1. Calibration of Radium 226

2. Introduction to Radium Discovered in 1898 by Marie Curie Radium (chemical symbol Ra) is a naturally-occurring radioactive metal. Its most common isotopes are radium-226, radium 224, and radium-228. Radium is a radionuclide formed by the decay of uranium and thorium in the environment. It occurs at low levels in virtually all rock, soil, water, plants, and animals. Early 1900s – radium was used in such products as toothpaste, hair tonic, ointments, elixirs, glow in the dark watch faces, and was an early source of radiation treatment for cancer Now is it used in some industrial radiography devices and added to the tips of lightning rods, improving their effectiveness

3. Ra226 Decay Chain

4. alphayieldenergyisotope a 11.90×10 -08 3.7282-LEAD-210 a 17.92×10 -07 4.64483-BISMUTH-210 a 25.28×10 -07 4.68383-BISMUTH-212 a 15.25×10 -07 4.94183-BISMUTH-214 a 24.41×10 -07 5.02483-BISMUTH-216 a 31.28×10 -06 5.18583-BISMUTH-218 a 41.22×10 -05 5.27383-BISMUTH-220 a 51.13×10 -04 5.45283-BISMUTH-222 a 68.23×10 -05 5.51683-BISMUTH-224 a 11.22×10 -05 4.51784-POLONIUM-210 a 215.30484-POLONIUM-212 a 16.00×10 -07 6.6184-POLONIUM-214 a 21.04×10 -04 6.90284-POLONIUM-216 a 11.10×10 -05 5.18184-POLONIUM-218 a 317.68784-POLONIUM-218 a 216.00284-POLONIUM-220 a 15.00×10 -06 4.82686-RADON-222 a 27.80×10 -04 4.98686-RADON-224 a 39.99×10 -01 5.48986-RADON-226 a 12.70×10 -06 4.1688-RADIUM-226 a 21.00×10 -05 4.19188-RADIUM-228 a 36.50×10 -05 4.3488-RADIUM-230 a 45.55×10 -02 4.60188-RADIUM-232 a 59.44×10 -01 4.78488-RADIUM-234 Natural Radioactive Series

5. Purpose To re-calibrate the radium-2 source and determine the correct energies for the alpha particles being emitted

6. “DOG” Calibration Layer of dirt, oil, and grease on the radium 1 source caused a downshift in energy 18 keV 15 keV 16 keV 10 keV 13 keV

7. Ra-1 Shifted with Gold

8. Ra-1 Spectrum with Am241 Peak

9. Centroid vs. Edge Energies 4.784 MeV Ra234 5.304 MeV Po212 5.489 MeV Rn226 6.002 MeV Po220 7.687 MeV Po218 4.601 MeV Ra232

10. 4.784 MeV 7.687 MeV 6.002 MeV 5.489 MeV 5.304 MeV 4.601 MeV

11. Centroid energies vs channel number

12. Based on new calibration

13. Re-Calibrated Radium 2 Source 3.997 MeV 4.696 MeV 7.044 MeV 5.307 MeV 4.22 MeV 7.04 MeV 5.48 MeV 4.91 MeV New in blue old in red Blue 2006 calibration Red 1972 calibration

14. http://www.epa.gov/radiation/radionuclides/radium.htm http://www.physics.umd.edu/lecdem/honr228q/notes/U238scheme.gif http://www.eserc.stonybrook.edu/ProjectJava/Radiation/index.html