A measurement of the parity conserving asymmetry in the neutron capture on $^3He$ at SNS.

The $n^3He$ experiment at the Spallation Neutron Source is motivated to measure the parity violating asymmetry of the recoil proton momentum $k_p$ with respect to the neutron spin $\sigma_n$ in the reaction n+ $^3$He $\to$ p +T+765 KeV. This is sensitive to isospin $\Delta I$ = 0 and 1 components of the Hadronic Weak Interaction (HWI), and is expected to be extremely small (~$10^{-7}$). There is an additional parity even nuclear asymmetry proportional to $\vec{k}_p \cdot \vec{\sigma}_n \times \vec{k}_n$ predicted by R-matrix analysis to be $1\times10^{-6}$ at 5 meV [1]. We measured this asymmetry for the first time for verification of nuclear theory in this new observable and for confirmation of the sensitivity of our experiment to the parity violating asymmetry. I will present the measurement of the PC asymmetry and discuss on data analysis. [1] G. Hale, Hadronic Parity Violation Workshop, Madison, WI, 2007.