The improvement of the energy resolution in epi-thermal neutron region of Bonner sphere using boric acid water solution moderator

• Boric acid solution is useful to improve the energy resolution of Bonner sphere.
• Uncertainty of the device configuration is critical for neutron spectrometry.
• It is important to reduce and evaluate the uncertainty.

Bonner sphere is useful to evaluate the neutron spectrum in detail. We are improving the energy resolution in epi-thermal neutron region of Bonner sphere, using boric acid water solution as a moderator. Its response function peak is narrower than that for polyethylene moderator and the improvement of the resolution is expected. The resolutions between polyethylene moderator and boric acid water solution moderator were compared by simulation calculation. Also the influence in the uncertainty of Bonner sphere configuration to spectrum estimation was simulated.