Isotopes of californium

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Actinides Half-life Fission products
244Cm 241Puƒ 250Cf 227Ac№ 10–22 y medium m is
meta		 85Kr 113mCd₡
232Uƒ 238Pu 243Cmƒ 29–90 y 137Cs 90Sr 151Sm₡ 121mSn
ƒ for
fissile		 249Cfƒ 242mAmƒ 251Cfƒ[1] 140 y –
1.6 ky

No fission products
have a half-life in the
range of 91 y – 210 ky
241Am 226Ra№[2] 247Bk
240Pu 229Th 246Cm 243Am 5–7 ky
4n 245Cmƒ 250Cm 239Puƒ 8–24 ky
236Npƒ 233Uƒ 230Th№ 231Pa№ 32–160 ky
248Cm 4n+1 234U№ 211–348 ky 99Tc ₡ can capture 126Sn 79Se
236U 237Np 242Pu 247Cmƒ 0.37–23 My 135Cs₡ 93Zr 107Pd 129I long
244Pu № for
NORM		 4n+2 4n+3 80 My 6-7% 4-5% 1.25% 0.1-1% <0.05%
232Th№ 238U№ 235Uƒ№ 0.7–14 Gy fission product yield[3]

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.

Contents

[edit] 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]

[edit] Table

nuclide
symbol		 Z(p) N(n)  
isotopic mass (u)
 		 half-life decay
mode(s)[6][n 1]		 daughter
isotope(s)		 nuclear
spin
excitation energy
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+#
β+ (rare) 239Bk
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-#
α (25%) 237Cm
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+)
α (14%) 239Cm
244Cf 98 146 244.066001(3) 19.4(6) min α (99%) 240Cm 0+
EC (1%) 244Bk
245Cf 98 147 245.068049(3) 45.0(15) min β+ (64%) 245Bk (5/2+)
α (36%) 241Cm
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+)#
α (.04%) 243Cm
248Cf 98 150 248.072185(6) 333.5(28) d α (99.99%) 244Cm 0+
SF (.0029%) (various)
249Cf 98 151 249.0748535(24) 351(2) a α 245Cm 9/2-
SF (5×10−7%) (various)
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+
SF (.077%) (various)
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+
SF (3.09%)[n 4] (various)
253Cf 98 155 253.085133(7) 17.81(8) d β- (99.69%) 253Es (7/2+)
α (.31%) 249Cm
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
  1. ^ Abbreviations:
    EC: Electron capture
    SF: Spontaneous fission
  2. ^ High neutron cross-section, tends to absorb neutrons
  3. ^ Most common isotope
  4. ^ High neutron emitter, average 3.7 neutrons per fission

[edit] 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.

[edit] References

  1. ^ Note: This is the heaviest isotope with a half-life of at least ten years before the "Sea of Instability".
  2. ^ Note: 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. ^ Note: 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. ^ http://www.nucleonica.net/unc.aspx
Isotopes of berkelium Isotopes of californium Isotopes of einsteinium
Table of nuclides
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
Retrieved from "http://en.wikipedia.org/w/index.php?title=Isotopes_of_californium&oldid=540466201"