Beryllium isotopic

Reagan MK, Volpe AM, Cashman KV (1992) and Th-series chronology of phonolite fractionation at Mount Erebus, Antartica. Geochim Cosmochim Acta 56 1401-1407 Reagan MK, Morris JD, Herrstrom EA, Murrell MT. (1994) Uranium series and beryllium isotope evidence for an extended history of subduction modification of the mantle below Nicaragua. Geochim Cosmochim Acta 58 4199-4212... 

This chapter focuses on subduction zone processes and their implications for mantle composition. It examines subduction contributions to the shallow mantle that may be left behind in the wedge following arc magma genesis, as well as the changing composition of the slab as it is processed beneath the fore-arc, volcanic front and rear arc on its way to the deep mantle. Much of this chapter uses boron and the beryllium isotopes as index tracers boron, because it appears to be completely recycled in volcanic arcs with little to none subducted into the deep mantle, and cosmogenic e, with a 1.5 Ma half-life, because it uniquely tracks the contribution from the subducted sediments. 

Uranium series and beryllium isotope evidence for an extended history of subduction modification of the mantle below Nicaragua. Geochim. Gosmochim. Acta 58, 4199-4212. 

Brown E., Edmond J. M., Raibeck G. M., Bourles D. E., Yiou F., and Measures C. I. (1992b) Beryllium isotope geochemistry in tropical river basins. Geochim. Cosmochim. Acta 56, 1607-1624. 

Decay Constants (k) and Half-Lives (fi/a) of Beryllium Isotopes... 

The rapid fission of a mass of or another heavy nucleus is the principle of the atomic bomb, the energy liberated being the destructive power. For useful energy the reaction has to be moderated this is done in a reactor where moderators such as water, heavy water, graphite, beryllium, etc., reduce the number of neutrons and slow those present to the most useful energies. The heat produced in a reactor is removed by normal heat-exchange methods. The neutrons in a reactor may be used for the formation of new isotopes, e.g. the transuranic elements, further fissile materials ( °Pu from or of the... 

Magnesium [7439-95-4] atomic number 12, is in Group 2 (IIA) of the Periodic Table between beryllium and calcium. It has an electronic configuration of 1T2T2 3T and a valence of two. The element occurs as three isotopes with mass numbers 24, 25, and 26 existing in the relative frequencies of 77, 11.5, and 11.1%, respectively. 

Beryllium has a high x-ray permeabiUty approximately seventeen times greater than that of aluminum. Natural beryUium contains 100% of the Be isotope. The principal isotopes and respective half-life are Be, 0.4 s Be, 53 d Be, 10 5 Be, stable Be, 2.5 x 10 yr. Beryllium can serve as a neutron source through either the (Oi,n) or (n,2n) reactions. Beryllium has alow (9 x 10 ° m°) absorption cross-section and a high (6 x 10 ° m°) scatter cross-section for thermal neutrons making it useful as a moderator and reflector in nuclear reactors (qv). Such appHcation has been limited, however, because of gas-producing reactions and the reactivity of beryUium toward high temperature water. 

One of the most obvious features of Figs. 1.1 and 1.5 is the very low cosmic abundance of the stable isotopes of lithium, beryllium and... 

Atomic weights are known most accurately for elements which have only 1 stable isotope the relative atomic mass of this isotope can be determined to at least 1 ppm and there is no possibility of variability in nature. There are 20 such elements Be, F, Na, Al, P, Sc, Mn, Co, As, Y, Nb, Rh, I, Cs, Pr, Tb, Ho, Tm, Au and Bi. (Note that all of these elements except beryllium have odd atomic numbers — why )... 

Soft, silver white metal that is isolated in the tiniest of amounts. All isotopes are radioactive, the longest-lived has a half-life of 22 years. The element is an intermediate in the decay series of 235U. Strong alpha emitter that is used in radioactivation analysis and forms an effective neutron source with beryllium. 

Tin hold the record with 10 stable isotopes. There are 19 so-called "pure elements" of which there is only one isotope. These anisotopic elements are beryllium, fluorine, sodium, aluminum, phosphorus, scandium, manganese, cobalt, arsenic, yttrium, niobium, rhodium, iodine, cesium, praseodymium, terbium, holmium, thulium, gold, and bismuth. 

Some elements do exist in only one naturally occurring stable isotope, and therefore, they are termed monoisotopic elements. Among these, fluorine ( ), sodium ( Na), phosphorus ( P) and iodine belong to the more prominent examples in organic mass spectrometry, but there are several more such as beryllium ( Be), aluminum ( Al), scandium (" Sc), manganese ( Mn), cobalt ( Co), arsenic... 

ISOTOPES There are nine isotopes of beryllium, ranging from Be-6 to Be-14. Only Be-9 is found in nature and makes up about 100% of the element found In the Earth s crust. 

However, not all pairs of stars will meet such a cataclysmic end. The proof stems from the existence of novas. These also arise from the tempestuous love affairs between a white dwarf and a healthy star. The difference is that their love bums in a more reasonable manner, ejecting only a small portion of then-envelope at a time (roughly 10 " Mq). These ejecta are nevertheless loaded like galleons with radioactive isotopes such as beryllium-7 and sodium-22. One day it is hoped that their signature will be detected by the great INTEGRAL observatory. 

Beryllium nitride is used in nuclear reactors and to produce radioactive carbon-14 isotope for tracer applications. 

Strontium has four naturally occurring isotopes (Table 4.2). It is a member of the alkaline earths (Group 2A) along with beryllium, magnesium, calcium, barium, and radium (Fig. 2.4). Strontium substitutes for calcium and is abundant in minerals such as plagioclase, apatite, and calcium carbonate. 

Another short-lived isotope of beryllium, 7Be, decays to 7Li by electron capture with a half-life of —53 days. This half-life is so short that any atoms present in chondrite components must have been produced in the solar system essentially immediately before the host object formed. A hint of the presence of 7Be in the form of large excesses of 7Li in an Allende CAI was presented by Chaussidon et al. (2006). However, these authors were not able to demonstrate a tight correlation with the 9Bc/ Li ratio. 

All naturally occurring beryllium compounds are. made up of the Be isotope. Artificially produced isotopes occur during some nuclear reactor operations and include 6Be, 7 Be, sBe, and l0Be. 

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