Dear Riya,
I think that Kerma includes the kinetic energy of charged particles only, so it should not include (highly energetic) X-rays which escape the region of interest. However - contrary to dose - it would include the escaping secondary electrons.
Regarding the transport cutoff for electrons, Paola suggested that the threshold should be as high as possible, but just below the energy of your primary photon - so maybe I wouldn't put it at 1 MeV exactly.
For the scoring, USRBIN would not include the energy of the escaping photons, but that is ok because it shouldn't be included in the kerma either.
If the scoring is done with USRBIN as energy, the result would be per cubic centimeter, so you need to take density into account. If it is done with "dose", then the mass is taken into account already.
Yours,
Matteo
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De : owner-fluka-discuss_at_mi.infn.itDe la part deriya dey Envoyé : lundi 16 juillet 2018 06:22:27 (UTC+01:00) Amsterdam, Berlin, Berne, Rome, Stockholm, Vienne À : paola.sala_at_mi.infn.it; fluka-discuss_at_fluka.org Objet : RE: [fluka-discuss]: TRANSPORT CUTOFF VALUES FOR ESTIMATION OF AIR KERMA
Dear Expert,
I want to estimate air kerma. Now suppose for 1 MeV source photon, the transport cutoff for electrons is chosen 1 MeV and the gamma cut off is chosen as low as possible ( 10 keV let's say ) . Now energy is scored in USRBIN . Now if we divide the energy with the mass of the detector , we will get the value of air kerma. Is it correct way to estimate air kerma in FLUKA ?
My concern is since for high energy photons, although some highly energetic secondary electrons and X-rays escape the region of interest before depositing their energy, their escaping energy is counted in kerma according to the theory. But if I score energy in USRBIN, is that escaping energy counted or not ?
With regards,
Riya dey
-----Original Message-----
From: owner-fluka-discuss_at_mi.infn.it [mailto:owner-fluka-discuss_at_mi.infn.it]
On Behalf Of Paola Sala
Sent: 14 July 2018 22:01
To: riya dey <riyadey_at_barc.gov.in>
Cc: fluka-discuss_at_fluka.org
Subject: Re: [fluka-discuss]: TRANSPORT CUTOFF VALUES FOR ESTIMATION OF AIR KERMA
Dear Riya Day
I am not sure that I understand, do you want to score kerma or dose?
Foe kerma, threshold should be as high as possible, just below the energy of your primary photon.
For dose..as low as possible
Scoring can be done with USRBIN in energy Regards Paola
> Dear FLUKA Experts,
>
>
>
> What transport cutoff values should be used to determine air kerma ??
> Also, what should be scored in USRBIN ??
>
> For low-energy photons, kerma is numerically approximately the same as
> absorbed dose. For higher-energy photons, kerma is larger than
> absorbed dose because some highly energetic secondary electrons and
> X-rays escape the region of interest before depositing their energy.
> The escaping energy is counted in kerma, but not in absorbed dose.
>
>
>
>
>
> With regards,
>
> Riya Dey
>
>
>
>
>
>
Paola Sala
INFN Milano
tel. Milano +39-0250317374
tel. CERN +41-227679148
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Received on Mon Jul 16 2018 - 12:44:49 CEST