Isotopes of californium

Actinides vs fission products
Actinides				Half-life (a)	Fission products
4n	4n+1	4n+2	4n+3
²²⁸Ra				4.75 – 5.75			¹⁵⁵Eu
²⁴⁴Cm	²⁴¹Pu^ƒ	²⁵⁰Cf	²²⁷Ac^№	10 – 22	medium		⁸⁵Kr	^113mCd^₡
²³²U^ƒ		²³⁸Pu	²⁴³Cm^ƒ	28 – 97	¹³⁷Cs	⁹⁰Sr	¹⁵¹Sm^þ	^121mSn
m is meta	²⁴⁹Cf^ƒ	^242mAm^ƒ	²⁵¹Cf^ƒ¹	141 – 1.6k	No fission products have a half-life in the range of 100 – 210k years.
m is meta	²⁴¹Am	²²⁶Ra^№²	²⁴⁷Bk	141 – 1.6k
²⁴⁰Pu	²²⁹Th	²⁴⁶Cm	²⁴³Am	4.7k – 7.4k
	²⁴⁵Cm^ƒ	²⁵⁰Cm	²³⁹Pu^ƒ	8.3k – 24.1k
²³⁶Np^ƒ	²³³U^ƒ	²³⁰Th^№	²³¹Pa^№	32k – 160k
²⁴⁸Cm		²³⁴U^№	ƒ for fissile	211k – 348k	⁹⁹Tc		¹²⁶Sn	⁷⁹Se
	²³⁷Np	²⁴²Pu	ƒ for fissile	375k – 6.5M	¹³⁵Cs^₡	⁹³Zr	¹⁰⁷Pd	₡ can capture þ is poison
²³⁶U			²⁴⁷Cm^ƒ	15M – 24M	long		¹²⁹I
²⁴⁴Pu	№ for NORM		²³⁵U^ƒ№	80M – 704M	6 – 7%	4.5 – 5.5%	0.1 – 1.25%
²³²Th^№	№ for NORM	²³⁸U^№		4.4G – 14G	Yield³	4.5 – 5.5%	0.1 – 1.25%	<0.05%

Californium (Cf) is a chemical element that is mainly produced synthetically, but trace quantities are found in nature from neutron capture by uranium atoms.⁴

It has no stable isotopes. The first isotope to be synthesized was ²⁴⁵Cf in 1950. There are 20 known radioisotopes ranging from ²³⁷Cf to ²⁵⁶Cf and one nuclear isomer, ^249mCf. The longest-lived isotope is ²⁵¹Cf with a half-life of 900 years.

Californium-252

Fission neutrons of californium-252 have an energy range of 0 to 13 MeV with a mean value of 2.3 MeV and a most probable value of 1 MeV.⁵

Table

nuclide symbol	Z(p)	N(n)	isotopic mass (u)	half-life	decay mode(s)⁶^{n 1}	daughter isotope(s)	nuclear spin
nuclide symbol	excitation energy			half-life	decay mode(s)⁶^{n 1}	daughter isotope(s)	nuclear spin
²³⁷Cf	98	139	237.06207(54)#	2.1(3) s	SF	(various)	5/2+#
					β⁺	²³⁷Bk
					α	²³³Cm
²³⁸Cf	98	140	238.06141(43)#	21.1(13) ms	SF	(various)	0+
					β⁺ (rare)	²³⁸Bk
					α (rare)	²³⁴Cm
²³⁹Cf	98	141	239.06242(23)#	60(30) s [39(+37-12) s]	α	²³⁵Cm	5/2+#
²³⁹Cf	98	141	239.06242(23)#	60(30) s [39(+37-12) s]	β⁺ (rare)	²³⁹Bk	5/2+#
²⁴⁰Cf	98	142	240.06230(22)#	1.06(15) min	α (98%)	²³⁶Cm	0+
					SF (2%)	(various)
					β⁺ (rare)	²⁴⁰Bk
²⁴¹Cf	98	143	241.06373(27)#	3.78(70) min	β⁺ (75%)	²⁴¹Bk	7/2-#
²⁴¹Cf	98	143	241.06373(27)#	3.78(70) min	α (25%)	²³⁷Cm	7/2-#
²⁴²Cf	98	144	242.06370(4)	3.49(15) min	α (80%)	²³⁸Cm	0+
					β⁺ (20%)	²⁴²Bk
					SF (.014%)	(various)
²⁴³Cf	98	145	243.06543(15)#	10.7(5) min	β⁺ (86%)	²⁴³Bk	(1/2+)
²⁴³Cf	98	145	243.06543(15)#	10.7(5) min	α (14%)	²³⁹Cm	(1/2+)
²⁴⁴Cf	98	146	244.066001(3)	19.4(6) min	α (99%)	²⁴⁰Cm	0+
²⁴⁴Cf	98	146	244.066001(3)	19.4(6) min	EC (1%)	²⁴⁴Bk	0+
²⁴⁵Cf	98	147	245.068049(3)	45.0(15) min	β⁺ (64%)	²⁴⁵Bk	(5/2+)
²⁴⁵Cf	98	147	245.068049(3)	45.0(15) min	α (36%)	²⁴¹Cm	(5/2+)
²⁴⁶Cf	98	148	246.0688053(22)	35.7(5) h	α	²⁴²Cm	0+
					EC (5×10⁻⁴%)	²⁴⁶Bk
					SF (2×10⁻⁴%)	(various)
²⁴⁷Cf	98	149	247.071001(9)	3.11(3) h	EC (99.96%)	²⁴⁷Bk	(7/2+)#
²⁴⁷Cf	98	149	247.071001(9)	3.11(3) h	α (.04%)	²⁴³Cm	(7/2+)#
²⁴⁸Cf	98	150	248.072185(6)	333.5(28) d	α (99.99%)	²⁴⁴Cm	0+
²⁴⁸Cf	98	150	248.072185(6)	333.5(28) d	SF (.0029%)	(various)	0+
²⁴⁹Cf	98	151	249.0748535(24)	351(2) a	α	²⁴⁵Cm	9/2-
²⁴⁹Cf	98	151	249.0748535(24)	351(2) a	SF (5×10⁻⁷%)	(various)	9/2-
^249mCf	144.98(5) keV			45(5) µs			5/2+
²⁵⁰Cf	98	152	250.0764061(22)	13.08(9) a	α (99.92%)	²⁴⁶Cm	0+
²⁵⁰Cf	98	152	250.0764061(22)	13.08(9) a	SF (.077%)	(various)	0+
²⁵¹Cf^{n 2}	98	153	251.079587(5)	900(40) a	α	²⁴⁷Cm	1/2+
²⁵²Cf^{n 3}	98	154	252.081626(5)	2.645(8) a	α (96.9%)	²⁴⁸Cm	0+
²⁵²Cf^{n 3}	98	154	252.081626(5)	2.645(8) a	SF (3.09%)^{n 4}	(various)	0+
²⁵³Cf	98	155	253.085133(7)	17.81(8) d	β^- (99.69%)	²⁵³Es	(7/2+)
²⁵³Cf	98	155	253.085133(7)	17.81(8) d	α (.31%)	²⁴⁹Cm	(7/2+)
²⁵⁴Cf	98	156	254.087323(13)	60.5(2) d	SF (99.69%)	(various)	0+
					α (.31%)	²⁵⁰Cm
					β^-β^- (rare)	²⁵⁴Fm
²⁵⁵Cf	98	157	255.09105(22)#	85(18) min	β^- (99.99%)	²⁵⁵Es	(7/2+)
					SF (.001%)	(various)
					α (10⁻⁵%)	²⁵¹Cm
²⁵⁶Cf	98	158	256.09344(32)#	12.3(12) min	SF (99%)	(various)	0+
					β^- (1%)	²⁵⁶Es
					α (10⁻⁶%)	²⁵²Cm
					β^-β^- (rare)	²⁵⁶Fm

^ Abbreviations:
EC: Electron capture
SF: Spontaneous fission
^ High neutron cross-section, tends to absorb neutrons
^ Most common isotope
^ High neutron emitter, average 3.7 neutrons per fission

Notes

Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC which use expanded uncertainties.

References

^ This is the heaviest isotope with a half-life of at least ten years before the "Sea of Instability".
^ Radium (element 88) is actually a sub-actinide, but it immediately precedes actinium (89) and follows a three element gap of instability after polonium (84) where no isotopes have half-lives of at least ten years (the longest-lived isotope in the gap is radon-222 with a half life of less than four days). Radium's longest lived isotope, at 1600 years, thus merits inclusion here.
^ Specifically from thermal neutron fission of U-235, e.g. in a typical nuclear reactor.
^ Emsley, John (2011). Nature's Building Blocks: An A-Z Guide to the Elements (New ed.). New York, NY: Oxford University Press. ISBN 978-0-19-960563-7.
^ Dicello, J. F.; Gross, W.; Kraljevic, U. (1972). "Radiation Quality of Californium-252". Physics in Medicine and Biology 17 (3): 345. Bibcode:1972PMB....17..345D. doi:10.1088/0031-9155/17/3/301.
^ http://www.nucleonica.net/unc.aspx

Isotope masses from:
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties". Nuclear Physics A 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
Isotopic compositions and standard atomic masses from:
- J. R. de Laeter, J. K. Böhlke, P. De Bièvre, H. Hidaka, H. S. Peiser, K. J. R. Rosman and P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry 75 (6): 683–800. doi:10.1351/pac200375060683.
- M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry 78 (11): 2051–2066. doi:10.1351/pac200678112051. Lay summary.
Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
- G. Audi, A. H. Wapstra, C. Thibault, J. Blachot and O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties". Nuclear Physics A 729: 3–128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001.
- National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005.
- N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9.
Other

Isotopes of berkelium	Isotopes of californium	Isotopes of einsteinium
Table of nuclides

[7] Abbreviations:
EC: Electron capture
SF: Spontaneous fission

[8] High neutron cross-section, tends to absorb neutrons

[9] Most common isotope

[10] High neutron emitter, average 3.7 neutrons per fission

[1] This is the heaviest isotope with a half-life of at least ten years before the "Sea of Instability".

[2] Radium (element 88) is actually a sub-actinide, but it immediately precedes actinium (89) and follows a three element gap of instability after polonium (84) where no isotopes have half-lives of at least ten years (the longest-lived isotope in the gap is radon-222 with a half life of less than four days). Radium's longest lived isotope, at 1600 years, thus merits inclusion here.

[3] Specifically from thermal neutron fission of U-235, e.g. in a typical nuclear reactor.

[4] Emsley, John (2011). Nature's Building Blocks: An A-Z Guide to the Elements (New ed.). New York, NY: Oxford University Press. ISBN 978-0-19-960563-7.

[5] Dicello, J. F.; Gross, W.; Kraljevic, U. (1972). "Radiation Quality of Californium-252". Physics in Medicine and Biology 17 (3): 345. Bibcode:1972PMB....17..345D. doi:10.1088/0031-9155/17/3/301.

[6] ttp://www.nucleonica.net/unc.aspx

1

2

3

4

5

6

n 1

n 2

n 3

n 4

v t e Isotopes of the chemical elements
1 H																	2 He
3 Li	4 Be											5 B	6 C	7 N	8 O	9 F	10 Ne
11 Na	12 Mg											13 Al	14 Si	15 P	16 S	17 Cl	18 Ar
19 K	20 Ca	21 Sc	22 Ti	23 V	24 Cr	25 Mn	26 Fe	27 Co	28 Ni	29 Cu	30 Zn	31 Ga	32 Ge	33 As	34 Se	35 Br	36 Kr
37 Rb	38 Sr	39 Y	40 Zr	41 Nb	42 Mo	43 Tc	44 Ru	45 Rh	46 Pd	47 Ag	48 Cd	49 In	50 Sn	51 Sb	52 Te	53 I	54 Xe
55 Cs	56 Ba	*	72 Hf	73 Ta	74 W	75 Re	76 Os	77 Ir	78 Pt	79 Au	80 Hg	81 Tl	82 Pb	83 Bi	84 Po	85 At	86 Rn
87 Fr	88 Ra	**	104 Rf	105 Db	106 Sg	107 Bh	108 Hs	109 Mt	110 Ds	111 Rg	112 Cn	113 Uut	114 Fl	115 Uup	116 Lv	117 Uus	118 Uuo

	*	57 La	58 Ce	59 Pr	60 Nd	61 Pm	62 Sm	63 Eu	64 Gd	65 Tb	66 Dy	67 Ho	68 Er	69 Tm	70 Yb	71 Lu
	**	89 Ac	90 Th	91 Pa	92 U	93 Np	94 Pu	95 Am	96 Cm	97 Bk	98 Cf	99 Es	100 Fm	101 Md	102 No	103 Lr
Table of nuclides Categories: Isotopes Tables of nuclides Metastable isotopes Isotopes by element

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Isotopes of californium

Contents

Californium-252

Table

Notes

References