Isotopes of europium
Encyclopedia
Naturally occurring europium
(Eu) is composed of 2 isotope
s, 151Eu and 153Eu, with 153Eu being the most abundant (52.2% natural abundance
). While 153Eu is stable, 151Eu was recently found to be unstable and to undergo alpha decay
with half-life
of . Besides natural radioisotope 151Eu, 36 artificial radioisotopes have been characterized, with the most stable being 150Eu with a half-life
of 36.9 years, 152Eu with a half-life of 13.516 years, and 154Eu with a half-life of 8.593 years. All of the remaining radioactive isotopes have half-lives that are less than 4.7612 years, and the majority of these have half-lives that are less than 12.2 seconds. This element also has 17 meta states, with the most stable being 150mEu (t½ 12.8 hours), 152m1Eu (t½ 9.3116 hours) and 152m2Eu (t½ 96 minutes).
The primary decay mode before the most abundant stable isotope, 153Eu, is electron capture
, and the primary mode after is beta minus decay. The primary decay product
s before 153Eu are isotopes of samarium
and the primary products after are isotopes of gadolinium
.
Standard atomic mass: 151.964(1) u.
with a half-life
of 4.76 years. It has a maximum decay energy
of 252 KeV
. In a thermal reactor
(almost all current nuclear power plant
s), it has a low fission product yield
, about half of one percent as much as the most abundant fission products.
155Eu's large neutron capture
cross section
(about 3900 barns for thermal neutrons, 16000 resonance integral) means that most of even the small amount produced is destroyed in the course of the nuclear fuel
's burnup
. Yield, decay energy, and halflife are all far less than 137Cs and 90Sr, so 155Eu is not a significant contributor to nuclear waste.
Some 155Eu is also produced by successive neutron capture on 153Eu (nonradioactive, 350 barns thermal, 1500 resonance integral, yield is about 5 times as great as 155Eu) and 154Eu (half-life 8.6 years, 1400 barns thermal, 1600 resonance integral, fission yield is extremely small because beta decay stops at 154Sm); however the differing cross sections mean that both 155Eu and 154Eu are destroyed faster than they are produced.
154Eu is a prolific emitter of gamma radiation.
Europium
Europium is a chemical element with the symbol Eu and atomic number 63. It is named after the continent of Europe. It is a moderately hard silvery metal which readily oxidizes in air and water...
(Eu) is composed of 2 isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
s, 151Eu and 153Eu, with 153Eu being the most abundant (52.2% natural abundance
Natural abundance
In chemistry, natural abundance refers to the abundance of isotopes of a chemical element as naturally found on a planet. The relative atomic mass of these isotopes is the atomic weight listed for the element in the periodic table...
). While 153Eu is stable, 151Eu was recently found to be unstable and to undergo alpha decay
Alpha decay
Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less...
with half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
of . Besides natural radioisotope 151Eu, 36 artificial radioisotopes have been characterized, with the most stable being 150Eu with a half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
of 36.9 years, 152Eu with a half-life of 13.516 years, and 154Eu with a half-life of 8.593 years. All of the remaining radioactive isotopes have half-lives that are less than 4.7612 years, and the majority of these have half-lives that are less than 12.2 seconds. This element also has 17 meta states, with the most stable being 150mEu (t½ 12.8 hours), 152m1Eu (t½ 9.3116 hours) and 152m2Eu (t½ 96 minutes).
The primary decay mode before the most abundant stable isotope, 153Eu, is electron capture
Electron capture
Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino...
, and the primary mode after is beta minus decay. The primary decay product
Decay product
In nuclear physics, a decay product is the remaining nuclide left over from radioactive decay. Radioactive decay often involves a sequence of steps...
s before 153Eu are isotopes of samarium
Isotopes of samarium
Naturally occurring samarium is composed of five stable isotopes, 144Sm, 149Sm, 150Sm, 152Sm and 154Sm, and two extremely long-lived radioisotopes, 147Sm and 148Sm , with 152Sm being the most abundant...
and the primary products after are isotopes of gadolinium
Isotopes of gadolinium
Naturally occurring gadolinium is composed of 6 stable isotopes, 154Gd, 155Gd, 156Gd, 157Gd, 158Gd and 160Gd, and 1 radioisotope, 152Gd, with 158Gd being the most abundant...
.
Standard atomic mass: 151.964(1) u.
Europium-155
Europium-155 is a fission productFission product
Nuclear fission products are the atomic fragments left after a large atomic nucleus fissions. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons and a large release of energy in the form of heat , gamma rays and neutrinos. The...
with a half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
of 4.76 years. It has a maximum decay energy
Decay energy
The decay energy is the energy released by a radioactive decay. Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting ionizing particles and radiation...
of 252 KeV
Kev
Kev can refer to:*Kev Hawkins, a fictional character.*Kevin, a given name occasionally shortened to "Kev".*Kiloelectronvolt, a unit of energy who symbol is "KeV".* Krefelder Eislauf-VereinKEV can refer to:...
. In a thermal reactor
Thermal reactor
A thermal reactor is a nuclear reactor that uses slow or thermal neutrons. Most power reactors are of this type. These type of reactors use a neutron moderator to slow neutrons until they approach the average kinetic energy of the surrounding particles, that is, to reduce the speed of the neutrons...
(almost all current nuclear power plant
Nuclear power plant
A nuclear power plant is a thermal power station in which the heat source is one or more nuclear reactors. As in a conventional thermal power station the heat is used to generate steam which drives a steam turbine connected to a generator which produces electricity.Nuclear power plants are usually...
s), it has a low fission product yield
Fission product yield
Nuclear fission splits a heavy nucleus such as uranium or plutonium into two lighter nuclei, which are called fission products. Yield refers to the fraction of a fission product produced per fission.Yield can be broken down by:#Individual isotope...
, about half of one percent as much as the most abundant fission products.
155Eu's large neutron capture
Neutron capture
Neutron capture is a kind of nuclear reaction in which an atomic nucleus collides with one or more neutrons and they merge to form a heavier nucleus. Since neutrons have no electric charge they can enter a nucleus more easily than positively charged protons, which are repelled...
cross section
Neutron cross-section
In nuclear and particle physics, the concept of a neutron cross section is used to express the likelihood of interaction between an incident neutron and a target nucleus. In conjunction with the neutron flux, it enables the calculation of the reaction rate, for example to derive the thermal power...
(about 3900 barns for thermal neutrons, 16000 resonance integral) means that most of even the small amount produced is destroyed in the course of the nuclear fuel
Nuclear fuel
Nuclear fuel is a material that can be 'consumed' by fission or fusion to derive nuclear energy. Nuclear fuels are the most dense sources of energy available...
's burnup
Burnup
In nuclear power technology, burnup is a measure of how much energy is extracted from a primary nuclear fuel source...
. Yield, decay energy, and halflife are all far less than 137Cs and 90Sr, so 155Eu is not a significant contributor to nuclear waste.
Some 155Eu is also produced by successive neutron capture on 153Eu (nonradioactive, 350 barns thermal, 1500 resonance integral, yield is about 5 times as great as 155Eu) and 154Eu (half-life 8.6 years, 1400 barns thermal, 1600 resonance integral, fission yield is extremely small because beta decay stops at 154Sm); however the differing cross sections mean that both 155Eu and 154Eu are destroyed faster than they are produced.
154Eu is a prolific emitter of gamma radiation.
| Isotope | Halflife | Relative yield | Thermal neutron | Resonance integral |
|---|---|---|---|---|
| Eu-153 | Stable | 5 | 350 | 1500 |
| Eu-154 | 8.6 years | Nearly 0 | 1500 | 1600 |
| Eu-155 | 4.76 years | 1 | 39000 | 16000 |
Table
| nuclide symbol |
Z(p Proton The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number.... ) |
N(n Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... ) |
isotopic mass (u) |
half-lifeBold for isotopes with half-lives longer than the age of the universe (nearly stable) | decay mode(s)Abbreviations: EC: Electron capture Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino... IT: Isomeric transition Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer.... |
daughter isotope(s)Bold for stable isotopes, bold italics for nearly-stable isotopes (half-life longer than the age of the universe) |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
|---|---|---|---|---|---|---|---|---|---|
| excitation energy | |||||||||
| 130Eu | 63 | 67 | 129.96357(54)# | 1.1(5) ms [0.9(+5-3) ms] |
2+# | ||||
| 131Eu | 63 | 68 | 130.95775(43)# | 17.8(19) ms | 3/2+ | ||||
| 132Eu | 63 | 69 | 131.95437(43)# | 100# ms | β+ Beta decay In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a... |
132Sm | |||
| p Proton emission Proton emission is a type of radioactive decay in which a proton is ejected from a nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay, in which case the process is known as beta-delayed proton emission, or can occur from the ground state of very... |
131Sm | ||||||||
| 133Eu | 63 | 70 | 132.94924(32)# | 200# ms | β+ | 133Sm | 11/2-# | ||
| 134Eu | 63 | 71 | 133.94651(21)# | 0.5(2) s | β+ | 134Sm | |||
| β+, p (rare) | 133Pm | ||||||||
| 135Eu | 63 | 72 | 134.94182(32)# | 1.5(2) s | β+ | 135Sm | 11/2-# | ||
| β+, p | 134Pm | ||||||||
| 136Eu | 63 | 73 | 135.93960(21)# | 3.3(3) s | β+ (99.91%) | 136Sm | (7+) | ||
| β+, p (.09%) | 135Pm | ||||||||
| 136mEu | 0(500)# keV | 3.8(3) s | β+ (99.91%) | 136Sm | (3+) | ||||
| β+, p (.09%) | 135Pm | ||||||||
| 137Eu | 63 | 74 | 136.93557(21)# | 8.4(5) s | β+ | 137Sm | 11/2-# | ||
| 138Eu | 63 | 75 | 137.93371(3) | 12.1(6) s | β+ | 138Sm | (6-) | ||
| 139Eu | 63 | 76 | 138.929792(14) | 17.9(6) s | β+ | 139Sm | (11/2)- | ||
| 140Eu | 63 | 77 | 139.92809(6) | 1.51(2) s | β+ | 140Sm | 1+ | ||
| 140mEu | 210(15) keV | 125(2) ms | IT Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer.... (99%) |
140Eu | 5-# | ||||
| β+(1%) | 140Sm | ||||||||
| 141Eu | 63 | 78 | 140.924931(14) | 40.7(7) s | β+ | 141Sm | 5/2+ | ||
| 141mEu | 96.45(7) keV | 2.7(3) s | IT (86%) | 141Eu | 11/2- | ||||
| β+ (14%) | 141Sm | ||||||||
| 142Eu | 63 | 79 | 141.92343(3) | 2.36(10) s | β+ | 142Sm | 1+ | ||
| 142mEu | 460(30) keV | 1.223(8) min | β+ | 142Sm | 8- | ||||
| 143Eu | 63 | 80 | 142.920298(12) | 2.59(2) min | β+ | 143Sm | 5/2+ | ||
| 143mEu | 389.51(4) keV | 50.0(5) µs | 11/2- | ||||||
| 144Eu | 63 | 81 | 143.918817(12) | 10.2(1) s | β+ | 144Sm | 1+ | ||
| 144mEu | 1127.6(6) keV | 1.0(1) µs | (8-) | ||||||
| 145Eu | 63 | 82 | 144.916265(4) | 5.93(4) d | β+ | 145Sm | 5/2+ | ||
| 145mEu | 716.0(3) keV | 490 ns | 11/2- | ||||||
| 146Eu | 63 | 83 | 145.917206(7) | 4.61(3) d | β+ | 146Sm | 4- | ||
| 146mEu | 666.37(16) keV | 235(3) µs | 9+ | ||||||
| 147Eu | 63 | 84 | 146.916746(3) | 24.1(6) d | β+ (99.99%) | 147Sm | 5/2+ | ||
| α Alpha decay Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less... (.0022%) |
143Pm | ||||||||
| 148Eu | 63 | 85 | 147.918086(11) | 54.5(5) d | β+ (100%) | 148Sm | 5- | ||
| α (9.39×10−7%) | 144Pm | ||||||||
| 149Eu | 63 | 86 | 148.917931(5) | 93.1(4) d | EC Electron capture Electron capture is a process in which a proton-rich nuclide absorbs an inner atomic electron and simultaneously emits a neutrino... |
149Sm | 5/2+ | ||
| 150Eu | 63 | 87 | 149.919702(7) | 36.9(9) a | β+ | 150Sm | 5(-) | ||
| 150mEu | 42.1(5) keV | 12.8(1) h | β- (89%) | 150Gd | 0- | ||||
| β+ (11%) | 150Sm | ||||||||
| IT (5×10−8%) | 150Eu | ||||||||
| 151Euprimordial Primordial nuclide In geochemistry and geonuclear physics, primordial nuclides or primordial isotopes are nuclides found on the earth that have existed in their current form since before Earth was formed. Only 288 such nuclides are known... radionuclide Radionuclide A radionuclide is an atom with an unstable nucleus, which is a nucleus characterized by excess energy available to be imparted either to a newly created radiation particle within the nucleus or to an atomic electron. The radionuclide, in this process, undergoes radioactive decay, and emits gamma... |
63 | 88 | 150.9198502(26) | 5×1018 a | α | 147Pm | 5/2+ | 0.4781(6) | |
| 151mEu | 196.245(10) keV | 58.9(5) µs | 11/2- | ||||||
| 152Eu | 63 | 89 | 151.9217445(26) | 13.537(6) a | β+ (72.09%) | 152Sm | 3- | ||
| β- (27.9%) | 152Gd | ||||||||
| 152m1Eu | 45.5998(4) keV | 9.3116(13) h | β- (72%) | 152Gd | 0- | ||||
| β+ (28%) | 152Sm | ||||||||
| 152m2Eu | 65.2969(4) keV | 0.94(8) µs | 1- | ||||||
| 152m3Eu | 78.2331(4) keV | 165(10) ns | 1+ | ||||||
| 152m4Eu | 89.8496(4) keV | 384(10) ns | 4+ | ||||||
| 152m5Eu | 147.86(10) keV | 96(1) min | 8- | ||||||
| 153EuFission product Fission product Nuclear fission products are the atomic fragments left after a large atomic nucleus fissions. Typically, a large nucleus like that of uranium fissions by splitting into two smaller nuclei, along with a few neutrons and a large release of energy in the form of heat , gamma rays and neutrinos. The... |
63 | 90 | 152.9212303(26) | Observationally StableBelieved to undergo α decay to 149Pm | 5/2+ | 0.5219(6) | |||
| 154Eu | 63 | 91 | 153.9229792(26) | 8.593(4) a | β- (99.98%) | 154Gd | 3- | ||
| EC (.02%) | 154Sm | ||||||||
| 154m1Eu | 145.3(3) keV | 46.3(4) min | IT | 154Eu | (8-) | ||||
| 154m2Eu | 68.1702(4) keV | 2.2(1) µs | 2+ | ||||||
| 155Eu | 63 | 92 | 154.9228933(27) | 4.7611(13) a | β- | 155Gd | 5/2+ | ||
| 156Eu | 63 | 93 | 155.924752(6) | 15.19(8) d | β- | 156Gd | 0+ | ||
| 157Eu | 63 | 94 | 156.925424(6) | 15.18(3) h | β- | 157Gd | 5/2+ | ||
| 158Eu | 63 | 95 | 157.92785(8) | 45.9(2) min | β- | 158Gd | (1-) | ||
| 159Eu | 63 | 96 | 158.929089(8) | 18.1(1) min | β- | 159Gd | 5/2+ | ||
| 160Eu | 63 | 97 | 159.93197(22)# | 38(4) s | β- | 160Gd | 1(-) | ||
| 161Eu | 63 | 98 | 160.93368(32)# | 26(3) s | β- | 161Gd | 5/2+# | ||
| 162Eu | 63 | 99 | 161.93704(32)# | 10.6(10) s | β- | 162Gd | |||
| 163Eu | 63 | 100 | 162.93921(54)# | 6# s | β- | 163Gd | 5/2+# | ||
| 164Eu | 63 | 101 | 163.94299(64)# | 2# s | β- | 164Gd | |||
| 165Eu | 63 | 102 | 164.94572(75)# | 1# s | β- | 165Gd | 5/2+# | ||
| 166Eu | 63 | 103 | 165.94997(86)# | 400# ms | β- | 166Gd | |||
| 167Eu | 63 | 104 | 166.95321(86)# | 200# ms | β- | 167Gd | 5/2+# | ||