Uncertainty for NPDGamma experiment in reaction Pil-Neyo Seo U of Virginia/TUNL HIGS2 Workshop, June...
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Transcript of Uncertainty for NPDGamma experiment in reaction Pil-Neyo Seo U of Virginia/TUNL HIGS2 Workshop, June...
Uncertainty for NPDGamma experiment in reaction
Pil-Neyo SeoU of Virginia/TUNL
HIGS2 Workshop, June 3-4, 2013
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
LANSCE SNS
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
Main handle to control systematic uncertainty : frequent reversal of neutron polarization spin direction
in match with beam pulse frequency
B= 𝐴𝛾❑𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑=
𝑈 ↑−𝐷↑−(𝑈 ↓−𝐷↓)𝑈 ↑+𝐷↑+(𝑈 ↓+𝐷↓)