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⁹Be(γ, n)⁸Be

Photonuclear reaction:

• overcome the binding energy of nucleus
  
• threshold at E=1.665 MeV for ⁹Be
  

1) Setup and source

Point source: γ-rays at 2614 keV for ²²⁸Th and 2204 keV, 2448 keV for ²²⁶Ra

2) Photonuclear cross-section

• photonuclear data library: ENDF7u https://nucleardata.lanl.gov/ace/endf7u
• comparison with the current data library https://www-nds.iaea.org/photonuclear/
• very small → biased technique and set a cut at 1.665 MeV to save the computation power
• A preliminary simulation using 10^9 γ photons at the 2614 keV is shown below,

3) A toy simulation

• 20 MeV uniformly injected on a cylindrical Be target (thickness 1 mm, diameter 1 cm)
• the target is surrounded by a sphere and the neutrons crossing the surface is accumulated.
• compare with the literature (https://www.sciencedirect.com/science/article/pii/S0168583X24000624) Fig.1.
• the spectra are similar, but the magnitude diverges, need more check
• change the γ energy to 2.614 MeV and the Be target thickness to 4 mm, 2.4 cm

Is there secondary interactions related to the setup?

• different configurations with the PE moderator
• neutron flux is calculated from a box volume surrounding the Be target (the y axis unit is different from the previous plot)

• varying the Be target thickness
• neutron flux is calculated from a box volume surrounding the Be target

5) Simulation with the ²²⁶Ra source emitting γ-rays with 2448 keV and 2204 keV

With the corresponding emission probability of γ photons at the two energies, in total 10^9 particles are simulated. The results are seen below,

^ γ-rays in the Be target ^

6) Al plate

7) Source locations

 /home/yingjiechu/simulation/gagg/Ra_Be/about.txt
 /home/yingjiechu/simulation/gagg/Ra_Be/2614/about.txt