Isotope: Cesium-126
General data
| Element name | Cesium |
|---|---|
| Chemical symbol | Cs |
| Atomic number Z | 55 |
| Isotope name (symbol) | Cesium-126 (Cs-126) |
| Neutron number N | 71 |
| Mass number A=Z+N | 126 |
Ground state
| Half-life | 1.643 ± 0.017 min |
|---|---|
| Spin / Parity | 1+ |
| Mass excess | -84351 ± 10 keV |
Decay branches
EC/β⁺ 100%Isomers
no isomers in the NNDC data
Produced by decay of
| Parent isotope | Half-life | Decay | % of parent decays |
|---|---|---|---|
| Barium-126 (Ba-126) | 98.6 min | EC/β⁺ | 100.0% |
The table shows only radioactive decays that lead directly to this isotope (NNDC data). The percentage is the share of that decay among all decays of the parent isotope, not the share in producing this isotope - that depends on how much of the parent is in the sample. Many isotopes are also produced, often mainly, in nuclear reactions (e.g. Co-60 from Co-59 by neutron capture, C-14 from nitrogen-14 in the atmosphere) and in fission (e.g. Cs-137, I-131) - those routes are not listed here.
Radioactive decay series
- Cesium-126 1.643 min
- Xenon-126 stable
Decay notation
| Notation | Name | On the chart | Description |
|---|---|---|---|
| α | alpha decay | Alpha decay is the emission of a helium nucleus (2 protons + 2 neutrons): Z−2, A−4. | |
| β⁻, 2β⁻ | beta-minus decay | In beta-minus decay a neutron turns into a proton and the nucleus emits an electron: Z+1, A unchanged. 2β⁻ is double beta decay. | |
| EC, EC/β⁺ | electron capture / beta-plus decay | A proton turns into a neutron: the nucleus captures a shell electron (EC) or emits a positron (β⁺): Z−1, A unchanged. | |
| p, 2p, 3p | proton emission | Proton emission is the ejection of a proton from the nucleus: Z−1, A−1. 2p, 3p - two, three protons. | |
| n, 2n…4n | neutron emission | Neutron emission is the ejection of a neutron from the nucleus: A−1, Z unchanged. 2n…4n - several neutrons. | |
| ¹⁴C, ²⁴Ne… | cluster emission | Cluster emission is the ejection of a light nucleus, e.g. ¹⁴C, ²⁰O, ²⁴Ne, ²⁸Mg, ³⁴Si. It is a very rare transformation. | |
| IT | isomeric transition | An isomeric transition takes a nucleus from an excited state (an isomer, e.g. Pa-234m) to the ground state, usually emitting a γ photon: Z and A unchanged. | |
| β⁻n, ECp, ECα… | delayed emission | Delayed emission is the emission of a particle (n, p or α) right after β⁻ decay or electron capture. The arrow has the colour of the emitted particle and its label shows the transformation, e.g. “β⁻n 63%”. | |
| SF | spontaneous fission | no arrow | Spontaneous fission is the splitting of a nucleus into two fragments of random masses. There is no single daughter, so the chart shows no arrow - it is listed in the decay branches and in the tile tooltip. |
Data sources
- NNDC Wallet Cards 2023 - Data as of 15 October 2024 - licence: Public domain