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Isotopes of Californium

List, data and properties of all known isotopes of Californium as well as radioactive decay products and intermediate products.

 

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.

Technically, the radioactive element has no meaning.

 

Isotope Table: Californium

 

Atomic Properties

Isotope
Nuclide
ZANNameAtomic Mass
[Nuclear Mass]
{Mass Excess}
Spin I
(h/2π)
μParent
123456789
237Cf98237139Californium-237237.06220(9) u
[237.0084469 u]
{57.93893 MeV}
238Cf98238140Californium-238238.06149(32) u
[238.0077369 u]
{57.27757 MeV}
0+
239Cf98239141Californium-239239.06255(22) u
[239.0087969 u]
{58.26495 MeV}
243Fm
240Cf98240142Californium-240240.062256(20) u
[240.0085029 u]
{57.99109 MeV}
0+
241Cf98241143Californium-241241.06369(18) u
[241.0099369 u]
{59.32685 MeV}
(7/2-)245Fm
242Cf98242144Californium-242242.063755(14) u
[242.0100019 u]
{59.3874 MeV}
0+246Fm
242Es
243Cf98243145Californium-243243.06547(12) u
[243.0117169 u]
{60.98491 MeV}
(1/2+)247Fm
243Es
244Cf98244146Californium-244244.0659995(28) u
[244.0122464 u]
{61.47814 MeV}
0+248Fm
244Es
245Cf98245147Californium-245245.0680468(26) u
[245.0142937 u]
{63.38519 MeV}
1/2+249Fm
245Es
246Cf98246148Californium-246246.0688038(16) u
[246.0150507 u]
{64.09033 MeV}
0+250Fm
247Cf98247149Californium-247247.070965(16) u
[247.0172119 u]
{66.10347 MeV}
(7/2+)251Fm
247Es
248Cf98248150Californium-248248.072183(5) u
[248.0184299 u]
{67.23803 MeV}
0+252Fm
248Es
248Bk
249Cf98249151Californium-249249.0748505(13) u
[249.0210974 u]
{69.72279 MeV}
9/2-- 0.28253Fm
249Es
249Bk
249mCf98249151Californium-249m249.0748505(13) u
[249.0210974 u]
{69.72279 MeV}
5/2+
250Cf98250152Californium-250250.0764046(17) u
[250.0226515 u]
{71.17043 MeV}
0+254Fm
250Es
250Bk
251Cf98251153Californium-251251.079587(4) u
[251.0258339 u]
{74.13481 MeV}
1/2+255Fm
251Es
251Bk
251mCf98251153Californium-251m251.079587(4) u
[251.0258339 u]
{74.13481 MeV}
11/2-
252Cf98252154Californium-252252.0816265(25) u
[252.0278734 u]
{76.03459 MeV}
0+256Fm
252Es
253Cf98253155Californium-253253.085134(5) u
[253.0313809 u]
{79.30181 MeV}
(7/2+)257Fm
254Cf98254156Californium-254254.087324(12) u
[254.0335709 u]
{81.34178 MeV}
0+254Es
255Cf98255157Californium-255255.09105(21) u
[255.0372969 u]
{84.81253 MeV}
(7/2+)
256Cf98256158Californium-256256.09344(34) u
[256.0396869 u]
{87.0388 MeV}
0+

 

Radioactive Decay Properties

IsotopeRadioactive DecayAEExtern
Half-lifeDecay ModeProbabilityEnergy
1101112131415
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 %
<< 1 %
<< 1 %
6.8616(10) MeV
0.120(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) μs144.98(5) keVAL
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) μs370.47(3) keV
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 - nuclide, isotope symbol.
2 - Z = number of protons (atomic number).
3 - Mass number A.
4 - N = number of neutrons.
5 - Identification of the Californium isotope.
6 - 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.
7 - Nuclear spin I, unit: h/2π.
8 - Nuclear magnetic moment μmag.
9 - 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.
10 - Decay: Half-live of the Californium isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
11 - Decay: 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.
12 - Decay percentage in percent (%).
13 - Decay energy; Particle energy related to decay type.
14 - AE = Excitation energy for metastable nuclei.
15 - 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.

 


Category: Isotopes

Last update: 05.07.2020



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