AmBe NeutronSource spectrum issues

Physics Processes, Models and Cross Sections
1

Dear All,

I’m simulating a Am241-Be9 neutron source, similar to the one in the extended/hadronic/NeutronSource example.

I have tried both the standard version as well as some modifications, but the output Neutron spectrum doesn’t match the reference one (see https://www.sciencedirect.com/science/article/abs/pii/0029554X73901997 and others). For instance, I’m missing the 5.5, 8 and 10 MeV peaks. I have tried simulating the spectrum both inside and outside the steel casing. The AmBe ratio is about 10/90% Am/Be.
In paper “NUCLEAR INSTRUMENTS AND METHODS III (I973) 435–440; © NORTH-HOLLAND PUBLISHING CO. THE NEUTRON SPECTRUM OF Am-Be NEUTRON SOURCES”, they show the following, so I take there is a problem with the ground state of 12C, and possibly with the 1st excited state too.

image
image539×593 17.7 KB

What am I missing? I think there is an issue with simulating the C12 excited states, but I don’t really know for sure.

Thank you

1 Like
2

have you worked out the issue?

MJ

4

Hi!

Have you guys figured out what is going on here? I’m trying to simulate an AmBe source using the /extended/hadronic/NeutronSource example as a reference, but I’m facing the same issue where I can’t see the 5.5, 8 and 10 MeV peaks. You can find the spectrum I get from my simulation attached.

QGSP_BIC_HP_neutron_spectrum
QGSP_BIC_HP_neutron_spectrum1579×846 12.2 KB

Version: Geant4 v10.7.4
Physics List: QGSP_BIC_HP

5

Do you have

G4ParticleHPManager::GetInstance()->SetUseNRESP71Model( true );

Set somewhere or in the macro? I know specifically it was implemented to help with neutron reactions on carbon and I have used it for sub 3 MeV reactions. I think the ultimate lineage of that was this paper. Any G4 developer feel free to correct me.

6

Hi there,

I’ve sorted out all the problems a short while ago. I’ve written an open access paper on this and it is in the review process.
Once it’s reviewed I’ll link it here.

7

Thank you to everyone for replying. I’m looking forward to reading the paper!

1 Like
8

Hi,

We passed peer review and are waiting for final pubblication. In the meanwhile, you can find the article here Redirecting

In there we explain how the AmBe generation process in the default simulation is flawed because of a lack of differential cross sections, and how we have fixed it.

We’re also in the process of publishing the updated code in the repository mentioned in the paper, as it’s going through clean up first.

Cheers,

Filippo

1 Like
9

Hi Filippo, I missed this message. This is cool, I’ll have a look at your paper.

Thanks!

Luis

1 Like