[en] Auger electron spectroscopy (A.E.S.) allows to characterize the atoms lying at surfaces of amorphous and crystalline materials and to investigate their chemical bond. In the case of single crystals it is generally associated with LEED which gives information on the surface structure. After having recalled some principles about radiationless deexcitation of atoms and the related Auger transitions, the problems of interpretation of energy spectra in the case of a single atom and their of an atom bound to neighbours either of the same kind or of a different one, are discussed. Some applications of A.E.S. as an analytical method are finally described

[en] The composition of the surface of a solid body is generally different from that of the bulk. There are many problems that cannot be solved simply by an analysis of the elements, information on the binding states of the detected elements, or rather on the molecules, being required also. The results obtainable depend on the nature of the problem. Where general surface analysis is concerned, e.g. in the areas of corrosion, catalysis, and high polymer technology, ESCA permits substantial characterization of the binding states. SIMS is opening up new opportunities in the use of surfaces and surface analysis methods to identify and investigate the structures of small quantities of substances. In model experiments under idealized conditions (performed by UPS and ELS, for example) it is possible to arrive at fundamental conclusions regarding the adsorbate/substrate interaction. (orig.)

No abstract available

[en] Published in summary form only

No abstract available

[en] The ability to reliably and securely automate the monitoring of SNM is an important goal in Safeguards. Although item level monitoring of SNM requires both seal and tag technologies, the two technologies thus far have been developed more or less independently, and had been a lack of an integrated compact system. An integrated seal-and-tag approach not only aids inspectors to perform their tasks effectively, this approach also allows real-time inspection in large scale facilities. A typical facility could be the size of a large warehouse with hundreds or thousands of items that need to be sealed and monitored in real-time. Previously we reported on advanced secure RF passive (battery-less) tags with special features including, long-range interrogation of passive tags, communicating with passive tags with strong encryption and dynamic authentication features, and the ability to place the tags directly on metal objects. In this paper, we report on a novel secure passive tag integrated with fibre optics seal that allows real-time monitoring of items through secure wireless communications that employs AES encryption and dynamic authentication. Furthermore, the devices can be networked for large scale operations. The proposed passive seal has the same capabilities as active seals in that it allows realtime monitoring. However, the battery lifetimes of conventional active seals are limited or unpredictable. As the long-term storage of SNM might last for several years, these passive seals having been integrated with passive RF tags, extends the lifetime of the physical seals and tags indefinitely, while getting the same performance of active seals and tags. The integrated seal-and-tag is transformational in addressing a critical need in Safeguards area for long-term real-time monitoring. (author)

[en] The primary electron bombardment induces the emission of back scattered or secondary electrons. Their intensity is high against that corresponding to Auger electrons. This is why Auger spectrometry extended as from 1967 only, when Harris finalized a system of energy modulation of the primary electron beam making it possible to obtain on the derived curve dN(E)/dE = f(E) a satisfactory signal to background ratio for a primary electron beam intensity in the vicinity of a microampere. It is the value of this signal to background ratio that limits the sensitivity of the Auger spectrometric system: 0.1 to 1% according to the elements

[en] CdS 'Q-state' particles, with average diameters varying from 2 nm to 10 nm, grown in arachidic acid Langmuir-Blodgett (LB) films, deposited onto optically transparent glass electrodes (OTES), were exposed to H₂ Se(g) to form the corresponding Q-state Cd S_x Se_(1-x) particles. Those particles are considered to be made up of a core of CdS and coated with a monolayer of Cd Se. Q-state Cd S-x Se_(1-x) particle formation was verified by X-ray photoelectron spectroscopy (XPS) and by monitoring a red shift in the UV-visible absorbance spectra relative to that of Cds. XPS results on 5 nm diameter CdS particles that had been grown in an LB film and then extensively exposed to H₂ S (g) revealed a stable average composition of Cd S₀.₄ Se₀₆. A study of the photoelectrochemical behaviour of these systems was conducted through current the open-circuit voltage and a marked increase in the short-circuit current was observed when LB films with Q-state CdS particles were exposed to H₂ Se(g). (author)

[en] After a survey of the general principles of Auger electron spectroscopy, experimental techniques and their limitations are given. Application to thin layers and light elements detection is a complement of other surace analysis methods

[en] Development of precise X-ray photoelectron spectroscopy using X-ray radiation hν< 1.5 KeV allowed to carry out immediate investigations of fine spectra structure of both weakly bond and deep electrons. Based on the experiments and the obtained results it may be concluded: 1. Under favourable conditions the inner valence molecular orbitals (IVMO) may form in all actinide compounds. 2. The XPS spectra fine structure stipulated by IVMO electrons allows to judge upon the degree of participation of the filled AO electrons in the chemical bond, on the structure o considered atom close environment and the bond lengths in compounds. For amorphous compounds the obtaining of such data based on X-ray structure analysis is restricted. 3. The summary contribution of IVMO electrons to the absolute value of the chemical bonding is comparable with the corresponding value of OMO electrons contribution to the atomic bonding. This fact is very important and new in chemistry. (author)