Question reg. error code 99

[Ophir Ruimi]

Hello,
We are writing a simulation for a gamma ray passing through a plasma window.
G4beamline yields an unclear error (see below) reg. improper definition of the element "beam", which is in fact defined (see g4bl file + particle phase-space file (beam input text file) attached). Can you let us know what could be the matter?

the errors:

**************************
* G4Exception: printError
*    severity: Warning
*   issued by:
* description: place: cannot find element 'beam'
**************************
**************************
* G4Exception: Input Errors
*    severity: Fatal Exception
*   issued by: main
* description: There were 1 errors in the input
**************************

Thank you in advance,
Ophir

[Daniel Kaplan]

Dear Ophir,

One thing I notice is you commented out the physics command. Isn’t a physics command mandatory?

I also wonder what the effect of particle=gamma would be. Your beam file already specifies that each particle is a gamma, so specifying it in the beam common seems redundant. 

Dan Kaplan

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On Mar 4, 2025, at 8:27 AM, Ophir Ruimi <ophir...@mail.huji.ac.il> wrote:

Hello,

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<SimSimp (2).g4bl>

<beam_particles.txt>

[Ophir Ruimi]

Dear Daniel,
Thank you very much for your prompt reply.
We uncommented the physics command and deleted the particle=gamma line (as it already appears in the input file, as you pointed out), and it yields the same errors.

Any other ideas?
Best regards,

Ophir

[Graeme Scott]

Dear Ophir,

I believe your error is coming from the place command after beam, I don't believe there's any need to 'place' the beam. Try commenting that out on line 26. I believe the position of the beam is defined by providing x, y, z co-ordinates after 'beam'.

Hopefully that resolves things for you,

Graeme

[Daniel Kaplan]

Yes, I agree. 

Dan

Sent from my iPhone

On Mar 4, 2025, at 10:35 AM, Graeme Scott <graemego...@gmail.com> wrote:

Dear Ophir,

To view this discussion visit https://groups.google.com/a/muonsinc.com/d/msgid/g4beamline/540ad33b-5a78-4e7f-a4bc-940dfd9ace76n%40muonsinc.com.

[Ophir Ruimi]

Dear Daniel and Graeme,
Thank you very much! It indeed helped us - it runs (with warnings but no errors), but now, the output file (TE) is empty (zero energy on all detectors).
Would you mind having another look?
Thanks again,

Yotam and Ophir