[en] Highlights: •We investigate flow and transport processes in landfills. •The considered landfills consists of wastes from decommissioning of nuclear facilities in Germany. •The deposited waste was not mixed with municipal waste. •We describe the characteristics of radionuclide release. -- Abstract: The German decision to phase out nuclear power will increase the quantity of very low level waste (VLLW) from nuclear power plant (NPP) decommissioning in the near future, which will cause a capacity shortage of landfills. As a likely consequence, landfills will have to be constructed that are exclusively built for decommissioning waste without addition of municipal waste, and assessments for such types of landfills are not available in Germany. The present study investigates flow and transport processes in generic landfills that only contain decommissioning waste. The generic landfills comply with German technical standards such as the Landfill Ordinance. Simulations of contaminant transport are performed using the codes SiWaPro DSS and SPRING. The simulations show that Sr-90 is the first radionuclide that leaves the landfill due to its low sorption in the waste body. In contrast, no release of Cs-134, Cs-137 and Am-241, which have higher sorption coefficients, was simulated. Our work also shows that three-dimensional modelling of flow and transport is required if the landfill has a lateral drainage. Results suggest that the migration of radionuclides into the environment could be reduced by installing a drainage layer with high sorption capacity on top of the landfill's bottom seal. Sorption of Sr-90 within this drainage layer would delay the release of Sr-90 from the landfill, thereby giving more time for the Sr-90 decay inside the landfill.

[en] At Brookhaven National Laboratory the Electron Beam Ion Source (EBIS) is presently being commissioned. The EBIS will be a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC). The new preinjector has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium. The background pressure in the ionization region of the EBIS required to be low enough that it does not produce a significant number of ions from background gas. The pressure in the regions of the electron gun and electron collector can be higher than in the ionization region provided there is efficient vacuum separation between the sections. For injection the ions must be accelerated to 100KV by pulsing the EBIS platform. All associated equipment including the vacuum equipment on the platform is at a 100KV potential. The vacuum system design and the vacuum controls for the EBIS platform and transport system will be presented as well as the interface with the Booster Ring which has a pressure 10-11 Torr.

[en] Heating tomato fruit (Lycopersicon esculentum) for 48 h at 38 degrees C prevented chilling injury from developing after 21 d at 2 degrees C, whereas unheated fruit developed high levels of injury. Although the overall protein pattern as seen by Coomassie blue staining was similar from heated and unheated fruit, some high- and many low-molecular-mass proteins were observed in the heated fruit that were absent or present in reduced amounts in unheated fruit. When fruit were injected with [35S]methionine at harvest and then heated, they accumulated high levels of specific radiolabeled proteins that could still be detected after 21 d at 2 degrees C. If the fruit were held at 20 degrees C after heating, the label in the proteins declined rapidly and these fruit were also sensitive to chilling injury. Hsp70 antibody reacted more strongly with proteins from heated and chilled fruit than with proteins from chilled fruit. Hsp18.1 antibody reacted strongly with proteins from heated fruit but not with those from unheated fruit. A 23-kD protein, highly labeled in heated fruit but not in unheated fruit, had its amino terminus sequenced. To our knowledge, this is the first report showing a relationship between the persistence of heat-shock proteins and chilling tolerance in a plant tissue

[en] Methods are described of obtaining rare earth elements from natural raw materials with various contents of the elements. Atomic absorption spectrometry and X-ray fluorescence analysis are mainly used for the analysis of these raw materials, which requires the preparation of representative solutions by suitable decomposition of the raw material. The decomposition which depends on the material's phase composition is effected using inorganic acids or by sintering the sample with a mixture of anhydrous sodium carbonate and sodium peroxide, by leaching the melt with water and dissolving the precipitate in diluted HCl or HNO₃. A chloride solution (pH 1.1-1.2) is the most suitable medium for quantitative precipitation of oxalates of rare earth elements. (J.C.)

[en] The transmission probabilities of an accurate and an approximate (triangular) Esaki barrier are evaluated. We show that the approximate results for transmission coefficients differ by orders of magnitude from the correct ones, however the approximate methods provide good results for physical quantities defined as ratios of transmission coefficients

[en] A method for the determination of rare earth elements, Y and Th in raw materials with different matrices is described. The sample is fused with Li₂B₄O₇ and Cr and Mo are added as internal standards. Single elements can be determined in a wide range of concentrations, viz. Ce, Nd, La and Pr from 0.02 to 25% and Sm, Gd, Y, Th and Eu from 0.005 to 1%. The use of the LiF (110) crystal and, possibly, chemical separation, reduces the coincidence of lines to a minimum. Mutual interaction between single elements is prevented by the application of empirical corrections. (author)

[en] The PTTL of CaWO₄ crystals was studied after exposure to X or β radiation at RT, and subsequent illumination with UV light at LNT. The main PTTL peaks appeared at 195 and 280 K, while TL peaks recorded at 165, 280, 340 and 400 K. TL could be excited only by band to band transitions, but PTTL could also be stimulated with photon energies smaller than the band gap. The trap responsible for the 340 K TL peak acts as a reservoir for the phototransfer. The PTTL and TL emission spectra showed a main broad 500 nm band composed of components at 490 and 520 nm. The XL and PL showed maxima at these wavelengths, indicating that the same luminescence centres are responsible for the PTTL as for TL, XL and PL emissions. The dependences of the PTTL intensity on the β dose and on that of the stimulating UV were both sub-linear. (author)

[en] As RHIC beam intensity increases beyond original scope, pressure rises have been observed in some regions. The luminosity limiting pressure rises are associated with electron multi-pacting, electron stimulated desorption and beam induced desorption. Non-Evaporable Getter (NEG) coated beamtubes have been proven effective to suppress pressure rise in synchrotron radiation facilities. Standard beamtubes have been NEG coated by a vendor and added to many RHIC UHV regions. BNL is developing a cylindrical magnetron sputtering system to NEG coat special beryllium beamtubes installed in RHIC experimental regions, It features a hollow, liquid cooled cathode producing power density of 500 W/m and deposition rate of 5000 Angstrom/hr on 7.5cm OD beamtube. The cathode, a titanium tube partially covered with zirconium and vanadium ribbons, is oriented for horizontal coating of 4m long chambers. Ribbons and magnets are arranged to provide uniform sputtering distribution and deposited NEG composition. Vacuum performance of NEG coated tubes was measured. Coating was analyzed with energy dispersion spectroscopy, auger electron spectroscopy and scanning electron microscopy. System design, development, and analysis results are presented

[en] The inner surfaces of the 248 m Spallation Neutron Source (SNS) accumulator ring vacuum chambers are coated with ∼100nm of titanium nitride (TiN) to reduce the secondary electron yield (SEY) of the chamber walls. There are approximately 135 chambers and kicker modules, some up to 5m in length and 36cm in diameter, coated with TiN. The coating is deposited by means of reactive DC magnetron sputtering -using a - cylindrical cathode with internal permanent magnets. This cathode configuration generates a deposition-rate sufficient to meet the required production schedule and produces stoichiometric films with good adhesion, low SEY and acceptable outgassing. Moreover, the cathode magnet configuration allows for simple changes in length and has been adapted to coat the wide variety of chambers and components contained within the arcs, injection, extraction, collimation and RF straight sections. Chamber types and quantities as well as the cathode configurations are presented herein. The unique coating requirements of the injection kicker ceramic chambers and the extraction kicker ferrite surface will be emphasized. A brief summary of the salient coating properties is given including the interdependence of SEY as a function of surface roughness and its effect on outgassing

[en] In the 1MW Spallation Neutron Source (SNS), the High-Energy Beam Transfer line (HEBT) connects the LINAC to the accumulator ring. A major requirement of the SNS complex is to have low uncontrolled beam loss (lnA/m), to allow hands on maintenance. The vacuum requirement for the HEBT is 5x10^-8 Torr. Excessive H^- stripping will occur above this pressure and increase losses in the machine. The HEBT is also equipped with three sets of beam halo scrapers, one for momentum and two for transverse collimation. The momentum scraper is located at a maximum dispersion point, between the 3rd dipole magnet (DD3) of HEBT and the 14th quadrupole (Q14) of the HEBT line. The momentum scraper uses movable foils that strip the H^- beam that has momentum spread (0.2%<δp/p<0.6%) into H⁺, and the H⁺ ions are then directed out of the HEBT beam line to a beam dump by the next bending magnet DD4 (4th dipole of HEBT). In order to ensure that the extracted H⁺ beam travels inside the extraction chamber to minimize the radiation in the beam dump station region, we performed H⁺ particle tracking to determine the outer boundaries and the angle of the Y-type vacuum chamber that will contain the H⁺ beam. The development and design of the special HEBT momentum scraper extraction and exit chamber, and the relevant H⁺ trajectories are presented in this paper