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What are Cosmic Rays?

What are Cosmic Rays?. Particles bombarding Earth from outer space Includes protons up to heavy elements Ionic charge and energy vary greatly. Cosmic Ray Detector. Jason Alicea University of Florida Dr. Muga Nuclear Chemistry Dept. Outline . Detector overview What I did Detector test

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What are Cosmic Rays?

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  1. What are Cosmic Rays? • Particles bombarding Earth from outer space • Includes protons up to heavy elements • Ionic charge and energy vary greatly

  2. Cosmic Ray Detector Jason Alicea University of Florida Dr. Muga Nuclear Chemistry Dept.

  3. Outline • Detector overview • What I did • Detector test • Scattering chamber design • Conclusion-What next? • Questions?

  4. Cosmic Ray Detector Measures... • Nuclear charge (Z) • Energy • Velocity • Mass • Ionic charge

  5. Detector Components • Thin film detector (TFD, measures luminescence) • Thin scintillator film • Photomultiplier tubes • Solid state detector (SSD, measures energy) Photomultiplier tubes Particles SSD Thin film

  6. Why Measure Luminescence? • Luminescence-Energy curves are unique for each atomic number Z. Z 1 Z 2 Luminescence Z 3 Energy

  7. Why Measure Luminescence? • Atomic number of particle corresponds to the curve data point lies on. Data Point Z 1 Z 2 Luminescence Z 3 Atomic # of Particle Energy

  8. What About Other 3 Properties? • Velocity: divide distance between thin film and SSD by time recorded between signals • From measured energy & velocity, mass is easily calculated • Ionic charge: compare luminescence & velocity after each of several thin films

  9. What Did I Do? • Fabricated a thin film, which was used in testing the detector. • Recorded response of thin film and SSD to fission fragments • Designed scattering chamber

  10. Detector Test • Used newly fabricated thin film • Test particles were californium (Cf) fission fragments • Measured response from thin film and solid state detector. • Computer recorded luminescence and energy data.

  11. Solid State Detector Response Good signal since peak is narrow.

  12. Thin Film Response Peak is too wide--results in uncertainty in Z determination

  13. Scattering Chamber: Why? • Beam from Van de Graaff accelerator is too strong for SSD and electronics • SSD can be damaged and electronics overloaded • By scattering the beam off a foil (Rutherford scattering), intensity will be adequately reduced

  14. Design Requirements • Scatter through angles between 0 and 60 degrees • Chamber must accommodate at least 3 scattering foils • Must be kept at vacuum pressure

  15. Plunger to raise/ lower foils Final Design Beam Pipe to Detector Scattering Foils (5) Fixed Cylinder Beam Pipe to Accelerator Rotating Collar

  16. What Next? • Improvements are underway to strengthen thin film signal • Copper thin film? • Design of scattering chamber is complete, construction is anticipated • If perfected, detector would be an excellent candidate for a space mission, which is the ultimate goal.

  17. Questions?

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