The Identification of Radioisotopes Using a Thick and Thin Panel

1. The Identification of Radioisotopes Using a Thick and Thin Panel • Eric Blue and Adam Jernigan • Advisor: Dr. Thomas Dooling • The University of North Carolina Pembroke Monte Carlo Method • The Monte Carlo method is a widely used class of algorithms to simulate mathematical systems by utilizing random numbers. The Monte Carlo is a method suitable for calculation using a computer due to the repetition of algorithms and the large number of calculations involved. Cs-137 Thin and Thick Paddle Results via Monte Carlo and Scintillator Cs-137 Simulated Paddle Results Ir-192 Simulated Paddle Results • A Monte Carlo algorithm is a numerical Monte Carlo method used to find solutions to mathematical problems that cannot easily be solved. Experimentally, the Monte Carlo algorithm is utilized to simulate the emissions of a radioactive isotope as it passes through various media. Monte Carlo Flowchart The figure to the right shows the sequence of events that forms the Monte Carlo program. The diagram tracks a particle through the simulated plastic scintillator based on the program and its subroutines. Sr/Y-90 Thin and Thick Paddle Results via Monte Carlo and Scintillator Sr/Y-90 Simulated Paddle Results I-131 Simulated Paddle Results Purpose Co-60 Thin and Thick Paddle Results via Monte Carlo and Scintillator Co-60 Simulated Paddle Results Sr-89 Simulated Paddle Results • Several different setups were tried while doing these experiments. The purpose of this one was to try to test for some sort of a way to identify radioactive isotopes. • The theory was that the plots of the energy loss through the scintillator would not be the same for each source but that maybe a pattern would evolve for recognizing the type of source and hopefully which source was present. Geometry • The sheet scintillator code was programmed to simulate a small sheet of plastic scintillator placed above a larger sheet of plastic scintillator. Both scintillators were individually wrapped in aluminum foil and black electrician’s tape. The radioactive source was placed in two locations so particles would pass through both paddles, and data was collected. Tl-204 Thin and Thick Paddle Results via Monte Carlo and Scintillator Tl-204 Simulated Paddle Results Double Paddle Diagram • As the diagram to the right describes there are two plastic sheet scintillators each wrapped in aluminum foil and then black electrician’s tape. • All experimental thin and thick scintillator runs were recorded for 2 hours. Final Acknowledgements • Then a phototube was mounted to each of the paddles using some optical grease and some electrical tape. Acknowledgement: This work was supported by the National Science Foundation’s Research Experience for Undergraduates program.(CHE-0353724) Materials Used Isotopes References: Hamamatsu Phototube http://usa.hamamatsu.com/index.php?id=13195780&language=1& Radioactive Sources http://www.spectrumtechniques.com/radioisotopes.htm UCS 20 Spectrometer Multi Channel Analyzer http://www.spectrumtechniques.com/ucs20.htm Physics Constants http://www.physics.nist.gov/ Stopping Power Curves http://www.physics.nist.gov/PhysRefData/Star/Text/ESTAR.html National Science Foundation Research Experiences for Undergraduates http://www.nsf.gov/funding/pgm_summ.jsp?pims_id=5517&from=fund • Through this phase of the testing there were five main isotopes used. • Sr-90 (beta source) 0.1 µCi 28.6 years • Tl-204 (beta source) 1.0 µC 3.78 years • Y-90 (beta source) • Cs-137 (gamma source) 5.0 µCi 30.2 years • Co-60 (gamma source) 1.0 µCi 5.27 years • There were other sources used which consisted of: • I-131 (beta source) • Sr-89 (beta source) • Ir-192 (beta source)