Nuclear activation

Nuclear activation analysis (NAA) is a method for qualitatively and quantitatively detg elemental compn by means of nuclear transmutations. The method involves the irradiation or bombardment of samples with nuclear particles or high-energy electromagnetic radiation for the specific purpose of creating radioactive isotopes from the stable or naturally-occurring elements present. From the numbers, types and quantities of radioactive elements or radionuclides, it is possible to deduce information about the elemental compn of the original sample... 

AS of this writing, 100% inspection by NAA of small arms primers in an actual production loading plant has not been implemented, nor is it contemplated in the near future. Technical problems exist related to coupling the present state-of-the-art nuclear components with the high production rates for the primers, namely, tens of units per sec per automatic loading line. The high intensity of the neutron source and the complexity of the detection system required detracts from the utility of the method in a plant environment where simplicity and safety of operation are of paramount importance. Nevertheless, the technical feasibility of the method has been demonstrated by the AMMRC study and future developments in nuclear activation hardware may ultimately make this non-destructive inspection for production primers more viable... 

In the discussion that follows we refer to nuclear activation detection reactions in lieu of analysis reactions since the signals that are measured are not necessarily always from a radioactive product. Again, we will use standard nuclear physics notation in specifying nuclear reactions, namely ... 

Chemical Effects of Nuclear Activation in Gases and Liquids I. G. Campbell Gaseous Hydroxides... 

Note Added in Proof. Since this review was completed, two significant experiments have been done whose results bear strongly on the question of the mechanism of molecule formation following nuclear activation. 

ANVERSA p and sussman m a (2001) Myocardial Akt activation and gender increased nuclear activity in females versus males. Circ Res. 88 (10) 1020-27. 

Notwithstanding the Iraqi lesson learned that the possibility of undeclared nuclear activities must be taken seriously and their possible existence sought out, the concern with undeclared activities as a proliferation risk is not new and their possible existence has always been recognized, indeed, presumed, in ary serious analysis of safeguards. Even purified plutonium or highly enriched uranium metals are harmless in bulk form. Further steps, specifically fabrication into weapons components, are necessary before these materials can result in proliferation and these steps, while perhaps not demanding, are not trivial. They are necessarily presumed to exist if the diversion of separated plutonium or HEU is discovered, since no reliable means for their detection are available. 

Recent developments dedicated to further improving the IAEA s capability to detect undeclared nuclear activities are desirable and should be implemented. However, undue concentration on implementation of the Protocol could undermine the effectiveness of classical safeguards on declared activities and could further weaken the Agency s ability to make use of its strong existing rights to deal with undeclared activities when necessary, especially in countries that do not accept the Protocol. 

Keisch, B. (2003), The Atomic Fingerprint Nuclear Activation Analysis, University Press of the Pacific. 

Shen, Q. FI., Saijo, Y., Mauch, S., Biskup, C., Bieri, S., Keller, B., Seki, FI., Ulker, B., Somssich, I. E. and Schulze-Lefert, P. (2007). Nuclear activity of MLA immune receptors links isolate-specific and basal disease-resistance responses. Science 315, 1098-103. 

Nova A temporary flash in the brightness of a star associated with extreme nuclear activity. Compare this with a supernova, which results in the destruction of a massive star. 

Nuclear activities such as electricity production by nuclear power plants, or accidents such as occurred at Chernobyl, release radionulides, including caesium, into the environment. The caesium concentrations in these matrices is very low, so that in addition to a sensitive analytical method, it is necessary to make use of an enrichment technique to bring the caesium concentration within the scope of the analytical method. 

High Field Photonics in Laser Plasmas Propagation Studies, Electron Acceleration, and Nuclear Activation With Ultrashort Intense Laser Pulses... 

Other experiments reported the production of high-energy electrons with a similar set-up, and showed the suitability of such relativistic bunches for nuclear activation techniques. It has been showed that nuclear reactions could be efficiently triggered by electrons from thin CH foil targets [69], and also that nuclear reactions can be a useful tool to characterize the electron beam accelerated with similar targets [70]. This point will be further developed in Sect. 8.4. 

Nuclear Activation Using Electron Bunches from Laser Plasmas... 

Particle-in-cell simulation, 154 Phonon stiffening, 36 Phonon-magnon coupled mode, 39 Photo-absorption cross section, 156 Photo-induced phase transitions, 42 Photo-nuclear activation, 173 PIC, 135... 

---