This issue of Microscopy and Microanalysis contains papers from the Seventh Regional Workshop of the European Microbeam Analysis Society (EMAS) on Electron Probe Microanalysis of Materials Today—Practical Aspects that took place May 13–16, 2006 in Karlsruhe, Germany. The meeting was organized in collaboration with the Institute for Transuranium Elements (ITU) of the Joint Research Centre of the European Commission.

Among the microanalytical techniques, electron probe microanalysis (EPMA) is one of the most powerful. Its performances can be used to provide an accurate characterization. In the present article the differences between the EPMA of highly irradiated materials and standard EPMA are highlighted. It focuses on the shielded EPMA specificities. Then, the article presents the difficulties encountered during the sample preparation and the analysis (mainly due to the radioactive background). In spite of these difficulties, some valuable results can be provided by a shielded EPMA on the in-pile behavior of nuclear irradiated fuel. Some results of specific examples analyzed by EPMA in nuclear fuel research are presented.

Environmental sampling (ES) is a powerful technique used by safeguards inspectors of the International Atomic Energy Agency and the European Safeguards Office for the detection of undeclared nuclear activities. Since its implementation in the 1990s, ES has proven to be very sensitive and effective. Considering the consequences, the measurements should be carried out under a quality management programme. At the Institute for Reference Materials and Measurements, a new production method is under development for the preparation of reference uranium particles from well-certified UF6, allowing uranium particles with certified isotopic abundances to be prepared that are representative of those found in uranium enrichment facilities. Using an aerosol deposition chamber designed and built for the purpose, particles are formed by the hydrolysis of UF6 and their morphology and (isotopic) composition measured using SEM-EDX and SIMS. The SEM measurements show that by varying the relative humidity of the air in the reaction chamber, the morphology of the particles can be changed. By making a distribution map of the chemical composition of the particles, the relationship between fluorine and uranium as main constituents of the particle could be established. The presence of fluorine is a valuable indicator for the occurrence of nondeclared enrichment activities.

Micro-focused synchrotron radiation techniques to investigate actinide elements in geological samples are becoming an increasingly used tool in nuclear waste disposal research. In this article, results using μ-focus techniques are presented from a bore core section of a U-rich tertiary sediment collected from Ruprechtov, Czech Republic, a natural analog to nuclear waste repository scenarios in deep geological formations. Different methods are applied to obtain various, complementary information. Elemental and element chemical state distributions are obtained from μ-XRF measurements, oxidation states of As determined from μ-XANES, and the crystalline structure of selected regions are studied by means of μ-XRD. We find that preparation of the thin section created an As oxidation state artifact; it apparently changed the As valence in some regions of the sample. Results support our previously proposed hypothesis of the mechanism for U-enrichment in the sediment. AsFeS coating on framboid Fe nodules in the sediment reduced mobile groundwater-dissolved U(VI) to less-soluble U(IV), thereby immobilizing the uranium in the sediment.

In the present article, electron probe microanalysis data for Pu and Nd is being used for validating the predictions of the radial power profile in a nuclear fuel rod at an ultrahigh burn-up of 95 and 102 MWd/kgHM. As such the validation of both the new Monte Carlo burn-up code ALEPH and the simpler TUBRNP model of the fuel rod performance code TRANSURANUS has been extended. The analysis of the absolute concentrations and individual isotopes also indicates potential improvements in the predictive capabilities of the simple TUBRNP model, based on the one-group cross sections inferred from the neutron transport calculations in the ALEPH code. This is a first important step toward extending the application range of the fuel rod performance code to burn-up values projected in nuclear power rods based on current trends.

The application of scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS) for characterization of mixed plutonium and uranium particles from nuclear weapons material is presented. The particles originated from the so-called Thule accident in Greenland in 1968. Morphological properties have been studied by SEM and two groups were identified: a “popcorn” structure and a spongy structure. The same technique, coupled with an energy-dispersive X-ray (EDX) spectrometer, showed a heterogeneous composition of Pu and U in the surface layers of the particles. The SIMS depth profiles revealed a varying isotopic composition indicating a heterogeneous mixture of Pu and U in the original nuclear weapons material itself. The depth distributions agree with synchrotron-radiation-based μ-XRF (X-ray fluorescence microprobe) measurements on the particle (Eriksson, M., Wegryzynek, D., Simon, R., & Chinea-Cano, E., in prep.) when a SIMS relative sensitivity factor for Pu to U of 6 is assumed. Different SIMS identified isotopic ratio groups are presented, and the influence of interferences in the Pu and U mass range are estimated. The study found that the materials are a mixture of highly enriched 235U (235U:238U ratio from 0.96 to 1.4) and so-called weapons grade Pu (240Pu:239Pu ratio from 0.028 to 0.059) and confirms earlier work reported in the literature.

The M emission spectrum of 68Er was reinvestigated using wavelength dispersive spectrometry, with a TAP diffracting crystal. By recording the spectra using the second-order reflection, an improved energy resolution was achieved, which is necessary to resolve the M5O3 line from the neighboring α M5N7 transition. In addition to the five lines/bands tabulated in the classical paper of Bearden, a number of further lines were observed. These are M1N3, M3O1, M2N1, M5O3, M3N1, and M4N3. For all the lines with an energy below the M5 absorption structure (M5O3, M3N1, M4N3, and ζ M5N3), an increasing relative intensity with increasing energy of the exciting electrons, E0, was observed. This dependence has its origin in the fact that these lines are normally absorbed whereas Mα (M5N7) and Mβ (M4N6) are additionally affected by anomalous line-type absorption.

The use of X-ray elemental analysis tools like energy dispersive X-ray (EDS) is described in the context of the investigation of nuclear materials. These materials contain radioactive elements, particularly alpha-decaying actinides that affect the quantitative EDS measurement by producing interferences in the X-ray spectra. These interferences originating from X-ray emission are the result of internal conversion by the daughter atoms from the alpha-decaying actinides. The strong interferences affect primarily the L X-ray lines from the actinides (in the typical energy range used for EDS analysis) and would require the use of the M lines. However, it is typically at the energy of the actinide's M lines that the interferences are dominant. The artifacts produced in the X-ray analysis are described and illustrated by some typical examples of analysis of actinide-bearing material.

Heart development, especially the critical phase of cardiac looping, is a complex and intricate process that has not yet been visualized “live” over long periods of time. We have constructed and established a new environmental incubator chamber that provides stable conditions for embryonic development with regard to temperature, humidity, and oxygen levels. We have integrated a video microscope in the chamber to visualize the developing heart in real time and present the first “live” recordings of a chick embryo in shell-less culture acquired over a period of 2 days. The time-lapse images we show depict a significant time window that covers the most critical and typical morphogenetic events during normal cardiac looping. Our system is of interest to researchers in the field of embryogenesis, as it can be adapted to a variety of animal models for organogenesis studies including heart and limb development.

The morphology of the outer and inner membranes of traumatic chronic subdural hematomas (CSDHs) surgically removed from eight patients was investigated by scanning electron microscopy (SEM). Hematomas were divided into three groups based on time that had passed from the initiation of trauma to surgery. Structure of the CSDHs showed gradual morphological changes of the developing hematoma capsule. They initially included angiogenic and aseptic inflammatory reactions followed by progressive involvement of fibroblasts—proliferating and producing collagen fibrils. Numerous capillaries suggesting formation of new blood vessels were observed mainly in young hematomas removed between 15 and 21 days after trauma. In “older” hematomas (40 days after trauma), more numerous capillaries and thin-walled sinusoids were accompanied by patent, larger diameter blood vessels. Within the fibrotic outer membrane of the “oldest” hematoma capsules (60 or more days after trauma), especially in the area over the hematoma cavity, blood vessels were frequently occluded by clots. The results suggest dynamic changes in cellular and vascular organization of traumatic CSDH capsules paralleling the progression in hematoma age.

The urinary bladder is an unusual organ in that its normal function includes filling and emptying with alternating changes in internal pressure. Although fluctuations in blood flow to the bladder wall are known to accompany these changes, detailed descriptions of the bladder microvasculature are sparse. The present study uses vascular corrosion casting and scanning electron microscopy to describe the three-dimensional anatomy of the microvasculature of the urinary bladder of the dog. Specialized features of that microvasculature, including collateral circulation, vessel folding, vessel orientation, the presence of valves and sphincters, and mucosal capillary density, that may enhance and control blood flow during normal bladder function, are described and discussed.

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