How many meta states does the first isotope to be synthesized in Am in 1944 have?
Americium-241 Americium-241 (Am) is an isotope of americium. Like all isotopes of americium, it is radioactive. Am is the most common isotope of americium. It is the most prevalent isotope of americium in nuclear waste. Americium-241 has a half-life of 432.2 years. It is commonly found in ionization type smoke detectors. It is a potential fuel for long-lifetime radioisotope thermoelectric generators (RTGs). Its common parent nuclides are β from Pu, EC from Cm and α from Bk. Am is fissile and the critical mass of a bare sphere is 57.6-75.6 kilograms and a sphere diameter of 19–21 centimeters. Americium-241 has a specific activity of 3.43 Ci/g (curies per gram or 117.29 gigabequerels (GBq) per gram). It is commonly found in the form of americium-241 dioxide (AmO). This isotope also has one meta state; Am, with an exitation energy of 2.2 MeV, and a half-life of 1.23 μs. Its presence in plutonium is determined by the original concentration of plutonium-241 and the sample age. Because of the low penetration of alpha radiation, americium-241 only poses a health risk when ingested or inhaled. Older samples of plutonium containing plutonium-241 contain a buildup of Am. A chemical removal of americium-241 from reworked plutonium (e.g. during reworking of plutonium pits) may be required in some cases.
Lawrencium Lawrencium is a synthetic chemical element with symbol Lr (formerly Lw) and atomic number 103. It is named in honor of Ernest Lawrence, inventor of the cyclotron, a device that was used to discover many artificial radioactive elements. A radioactive metal, lawrencium is the eleventh transuranic element and is also the final member of the actinide series. Like all elements with atomic number over 100, lawrencium can only be produced in particle accelerators by bombarding lighter elements with charged particles. Twelve isotopes of lawrencium are currently known; the most stable is Lr with a half-life of 11 hours, but the shorter-lived Lr (half-life 2.7 minutes) is most commonly used in chemistry because it can be produced on a larger scale.