Isotope: Protactinium-239
General data
| Element name | Protactinium |
|---|---|
| Chemical symbol | Pa |
| Atomic number Z | 91 |
| Isotope name (symbol) | Protactinium-239 (Pa-239) |
| Neutron number N | 148 |
| Mass number A=Z+N | 239 |
Ground state
| Half-life | 1.8 ± 0.5 h |
|---|---|
| Spin / Parity | (3/2) |
| Mass excess | 53340 ± 200 keV (S) |
Decay branches
β⁻ 100%Isomers
no isomers in the NNDC data
Produced by decay of
NNDC data contain no decay that leads to this isotope.
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
- Protactinium-239 1.8 h
- Uranium-239 23.45 min
- Neptunium-239 2.356 d
- Plutonium-239 24109 a
- Uranium-235 7.040×10⁸ a
- Thorium-231 25.52 h
- Protactinium-231 32740 a
- Actinium-227 21.773 a
- Thorium-227 18.694 d · 98.6%
- Francium-223 21.99 min · 1.4%
- Radium-223 11.4352 d
- Radon-219 3.96 s
- Polonium-215 1.781 ms
- Lead-211 36.1648 min
- Bismuth-211 2.14 min
- Polonium-211 0.516 s · 0.28%
- Thallium-207 4.77 min · 99.7%
- Lead-207 stable
Rare branches (below 0.01%)
Rare branches are transformations that occur in fewer than 0.01% of decays, e.g. double beta decay or cluster emission. The nuclides they produce are practically absent from a sample, so they are hidden by default to keep the main path clear. In this series: branches - 6, nuclides - 14.
- Astatine-219 56 s · 8.3×10⁻⁵%
- Lead-209 3.235 h · 8.9×10⁻⁸%
- Bismuth-209 2.01×10¹⁹ a · 8.9×10⁻⁸%
- Thallium-205 stable · 8.9×10⁻⁸%
- Lead-215 142 s · 8.0×10⁻¹⁰%
- Bismuth-215 7.6 min · 7.8×10⁻⁵%
- Astatine-215 37 μs · 2.3×10⁻⁴%
- Lead-210 22.20 a · 8.0×10⁻¹⁰%
- Mercury-207 2.9 min · 8.0×10⁻¹⁰%
- Bismuth-210 5.012 d · 8.0×10⁻¹⁰%
- Polonium-210 138.378 d · 8.0×10⁻¹⁰%
- Mercury-206 8.32 min · 1.5×10⁻¹⁷%
- Thallium-206 4.202 min · 1.1×10⁻¹⁵%
- Lead-206 stable · 8.0×10⁻¹⁰%
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