Dear Alexy,
On Mon, Feb 04 2019, at 15:54 +0000, Загороднюк Алексей А. wrote:
>
>Dear Fluka users,
>
>
>I'm trying to simulate the optical response function from scintillation detector. To solve this problem i want to calculate the total photon quantity in the specified region and the average photon density in this region per unit volume. I have some questions about USRBIN output:
Considering your full message, it sounds like you're interested in the
number of optical photons which eventually cross the boundary from the
scintillator region into a region where a photomultiplier would be.
For this, a one-way scoring of the optical-photon current from your
scintillator across the surface towards the relevant region with a
USRBDX would be more natural. With this you would be counting optical
photons crossing the surface (per unit primary of course).
>1) If i use USRBIN with WHAT(1) = region and WHAT(2) = OPTIPHOT and define only one region, do i get the total optical photon quantity in the specified region per 1 Gev of consumed energy (Sum of optical photons per 1 GeV) in this region?
When scoring per region, you will have noticed there is no volume
information available to the code to normalize scored quantities. So you
have to be alert when it comes to physical units.
In the case you mention, you get an optical-photon tracklength in the
region, per primary, i.e., a quantity in units of cm/primary.
If you manually divide by the region volume, you would get the fluence
(tracklength density) averaged in the region, in units of
1/cm^2/primary.
Neither corresponds to the number (or density) of optical photons
produced: the physical dimensions do not match.
Note also, that at this stage there is no "per GeV", just "per primary".
>2) If i use USRBIN with WHAT(1) = X-Y-Z WHAT(2) = OPTIPHOT and define only one bin which is exactly the size of the specified region, do i get an Average photon density per unit volume (photon per cm3) in this region?
>
No, you get an optical-photon fluence averaged in the whole region, in
units of 1/cm^2/primary (in this case the code knows what is the volume
of the Cartesian/cylindrical USRBIN and can divide by the volume to
yield the 1/cm^2 part of the physical dimensions).
>
>Thank you in advance,
>
>
>Alexy
With kind regards,
Cesc
--
Francesc Salvat Pujol
CERN-EN/STI
CH-1211 Geneva 23
Switzerland
Tel: +41 22 76 64011
Fax: +41 22 76 69474
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Received on Tue Feb 05 2019 - 14:28:50 CET