Using the Doppler broadened γ line of the 10B(n,αγ)7Li reaction for thermal neutron detection

Y. Ben-Galim, U. Wengrowicz, R. Moreh, I. Orion, A. Raveh

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


When a thermal neutron is absorbed by 10B in the 10B(n,α)7Li reaction, there is a chance of 94% that a 478 keV photon be emitted by an excited 7Li nucleus. This reaction is exothermic with a Q-value of 2.31 MeV and the nuclei are emitted with kinetic energies of E(α)=1.47 MeV and E(7Li∗)=0.84 MeV. This implies that the 478 keV γ line is emitted by a moving 7Li nucleus and hence is expected to be Doppler broadened. In the present work we suggest to use this broadening of the γ line as a fingerprint for the detection of thermal neutrons using a high resolution gamma spectrometer. We thus developed a Monte Carlo program using a MATLAB code based on a High Purity Germanium (HPGe) detector coupled with a Boron Carbide (B4C) sheet to calculate the γ line broadening. Our simulation shows that the FWHM width of the resulting γ line is 12.6 keV, in good agreement with our measurement. Hence the broadened γ line emitted by the 10B(n,αγ)7Li reaction and detected by a HPGe detector shows that this method is an effective tool for neutron detection while maintaining good gamma discrimination.


  • BC
  • Boron carbide
  • Doppler broadening
  • HPGe
  • Neutron detection

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation


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