Neutron production from a 5 MeV proton beam on a beryllium target


I am trying to generate neutrons from bombarding a 5 MeV proton beam on a beryllium target.
I have tried many different physics lists such as FTFP_BERT, QGSP_BERT, and QBBC, etc.

None of the lists gives me good enough neutron kinematics compared with measurements. In particular, with a 1 mA proton beam on beryllium, I am expecting 3e12 neutrons.
However, I only get 1/4 neutron flux with the QBBC physics list, which is already the list with the most generated neutrons.

Would experts here recommend a physics list, or an example for me to generate neutrons that best match measurements?



May be you will find this review of physics lists helpful:
Pay special attention to lists with the “_HP” at the end, which indicates using a high precision neutron package.
Note: physics lists with _HP consume a lot more CP-time. For example, in my special case one event with QGSP_BERT generated approximately ten times faster then with QGSP_BERT_HP

You may use G4QGSP_BIC_AllHP, with the AllHP option you will get the neutron production from the ENDF/B-VII.1 database. See for example

Here, a run of example Hadr03, with G4HadronPhysics_BIC_AllHP (see
You need to have G4TENDL1.3.2 installed.

shihkai.mac.txt (285 Bytes)
shihkai.out.txt (2.5 KB)