Karlsruhe Nuclide Chart

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eu/jrc/ 2 ucleonica GmbH, 76344 Eggenstein-Leopoldshafen, Germany http://www.nucleonica.com The first edition was published in 1958. The 9 th edition was printed in 2015.

1 Karlsruhe uclide Chart The ew Edition in 2015 s. Sóti 1, J. Magill 2 1 European Commission, Joint Research Centre, Institute for Transuranium Elements, Postfach 2340, Karlsruhe, Germany 2 ucleonica GmbH, Eggenstein-Leopoldshafen, Germany The first edition was published in The 9 th edition was printed in Karlsruhe uclide Chart Atoms with different numbers of protons and neutrons in their nucleus are generally known as nuclides. The Karlsruhe uclide Chart shows all known nuclides in a clear two dimensional co-ordinate system of nuclide boxes depicting the number of protons and neutrons in the atomic nucleus. A nuclide box in the chart contains the element symbol, the mass number and other nuclear data on the nuclide characterised by the position in the neutron-proton co-ordinate system. The colours of the nuclide boxes represent the different radioactive decay modes of the radionuclides. umber of protons umber of neutrons 1

2 Karlsruhe uclide Chart uclides with approximately equal numbers of protons and neutrons are stable and marked in black. uclides with an excess of protons have the colour red or yellow whereas those with an excess of neutrons have the colour blue. Each horizontal row on the Chart starts with a box describing the element and it is followed by the isotopes of this chemical element. ( is constant) If is constant - Isotones If A=+ is constant - Isobars These nuclides are continuously produced in stars and supernovae explosions. On Earth, they are also produced in particles accelerators and nuclear reactors. Isotopes =constant Isobars +=A=constant Isotones =constant 2

ew 9 th Edition in 2015 The Karlsruhe uclide Chart is printed in three different standard formats: Fold-out Chart, Wall Chart and Auditorium Chart (0.43 x 3.16 m).

The section Reduced Decay Schemes contains about 50 nuclide decay schemes to aid the user to interpret the highly condensed information in the nuclide boxes.

In the case of ß decay the nuclide box contains a maximum of two ß endpoint energies.

The excited states of the daughter nuclide K 41 release their energy through gamma emissions.

3 ew 9 th Edition in 2015 The Karlsruhe uclide Chart is printed in three different standard formats: Fold-out Chart, Wall Chart and Auditorium Chart (0.43 x 3.16 m). The accompanying booklet provides a detailed explanation of the nuclide box structure used in the Chart. The section Reduced Decay Schemes contains about 50 nuclide decay schemes to aid the user to interpret the highly condensed information in the nuclide boxes. The colour blue indicates that the nucleus decays by ß emission. Ar 41 is characterised by the emission of several beta particles with different endpoint energies. In the case of ß decay the nuclide box contains a maximum of two ß endpoint energies. The first number corresponds to the strongest transition whereas the second corresponds to the highest ß endpoint energy. Additional transitions are indicated by dots. The excited states of the daughter nuclide K 41 release their energy through gamma emissions. Theoretical background The colours indicate various modes of radioactive decay: α decay neutron decay ß decay proton decay ec/ß + decay spontaneous fission isomeric transition stable nuclide The mass number in a nuclide box is the number of protons plus the number of neutrons: A = +. The number of protons defines the chemical element, the number of neutrons: = A A nuclide position in the chart is defined by co-ordinates (,). 3

Alpha (α) Decay In alpha decay, the parent atom (A,)P emits an alpha particle (4,2)α and results in a daughter

Immediately following the alpha particle emission, the daughter atom still has the electrons of the parent hence

These extra electrons are lost soon after the alpha particle emission leaving the daughter atom electrically

4 Alpha (α) Decay In alpha decay, the parent atom (A,)P emits an alpha particle (4,2)α and results in a daughter nuclide (A-4,-2)D. Immediately following the alpha particle emission, the daughter atom still has the electrons of the parent hence the daughter atom has two electrons too many and should be denoted by [A-4,-2]D 2-. These extra electrons are lost soon after the alpha particle emission leaving the daughter atom electrically neutral. In addition, the alpha particle will slow down and lose its kinetic energy. At low energies the alpha particle will acquire two electrons to become a neutral helium atom. The alpha decay process is described by: Gamma Spectrum Characteristics 4

Beta-minus (β ) Decay ß radioactivity occurs when a nucleus emits a negative electron from an unstable radioactive nucleus. This happens when the nuclide has an excess of neutrons.

5 Beta-minus (β ) Decay ß radioactivity occurs when a nucleus emits a negative electron from an unstable radioactive nucleus. This happens when the nuclide has an excess of neutrons. Theoretical considerations (de Broglie wavelength of MeV electrons is much larger than nuclear dimensions), however, do not allow the existence of a negative electron in the nucleus. For this reason the beta particle is postulated to arise from the nuclear transformation of a neutron into a proton through the reaction whereνis an anti-neutrino. The ejected high energy electron from the nucleus denoted byβ to distinguish it from other electrons denoted by e. Beta emission differs from alpha emission in that beta particles have a continuous spectrum of energies between zero and some maximum value, the endpoint energy, characteristic of that nuclide. The β decay process can be described by: Gamma Spectrum Peak at 1294 kev 5

Beta-plus (β + ) Decay (Positron Emission) In nuclides where the neutron to proton ratio is low, and alpha emission is not energetically possible, the nucleus may become more stable by the

The positron, after being emitted from the nucleus, undergoes strong electrostatic attraction with the atomic electrons.

6 Beta-plus (β + ) Decay (Positron Emission) In nuclides where the neutron to proton ratio is low, and alpha emission is not energetically possible, the nucleus may become more stable by the emission of a positron (a positively charged electron). Within the nucleus a proton is converted into a neutron, a positron, and a neutrino i.e. Similarly to the β, the positron β + is continuously distributed in energy up to a characteristic maximum energy. The positron, after being emitted from the nucleus, undergoes strong electrostatic attraction with the atomic electrons. The positron and negative electrons annihilate each other and result in two photons (gamma rays) each with energy of 511 kev moving in opposite directions. Gamma Spectrum Annihilation Peak Annihilation Peak 511 kev 6

Electron Capture (ε) eutron deficient nuclides can also attain stability by capturing an electron from the inner K or L shells of the atomic orbits.

The electron capture decay process can be described by: and the daughter is usually produced in an excited state.

7 Electron Capture (ε) eutron deficient nuclides can also attain stability by capturing an electron from the inner K or L shells of the atomic orbits. As a result, a proton in the nucleus transforms to a neutron i.e. The process is similar toβ + decay in that the charge of the nucleus decreases by 1. The electron capture decay process can be described by: and the daughter is usually produced in an excited state. The resulting nucleus is unstable and decays by the ejection of an neutrino (ν) and the emission of an X-ray when the electron vacancy in the K or L shell is filled by outer orbital electrons. Gamma Spectrum 7

Isomeric Transition, IT After a radioactive nucleus undergoes an isobaric transition (beta emission, positron emission, or electron

uclei in these intermediate and final states are isomers, since they have the same atomic and mass numbers.

In contrast to normal gamma emission, isomeric transitions occur on a longer timescale.

8 Isomeric Transition, IT After a radioactive nucleus undergoes an isobaric transition (beta emission, positron emission, or electron capture), it usually contains too much energy to be in its final stable or daughter state. uclei in these intermediate and final states are isomers, since they have the same atomic and mass numbers. uclei in the intermediate state will undergo an isomeric transition by emitting energy and dropping to the ground state. In contrast to normal gamma emission, isomeric transitions occur on a longer timescale. If the lifetime for gamma emission exceeds about one nanosecond, the excited nucleus is defined to be in a metastable or isomeric state. The decay process from this excited state is known as an isomeric transition (IT) e.g. The letter m after the mass number denotes the metastable state. Gamma Spectrum 8

Internal Conversion, e - The excess energy of radioactive nuclei in excited states is usually relieved through gamma emission.

Hence, as an alternative to gamma emission, the excited nucleus may return to the ground state by ejecting an orbital electron.

Following the internal conversion, outer orbital electrons fill the deeper energy levels and result in characteristic X-ray emission.

9 Internal Conversion, e - The excess energy of radioactive nuclei in excited states is usually relieved through gamma emission. However, if the wave function of the orbital electron is such that it can exist close to or in the nucleus, the excess energy can be transferred directly to the orbital electron. Hence, as an alternative to gamma emission, the excited nucleus may return to the ground state by ejecting an orbital electron. This is known as internal conversion and results in an energetic electron and X-rays due to electrons cascading to lower energy levels. Following the internal conversion, outer orbital electrons fill the deeper energy levels and result in characteristic X-ray emission. The ratio of internal conversion to gamma emission photons is known as the internal conversion coefficient denoted asα T =α K +α L +.. Consider the decay of the isomeric state 60m Co. This excited nuclide state can lose its energy (59 kev) either by gamma emission or by the emission of a conversion electron. Sinceα T = 47, the state de-excites mainly via internal conversion. Spontaneous Fission (sf) Actinides and trans-actinides can undergo radioactive decay by spontaneous fission. In this process the nucleus splits into two fragment nuclei, with mass and charge roughly half that of the parent, and several neutrons. The spontaneous fission decay process can be described qualitatively by: A parent nuclide splits into two daughter nuclides and together with the release of n prompt neutrons and energy E*. Typically n ranges from 2 4 and E* is approximately 200 MeV. The daughter nuclides or fission products have in general different mass numbers A and atomic numbers. Colour green denotes the spontaneous fission 9

Multiple Decay Modes and Branching Ratios When a nuclide has more than one mode of decay, the use of coloured triangles gives an indication of the branching ratios of the different decay modes.

otice that the order of the branching ratios in the text box indicates the most important,second most important etc. Right: The small triangle in Tc-100 indicates that ε branching ratio 5 % is.

Cs 137 is characterized by the emission of three ß particles with different endpoint energies. The most probable ß emission is at 0.5 MeV whereas the highest energy emission occurs at 1.2 MeV.

10 Multiple Decay Modes and Branching Ratios When a nuclide has more than one mode of decay, the use of coloured triangles gives an indication of the branching ratios of the different decay modes. Left: The large triangles in I-126 indicates that the branching ratios for electron capture and beta emission are 5 %, but 95 %. otice that the order of the branching ratios in the text box indicates the most important,second most important etc. Right: The small triangle in Tc-100 indicates that ε branching ratio 5 % is. The corresponding value for ß - emission 95 %. Example The colour blue indicates that the nucleus decays by ß emission. Cs 137 is characterized by the emission of three ß particles with different endpoint energies. The most probable ß emission is at 0.5 MeV whereas the highest energy emission occurs at 1.2 MeV. Additional beta particles are also emitted indicated by the dots. The box entry m indicates that the main ß decay is to the metastable state (94.7%) Ba 137m. The gamma transition from this metastable state is found in the nuclide box Ba 137m. The use of the symbol g indicates that the direct transition to the ground state has a branching greater than 5%. Actually in this case it is 5.3%. Decay to an excited state of the daughter Ba 137 is less probable (less than 1%) and gives rise to the weak gamma emission at 284 kev indicated by the entry (284). eutron capture in Cs 137 leads to the formation of Cs138m (cross section 0.20 barn) and Cs 138g (cross section 0.07 barn) 10

11 Example Only Cs 137 Special Editions of KC Some special editions have been produced in the previous three years for various institutes and organisations. uclide Carpet (CER), the Contour Chart (European Dialogue Centre) and the Ceramic Tiles version of Karlsruhe uclide Chart (Institute for Transuranium Elements) 11

Overview For almost 60 years, the Karlsruhe uclide Chart has provided scientists and students with structured, accurate information on the half-lives and decay modes of radionuclides, as well as the

It has been used in training programs worldwide and is a valuable addition to many books on nuclear science including school physics textbooks.

12 Overview For almost 60 years, the Karlsruhe uclide Chart has provided scientists and students with structured, accurate information on the half-lives and decay modes of radionuclides, as well as the energies of emitted radiation. An important characteristic of the Chart is its great didactic value for education and training in the nuclear sciences. It has been used in training programs worldwide and is a valuable addition to many books on nuclear science including school physics textbooks. The Karlsruhe uclide Chart shows all known nuclides in a two dimensional co-ordinate system depicting the number of protons and neutrons in the atomic nucleus. uclides with approximately equal numbers of protons and neutrons are stable and marked in black. uclides with an excess of protons have the colour red or yellow whereas those with an excess of neutrons have the colour blue. Each horizontal row on the Chart starts with a box describing the element and is followed by the isotopes of this chemical element. The End 12

Chapter Three (Nuclear Radiation)

Al-Mustansiriyah University College of Science Physics Department Fourth Grade Nuclear Physics Dr. Ali A. Ridha Chapter Three (Nuclear Radiation) (3-1) Nuclear Radiation Whenever a nucleus can attain a