@article{helmer_1977, 
  title={Investigation of electric quadrupole strength in ¹³N using the ¹²C(p,Ύ₀)¹³N reaction}, 
  DOI={10.14288/1.0084769}, 
  abstractNote={The E2 cross section for the ¹²C(p,Ύ₀)¹³N reaction has been measured from 10 MeV to 17 MeV in the laboratory system by bombarding an enriched carbon-12 target with beams of polarized protons. A 10 in. φ x 10 in, Nal(Tl) detector with a plastic anti-coincidence shield was used to detect the gamma rays. The total E2 capture cross sections were of the order of 0.2 ybarns and no resonance effects were observed. The amount of the E2 energy-weighted sum rule depleted in this energy range is (10.3 ± 4.0)%. Calculations based on a direct semi-direct capture model provide a good description of the experimental results by including only direct E2 capture and direct plus collective E1 capture.}, 
  publisher={The University of British Columbia}, 
  author={Helmer, Richard Lloyd}, 
  year={1977}
  }