Why the same one simulation writed with two different libraries, lead to different result and ptracks??

[kstcmcjw]

Still is my program, as the dose can't display in the EGS_gui, so i think if i should change the geometry programming?
the same simulation, i set a point collimated_source, and target shape with a rectangle, in the Z-plane direction, -80 -24.2 -0.2 0 500, stand for the air, brick, lead plate, air,respectively.

I use the "library = egs_ndgeometry+type = EGS_XYZGeometry", get the ptracks, it seems that the photons can't through the lead plate, and there is no photon in the 24cm brick. And there is no fluence in the region 1

###1.RUN CONTROL
:start run control:
    ncase = 1e5
:stop run control:

###2.GEOMETRY
:start geometry definition:
:start geometry:
name = protection
library = egs_ndgeometry
type = EGS_XYZGeometry
x-planes = -100, 100 # in cm
y-planes = -100, 100 # in cm
z-planes = -80, -24.2, -0.2, 0, 500 # in cm
:start media input:
media = air brick lead  # Indexed as 0 1
set medium = 0 0
set medium = 1 1
set medium = 2 2
set medium = 3 0
:stop media input:
:stop geometry:
simulation geometry = protection
:stop geometry definition:

###3.MEDIA
:start media definition: 
  ae = 0.521 # lowest energy for electrons (kinetic+0.511)
  ap = 0.01 # lowest energy for photons (kinetic)
  ue = 50.511 # maximum energy for electrons (kinetic+0.511)
  up = 50 # maximum energy for photons (kinetic)
 
  :start brick: # this name can be anything
           density correction file = brick
  :stop brick:
   
  :start lead:
      density correction file = lead
  :stop lead:

  :start air:
      density correction file = air_dry_nearsealevel
  :stop air:

  :start glass:
      density correction file = glass_borosilicate__pyrex__corning7740
  :stop glass:

:stop media definition:

###4.SOURCE
:start source definition:
    :start source:
        library = egs_collimated_source
        name = tube_source
        :start source shape:
            type = point
            position = 0 0 200
        :stop source shape:
        :start target shape:
            library = egs_rectangle
            rectangle = -20 -20 20 20
        :stop target shape:
            distance = 200
            charge = 0
        :start spectrum:
            type = monoenergetic
            energy = 0.12
        :stop spectrum:
    :stop source:
    simulation source = tube_source
:stop source definition:

###5.VIEWER CONTROL
:start view control:
  set color = lead 128 128 128 255
  set color = brick 64 128 128 255
  set color = air 0 200 200 200 
:stop view control:

###6.AUSGAB OBJECTS
:start ausgab object definition: 
    :start ausgab object:
      name = tracks
      library = egs_track_scoring
    :stop ausgab object:

  :start ausgab object:
      library = egs_dose_scoring
      name = air_chambers
      medium dose  = no
      region dose  = yes
      volume = 1
      dose regions = 1
  :stop ausgab object:
:stop ausgab object definition:

![image](https://user-images.githubusercontent.com/96934217/177791839-47ec7b5d-1d6f-4c91-9d81-e9da8db2c520.png)

![image](https://user-images.githubusercontent.com/96934217/177792434-f67d9e0c-da61-4024-ade5-40c8a49da55d.png)

As the picture shows, the photon can't penetrate the lead and brick!

But use the "library = egs_planes+library = egs_cdgeometry", get the ptracks, it seems that the photons through the lead plate easily, and there are much photon go through the 0.2cm lead plate and 24cm brick. And there is 3.5145e-007  fluence in the region dose.

###1.RUN CONTROL
:start run control:
    ncase = 1e5
:stop run control:

###2.GEOMETRY
:start geometry definition:
  :start geometry: 
    name = cd_planes
    library = egs_planes
    type = EGS_Zplanes
    positions = -80 -24.2 -0.2 0 500
  :stop geometry:

  :start geometry:
    name = air
    library = egs_box
    box size = 100 100 600
        :start media input:
            media = air
        :stop media input:
  :stop geometry:
  simulation geometry = air

  :start geometry:
    name = barrier_lead
    library = egs_box
    box size = 100 100 10
        :start media input:
            media = lead
        :stop media input:
  :stop geometry:
  simulation geometry = barrier_lead

 :start geometry:
    name = barrier_brick
    library = egs_box
    box size = 100 100 50
        :start media input:
            media = brick
        :stop media input:
  :stop geometry:
  simulation geometry = barrier_brick
  
  :start geometry:
    name = chamber
    library = egs_spheres
    library = egs_planes
    type = EGS_Zplanes
    midpoint = 0 0 -54.2
    radii = 0.6204 0.7204
    :start media input:
        media = air glass
        set medium = 1 1
        set medium = 2 2
    :stop media input:
  :stop geometry:
  simulation geometry = chamber

    :start geometry:
        library  = egs_genvelope
        name = air_chambers
        base geometry = air
        inscribed geometries = chamber 
    :stop geometry:
    simulation geometry = air_chambers
  
  :start geometry:
    name = protection
    library = egs_cdgeometry
    base geometry =cd_planes
    set geometry = 3 air
    set geometry = 2 barrier_lead
    set geometry = 1 barrier_brick
    set geometry = 0 air_chambers

  :stop geometry:
  simulation geometry = protection

:stop geometry definition:

###3.MEDIA
:start media definition: 
  ae = 0.521 # lowest energy for electrons (kinetic+0.511)
  ap = 0.01 # lowest energy for photons (kinetic)
  ue = 50.511 # maximum energy for electrons (kinetic+0.511)
  up = 50 # maximum energy for photons (kinetic)
 
  :start brick: # this name can be anything
           density correction file = brick
  :stop brick:
   
  :start lead:
      density correction file = lead
  :stop lead:

  :start air:
      density correction file = air_dry_nearsealevel
  :stop air:

  :start glass:
      density correction file = glass_borosilicate__pyrex__corning7740
  :stop glass:

:stop media definition:

###4.SOURCE
:start source definition:
    :start source:
        library = egs_collimated_source
        name = tube_source
        :start source shape:
            type = point
            position = 0 0 200
        :stop source shape:
        :start target shape:
            library = egs_rectangle
            rectangle = -20 -20 20 20
        :stop target shape:
            distance = 200
            charge = 0
        :start spectrum:
            type = monoenergetic
            energy = 0.12
        :stop spectrum:
    :stop source:
    simulation source = tube_source
:stop source definition:

###5.VIEWER CONTROL
:start view control:
  set color = lead 128 128 128 255
  set color = brick 64 128 128 255
  set color = air 0 200 200 200
  set color = glass 255 0 255 255
 
:stop view control:

###6.AUSGAB OBJECTS
:start ausgab object definition: 
    :start ausgab object:
      name = tracks
      library = egs_track_scoring
    :stop ausgab object:

  :start ausgab object:
      library = egs_dose_scoring
      name = air_chambers
      medium dose  = no
      region dose  = yes
      volume = 1
      dose regions = air_chambers
  :stop ausgab object:
:stop ausgab object definition:

In my opinion, same simulation, same geometry, same collimated_source, same target, and same energy, same distance, then the same result, but, the output is different!

Why? Only the library and type lead the different result???

[rtownson]

There are mistakes in your inputs, this is why your results don't make sense.

simulation geometry = chamber

You can only have 1 line defining the simulation geometry. You have several lines redefining it. I'm not sure which it is using, but judging by the tracks the simulation is just running in air. This input parameter defines the single geometry in which to run simulations.

dose regions = air_chambers

This is not valid. The dose regions must either be a list of numbers, or the name of a label. If you are interested, region labels are described here: https://nrc-cnrc.github.io/EGSnrc/doc/pirs898/egs_chamber.html (but you don't need to use them).

[kstcmcjw]

Thank you, i know my second dose output programming has something wrong, in the #890 we had disscussed, so I changed another program method, use the different library and type, but it shocked me as the figures difference!
Well, i don't think the dose_scoring would affect the output, in other words, it would be affect and change the photons strick and through the lead plate, as you see the two figures.
https://user-images.githubusercontent.com/96934217/177792434-f67d9e0c-da61-4024-ade5-40c8a49da55d.png
https://user-images.githubusercontent.com/96934217/177793815-7bce8b45-1ae3-4c1c-99df-202e26a643b9.png

But i quite want know why the two program has two difference output GES_VIEW figures? I am puzzled at these two output figures!

[ftessier]

In egs_view there is no constraint linking the .egsinp file (geometry) and the .ptracks (particle tracks) file that you load. You can load any geometry with any tracks file, which would then look inconsistent. It is your responsibility to ensure that the tracks correspond to the geometry you are viewing.

[kstcmcjw]

Thank you, that you mean, different programming would lead to the different figure, the two method which I used may all programmed correct, but I should select the right one, the one fit for the objective facts' figure，is it right？