low. In theory I should obtain 29 uSv/h for 1% beam
>> loss (2.5x10^7 ions/s)
>> Could you, please, check my input and tell me what I'm doing wrong?
>>
>> Thank you!
>>
>> Regards,
>>
>> Roxana
>> University of Huddersfield inspiring tomorrow's professionals.
>>
>>
>> This transmission is confidential and may be legally privileged. If you
>> receive it in error, please notify us immediately by e-mail and remove it
>> from your system. If the content of this e-mail does not relate to the
>> business of the University of Huddersfield, then we do not endorse it and
>> will accept no liability.
>>
>
> University of Huddersfield inspiring tomorrow's professionals.
>
>
> This transmission is confidential and may be legally privileged. If you
> receive it in error, please notify us immediately by e-mail and remove it
> from your system. If the content of this e-mail does not relate to the
> business of the University of Huddersfield, then we do not endorse it and
> will accept no liability.
>
Received on Mon Dec 08 2014 - 06:59:38 CET

This archive was generated by hypermail 2.3.0 : Mon Dec 08 2014 - 06:59:47 CET