[Gate-users] Energy Resolution

Khalid Hussain khalidhussain1134 at gmail.com
Mon Aug 24 06:46:51 CEST 2020

Dear Miriam,

As per my experience , the below script
0.085, *Set the value of the energy window, so changing the energy window
will change the value of energy resolution that you get from singles.
Let assume Tc-99 which has reference energy 140kev, so, in this case if you
set  *setResolution 0.085 *, you are using energy window of 8.5 % which
means energy above 140+8.5=148.5kev and below 140-8.5=131.5 will not appear
in your energy resolution graph, and FWHM will be calculated within in this

Similarly, if you increase the energy window to 10%  *setResolution 0.10 *the
energy below 130kev and above 150kev will be skipped. and hence FWHM will
be calculated from this window and this value with 10% energy window will
be a gigger value then the energy window of 8.5%.


On Mon, Aug 24, 2020, 9:24 AM Miriam Dixon <miriam.gatemc at gmail.com> wrote:

> Hi Gate Users,
> I am modelling a physical SPECT system in GATE, and so trying to get my
> simulation parameters as close as possible to the physical system
> parameters. I am slightly confused about the energy resolution settings
> within GATE. When I set the energy resolution in the digitizer to match the
> measured energy resolution of my physical system (0.095, 9.5%) the energy
> spectrum output shows a FWHM of my photo peak of ~10.6%. When I reduce the
> given energy resolution to 0.085, I get a FWHM of 9.5%. The
> EnergyOfReference is the same as the value of the photo peak of my
> spectrum. What I have is usable, but I am very interested to know if anyone
> has an explanation for this difference.
> The energy resolution section of my digitizer macro reads:
> # Energy Blurring
> /gate/digitizer/Singles/insert blurring
> /gate/digitizer/Singles/blurring/setLaw inverseSquare
> /gate/digitizer/Singles/blurring/inverseSquare/setResolution 0.085
> /gate/digitizer/Singles/blurring/inverseSquare/setEnergyOfReference 140.0
> keV
> I am using vGate v9.0
> Cheers,
> Miriam
> _______________________________________________
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> Gate-users at lists.opengatecollaboration.org
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