A Selected Data on Radionuclides of Health Physics Interest

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1 663 A Selected Data on Radionuclides of Health Physics Interest A.1 Introduction Although there are over 2500 known radionuclides, it is important to become familiar with the fundamental characteristics of those systems commonly encountered in the radiation protection field. These characteristics include the decay mode, type of radiation, energy of the radiation, half-life, and production mode. Table A.1 outlines the fundamental characteristics of selected radionuclides. These radionuclides include those emphasized in the American Board of Health Physics Examination Preparation Guide. Nuclear systems move toward stability through a number of modes noted in Table A.1. These include alpha, beta, and gamma decay. Electron capture, internal conversion, positron emission, and spontaneous fission () are additional nuclear deexcitation mechanisms. A.2 Alpha Decay Almost all naturally occurring alpha emitters are heavy elements. Alpha decay becomes the dominant decay mode for proton (neutron)-rich nuclides with A 160 ( 211). This decay mode occurs preferentially in the 232 Th, 235 U, and 238 U natural decay series. In the heaviest known transuranic nuclear systems, alpha emission competes with spontaneous fission as the dominant decay mode. Other decay modes (e.g., beta decay) occur but are usually not the dominant decay mechanism. A.3 Beta Decay In beta decay, a nucleus emits an electron and an antielectron neutrino. These particles arise from the decay of a neutron into a proton in an unstable nuclear system. Health Physics: Radiation-Generating Devices, Characteristics, and Hazards, First Edition. Joseph John Bevelacqua Wiley-VCH Verlag GmbH & Co. KGaA. Published 2016 by Wiley-VCH Verlag GmbH & Co. KGaA.

2 664 A Selected Data on Radionuclides of Health Physics Interest Table A.1 Fundamental characteristics of commonly encountered radionuclides a) c). 3 H β (max) years 2 H(n, γ) 3 H He(n, p) 3 H Li(n, α) 3 H B(n, 2α) 3 H Spallation of atmospheric nuclides induced by cosmic rays 7 Be γ days 10 B(p, α) 7 Be Spallation of atmospheric nuclides induced by cosmic rays 11 C β (max) min 12 C(γ, n) 11 C γ C(n, 2n) 11 C 14 N(p, α) 11 C 13 N β (max) 9.97 min 12 C(p, γ) 13 N γ C(p, n) 13 N N(γ, n) 13 N N(n, 2n) 13 N O(p, α) 13 N 14 C β (max) 5715 years 13 C(n, γ) 14 C N(n, p) 14 C O(n, α) 14 C 15 O β (max) min 12 C(α, n) 15 O γ N(p, γ) 15 O 16 O(γ, n) 15 O O(n, 2n) 15 O 16 N β 4.27 (max) 7.13 s 15 N(n, γ) 16 N (max) 16 O(n, p) 16 N γ F(n, α) 16 N α F β (max) h 18 O(p, n) 18 F γ F(n, 2n) 18 F 16 O( 3 He, p) 18 F 22 Na β (max) years 19 F(α, n) 22 Na γ Na(n, 2n) 22 Na Na(γ, n) 22 Na

3 A.3 Beta Decay 665 Table A.1 (Continued) 24 Na β (max) h 23 Na(n, γ) 24 Na γ Mg(n, p) 24 Na Al(n, α) 24 Na 32 P β (max) days 31 P(n, γ) 32 P S(n, p) 32 P Cl(n, α) 32 P 35 S β (max) 87.2 days 34 S(n, γ) 35 S Cl(n, p) 35 S 40 K β years Naturally occurring γ Ar β (max) 1.83 h 40 Ar(n, γ) 41 Ar γ K(n, p) 41 Ar Ca(n, α) 41 Ar 55 Fe γ years 54 Fe(n, γ) 55 Fe 58 Ni(n, α) 55 Fe Fe(γ, n) 55 Fe 58 Co β (max) days 57 Co(n, γ) 58 Co γ Co(n, 2n) 58 Co Ni(n, p) 58 Co 60 Co β (max) years 59 Co(n, γ) 60 Co γ Ni(n, p) 60 Co Cu(n, α) 60 Co 65 Zn β (max) days 64 Zn(n, γ) 65 Zn γ Zn(n, 2n) 65 Zn Kr β (max) years Fission product γ Kr(n, γ) 85 Kr 90 Sr β (max) 28.8 years Fission product Sr + n 89 Sr + n 90 Sr 90 Y β (max) days Fission product Sr daughter Y(n, γ) 90 Y Zr(n, p) 90 Y Nb(n, α) 90 Y (continued overleaf)

4 666 A Selected Data on Radionuclides of Health Physics Interest Table A.1 (Continued) 99m Tc e h 98 Tc(n, γ) 99m Tc γ Mo(n, γ) 99 Mo β Tc 125 I γ days Fission product 124 Xe + n 125 Xe β+ I e 129 I β 0.15 (max) years Fission product γ Te + n 129 Te β I 131 I β (max) days Fission product γ Te + n 131 Te β I 133 Xe β (max) days Fission product γ Xe(n, γ) 133 Xe 137 Cs β (max) years Fission product γ Xe + n 137 Xe β Cs 201 Tl γ days 203 Tl(p, 3n) 201 Pb β+ Tl Pb β 0.67 (max) 27 min 238 U decay series 0.73 (max) γ Bi β 1.51 (max) 19.9 min 238 U decay series 1.54 (max) 3.27 (max) γ α Po γ μs 238 U decay series α Po γ min 238 U decay series α

5 A.3 Beta Decay 667 Table A.1 (Continued) 220 Rn γ s 232 Th decay series α Rn γ days 238 U decay series α Ra γ years 238 U decay series α Th γ years Naturally occurring α U γ years Naturally occurring α Pu γ years 238 U + n α Np 239 Pu Am γ years 239 Pu + n 240 Pu + n Pu β Am α Cf γ years Multiple neutron capture from a α a) Baum et al. (2010). b) Electron capture (). c) Conversion electron (e ). 239 U β β varietyofnuclides(e.g., 238 U, 239 Pu, and 244 Cm) Beta decay predominates in systems with excess neutrons (e.g., fission products). This decay mode is an efficient method to move the unstable nucleus toward the line of stability.

6 668 A Selected Data on Radionuclides of Health Physics Interest A.4 Gamma Emission Gamma emission is a common nuclear decay mode. The emission of photons reduces the energy of an excited nucleus and permits it to reach its ground state or facilitates its decay to a more stable nuclear system. A.5 Internal Conversion Internal conversion is a process that transfers the energy of an excited nuclear system to an atomic electron. The electron, usually in the K or L shell, is ejected from the atom. This process competes with gamma emission. A.6 Electron Capture Orbital electron capture competes with positron emission to move a nucleus with excess protons toward the line of stability. A nucleus with excess protons captures an orbital electron, usually from the K shell. The result of this capture is the conversion of a proton into a neutron and the emission of an electron neutrino. A.7 Positron Emission Positron emission occurs in systems with excess protons (e.g., accelerator products). The decay results in the conversion of the proton into a neutron within the nucleus with the emission of a positron and electron neutrino. Competition between positron emission and electron capture is governed by the specific nuclear systems and their energy level structures. A.8 Spontaneous Fission Spontaneous fission is a decay mode of some heavy nuclear systems that splits the nucleus into two intermediate mass fragments and several neutrons. Because the maximum in the binding energy per nucleon curve occurs near A = 56 ( 56 Fe), nuclides with A greater than about 100 are theoretically unstable with respect to spontaneous fission. However, measurable spontaneous fission rates are only observed in nuclei with A > 230. This occurs because higher energies are required for fission product emission through the Coulomb barrier. For very heavy nuclei,

7 References 669 spontaneous fission becomes an important decay mode. spontaneous fission produces a variety of radiation types including fission fragments, neutrons, gamma rays, beta particles, positrons, and neutrinos. References Baum, E.M., Ernesti, M.C., Knox, H.D., Miller, T.R., and Watson, A.M. (2010) s and Isotopes, Chart of the s, 17th edn, Knolls Atomic Power Laboratory, Bechtel Marine Propulsion Corporation, Schenectady, NY. Bevelacqua, J.J. (2008) Health Physics in the 21st Century, Wiley-VCH Verlag GmbH, Weinheim. Bevelacqua, J.J. (2009) Contemporary Health Physics, Problems and Solutions, 2nd edn, Wiley-VCH Verlag GmbH, Weinheim. Bevelacqua, J.J. (2010) Basic Health Physics, Problems and Solutions, 2nd edn, Wiley- VCH Verlag GmbH, Weinheim. Brookhaven National Laboratory, National Nuclear Data Center (accessed 08 August 2015). Firestone, R.B., Frank Chu, S.Y., and Baglin, C.M. (1998) Table of Isotopes, 8th edn, John Wiley & Sons, Inc., New York. ICRP (2008) Nuclear decay data for dosimetric calculations, ICRP Report No Ann. ICRP, 38 (3), 1. Magill, J., Pfennig, G., Dreher, R., and Sóti, Z. (2012) Karlsruhe Chart, 8th edn, Karlsruher Institut für Technologie, Karlsruhe, (accessed 08 August 2015). Shleien,B.,Slaback,L.A.Jr.,andBirky,B.K. (1998) Handbook of Health Physics and Radiological Health, 3rd edn, Lippincott, Williams, and Wilkins, Philadelphia, PA. Tuli, J.K. (ed.) (2015) Nuclear Data Sheets. The Nuclear Structure and Decay Data in Nuclear Data Sheets is also Available in the Evaluated Nuclear Structure Data File (END), (accessed 14 August 2015). Tuli, J.K. (2004) Nuclear Wallet Cards for Radioactive s, Brookhaven National Laboratory, Upton, NY. Tuli, J.K. (2011) Nuclear Wallet Cards, 8th edn, Brookhaven National Laboratory, Upton, NY. Turner, J.E. (2007) Atoms, Radiation, and Radiation Protection, 3rd edn, Wiley-VCH Verlag GmbH, Weinheim.

Nuclear Chemistry Notes

Nuclear Chemistry Notes Definitions Nucleons: Subatomic particles in the nucleus : protons and neutrons Radionuclides: Radioactive nuclei. Unstable nuclei that spontaneously emit particles and electromagnetic