Fission decay of N = Z nuclei at high angular momentum: 60^{60}Zn

Using a unique two-arm detector system for heavy ions (the BRS, binary reaction spectrometer) coincident fission events have been measured from the decay of $^{60}$Zn compound nuclei formed at 88MeV excitation energy in the reactions with $^{36}$Ar beams on a $^{24}$Mg target at $E_{lab}(^{36}$Ar) = 195 MeV. The detectors consisted of two large area position sensitive (x,y) gas telescopes with Bragg-ionization chambers. From the binary coincidences in the two detectors inclusive and exclusive cross sections for fission channels with differing losses of charge were obtained. Narrow out-of-plane correlations corresponding to coplanar decay are observed for two fragments emitted in binary events, and in the data for ternary decay with missing charges from 4 up to 8. After subtraction of broad components these narrow correlations are interpreted as a ternary fission process at high angular momentum through an elongated shape. The lighter mass in the neck region consists dominantly of two or three-particles. Differential cross sections for the different mass splits for binary and ternary fission are presented. The relative yields of the binary and ternary events are explained using the statistical model based on the extended Hauser-Feshbach formalism for compound nucleus decay. The ternary fission process can be described by the decay of hyper-deformed states with angular momentum around 45-52 $hbar$.Comment: 23 pages, 25 figure

The leaching of natural colloids from forest surface soils and their role for the P transfer

Soil nanoparticles (d<100nm) and colloids (d<1µm) exert a decisive control on the mobilisation of strongly sorbing compounds such as phosphorus (P). We investigated the nanoparticles and colloids present in forest soil leachates examining their role for the P fixation and for the vertical P transfer in forest soils. Mesocosm experiments with three German forest soils (upper 20 cm) were conducted. The mesocosms were irrigated with artificial rain for 22 months and the nanoparticles and colloids were characterised in the soil leachates with special attention to P. The field flow fractionation (FFF) technique coupled online to UV- and DLS- detectors and inductively coupled plasma mass spectrometry (ICP-MS) or to an organic carbon detector (OCD) enabled a size resolved characterization and quantification of the nanoparticulate and colloidal fractions and their elemental composition (P, Corg, Fe, A, Si, Ca. Mn). To visualise and better characterise the particles present in the leachates, transmission electron microscopy with energy-dispersive x-ray spectroscopy (TEM-EDX) measurements were performed. The translocated particles exhibited sizes up to 350 nm. Using FFF we separated the colloids in three size fractions i) 3-20 nm ii) 20-70 nm and iii) 70-350 nm. The particle fractions showed different chemical compositions. However their composition and characteristics were similar between the three forest sites and comparable to the natural nanoparticles and colloids from soils (“water dispersible colloids”) and streams described in literature. Up to 90% (on average ~45 %) of the leached P was associated with the nanoparticles and colloids. Our qualitative and quantitative analysis of the soil leachates showed that nanoparticles and colloids are crucial vectors controlling the P fluxes in forest ecosystems and could be a significant, but as yet still poorly quantified P loss factor

Some foundational and methodical problems of the empirical theory of literature

Kindt W. Some foundational and methodical problems of the empirical theory of literature. Poetics. 1981;10(4-5):483-513

Investigations of a THGEM-based imaging detector

We present the results of our recent studies on a Thick Gas Electron Multiplier (THGEM)-based imaging detector prototype. It consists of two 100x100 mm^2 THGEM electrodes in cascade, coupled to a resistive anode. The event location is recorded with a 2D double-sided readout electrode equipped with discrete delay-lines and dedicated electronics. The THGEM electrodes, produced by standard printed-circuit board and mechanical drilling techniques, a 0.4 mm thick with 0.5 mm diameter holes spaced by 1 mm. Localization resolutions of about 0.7 mm (FWHM) were measured with soft x-rays, in a detector operated with atmospheric-pressure Ar/CH4; good linearity and homogeneity were achieved. We describe the imaging-detector layout, the resistive-anode 2D readout system and the imaging properties. The THGEM has numerous potential applications that require large-area imaging detectors, with high-rate capability, single-electron sensitivity and moderate (sub-mm) localization resolution.Comment: Published in JINST, 22 pages, 18 figure

Vanadium based neutron beam monitor

A prototype quasiparasitic thermal neutron beam monitor based on isotropic neutron scattering from a thin natural vanadium foil and standard 3He proportional counters is conceptualized, designed, simulated, calibrated, and commissioned. The European Spallation Source designed to deliver the highest integrated neutron flux originating from a pulsed source is currently under construction in Lund, Sweden. The effort to investigate a vanadium based neutron beam monitor was triggered by a list of requirements for beam monitors permanently placed in the ESS neutron beams in order to provide reliable monitoring at complex beamlines low attenuation, linear response over a wide range of neutron fluxes, near to constant efficiency for neutron wavelengths in a range of 0.6 10 , calibration stability and the possibility to place the system in vacuum are all desirable characteristics. The scattering based prototype, employing a natural vanadium foil andstandard 3He proportional counters, was investigated at the V17 and V20 neutron beamlines of the Helmholtz Zentrum in Berlin, Germany, in several different geometrical configurations of the 3He proportional counters around the foil. Response linearity is successfully demonstrated for foil thicknesses ranging from 0.04 mm to 3.15 mm. Attenuation lower than 1 for thermal neutrons is demonstrated for the 0.04 mm and 0.125 mm foils. The geometries used for the experiment were simulated allowing for absolute flux calibration and establishing the possible range of efficiencies for various designs of the prototype. The operational flux limits for the beam monitor prototype were established as a dependency of the background radiation and prototype geometry. The herein demonstrated prototype monitors can be employed for neutron intensities ranging from 103 1010 n s

Conspiracy theory as spatial practice: the case of the Sivas arson attack, Turkey

This article discusses the relationship between conspiratorial thinking and physical space by focusing on the ways conspiracy theories regarding political violence shape and are shaped by the environments in which it is commemorated. Conspiratorial thinking features space as a significant element, but is taken to do so mainly figuratively. In blaming external powers and foreign actors for social ills, conspiracy theorists employ the spatial metaphor of inside versus outside. In perceiving discourses of transparency as the concealment rather than revelation of mechanisms of governance, conspiracy theorists engage the trope of a façade separating the space of power’s formulations from that of its operations. Studying the case of an arson attack dating from 1990s Turkey and its recent commemorations, this article argues that space mediates conspiracy theory not just figuratively but also physically and as such serves to catalyze two of its deadliest characteristics: anonymity and non-linear causality. Attending to this mediation requires a shift of focus from what conspiracy theory is to what it does as a spatial practice

Ten simple rules for implementing open and reproducible research practices after attending a training course

Open, reproducible, and replicable research practices are a fundamental part of science. Training is often organized on a grassroots level, offered by early career researchers, for early career researchers. Buffet style courses that cover many topics can inspire participants to try new things; however, they can also be overwhelming. Participants who want to implement new practices may not know where to start once they return to their research team. We describe ten simple rules to guide participants of relevant training courses in implementing robust research practices in their own projects, once they return to their research group. This includes (1) prioritizing and planning which practices to implement, which involves obtaining support and convincing others involved in the research project of the added value of implementing new practices; (2) managing problems that arise during implementation; and (3) making reproducible research and open science practices an integral part of a future research career. We also outline strategies that course organizers can use to prepare participants for implementation and support them during this process