Radionuclide Half-Life Measurements

M. P. Unterweger,¹ D. D. Hoppes,¹ F. J. Schima,¹, and J. S. Coursey²

¹National Institute of Standards and Technology, Physics Laboratory, Ionizing Radiation Division
²NIST, Physics Laboratory, Office of Electronic Commerce in Scientific and Engineering Data

Radionuclide	Number of Sources	Number of Half Lives Followed	Half Life^*	Statistical Standard Uncertainty	Other Standard Uncertainty	Reference

³H	18	3	4500 ± 8 d	8	0	1 (a)
¹⁸F	3	13.1	1.82951 ± 0.00034 h	0.00024	0.00024	§
²²Na	5	1.9 - 4.7	950.97 ± 0.15 d	0.09	0.12	§
²⁴Na	14	1.1 - 7.6	14.9512 ± 0.0032 h	0.0009	0.0031	§
³²P	2	2.8	14.263 ± 0.003 d	0.003	0.0	6
⁴⁴Ti	1	0.35	22154 ± 456 d	180	419	2
⁴⁶Sc	4	3.6 - 10.3	83.831 ± 0.066 d	0.030	0.059	§
⁵¹Cr	11	2.3 - 8.9	27.7010 ± 0.0012 d	0.0007	0.0009	§
⁵⁴Mn	2	3.3 - 7.4	312.028 ± 0.034 d	0.034	0.0	§
⁵⁷Co	7	4.7 - 10.4	272.11 ± 0.26 d	0.09	0.25	§
⁵⁸Co	1	9.1	70.77 ± 0.11 d	0.11	0.0	§
⁵⁹Fe	6	4.0 - 9.3	44.5074 ± 0.0072 d	0.0048	0.0053	§
⁶⁰Co	8	3.7 - 5.3	1925.20 ± 0.25 d	0.10	0.23	§,6
⁶²Cu	3	2.7 - 3.9	9.6725 ± 0.0080 min	0.0080	0.0	3,6
⁶⁵Zn	1	3.2	244.164 ± 0.099 d	0.099	0.0	§
⁶⁷Ga	13	1.8 - 8.3	3.26154 ± 0.00054 d	0.00015	0.00052	§
⁷⁵Se	19	2.4 - 8.7	119.809 ± 0.066 d	0.014	0.065	§
⁸⁵Kr	1	1.9	3935.7 ± 1.2 d	1.2	0.0	§,6
⁸⁵Sr	8	1.1 - 4.8	64.8530 ± 0.0081 d	0.0039	0.0071	§
⁸⁸Y	8	1.3 - 8.1	106.626 ± 0.044 d	0.017	0.041	§
⁹⁹Mo	14	3.6 - 9.5	65.9239 ± 0.0058 h	0.0031	0.0049	§
^99mTc	33	2.1 - 12.0	6.00718 ± 0.00087 h	0.00015	0.00086	§ (b)
^99mTc	17	1.9 - 8.0	6.0123 ± 0.0032 h	0.0007	0.0031	6 (c)
¹⁰³Ru	7	0.4	39.310 ± 0.044 d	0.044	0.0	6
¹⁰⁹Cd	2	3.4 - 5.3	463.26 ± 0.63 d	0.36	0.51	§
^110mAg	1	9.3	249.950 ± 0.024 d	0.024	0.0	§
¹¹¹In	11	1.4 - 9.3	2.80477 ± 0.00053 d	0.00017	0.00051	§
¹¹³Sn	11	2.3 - 11.0	115.079 ± 0.080 d	0.025	0.076	§
^117mSn	10	1.5 - 4.0	14.00 ± 0.05 d	0.05	0.0	4
¹²³I	3	5.4 - 12.7	13.2235 ± 0.0019 h	0.0019	0.0	§
¹²⁵I	18	1.4 - 6.2	59.49 ± 0.13 d	0.03	0.12	§
¹²⁵Sb	1	5.4	1007.56 ± 0.10 d	0.10	0.0	§,6
¹²⁷Xe	5	1.1 - 11.5	36.3446 ± 0.0028 d	0.0028	0.0	§
¹³¹I	21	1.0 - 10.9	8.0197 ± 0.0022 d	0.0005	0.0021	§
^131mXe	2	1.8	11.934 ± 0.021 d	0.014	0.016	§
¹³³Ba	4	2.0	3854.7 ± 2.8 d	1.3	2.5	§,6
¹³³Xe	3	4.8 - 11.2	5.24747 ± 0.00045 d	0.00045	0.0	§
¹³⁴Cs	5	1.7 - 3.0	753.88 ± 0.15 d	0.11	0.11	§
¹³⁷Cs	6	0.7 - 0.9	11018.3 ± 9.5 d	3.5	8.8	§,6
¹³⁹Ce	9	1.5 - 6.4	137.734 ± 0.091 d	0.029	0.086	§
¹⁴⁰Ba	10	1.8 - 4.4	12.7527 ± 0.0023 d	0.0009	0.0022	§
¹⁴⁰La	2	4.2	40.293 ± 0.012 h	0.008	0.009	§
¹⁴¹Ce	1	6.1	32.510 ± 0.024 d	0.024	0.0	§
¹⁴⁴Ce	1	3.9	284.534 ± 0.032 d	0.032	0.0	§,6
¹⁵²Eu	4	1.6 - 1.8	4947.2 ± 1.1 d	0.7	0.8	§,6
¹⁵³Gd	2	7.3	239.472 ± 0.069 d	0.041	0.055	§
¹⁵³Sm	1	7.3	46.2853 ± 0.0014 h	0.0014	0.0	§
¹⁵⁴Eu	3	2.4	3145.2 ± 1.1 d	1.1	0.0	§,6
¹⁵⁵Eu	2	3.1 - 4.3	1739.06 ± 0.45 d	0.45	0.0	§,6
¹⁶⁶Ho	2	5.4 - 7.2	26.794 ± 0.023 h	0.013	0.019	§,6
¹⁶⁹Yb	14	3.4 - 9.5	32.0147 ± 0.0093 d	0.0026	0.0089	§
¹⁷⁷Lu	4	2 - 5	6.64 ± 0.01 d	0.01	0.0	5
¹⁸¹W	3	5.9 - 6.6	121.095 ± 0.064 d	0.042	0.048	§
¹⁸⁶Re	2	5.7 - 6.5	89.248 ± 0.069 h	0.018	0.067	§
¹⁸⁸Re	3	4.2 - 7.1	17.001 ± 0.022 h	0.09	0.021	§,6
¹⁸⁸W	1	4.0	69.783 ± 0.048 d	0.048	0.0	6
¹⁹²Ir	1	2.4	73.810 ± 0.019 d	0.019	0.0	§
¹⁹⁵Au	5	0.6 - 6.0	186.098 ± 0.047 d	0.021	0.042	§
¹⁹⁸Au	4	4.5 - 7.4	2.69517 ± 0.00021 d	0.00021	0.0	§
²⁰¹Tl	12	2.6 - 11.5	3.0456 ± 0.0015 d	0.0004	0.0014	§
²⁰²Tl	1	1.4	12.466 ± 0.081 d	0.081	0.0	§
²⁰³Hg	14	1.7 - 6.6	46.619 ± 0.027 d	0.007	0.026	§
²⁰³Pb	7	1.8 - 2.8	51.923 ± 0.037 h	0.013	0.034	§
²⁰⁷Bi	2	0.9	11523. ± 15. d	9	12	§,6
²²⁸Th	6	1.7 - 8.3	698.60 ± 0.36 d	0.14	0.33	§

*	The stated uncertainties are the sum, in quadrature, of the statistical uncertainty (the "external standard deviation" in the weighted mean) and other uncertainties which include those from the Stevenson equation (NBS Special Publication 626) and from the correction for the ²¹⁰Bi ingrowth in the radium reference sources.
(a)	Measured by internal gas proportional counting.
(b)	Normal saline solution.
(c)	Acid solution.

Code		Reference
§		Unterweger, M.P., Hoppes, D.D., and Schima, F.J., "New and revised half-life measurements results," Nucl. Instrum. Meth. Phys. Res. A312, 349-352 (1992).
1		Lucas, L.L. and Unterweger, M.P., "Comprehensive Review and Critical Evaluation of the Half-Life of Tritium," J. Res. Natl. Inst. Stand. Technol. 105, 541-549 (2000).
2		Wietfieldt, F.E., Schima, F.J., Coursey, B.M., and Hoppes, D.D., "Long-term measurement of the half-life of ⁴⁴Ti," Phys. Rev. C 59, 528 (1999).
3		Zimmerman, B.E., Unterweger, M.P., and Cessna, J.T., "The Half-life of ⁶²Cu," J. Phys. G 23, 1707-1714 (1997).
4		Zimmerman, B.E., Cessna, J.T., and Schima, F.J., "The Standardization of the Potential Bone Palliation Radiopharmaceutical ^117mSn(+4)DTPA," Appl. Radiat. Isot. 49, 317-328 (1998).
5		Zimmerman, B.E., Unterweger, M.P., and Brodack, J.W., "Development of a Radioactivity Measurement Standard for the Potential Radiotherapy Radionuclide ¹⁷⁷Lu," J. Labelled Cpd. Radiopharm. 42 Suppl. 1, S870 (1999). (Abstract)
6		Unterweger, M.P., "Half-life measurements results at the National Institute of Standards and Technology," Proc. Tenth ICRM meeting, Appl. Radiat. Isot. 56, 125-130 (2002).

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Radionuclide Half-Life Measurements