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Kemar James

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Spark Purification System

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Kemar James

  1. 1. Spark Purification System <br />By <br />Kemar James<br />NSF funded REU at Case Western Reserve University<br />Advisor: Dr. Thomas Shutt, Dr. Dan Akerib<br /> and <br />Dr. Carmen Carmona<br />
  2. 2. Introduction:<br />Cosmological evidence of “Dark Matter”<br /> To confirm its existence and thoroughly understand it to explain the our universe and its formation.<br /> The LUX collaboration is attempting this through “direct detection” using a dual phase xenon detector.<br /> Unfortunately due to the impurity levels, the xenon needs to be purified to make longer electron drift paths possible.<br /> Thus allowing the nuclei recoil of the WIMP ( dark matter candidate) interaction to be detected.<br />
  3. 3. The Spark Purification System <br />Noble Gas/Liquid<br />   <br /> <br />  <br />  <br />    <br />Spark Tube<br />Filtration System <br />Pump <br />  <br />  <br />  <br />      <br />
  4. 4. Why use a titanium electrode?<br /> It readily reacts with O2 to form titanium oxide, thus reducing the O2 impurities in xenon/argon<br /> It’s a good conductor, thus making it ideal for the electrode<br />High resistivity to corrosion<br />
  5. 5. LUX Detector uses xenon noble gas/liquid <br />Why xenon ?<br />Dense and homogeneous large detector masses (crucial to explore lower cross section values).<br />Inert, not flammable and very good dielectrics. <br />High electron motilities, which allows long drift distances.<br />Good scintillating abilities.<br />
  6. 6. Experimental Setup:<br />
  7. 7. Results and Observations:<br />Regular rod<br />Modified rod<br />
  8. 8. Results and Observations:<br />Threaded rod<br />Strip<br />
  9. 9. Results and Observations:<br />The spark box breakdown voltage vs. the distance between the electrodes<br />
  10. 10. Results and Observations<br />
  11. 11. Results and Observations:<br />
  12. 12. Conclusions:<br />The experiment was successful in generating the sparks necessary to produce getter material (Titanium dust particles) for various electrodes geometries.<br />The curvature of the titanium electrode is proportional to the breakdown voltage .<br />The spark box without a doubt is superior, since sparks are generated at a lower voltage with the same separation between the electrodes as in the spark tube.<br />
  13. 13. Acknowledgements<br />This work was supported the NSF grant numbers DMR-0850037. <br />I would also like to acknowledge the program coordinators Kathleen Kash and Edith Gaffney. <br />Finally I would also like to thank my advisors Dr. Thomas Shutt , Dr. Dan Akerib, and Carmen Carmona for the tremendous work they have done to equip and guide me along this wonderful experience.<br />
  14. 14. References<br /> Gaitskell, R. J., Direct detection of dark matter, Ann . Rev. Nucl. Part. Sci. 54(2004) 315-359.<br /> Sorensen, P. F., “A Position-Sensitive Liquid Xenon Time-Projection Chamber for Direct detection of Dark Matter”. Ph.D. thesis (2008).<br /> Griffiths, D. J., Introduction to Electrodynamics, Third Edition. Upper Saddle River, New Jersey: Prentice Hall , 1999.<br /> Ramsey, B., Bolotnikov A., "Purification techniques and purity and density measurements of high-pressure Xe." Nucl. Inst. Meth. A 383 (1996): 619-623.<br />
  15. 15. Any Questions ?<br />
  16. 16. What is a Spark ?<br />This is a type of ESD that occurs when the electric field strength exceeds the dielectric field strength, thus ionizing the conductive channel in the gas.<br /> This may cause a rapid increase in the number of free electrons and ions in the gas, temporarily causing the air to abruptly become an electrical conductor<br />At this point a sudden and momentary electric currentflows between two objects at different electrical potentials caused by direct contact or induced by an electrostatic field<br />
  17. 17. Breakdown voltage in different gaseous enviroments<br />R8778 PMT base (d=5mm)<br />
  18. 18. Objectives <br />Spark Purification System<br />Spark Tube<br />Identify tube and titanium electrode geometry suitable and assemble them. <br />Generate continuous sparks within a localized argon gas environment and then observe how the geometry of the titanium electrode, tube size, current and voltage affects the spark rate.<br /> Identify the dust particles generated from the sparks <br /> Make a correlation between the duration of the sparks to the mass of particles produce and the amount required to purify “x” amount of argon to a purification level of “y”. <br /> Filtration system<br />
  19. 19. Why the use of heavy noble gases/liquids? <br />These liquids are dense and homogeneous. This allows to construct large detector masses. This is crucial to explore lower cross section values.<br />Noble gases are inert, not flammable and very good dielectrics. <br />Liquefied noble gases do not attach electrons, and electron mobilities are high for the heavier noble gases, which allows long drift distances.<br />They are bright scintillators.<br />

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