Planar/RPP Source

Source Definition
1

Dear Experts,

I have a Ge-Ga Target plate placed in a lead container. As I understand the Ga-68 will decay by positron emission (89 %) followed by 2 annihilation photons (511 keV). So, I thought of using a single photon of 511 keV in the input. I want to simulate the dose rate on the surface of the shielding container.
I took guidance from the previous posts on defining a RPP / Planar source, but my case is a little different. The dimensions are 2 x 11 cm along XZ while it is only 20 microns thick (along Y), centred at (0,0,0)
Can this be a planar source also?
Or, when I define it as a RPP source - and write the co-ordinates from .f file, all the x,y,z coordinates have zero value in the text file generated. I am not able to find why? Kindly guide. PFA the input and .f files.
RPP_source.f (9.7 KB)
SinglePhoton_RPPSource.inp (3.2 KB)

Then we also tried, taking it as a planar source: the following is used in .f file: [Ref.: Doubt regarding beam intensity (p/s) in IRRPROFI card - #4 by riya ]

  •  Planar Source        
  open (unit=10, file = 'test.txt')
  random_prob1 = FLRNDM (xdummy1) 
  random_prob2 = FLRNDM (xdummy2) 

 coordinate_x = -1.0D0 + 2.0D0*random_prob1
 coordinate_y = 0.0D0 
 coordinate_z = -5.5D0 + 11.0D0*random_prob2
 WRITE (10, *) coordinate_x,coordinate_y,coordinate_z

With this, the values obtained are very less. PFA the input, .f and .lis. Am I doing something wrong?
SinglePhoton_PlanarSource.inp (3.2 KB)
SinglePhoton_PlanarSource_21.bnn.lis (4.7 KB)
Planar_source.f (19.0 KB)

I am also not sure of using SDUM=CART-VOL in BEAMPOS card, although I will try and produce results with that too.

Thanks and Regards.
Jyoti Garg

3

Dear @jyoti.grg,

Thanks for your message.

  1. Can you explain me in more detail what you are trying to have as a source of particles?
    If I understand correctly, you want to create a planar source, i.e. a flat 2D surface, where on each point, selected uniformly, the particles are emitted isotropically emitting 511 keV photons. In that case, you can do this in an easier manner with the BEAM and BEAMPOS card in the following way:

Screenshot from 2023-08-16 13-57-44

  1. For the RPP case, you can use, as you said at the end of your message, the CART-VOL option:

Screenshot from 2023-08-16 14-04-33

You can find more information about the source definition here:

Hope this helps,
Let me know if you have any other questions,

Cheers,
André

1 Like