|Message: Re: Question about the photocathode simulation and how to Detect the photon?||Not Logged In (login)|
Click on the Forum title, e.g. on the "Forums by Category" page, to read a sequence of postings to the Forum and its threads all in one page. If you are only interested in one thread or the thread following a specific posting, click the thread or the posting, which takes you to a smaller page, which contains only the part you are interested in and may be easier to navigate.
Messages are "chained" if there are only replies at the first level, i.e. 1/1.html, 1/1/1.html etc. In case of "chained" messages the message number is replaced by the icon and there is no indentation.
Inline: Display the subject line only or also the text of the posting(s); for the choice "All" the "Outline" choices are switched off.
|1||0||1||no text / full text of posting|
|2||1||All||text for level 1 only / text for All postings|
Outline: Choose the depth of the posting thread, successive toggle controls provide increasing detail.
|1||2||1||2 levels / 1 level (original posting)|
|2||3||2||3 levels / 2 levels|
|3||3||All||3 levels / all levels (all postings)|
for completeness I reply to this posting:
> I use Geant4.9.4.p01. Sorry, I think I made a mistake to decode the > value of 12. In this version, I think it should mean "StepTooSmall"
It is normal to have a step whose status is "StepTooSmall" for the so called reallocation step after the program determined that an optical photon reflects off a surface.
> When I run the program, I saw the un-correct value > > PMT-windows and Photocathode interface: > > theLocalPoint: (-2.39593,-1.56864,1.15e-05) > > theGlobalPoint: (0.644071,7.55136,-6.87) ====> correct > > theLocalNormal: (-0,-0,-1) ====> correct > > theGlobalNormal: (0,0,1)
This all looks correct to me - theLocalPoint is the coordinate in the coordinate system centered about the 'local volume' (e.g. the deepest volume in the geometry hierarchy). Similarly, theLocalNormal is the direction in the coordinate system 'attached' to that local volume. The global point and normal are the coordinates and direction cosign with respect to the global coordinate system. This come in when the local volume is positioned from the origin wrt its mother and/or positioned with a rotation.
> Length of this Step: 1.54227 mm =====> step length > > 6 +++++++++++++++++++++++++>>>> Status of boundary: SpikeReflection > > Process name:Transportation > > Length of tghis Step: 0 mm > > 12 =========================>>StepTooSmall
As I said, this is to be expected upon a reflection on a geometry boundary.