Radionuclide Half-Life Measurements Made at NIST

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Radionuclide Half Life Measurements Made at NIST

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

The half lives of many radionuclides have been measured in the Radioactivity Group of NIST. The table below, based on "New and revised half-life measurements results,"^§ by M.P. Unterweger, D.D. Hoppes, and F.J. Schima (1992), is a revised listing of the half lives determined at NIST since 1967. This table supersedes the table presented in NBS Special Publication 626 [D.D. Hoppes and F.J. Schima, ed. (1982), p. 85] as well as that presented in "New and revised half-life measurements results." Included in this table are new values not previously tabulated in either publication. The references are given for these values. Values revised since NBS Special Publication 626 for the half lives of various "short-lived" radionuclides arise from improved impurity analysis, incorporation of additional data from new sources, and reevaluation of old data.
Values in common usage in certificates and reports are available from the National Nuclear Data Center. In case of discrepant data, the NIST value is recommended.

ASCII table (good for cutting and pasting)

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.

This work was supported in part by NIST's Systems Integration for Manufacturing Applications (SIMA) Program.

NIST Standard Reference Database 120
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Online: May 1997 Last Update: April 2003