New Elements Einsteinium and Fermium, Atomic Numbers 99 and 100

De los dioses a los hombres: Un recorrido histórico del descubrimiento de los elementos químicos

“…Galissard de Marignac (1817-1894) en 1878, y en 1907, el quí-mico francés G. Urbain (1872Urbain ( -1938 Fermi (1901Fermi ( -1954 se descubrieron en diciembre de 1952 en los restos de la primera explosión termonuclear realizada un mes antes en el Pacífico. Cuando fueron propuestas las dos denominaciones no entraron en polémica porque Einstein y Fermi ya habían fallecido (Ghiorso, 1955).…”

Heavy and Superheavy Elements Production in High Intensive Neutron Fluxes of Explosive Process

“…Investigations of transuranium nuclei production in such a process were performed in 1952 -1964 years in the USA in thermonuclear tests. In these "experimental" thermonuclear explosions the neutron flux on the 238 U target was from (1.2 -1.8)⋅10 24 ("Mike") [5] to ~ 6.6 ⋅10 24 ("Par", "Barbel") neutron/cm 2 [6,7]. Transuranium isotopes (up to 255 Fm) were registered for the first time in the "Mike" thermonuclear explosion in 1952 [5].…”

Beta Decay of Neutron-Rich Transuranic Nuclei

“…If 238(1 target atoms are given such exposure, the phenoaenon becoaes * way to probe the nuclear properties of very neutron-rich uraniua nuclei and to produce heavy isotopes of the transuranium eleaents that survive the chains of beta decay following the initial phase of the reaction. This unique aethod of transuranium element production was investigated by U.S. scientists in a series of thermonuclear explosions during the period 1952-1969, first as an unexpected result of the Mike explosion [1] that occurred in November 1952 and later in a series of underground explosions where the explosive devices were designed specifically for this purpose [2,3]. The heaviest species identified in this work was 257Fa, which Implies the production of 257D during the capture phase.…”