From: Mina Nozar <nozarm_at_triumf.ca>

Date: Mon, 16 Apr 2012 16:43:56 -0700

Date: Mon, 16 Apr 2012 16:43:56 -0700

Dear Anna and Stefan,

Thank you for your clear explanations.

I have also checked the results of a USRTRACK estimator with the results of a USRBIN estimator (region binning) where I

have scored DOSE-EQ and the region of interest in each estimator is the same.

Integrating the DOSE-EQ over all energy bins in USRTRACK gives me the same result as the USRBIN estimator (once I divide

by the region's volume).

So I understand what is going now.

Thanks again and best wishes,

Mina

On 12-04-15 02:48 PM, Anna Ferrari wrote:

*> Dear Mina,
*

*>
*

*> no, the problem must not be seen in this way.
*

*> The units are exactly as written in the manual and as you reported:
*

*>
*

*> 13) The results from USRBIN are normalised per unit volume and per unit
*

*> primary weight,except for (...) and for dose equivalent,
*

*> <==============
*

*> expressed as pSv per unit primary weight.<==============
*

*>
*

*> First: it does not make sense to express the dose equivalent in pSv/cm3!
*

*> You have always to remember how an average dose equivalent in a given volume
*

*> is evaluated: you calculate the average fluence (in part./cm^2 per primary) of
*

*> the components of the radiation field in the volume and then you apply the
*

*> appropriate conversion coefficients (in pSv cm^2) to get the dose equivalent
*

*> due to this average radiation field . To each point of the volume you
*

*> associate then this average dose equivalent, which is expressed in pSv/primary
*

*> (thinking to the meaning of the dose equivalent is helpful).
*

*>
*

*> Let's think then about your examples:
*

*>
*

*> a) USRBIN scoring with space binning
*

*> An average radiation field is calculated in each element of the defined USRBIN
*

*> mesh in the space. The dose equivalent values you get (in pSv/primary) refer
*

*> to these elements. They refer to 1 cm^3 volumes only if you have set this
*

*> granularity.
*

*>
*

*>
*

*> b) USRBIN scoring with region binning
*

*> We have to take care here.
*

*> The manual states that this is the only case where USRBIN results are NOT
*

*> normalized by volume. The delicate point is that at the moment this is not
*

*> dependent on the specification or not of the volume in the geometry section,
*

*> which applies only to the quantities calculated via the SCORE option.
*

*> [ From the FLUKA manual, section: 2.2.6:
*

*> "The only effect of specifying region volumes is to normalise per cm3 the
*

*> quantities calculated via the SCORE option (...): for other estimators
*

*> requiring volume normalisation the volume is input as part of the detector
*

*> definition (USRTRACK, USRCOLL, USRYIELD), or is calculated directly by the
*

*> program (USRBIN)", where the last sentence refers only to the USRBIN scoring
*

*> with space mesh (I admit here it is not too clear).]
*

*>
*

*> This means that with the region binning option you will not get the average
*

*> fluence in the volume (in part/cm^2), but the total tracklength in the
*

*> selected region. To get the fluence and finally the correct average dose
*

*> equivalent (always in pSv/primary) you have to divide offline by the volume.
*

*> I think this is a complication (!) that can be easily avoided by using USRBIN
*

*> with space mesh, a choice that I prefer also under the dosimetric point of
*

*> view (I can choose how well I want to approximate the radiation field -and
*

*> then the dose equivalent calculation- and I can avoid to average on large
*

*> volumes, with probable dangerous underestimations of the dose in critical
*

*> points).
*

*>
*

*> Last: yes, you know already that with the IRRPROF card you pass from pSv/prim
*

*> to pSv/s, because you input the current in prim/s.
*

*>
*

*> I hope this helps to clarify a bit,
*

*> best regards,
*

*> Anna
*

*>
*

*>
*

*> Am Thu, 12 Apr 2012 13:05:43 -0700 schrieb Mina Nozar<nozarm_at_triumf.ca>:
*

*>> Dear FLUKA users, can someone confirm whether the following statements are
*

*>> correct?
*

*>>
*

*>> - USRBIN scoring (spacial binning)
*

*>> pSv/cm^3*prim - with no IRRPROF card
*

*>> pSv/cm^3*sec - with an IRRPROF card
*

*>>
*

*>>
*

*>> - USRBIN scoring (region binning)
*

*>> pSv/prim - with no IRRPROF card and with no volume input for the given in
*

*>> the geometry section)
*

*>> pSv/sec - with an IRRPROF card and with no volume input for the given in
*

*>> the geometry section)
*

*>>
*

*>>
*

*>> pSv/prim - with no IRRPROF card and with the region volume given in the
*

*>> geometry section)
*

*>> pSv/sec - with an IRRPROF card and with the region volume given in the
*

*>> geometry section)
*

*>>
*

*>>
*

*>> So regardless of whether region volumes are given in the geometry section,
*

*>> units are pSv/prim or pSv/sec in the region
*

*>> binning? This is how I interpret the manual under USRBIN:
*

*>>
*

*>>
*

*>> 13) The results from USRBIN are normalised per unit volume and per unit
*

*>> primary weight, except for region binnings and special user-defined
*

*>> binnings, which are normalised per unit primary weight only, for
*

*>> DPA, which are given as number of displacements per atom per unit
*

*>> primary weight, averaged over the bin volume, and for dose
*

*>> <==============
*

*>> equivalent, expressed as pSv per unit primary weight.
*

*>> <==============
*

*>> In case symmetries are requested, proper rescaled volumes are taken
*

*>> into account for normalisation (that is, an extra factor 2 is
*

*>> applied to the volume if symmetry around one plane is required, 8 if
*

*>> the symmetry is around the origin)
*

*>>
*

*>>
*

*>> Thank you for the clarification,
*

*>> Mina
*

*>>
*

*>
*

Received on Tue Apr 17 2012 - 13:56:10 CEST

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