1. Uncertainty for NPDGamma experiment in reaction Pil-Neyo Seo U of Virginia/TUNL HIGS2 Workshop, June 3-4, 2013

2. NPDGamma experiment

3. , where NPDGamma experiment

4. Uncertainties in NPDGamma experiment -Statistical uncertainty : associated with detected gamma rays, unavoidable : limit by beam intensity and detector solid angle : electronic noise and drift was small compared to counting statistics LANSCESNS

5. Uncertainties in NPDGamma experiment -Systematic uncertainty : not associated with the beam : gain drift and additive couplings (mag field on detector gain, leakage of control signal into preamp, shift in main voltage when pwr supply on and off…) - additive couplings diagnosed by no beam for up-down asymmetry - gain drift by illuminating a detector with light - isolating PV signal from neutron spin flip

8. Main handle to control systematic uncertainty : frequent reversal of neutron polarization spin direction in match with beam pulse frequency