I have created a cylinder which is at the center of the world volume (Box) replacing the existing geometries in B1 example. I have used subtraction operation to get the existing volume of the box outside the cylinder (Box - Cylinder) and have filled this existing volume with water. Now I want to measure the dose in this water body by making it the scoring volume and setting up a line source at the center of the cylinder. The visuals are working but I am getting no values (0 nano-gray; even though the gamma(s) are being absorbed by the water body in the visuals). How can I get the deposited dose value in the water body?
Why do any subtraction? Place your cylinder of water directly as a daughter volume of the world. The way you have described it, I would expect you to get error messages about the cylinder being placed outside the World.
I am using the cylinder (made of Pb) as a shielding body and trying to get the dose estimation that would be caused by the gamma rays escaping the cylinder. Normally the gamma rays would scatter at any random direction; so to cover all directions, I was thinking of using the water body. But now that you have said it, I think if I made a bigger cylinder that can cover the primary cylinder and fill it with water, I can get the desired output.
Thank you so much for the insight.
I’m still facing the same problem. Even if I place a larger cylinder outside my primary cylinder and set this larger one as the sensitive volume, I will only get the dose for the gamma rays that have escaped radially. The top and bottom of the sensitive cylinder is still hollow, so most of the gamma will escape from there and won’t be accounted for the dose. Is there any way to enclose the whole primary cylinder?
I must admit to not being particularly versed in scoring volumes or scoring surfaces. In our experiment we make use of “sensitive detectors” (G4VSensitiveDetector subclasses) which create hit objects for later analysis.
I read the section of the Developers Guide on scorers (https://geant4-userdoc.web.cern.ch/UsersGuides/ForApplicationDeveloper/html/Detector/commandScore.html). I wonder if what you’re looking for is what’s called “passageCellFlux”, with the scorer assigned directly to your lead volume. That should report the gammas escaping through the lead shield.
Otherwise, if you set your scoring volume to be a water (or any other material) completely surrounding the lead (make sure it’s bigger in Z as well as R), then the endcaps won’t be open.
I tried using sensitive detectors in the past, but I still haven’t got hold of Root analysis. That’s why I was trying to get the results in a basic way(by using scoring volume). But I think I will stick with the later part of your suggestion, by creating a bigger volume around my primary volume.
Thank you so much for your suggestions and your time. Really appreciated.