The 4·77 MeV level in boron 10

Abstract

The angular distribution of the γ-rays in ⁶Li(αγ)¹⁰B has been measured for the 500 kev resonance. Spin and parity of the 4.77 MeV level in ¹⁰B are 2+ or 3+. The intensity of the direct transition to the ground state is lees than 3% of the intensity of the 4·06 mev γ transition. The width of the level _ωΓ_αΓ_γ/Γ_α+Γ_γ, is about 5×10⁻² ev. The 4·05 mev E2 transition is at least twice as strong as one would expect from the Weisskopf formula.