[Gate-users] Materials.xml collaboration !

[Samuel BURG]

Thank you very much !

I've misunderstanding the equations,
and about the energy resolution I've mismatch 'overall
resolution' (cristal+PM, R at 511 = 0.12) and 'intrinsic
resolution' (cristal alone, R at 511 = 0.09) !

Best regards,

Samuel

--- D.J.vanderLaan at IRI.TUDELFT.NL a écrit :

> Hi Samuel,
> 
> I had another look at the equations, but as far I
> can see the equations in
> the manual are correct.
> 
> The standard deviation in the number of optical
> photons generated by the
> scintillation event N at E is given by:
>   s = RS*sqrt(N at E),
> with N at E = E * SY. Using this in the equation for
> the energy resolution:
>   R at E = FWHM at E/N at E = 2.35*s/N at E
>       = 2.35*RS*sqrt(N at E)/N at E
>       = 2.35*RS/sqrt(N at E)
> From which the resolution scale can be derived:
>   RS = R at E*sqrt(N at E)/2.35
> 
> Using the following numbers for LSO:
>   SY = 26000 1/MeV
>   R at 511 = 0.09 (this is the value used in the
> Materials.xml file)
>   E = 0.511 MeV
> 
> Gives
>   RS = 0.09*sqrt(26000*0.511)/2.35 = 4.41
> 
> 
> 
> Regards,
> Jan
> 
> 
> 
> 
> 
> > Hi all,
> >
> > a litle update/fix about "RESOLUTIONSCALE", but
> not a
> > solution.
> >
> > Best regards,
> >
> > Samuel Burg
> >
> >
> > --- Samuel BURG <samuel_burg at yahoo.fr> a écrit :
> >
> >> Hi Simon,
> >> Hi all,
> >>
> >> 1)
> >> here's some data I've collected about most used
> >> cristals : NaI(Tl), BGO, GSO, LSO:Ce, YSO,
> YAP:Ce,
> >> CsI(Tl), CsI(Na).
> >>
> >> I have not put them in a structured XML file, as
> >> there
> >> is still some missing data (mostly ABSLENGHT at PEAK
> >> and
> >> RESOLUTIONSCALE).
> >>
> >> 2)
> >> I'm also very confuesed about page 162 of the
> >> GateUserGuide_v3.1.2, § "12.2.1 Scintillation
> >> properties" :
> >>
> >> Knowing number of photons follow a normal
> >> distribution
> >> (Gauss Law), and assuming equation 12.2 [s = RS *
> >> sqrt
> >> (E * SY)] is right,
> >> then equation 12.3 [RS = R at E / 2.35 * sqrt(E *
> SY)]
> >> is
> >> false and should be : [ RS = R at E / (2.35 * sqrt(E
> *
> >> SY)) ].
> >>
> >> s = standar deviation
> >> RS = ResolutionScale
> >> sqrt = square root
> >> E = energy (511000 eV)
> >> SY = ScintillationYield
> >> R at E = energy résolution @ E
> >>
> >> as we have a normal law : FWHM = 2,354820045 *
> Simga
> >>
> >> 3)
> >> Then I have had a look in the Materials.xml
> sample
> >> file given with Gate 3.1.2, and found the data
> about
> >> LSO:
> >>
> >> .../...
> >> <material name="LSO">
> >> <propertiestable>
> >> <property name="SCINTILLATIONYIELD" value="26000"
> >> unit="1/MeV"/>
> >> <property name="RESOLUTIONSCALE" value="4.41"/>
> >> .../...
> >>
> >> but when I use [ RS = R at E / (2.35 * sqrt(E * SY))
> ]
> >> with :
> >>
> >> R = 0,12
> >> E = 511000
> >> SY = 26000
> >>
> >> I found RS = 0,23, witch is about 1/4.41 !
> >>
> >> So, what do we need to put in Materials.xml for
> >> RESOLUTIONSCALE, and how to compute it ?!?
> >>
> >>
> >>
> >> Best regards,
> >>
> >> Samuel Burg
> >>
> >>
> >>
> >> --- Simon Stute <gate.stute at gmail.com> a écrit :
> >>
> >> > Hi all,
> >> >
> >> >
> >> > I suggest to everybody that have done some
> optical
> >> > photon tracking with Gate
> >> > to answer this mail and to post your
> Materials.xml
> >> > file if it contains some
> >> > additional material definitions. It would be
> nice
> >> to
> >> > merge them and to put
> >> > the more complete file as possible in the next
> >> Gate
> >> > release. And I propose
> >> > to do the job :-)
> >> > When you post your file, could you just write
> the
> >> > list of materials included
> >> > in this file to easily avoid multiple
> definition
> >> ??
> >> >
> >> > Thanks in advance for your collaboration,
> >> > Simon Stute
> >> > >
> _______________________________________________
> >> > Gate-users mailing list
> >> > Gate-users at lists.healthgrid.org
> >> >
> >>
> >
>
http://lists.healthgrid.org/mailman/listinfo/gate-users
> >> >
> >>
> >>
> >>
> >>
> >>
> >
>
_____________________________________________________________________________
> >>
> >> Ne gardez plus qu'une seule adresse mail ! Copiez
> >> vos mails vers Yahoo! Mail http://mail.yahoo.fr>
> > _______________________________________________
> >> Gate-users mailing list
> >> Gate-users at lists.healthgrid.org
> >>
> >
>
http://lists.healthgrid.org/mailman/listinfo/gate-users
> >>
> >
> >
> >
> >      
>
_____________________________________________________________________________
> > Ne gardez plus qu'une seule adresse mail ! Copiez
> vos mails vers Yahoo!
> > Mail http://mail.yahoo.fr
> > _______________________________________________
> > Gate-users mailing list
> > Gate-users at lists.healthgrid.org
> >
>
http://lists.healthgrid.org/mailman/listinfo/gate-users
> >
> 
> 



      _____________________________________________________________________________ 
Ne gardez plus qu'une seule adresse mail ! Copiez vos mails vers Yahoo! Mail http://mail.yahoo.fr