Calibration of Apparatus for Parity-Violating Neutron Spin Rotation in $^{4}$He Using Heavy Nuclei and Small Angle Scattering Standards

A measurement of parity-violating (PV) neutron spin rotation in liquid $^{4}$He, is being prepared at the NIST Center for Neutron Research (NCNR). To test the apparatus and amplify certain possible systematic effects we plan to conduct spin rotation measurements in the nuciei $^{139}$La, $^{81}$Br, and $^{35}$Cl. Large PV spin rotation effects have been seen in the past in $^{139}$La and $^{81}$Br, and $^{35}$Cl possesses a large P-odd gamma asymmetry. We also plan to use D$_{2}$O, whose small angle neutron scattering is well-known, to verify our estimates of systematic effects from small angle scattering and longitudinal magnetic fields. I will talk about our choices of targets and the design of target system. Work supported in part by NSF PHY-0457219.