isotope dilution-mass
31Enriched uranium — Proportions of uranium 238 (blue) and uranium 235 (red) found naturally versus enriched grades Enriched uranium is a kind of uranium in which the percent composition of uranium 235 has been increased through the process of isotope separation.… …
32Helium-3 — This article is about the elemental isotope. For the record label Helium 3, see Muse or A E Records .infobox isotope background = #F99 isotope name = Helium 3 alternate names =Helium 3,He 3 symbol =He mass number =3 mass =3.016 num neutrons =1… …
33Isotopes of helium — Although there are eight known isotopes of helium (He) (standard atomic mass: 4.002602(2) u), only helium 3 (SimpleNuclide|Helium|3) and helium 4 (SimpleNuclide|Helium|4) are stable. In the Earth s atmosphere, there is one SimpleNuclide|Helium|3… …
34Environmental radioactivity — is produced by radioactive materials in the human environment. While some radioisotopes, such as strontium 90 (90Sr) and technetium 99 (99Tc), are only found on Earth as a result of human activity, and some, like potassium 40 (40K), are only… …
35Helium — otherusesHelium (He) is a colorless, odorless, tasteless, non toxic, inert monatomic chemical element that heads the noble gas group in the periodic table and whose atomic number is 2. Its boiling and melting points are the lowest among the… …
36Oxygen — This article is about the chemical element and its most stable form, O2 or dioxygen. For other forms of this element, see Allotropes of oxygen. For other uses, see Oxygen (disambiguation). nitrogen ← oxygen → fluorine ↑ O ↓ …
37hydrologic sciences — Introduction the fields of study concerned with the waters of the Earth. Included are the sciences of hydrology, oceanography, limnology, and glaciology. In its widest sense hydrology encompasses the study of the occurrence, the… …
38Radioactive waste — 2007 ISO radioactivity danger logo, designed in part for long term radioactive waste depositories which might survive into a far future time in which all knowledge of the meaning of present common radiation danger symbols and signs has been lost… …
39Uranium-238 — Infobox isotope background =#fc6 text color = image caption = 10 gram sample alternate names = mass number =238 symbol =U num neutrons =146 num protons =92 abundance = 99.284% halflife = 4.46 billion years error halflife = decay product = Thorium …
40Datation par le couple Rubidium-Strontium — Le Rubidium (Rb) et le Strontium (Sr) sont deux éléments chimiques existant le plus souvent à l état de traces dans les roches. Ils se substituent en partie au potassium pour le rubidium et au calcium pour le strontium. Ainsi les minéraux riches… …
