A Fully Depleted pn-Junction CCD for Infrared-, UV- and X- ray detection

This paper describes the performance of the Fully Depleted pn-junction CCD (pn-CCD) system, developed for ESA's XMM-satellite mission for soft x-ray imaging and spectroscopy in the single photon counting mode in the 100 eV to 10 keV photon range. The 58 mm x 60 mm large pn-CCD array, designed and fabricated at the Semiconductor Lab (Halbleiterlabor) of the Max-Planck-Institut, uses pn-junctions for registers and as backside structure. This concept naturally enables full depletion of the detector volume independent of the silicon wafer's resistivity and thickness, and as such make it an efficient detector for the x-ray region and the infrared. For high detection efficiency in the soft x-ray region and UV, an ultrathin pn-CCD backside deadlayer has been realized. Each pn-CCD-channel is equipped with its own on-chip JFET amplifier which, in combination with the CAMEX-amplifier and multiplexing chip, facilitates parallel readout and fast data rate: the cooled pn-CCD system can be read out at a data rate up to 3 MHz with an electronic noise floor of ENC < 5 e-.     

Neubenennungen lithostratigraphischer Einheiten in der Helvetischen Kreide

In September 2007 Föllmi and coauthors requested the approval of four lithostratigraphic terms of the Swiss Committee of Stratigraphy (SCS). These terms were to be used in their publication on the Cretaceous in the Helvetic realm (Föllmi et al. 2007). At its meeting on October 18, 2007, the SCS decided the following: The Tierwis Formation (replacing the Drusberg Formation) was accepted, with the reserve that a section at Tierwis should be published in the near future. For the former “Lower Orbitolina Beds” the term Rawil Member was accepted, but here too a better type section than the one at Rawil Pass should be published. The term Rohrbachstein bed should not be used as a formal unit because it describes only a minor lithologic variation within the Grünten Member. The term Plaine Morte bed for a thin condensed horizon can not be accepted due to the fact that its definition is based mainly on biostratigraphy. Furthermore, the duplication a locality term which is in use for a previously established lithostratigraphic unit should be avoided.     

How to survive a Lunar night

In the frame of the recent worldwide activities of Lunar research, including various studies for surface stations, the aspect of longevity of such stations has been identified as a particular technical challenge. The reason for this lies in the long (about 14 days) and cold Lunar night during which it is non-trivial to keep spacecraft systems alive and sensitive equipment within an acceptable temperature range.The following paper analyzes and compares various concepts to survive Lunar night, both with and without radioisotope heater technology.The latter normally implies the use of highly toxic material (typically plutonium), which is politically problematic and a driver for cost and safety procedures.Concepts without radioisotope heating need to foresee special measures, like extremely efficient thermal insulation or sub-surface positioning of all temperature sensitive components.Special emphasis has been taken on the thermal analysis of a penetrator-type surface station. The relevant issues are discussed and results for day–night cycles are presented, assuming a typical set of engineering parameters. This concept appears to be the easiest to implement from a thermal point of view, if the use of radioisotope heaters has to be avoided.     

Astrophysical smooth particle hydrodynamics

The paper presents a detailed review of the smooth particle hydrodynamics (SPH) method with particular focus on its astrophysical applications. We start by introducing the basic ideas and concepts and thereby outline all ingredients that are necessary for a practical implementation of the method in a working SPH code. Much of SPH’s success relies on its excellent conservation properties and therefore the numerical conservation of physical invariants receives much attention throughout this review. The self-consistent derivation of the SPH equations from the Lagrangian of an ideal fluid is the common theme of the remainder of the text. We derive a modern, Newtonian SPH formulation from the Lagrangian of an ideal fluid. It accounts for changes of the local resolution lengths which result in corrective, so-called “grad-h-terms”. We extend this strategy to special relativity for which we derive the corresponding grad-h equation set. The variational approach is further applied to a general-relativistic fluid evolving in a fixed, curved background space-time. Particular care is taken to explicitly derive all relevant equations in a coherent way.     

Concepts for reference frames in geodesy and geodynamics: The reference directions

Modern high accuracy measurements of the non-rigid earth are to be referred to four-dimensional, i.e., time- and space-dependent reference frames. Geodynamic phenomena derived from these measurements are to be described in a terrestrial reference frame in which both space- and time-like variations can be monitored. Existing conventional terrestrial reference frames (e.g. CIO, BIH) are no longer suitable for such purposes. The ultimate goal of this study is the establishment of a reference frame, moving with the earth in some average sense, in which the geometric and dynamic behavior of the earth can be monitored, and whose motion with respect to inertial space can also be determined. The study is conducted in several parts. In the first part problems related to reference directions are investigated, while subsequent parts deal with positions, i.e., with reference origins and scale. Only the first part is treated in this paper. The approach is based on the fact that reference directions at an observation point on the earth surface are defined by fundamental vectors (gravity, earth rotation, etc.), both space and time variant. These reference directions are interrelated by angular parameters, also derived from the fundamental vectors. The interrelationships between these space- and time-variant angular parameters are illustrated in a commutative diagram, tower of triads, which makes the derivation of the various relationships convenient. In order to determine the above parameters from observations using least squares techniques, a model tower of triads is also presented to allow the formation of linear observation equations. Although the model tower is also space and time variant, its variations are described by adopted parameters representing our current knowledge of the earth.     

Do Cloud Properties in a Puerto Rican Tropical Montane Cloud Forest Depend on Occurrence of Long-Range Transported African Dust?

We investigated cloud properties of warm clouds in a tropical montane cloud forest at Pico del Este (1,051 m a.s.l.) in the northeastern part of Puerto Rico to address the question of whether cloud properties in the Caribbean could potentially be affected by African dust transported across the Atlantic Ocean. We analyzed data collected during 12 days in July 2011. Cloud droplet size spectra were measured using the FM-100 fog droplet spectrometer that measured droplet size distributions in the range from 2 to 49 µm, primarily during fog events. The droplet size spectra revealed a bimodal structure, with the first peak (D < 6 µm) being more pronounced in terms of droplet number concentrations, whereas the second peak (10 µm < D < 20 µm) was found to be the one relevant for total liquid water content (LWC) of the cloud. We identified three major clusters of characteristic droplet size spectra by means of hierarchical clustering. All clusters differed significantly from each other in droplet number concentration ( \(N_{\rm tot}\) ), effective diameter (ED), and median volume diameter (MVD). For the cluster comprising the largest droplets and the lowest droplet number concentrations, we found evidence of inhomogeneous mixing in the cloud. Contrastingly, the other two clusters revealed microphysical behavior, which could be expected under homogeneous mixing conditions. For those conditions, an increase in cloud condensation nuclei—e.g., from processed African dust transported to the site—is supposed to lead to an increased droplet concentration. In fact, one of these two clusters showed a clear shift of cloud droplet size spectra towards smaller droplet diameters. Since this cluster occurred during periods with strong evidence for the presence of long-range transported African dust, we hypothesize a link between the observed dust episodes and cloud characteristics in the Caribbean at our site, which is similar to the anthropogenic aerosol indirect effect.     

Bücher- und Zeitschriftenschau

Ohne Zusammenfassung     

Impaktite von Köfels,Tirol

Zusammenfassung Die glasführenden Gesteine von Köfels, Tirol, wurden petrologisch untersucht. Sowohl Elektronenstrahl-Mikrosondenanalysen der Phasen als auch chemische Pauschalanalysen einiger Gesteine werden angegeben.Das Vorhandensein von Cr- und Si-führendem Nickeleisen, Lechatelierit, Kalifeldspatglas, Fe-reichen Gläsern, Olivin sowie die kräftigen Inhomogenitäten in der Glasphase sind nur durch eine Impakt-Entstehung dieser Gesteine erklärbar.

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Impactites from Koefels, Tyrol, Austria

Summary The glass-bearing rocks from Koefels, Tyrol, have been investigated petrologically. Electron-microprobe Analyses of the phases and chemical bulk analyses of some rocks are presented.The presence of Cr- and Si-bearing nickel-iron, lechatelierite, potassium-feldspar-glass, olivine, as well as the pronounced inhomogenities of the glasses strongly suggest an impact origin of these rocks.

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Mit 7 Abbildungen     

Deep‐sea channel evolution and stratigraphic architecture from inception to abandonment from high‐resolution Autonomous Underwater Vehicle surveys offshore central California

The Lucia Chica channel system is an avulsion belt with four adjacent channels that progressively avulsed to the north‐east from a single, upslope feeder channel. Avulsion occurred from underfilled channels, leaving open channels that were reactivated by flows stripped from younger, adjacent channels. Differences in relief (height from channel thalweg to levée crest), sinuosity and levée stratigraphy between adjacent channels correspond to relative channel age, and indicate a change in channel morphology and architecture with time. Potential triggers for the change over time include differences in gradient, flow behaviour and characteristics, and channel evolution. Gradient does not appear to be a major control on channel formation and avulsion because adjacent channels formed on the same gradient. Based on available ultra‐high‐resolution remote imaging obtained with an Autonomous Underwater Vehicle, differences in adjacent channel morphology are interpreted to be primarily a result of differences in channel maturity. The interpreted sequence of channel maturity involves erosional channel inception through scouring and incipient channels (defined by linear trains of scours) prior to development of continuous thalwegs. Channel narrowing, formation and growth of levées, increasing channel relief and development of sinuosity occurred as channels evolved. The evolutionary sequence interpreted from the high‐resolution Lucia Chica dataset provides a unique perspective on intrinsic controls of architecture for single channel elements. In addition to helping bridge the gap between outcrop and industry‐standard reflection‐seismic data resolutions and scopes, interpretations in this study also expose potential problems with hierarchical classifications in three‐dimensional imaging of distributary systems, and provide potentially important analogues for evolutionary morphologies not resolved in other deep‐water channel systems.