Past Experience of reactor neutrino experiments

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Past Experience of reactor neutrino experiments

• Yifang Wang
• Institute of High Energy Physics, Beijing
• Nov. 28, 2003

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Contents

• Reactor neutrino sources
• Reactor neutrino detection
• Past experiments
• Summary

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Daya Bay
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Reactor Source of neutrinos
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How Neutrinos are produced in reactors ?

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Systematic Error Power
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Reactor thermal power
Known to lt1
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Fission rate in the Reactor
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Prediction of reactor neutrino spectrum

• Three ways to obtain reactor neutrino spectrum
• Direct measurement
• First principle calculation
• Sum up neutrino spectra from 235U, 239Pu, 241Pu
  and 238U
• 235U, 239Pu, 241Pu from their measured b
  spectra
• 238U(10) from calculation (10)
• They all agree well within 3

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Total error on neutrino spectrum
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Reactor neutrino detection
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Observed neutrino spectrum
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Background - Correlated
Background - Uncorrelated environmental

radioactivity
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Precautions for a reactor n experiment

• Cosmic-ray induced correlated background
• Enough overburden and shielding
• Active shielding, small enough and well known
  ineff.
• Environmental radiation(uncorrelated background)
• Clean scintillator
• PMT with Low radioactivity glass
• Clean surrounding materials
• Rn free environment
• Enough shielding
• Gd-loaded scintillator, good for bk. But aging
• Calibration
• Many sources at different positions
• Birk