A Large Solid Angle Study of Pion Absorption on He3
  Measurements have been made of pi+ absorption on He3 at T_pi+ = 118, 162, and 239 MeV using the Large Acceptance Detector System (LADS). The nearly 4pi solid angle coverage of this detector minimizes uncertainties associated with extrapolations over unmeasured regions of phase space. The total absorption cross section is reported. In addition, the total cross section is divided into components in which only two or all three nucleons play a significant role in the process. These are the first direct measurements of the total and three nucleon absorption cross sections. 
LADS collaboration, T.Alteholz, D.Androic, G.Backenstoss, D.Bosnar,   H.Breuer, A.Brkovic, H.Dobbeling, T. Dooling, W.Fong, ...