Californium nuclide

Every 2 years, a special issue of Analytical Chemistry is published with a literature survey on the MS of polymers [10-12]. At least two other literature surveys are worthwhile to mention here because they provide a more in-depth review on specific topics than this review. One survey focuses exclusively on copolymers (i.e., with polymers in which two or more repeat units are found along the macromolecular backbone) [13]. A large part of this review deals with the determination of an important quantity, namely the relative abundance of the monomers (usually referred to as copolymer composition). A review by Klee [14] appeared in 2005 that deals exclusively with step-growth polymers. A section describes poly(imide)s in detail, especially with those made of PYM (pyromellitic anhydride), and PYM derivatives (even highly fluorinated, such as hexafluoro-PYM). Other sections of the review discuss plasma desorption MS experiments using a radioactive Californium nuclide, namely Ca. 

As evidenced by the tremendous power of nuclear bombs, nuclear reactions involve quite a lot of energy. In the laboratory, researchers fabricate nuclides with the aid of special, high-energy equipment such as reactors in which nuclear reactions can take place, or particle accelerators in which particles such as protons are accelerated to high speed and crash into one another, or some other target. For example, in 2006, researchers at the Joint Institute for Nuclear Research in the Russian Federation and the Lawrence Livermore National Laboratory in California synthesized isotopes of element 118 for the first time. To make the new isotope, researchers smashed calcium atoms into a target made of californium (which has an atomic number of 98). These new isotopes decayed quickly. (Element 118 and other recently discovered elements have not yet been named.)... 

Sill et al. [26] have discussed a spectrometric method for the determination of americium and other alpha-emitting nuclides, including curium and californium, in potassium fluoride-pyrosulfate extracts of soils. Sekine [27] used a-spectrometry to determine americium in soils with a chemical recovery of 60-70%. Joshi [28] and Livens et al. [29] have discussed methods for the determination of241 americium in soils. 

Sill et al. [26] have described a procedure by which virtually all alpha-emitting nuclides of radium through californium can be determined in soil, singly or in any combination in a single sample. 

More definitions are necessary to attempt this sort of optimization Potential californium is a measure of the maximum amount of californium that can be produced from a given batch of feed, taking into account the fact that many atoms undergo fission along the path from feed to product. The efficiency of a particular irradiation is the amount of californium produced divided by the amount of potential californium consumed in the irradiation and subsequent processing. This efficiency measure takes into consideration the destruction of the 2 2Cf by decay and neutron capture and processing losses of all the nuclides in the chain. 

Modifications to this process can be made to effect recovery of neptunium, americium, curium, californium, strontium, cesium, technetium, and other nuclides. The efficient production of specific transuranic products requires consideration of the irradiation cycle in the reactor and separation of intermediate products for further irradiation. 

These data will be valuable for comparison purposes if the proposed expansion of the nuclear industry proceeds as planned and the use of some of these nuclides, e.g., plutonium-238 and californium-252, becomes widespread. 

Curium, berkelium, californium and einsteinium were separated from the americium samples irradiated by neutrons. For preliminary separation the anion exchange in hydrochloric acid and lithium chloride solutions was used as well as the HDEHP extraction. Mutual separation of the transamericium elements was made by using DIAION CK08Y cation exchange resin. Nuclides prepared and separation methods adopted are summarized in Table 1 (1-15). 

A nuchde of element rutherfordium, i Rf, is formed by the nuclear reaction of californium-249 and carbon-12, with the emission of four neutrons. This new nuclide rapidly decays by emitting an a-particle. Write the equation for each of these nuclear reactions. 

The nuclide gCf emits neutrons through spontaneous fission in 3% of all decays, the rest being a-decays. All the other neutron sources listed involve a radioactive nuclide whose decay causes a nuclear reaction in a secondary substance which produces neutrons. For example, ffSb produces neutrons in beryllium powder or metal as a result of the initial emission of 7-rays, in which case there is no coulomb barrier to penetrate. Radium, polonium, plutonium, and americium produce neutrons by nuclear reactions induced in beryllium by the a-particles from their radioactive decay. For the neutrons produced either by spontaneous fission in californium or by the a-particle reaction with beryllium, the... 

Sill, C. W., Puphal, K. W., and Hindman, F. D. 1974. Simultaneous determination of alpha-emitting nuclides of radium through californium in soil. Anal Chem 46, 1725-1737. 

The U.S. Department of Energy sells an isotope of the transuranium element californium for approximately 10 per microgram to qualified researchers. What would a poimd of the Cf nuclide cost ... 

Deduce the identity of the unknown daughter nuclide from the atomic number. Since the atomic number is 98, the daughter nuclide is californium (Cf). 2 Bk-, 249 rf 4. o > 98Lt + ie... 

The radioactive decay of the nuclide californium-252 is largely by alpha emission, but part of the decay is by spontaneous fission. Cf thus provides an intense neutron source 1 g emits 2.4 x 10 neutrons per second. Cf is the only commerdally available nuclide that can be fabricated into small neutron sources that produce an intense neutron flux over a useful period of time. The physical size of these sources is considerably smaller than a- or y-neutron sources, and less space must be provided in the Cf sources to accommodate gaseous products. Since Cf neutron sources became available in 1975, a surprising variety of industrial and scientific uses have been developed for them. 

This element was named californium (Cf) because it was first produced (by a slightly different nuclear reaction) at the University of CaUfomia at Berkeley. Many other nuclides with atomic numbers larger than that of uranium have been synthesized since the 1940s. These synthetic elements—called transuranium elements— have been added to the periodic table. 

Californium-252. Cf has recently been introduced as a commercial product by the U.S. Atomic Energy Commission. This nuclide decays by a-particle emission (96.9%) and by spontaneous fission (3.1 %) with a half-life of 2.65 years. The average neutron yield is 3.8 per fission and consequently the specific neutron output is 2.34 x 10 s g", considerably higher than that of (a,n) sources. The neutron spectrum of Cf is very similar to that of the U fission. There is no criticality hazard associated with Cf and shielding of such a source is relatively simple. 

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