Different deposited energy depending if beam comes from X/Z

Geometry and Materials
1

Dear Experts,

I am shooting a beam to copper cylinder and when beam comes from z direction energy deposition is smaller than if beam comes from x.
There are the input files, where beam comes from X/Z:
exampleX.inp (1.2 KB)
exampleZ.inp (1.2 KB)

On this plots you can see the difference:
plotX.pdf (52.4 KB)
plotZ.pdf (53.3 KB)

Thank you very much for explanation
David

3

Dear @dgancarc,

I had a look at your plots and inputs and I have a couple of comments for you.
1-Both your plots show energy deposited between -15 and 15 cm while the geometry in both your input file has a target between -5 and 5 cm and vacuum outside this range. How is this possible? Is it just a plotting problem or maybe you ran a different input?
2-Your beam has a rectangular shape. When you “moved the beams”, you moved its center without rotating it. To rotate the beams you have to use the BEAMAXES card. This is likely to cause a difference in the energy deposition distribution.

4

Dear @amario ,

thank you for contacting me.

  1. I swap the plots with a run I did before this one sorry for that. Nevertheless the correct ones also differ.
    exampleXplot.pdf (23.0 KB)
    exampleZplot.pdf (19.7 KB)

  2. Thank you very much for this information. So assuming the original beam has energy of 440GeV and gaussian profile with x(FWHM) = y(FWHM) = 0.2596 and y coordinate of the beam is -0.5 and beam starts at z = -50 and going through the target

BEAM          -440.0                       -0.2596   -0.2596          PROTON
BEAMPOS                   -3.0     -50.0

and I want to have exactly the same beam coming from negative X direction. Then the cards should be:

BEAM          -440.0                       -0.2596   -0.2596          PROTON
BEAMPOS         -50.      -3.0
BEAMAXES                             1.0       1.0

Is this correct?

Thank you
David

5

1-These are indeed the same plots I got.

2-No, it’s not correct. The card should be

BEAMAXES           1         0         0         0         0         1

also, but that’s minor, you said that the y coordinate should be -0.5 but in the BEAMPOS card you wrote -3.0 .
You can check the beam direction looking at the “BEAM” in the geometry tab and you can check the beam profile adding a USRBIN scoring just downstream of the beam origin.

6

  1. They look same but the x axis is different

  2. Thank you for correcting me. I viewed the beam in geometry but to check beam profile at beam origin is very good idea.

Thank you very much for the help!

ADDED LATER:

After some tests I can see that correct way is to use this:

BEAM          -440.0                       -0.2596   -0.2596          PROTON
BEAMPOS         -50.      -5.0                  0.       0.0
BEAMAXES          0.        1.        0.        1.        0.        0.