you have to write all particles that you want to study

Hi Modeste Tchakoua Tchouaso i'm having the same problem.

Were you able to solve the problem?

Dear Augusto Di Chicco & Modeste Tchakoua Tchouaso

1) in mode card you must define particle alpha,gamma and neutron

2)also you must configure physic card for all particle

3) be carefuller that imp card define correctly

best way is that you attach your program

Dear Rasul Shamohamadi

This is a simple example of spherical stilbene.

Title : Sfera Stil

c One Stilbene scintillator

c CELL CARDS

100 1 -1.15 -10 $ Stilbene

800 0 -90 10 $ air

900 0 90 $ everything else

c END CELL CARDS - BLANK LINE FOLLOWS

c SURFACE CARDS

c Detector, 100 cm left of source

10 SO 10

c Bounding box

90 SO 500

c END SURFACE CARDS - BLANK LINE FOLLOWS

c DATA CARDS

MODE N P A

IMP:n 1 1 0

IMP:p 1 0 0

IMP:a 1 0 0

PHYS:N j 20 0 -1 -1 0 1

PHYS:A 20 0 -1 J 0 J 1

PHYS:P j 1

CUT:N 2j 0 $ Analog capture

CUT:P 2j 0

CUT:A J 0 $ Energy cut

NPS 1e7

PRINT

DBCN

PRDMP 2j 1

c SOURCE cards

sdef POS=0 0 -12 ERG = 9.25 PAR=1

c MATERIAL SPECIFICATION

c Organic Scintillator

M1 6000 0.5385

1001 0.4615

E0 1.000E-6 500I 20

F14:N 100

c FM34 (1.15 1 107) $ 107 for (n,alpha) reaction

c F24:H 100

F34:A 100

F38:A 100

E38 0 500i 20

FT138 CAP

c F44:# 100

ptrac buffer=10000 file=asc write=all max=2e9 cell=100 type=A

c END OF FILE

When I try to ask PTRAC to record only alpha particles the file is completely empty. I chose to simulate 9.25 MeV neutrons because there is a resonance for reaction C(n,a)Be MT=107. I can't really understand why there are no alpha particles.

Thanks for your help.

Dear Augusto Di Chicco

I checked. As you said, alpha particles were not produced. But the reason was because of the following:

*)alpha cross section not found

I attach a file of photon production cross section to show what we want and table that show alpha particle really not created .

I ran it with MCNPx2.6. But I don't know which version you are using.

on order to solve your problem, you must define cross section anually.

Dear Rasul Shamohamadi ,

Thank you so much for your answer. I am using MCNPX 2.7. It seems very strange to me that the reaction is not found. However I will try to use other nuclear libraries to see if the problem persists.

Best regards

chère Augusto Di Chicco

vous êtes les bienvenus.

Je suggère deux façons

1) Utilisez d'autres logiciels tels que Talys.

2) Entrez la section transversale liée aux interactions dans MCNP

Augusto Di Chicco,

You need more than indicate the particles that are produced in the reaction ,.i.e alpha,gammas etc. You need to also add the following lines when running the code: export G4PHP_USE_NRESP71_MODEL was used in Geant4.

See attachment. Let me know if this helps.

Modeste

Modeste Tchakoua Tchouaso ,

In the end, I too developed a model with G4 is much more accurate. Thanks for the reply.

Best regards

ADC

Augusto Di Chicco I am glad you could find an answer.

Regards,

Modeste