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BASE Project

BASE Project. DePauw University Ruizhe Ma, Mark Tolley, Professor Brooks. BASE. The Balloon Assisted Stratospheric Experiments (BASE) project is operated under the Physics and Astronomy Department at DePauw University. 

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BASE Project

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  1. BASE Project DePauw University Ruizhe Ma, Mark Tolley, Professor Brooks

  2. BASE • The Balloon Assisted Stratospheric Experiments (BASE) project is operated under the Physics and Astronomy Department at DePauw University.  • Presently, the program uses helium filled weather balloons to carry scientific experiments into the stratosphere. • The communications and support system was purchased from StratoStar Systems of Upland, Indiana.

  3. BASE – Summer 2010 • Our project this summer aims to measure cosmic activities in the atmosphere by flying Geiger counters through the region of the stratosphere where these particles are produced. • Inside a • Geiger counter

  4. Cosmic Rays and Energetic Particles • Cosmic rays are continually bombarding the stratosphere and produce energetic particles • Ionizing radiation: Beta particles and Gamma rays • Geiger counters record the number of particles detected

  5. Ionizing Radiation and Secondary Particles Reference: http://www.ams02.org/what-is-ams/tecnology/ecal/

  6. Cosmic Rays and Energetic Particles • Number of particles is positively related to: - density of air molecules - intensity of cosmic rays • We expect to see the counts increase first then decrease after a critical altitude

  7. Lead Shielding • Lead shielding is a commonly used form of protection from radiation such as beta particles and gamma rays because of its high total mass per area in the path of radiation particles. • We have adopted this form of shielding to our experiment. We expect a decrease in counts due to the lead shielding.

  8. Equipment • Latex weather balloon • Parachute • GPS and Radio • Geiger counter • Tilt • Camera • anchored in styrofoam boxes

  9. GeigerCounters

  10. Geiger Counters • attached to BASIC Stamp microprocessor • a simple 555 timer circuit processes the raw information into readable data

  11. Geiger Counters • programmed to record the total counts for every consecutive minute or 30 seconds up to sixteen hours • shielded with different thickness of lead

  12. Data from BASE 41- counts per minute against time

  13. Data from BASE 42- counts per minute against time

  14. Data from BASE 43- counts per minute against time

  15. Data from BASE 43b- counts per minute against time

  16. Data from BASE 44- counts per minute against time

  17. Data from BASE 45- counts per minute against time

  18. Data Analysis Critical Altitude • “M” shape • Critical altitude at the top of “M”, known as the Pfotzer maximum Burst

  19. Data from BASE 43- counts versus altitude

  20. Summary of Critical Altitudes • Average: 67.6 ± 2.2 k feet (68% significance) • 82.6% of our data are within one Standard Deviation

  21. Crossover Altitudes

  22. Data Analysis • The “showering effect” of the lead shield

  23. Ground Tests *Had only one run

  24. Ground Tests

  25. Geometry of the Shower Effect

  26. Geometry of the Shower Effect Low Energy Case High Energy Case

  27. Geometry of the Shower Effect

  28. Data from BASE 45- counts per minute against time

  29. Data from BASE 42- counts per minute against time

  30. Conclusions • 1. The number of energetic particles increases as the altitude increases until a critical altitude beyond which the counts start to decrease. No seasonal variation has been seen. • 2. A lead shield of a given thickness can only provide a protection from energetic particles of up until a particular energy. If the particles are too energetic there exists the “showering effect” which increases the number of energetic particles.

  31. Conclusions • 3. The enclosed volume and the shield thickness both affect counts. With the same shield thickness, more volume enclosed by the shield leads to more counts. With the same enclosed volume, the thicker shield leads to less counts on ground but higher counts at high altitudes.

  32. Further Work • Try to find a quantitative relationship between counts and the enclosed volume/shield thickness • Floating valve • Hydrogen

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