Input interpretation
Ac-231 (actinium-231)
Decay properties
half-life | 7.5 minutes (7.32 to 7.68 min) mean lifetime | 10.8 minutes (10.6 to 11.1 min) decay constant | 0.00154 per second specific activity | 4.01×10^6 TBq/g (terabecquerels per gram) width | 1×10^-18 eV (electronvolts) decay modes | β^- (electron emission) final decay products | Pb-207 (100%) | Tl-205 (9×10^-8%) | Pb-208 (1×10^-12%)
Decay mode
decay mode | β^- (electron emission) Q-value | 2.1 MeV (megaelectronvolts) daughter nuclide | Th-231
Radiation shielding
lead | 1.51 mm portland concrete | 5.26 mm water | 10.3 mm air | 8.96 m
Decay chain
Decay chain
Mass properties
atomic number (Z) | 89 mass number (A) | 231 neutron number | 142 atomic mass | 231.038558786 u (unified atomic mass units) mass excess | 35.917278 MeV (megaelectronvolts) binding energy per nucleon | 7.614407 MeV (megaelectronvolts)
Mass properties
Nearby isotopes
Nearby isotopes
Quantum properties
spin parity J^π | 1/2^+ (atomic boson)
Quantum properties
Excitations
E_level | spin parity J^π | half-life τ_1/2 | width Δ 38 keV (kiloelectronvolts) | 3/2^+ | (unknown) | (unknown) 38 keV (kiloelectronvolts) | 3/2^- | (unknown) | (unknown) 76 keV (kiloelectronvolts) | 9/2^+ | (unknown) | (unknown) 94 keV (kiloelectronvolts) | 7/2^- | (unknown) | (unknown) 135 keV (kiloelectronvolts) | 13/2^+ | (unknown) | (unknown) 162 keV (kiloelectronvolts) | 5/2^+ | (unknown) | (unknown) 235 keV (kiloelectronvolts) | 3/2^+ | (unknown) | (unknown) 257 keV (kiloelectronvolts) | 5/2^+ | (unknown) | (unknown) 305 keV (kiloelectronvolts) | (unknown) | (unknown) | (unknown) 350 keV (kiloelectronvolts) | (unknown) | (unknown) | (unknown)