Bragg Scattering by Neutrons

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Bragg Scattering by Neutrons

• Chintan Hossain

MIT Junior Lab November 2, 2004
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Outline

• Background/Theory
• Our Experiment
• Data and Results
• Conclusion

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Background and Theory

• Wave particle duality -gt Neutrons are waves
• Wavelength given by De Broglie Relation ?h/p
• Neutrons can be diffracted by crystals.

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Crystal Diffraction
For (200) planes
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Experimental Apparatus
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Measured Flight Time Close to Chopper
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Flight Time After Diffraction
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Flight Time vs. Angle
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Final Results

• Travel time proportional to sin? t(1.740.11
  ms)sin?
• Follows De Broglie prediction ?ht/mLdsin(?)
• 1.740.11 ms mLd/h
• h/m (4.00.2)x10-7 m2/s

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Sources of Error

• Poisson random error
• Systematic time of flight error
• Travel distance error
• Angle measurement error

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Conclusion

• t is proportional to sin? -gt 1/p is proportional
  to sin?
• Agrees with De Broglie relationship
• h/m (4.00.2)x10-7 m2/s agrees with known
  values
• Improvements to experiment
• More data points
• Take data for longer time