Input interpretation
Pu-240 (plutonium-240)
Decay properties
half-life | 6561 years (6540 to 6580 yr) mean lifetime | 9466 years (9430 to 9500 yr) decay constant | 3.35×10^-12 per second specific activity | 8.404 GBq/g (gigabecquerels per gram) width | 1.528×10^-27 eV (electronvolts) decay modes | α (alpha emission) | SF (spontaneous fission) | ^34Si (cluster emission) final decay products | Pb-208 (100%) | Pb-206 (4×10^-9%) | Pb-204 (0%) | Hg-200 (0%) | Hg-204 (0%)
Critical properties
critical mass | 40 kg (kilograms) critical diameter | 15 cm (centimeters) (for a uniform sphere)
Decay modes
decay mode | α (alpha emission) branching ratio | 100% Q-value | 5.25575 MeV (megaelectronvolts) daughter nuclide | U-236 decay mode | SF (spontaneous fission) branching ratio | 5.7×10^-6% decay mode | ^34Si (cluster emission) branching ratio | 1.3×10^-13% daughter nuclide | Hg-206
Radiation shielding
lead | 16 µm water | 40.5 µm air | 36.9 mm
Decay chain
Decay chain
Mass properties
atomic number (Z) | 94 mass number (A) | 240 neutron number | 146 atomic mass | 240.053813545 u (unified atomic mass units) mass excess | 50.126995 MeV (megaelectronvolts) binding energy per nucleon | 7.556036 MeV (megaelectronvolts)
Mass properties
Nearby isotopes
Nearby isotopes
Quantum properties
spin parity J^π | 0^+ (atomic boson) magnetic moment | 0 μ_N
Quantum properties
Excitations
E_level | spin parity J^π | half-life τ_1/2 | width Δ 42.824 keV (kiloelectronvolts) | 2^+ | 1.64×10^-10 seconds | 2.78×10^-6 eV (electronvolts) 141.69 keV (kiloelectronvolts) | 4^+ | (unknown) | (unknown) 294.319 keV (kiloelectronvolts) | 6^+ | (unknown) | (unknown) 497.52 keV (kiloelectronvolts) | 8^+ | (unknown) | (unknown) 597.34 keV (kiloelectronvolts) | 1^- | (unknown) | (unknown) 648.85 keV (kiloelectronvolts) | 3^- | (unknown) | (unknown) 742.33 keV (kiloelectronvolts) | 5^- | 2×10^-9 seconds | 2×10^-7 eV (electronvolts) 747.8 keV (kiloelectronvolts) | 10^+ | (unknown) | (unknown) 860.71 keV (kiloelectronvolts) | 0^+ | (unknown) | (unknown) 900.32 keV (kiloelectronvolts) | 2^+ | (unknown) | (unknown)