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Isotopes of Californium

List, data and properties of all known isotopes of Californium.

Content
Atomic properties
Decay properties
NMR active nuclides
Radiation protection
References
Californium isotopes

All of the atomic nuclei of the chemical element Californium are summarized under californium isotopes; these consist of an atomic nucleus with 98 protons and in the uncharged state of 98 electrons. The difference between the individual Californium isotopes lies in the number of neutrons in the nucleus - and thus in the mass number

The chemical element californium occurs in nature only in extremely small traces, which are created by neutron capture from uranium. Measurable and characterizable quantities can only be generated synthetically.

To date, a total of 20 different, exclusively unstable isotopes of californium have been produced and described, of which the isotope 251 has the longest half-life at almost 900 years.

 

Isotope Table: Californium

The two following tables list the most important data and properties of the Californium isotopes. Further information on the individual Californium isotopes is listed on separate pages and can be accessed via the link in column 1.

 

Atomic Properties

Isotope
Nuclide		ENAtomic Mass
[Nuclear Mass]
{Mass Excess}		Spin I
(h/2π)		Parent
123456
Californium-23723798Cf139237.06220(9) u
[237.0084469 u]
{57.93893 MeV}
Californium-23823898Cf140238.06149(32) u
[238.0077369 u]
{57.27757 MeV}		0+
Californium-23923998Cf141239.06255(22) u
[239.0087969 u]
{58.26495 MeV}		243Fm
Californium-24024098Cf142240.062256(20) u
[240.0085029 u]
{57.99109 MeV}		0+
Californium-24124198Cf143241.06369(18) u
[241.0099369 u]
{59.32685 MeV}		(7/2-)245Fm
Californium-24224298Cf144242.063755(14) u
[242.0100019 u]
{59.3874 MeV}		0+246Fm
242Es
Californium-24324398Cf145243.06547(12) u
[243.0117169 u]
{60.98491 MeV}		(1/2+)247Fm
243Es
Californium-24424498Cf146244.0659995(28) u
[244.0122464 u]
{61.47814 MeV}		0+248Fm
244Es
Californium-24524598Cf147245.0680468(26) u
[245.0142937 u]
{63.38519 MeV}		1/2+249Fm
245Es
Californium-24624698Cf148246.0688037(16) u
[246.0150506 u]
{64.09023 MeV}		0+250Fm
Californium-24724798Cf149247.070965(16) u
[247.0172119 u]
{66.10347 MeV}		(7/2+)251Fm
247Es
Californium-24824898Cf150248.072183(5) u
[248.0184299 u]
{67.23803 MeV}		0+252Fm
248Es
248Bk
Californium-24924998Cf151249.0748505(13) u
[249.0210974 u]
{69.72279 MeV}		9/2-253Fm
249Es
249Bk
Californium-249m249m98Cf151249.0748505(13) u
[249.0210974 u]
{69.72279 MeV}		5/2+
Californium-25025098Cf152250.0764046(17) u
[250.0226515 u]
{71.17043 MeV}		0+254Fm
250Es
250Bk
Californium-25125198Cf153251.079587(4) u
[251.0258339 u]
{74.13481 MeV}		1/2+255Fm
251Es
251Bk
Californium-251m251m98Cf153251.079587(4) u
[251.0258339 u]
{74.13481 MeV}		11/2-
Californium-25225298Cf154252.0816265(25) u
[252.0278734 u]
{76.03459 MeV}		0+256Fm
252Es
Californium-25325398Cf155253.085134(5) u
[253.0313809 u]
{79.30181 MeV}		(7/2+)257Fm
Californium-25425498Cf156254.087324(12) u
[254.0335709 u]
{81.34178 MeV}		0+254Es
Californium-25525598Cf157255.09105(21) u
[255.0372969 u]
{84.81253 MeV}		(7/2+)
Californium-25625698Cf158256.09344(34) u
[256.0396869 u]
{87.0388 MeV}		0+

 

Radioactive Decay Properties

IsotopeRadioactive DecayExtern
Half-lifeDecay ModeProbabilityEnergy
789101112
Cf-2372.1(3) sSF AL
Cf-23821.1(13) msSF div
α → 234Cm		> 95 %
< 5 %
8.13(30) MeV		AL
Cf-239ca. 39 sα → 235Cm
EC → 239Bk		?
?		7.81(6) MeV
4.02(29) MeV		AL
Cf-2400.96(15) minα → 236Cm
EC/β+ → 240Bk
SF div		ca. 98 %
?
ca. 2 %		7.711(4) MeV
2.33(15) MeV
AL
Cf-2413.78(70) minα → 237Cm
EC/β+ → 241Bk		ca. 25 %
ca. 75 %		7.65(15) MeV
3.29(26) MeV		AL
Cf-2423.7(5) minα → 238Cm
EC/β+ → 242Bk
SF div		80(20) %
20(20) %
< 0.014 %		7.514(4) MeV
1.65(20) MeV
AL
Cf-24310.7(5) minα → 239Cm
EC/β+ → 243Bk		ca. 14 %
ca. 86 %		7.42(10) MeV
2.30(11) MeV		AL
Cf-24419.4(6) minα → 240Cmca. 100 %7.3290(18) MeVAL
Cf-24545.0(15) minα → 241Cm
EC → 245Bk		35.3(25) %
64.7(25) %		7.2585(18) MeV
1.571(18) MeV		AL
Cf-24635.7(5) hα → 242Cm
EC/β+ → 246Bk
SF div		> 99 %
< 0.004 %
0.00024 %		6.8616(10) MeV
0.123(60) MeV
AL
Cf-2473.11(3) hα → 243Cm
EC → 247Bk		0.035(5) %
99.965(5) %		6.497(15) MeV
0.614(16) MeV		AL
Cf-248333.5(28) dα → 244Cm
SF div		99.9971(3) %
0.0029(3) %		6.361(5) MeV
AL
Cf-249351(2) aα → 245Cm
SF div		ca. 100 %
Spuren		6.2933(5) MeV
AL
Cf-249m45(5) μsAL
Cf-25013.08(9) aα → 246Cm
SF div		99.923(3) %
0.077(3) %		6.12851(19) MeV
AL
Cf-251898(44) aα → 247Cm
SF div		ca. 100 %
?		6.1770(9) MeV
AL
Cf-251m1.3(1) μs
Cf-2522.645(8) aα → 248Cm
SF div		96.908(8) %
3.092(8) %		6.21695(4) MeV
AL
Cf-25317.81(8) dα → 249Cm
β- → 253Es		0.31(4) %
99.69(4) %		6.126(4) MeV
0.291(4) MeV		AL
Cf-25460.5(2) dα → 250Cm
SF div		0.31(2) %
99.69(2) %		5.927(5) MeV
AL
Cf-25585(18) minβ- → 255Es100 %0.72(20) MeVAL
Cf-25612.3(12) minSF div
α → 252Cm		100 %
Spuren
5.56(10) MeV		AL

 

Notes (related to the columns):

1 - name of the nuclide, isotope.
2 - E: isotope symbol with mass number (superscript; number of nucleons) and Atomic number (subscript; number of protons).
3 - N: number of neutrons.
4 - relative atomic mass of the Californium isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to 12C = 12.00000 [2]. In addition, the mass excess is given in MeV.
5 - nuclear spin I, unit: h/2π.
6 - source nuclides: Possible, assumed or actual source nuclides (mother nuclides, parent nuclides). If applicable, the corresponding decay modes can be found in the data for the respective starting nuclide.

7 - isotope notation in short form.
8 - decay: half-live of the Californium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
9 - decay mode: type of decay into the respective daughter nuclides with n = neutron emission; p = proton emission; α = alpha decay; β- = beta minus decay with electron emission; EC = electron capture; β+ = positron emission; ε = β+ and/or EC; Iso = isomeric transition; CD = cluster decay; SF = spontaneous decay.
10 - decay probability in percent (%).
11 - decay energy; Particle energy related to decay type.
12 - other information and notes: AL = Adopted Levels (link to external data [1]).

Miscellaneous:

()- Numbers in brackets: uncertainty to represent the spread of the reported value.
~ - Theoretical values or systematic trends.
  - unlisted-: Nuclides that have already been mentioned in the literature but for some reason can no longer be found in the current nuclide tables because their discovery e.g. has not confirmed.

 

Radiation Protection

According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Californium radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
Cf-244107 Bq10000 Bq/g19.4 min
Cf-246106 Bq1000 Bq/g10 Bq cm-235.7 h
Cf-249103 Bq0,1 Bq/g0,1 TBq0,1 Bq cm-2351.0 a
Cf-250104 Bq1 Bq/g0,1 TBq0,1 Bq cm-213.1 a
Cf-251103 Bq0,1 Bq/g0,1 TBq0,1 Bq cm-2898.0 a
Cf-252104 Bq1 Bq/g0,02 TBq0,1 Bq cm-22.6 a
Cf-253+105 Bq100 Bq/g1 Bq cm-2Cm-24917.8 d
Cf-254103 Bq1 Bq/g0,003 TBq0,1 Bq cm-260.5 d

(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)

 

Literature Sources and References

Properties of the Californium nucleides

[1] - NuDat: National Nuclear Data Center, Brookhaven National Laboratory, based on ENSDF and the Nuclear Wallet Cards.

[2] - G. Audi et. al.: The NUBASE evaluation of nuclear and decay properties. Nuclear Physics, (2003), DOI 10.1016/j.nuclphysa.2003.11.001.

[3] - Live Chart of Nuclides. Nuclear structure and decay data.

Californium: NMR properties

[4] - N. J. Stone: Table of nuclear magnetic dipole and electric quadrupole moments. Atomic Data and Nuclear Data Tables, (2005), DOI 10.1016/j.adt.2005.04.001.

[5] - Pekka Pyykkö: Year-2008 nuclear quadrupole moments. Molecular Physics, (2008), DOI 10.1080/00268970802018367.

[6] - Pekka Pyykkö: Year-2017 nuclear quadrupole moments. Molecular Physics, (2018), DOI 10.1080/00268976.2018.1426131.

[7] - N. J. Stone: Table of recommended nuclear magnetic dipole moments. IAEA, (2019).

More sources:

[8] - Isotopic abundances, atomic weights and isotopic masses: see respective keyword.

[9] - L. B. Magnusson et al.:
Berkelium and Californium Isotopes Produced in Neutron Irradiation of Plutonium.
In: Physical Review, (1954), DOI 10.1103/PhysRev.96.1576.

[10] - T. A. Eastwood, J. P. Butler, M. J. Cabell, H. G. Jackson:
Isotopes of Berkelium and Californium Produced by Neutron Irradiation of Plutonium.
In: Physical Review, (1957), DOI 10.1103/PhysRev.107.1635.

 

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