0000000001329465
AUTHOR
Lars Westerberg
Calibration of a neutron time-of-flight multidetector system for an intensity interferometry experiment
We present the details of an experiment on light particle interferometry. In particular, we focus on a time-of-flight technique which uses a cyclotron RF signal as a start and a liquid scintillator time signal as a stop, to measure neutron energy in the range of En approximate to 1.8-150 MeV. This dynamic range (up to 300 ns) is much larger than the beam bunch separation (54 ns) of the AGOR cyclotron (KVI). However, the problem of a short burst period is overcome by using the time information obtained from a fast projectile fragment phoswich detector. The complete analysis procedure to extract the final neutron kinetic energy spectra, is discussed. (C) 2003 Elsevier B.V. All rights reserved.
Studies of Inelastic Scattering of Fast Heavy Ions
In the present experiment 250A MeV O-17 ions were melastically scattered front xenon and argon in the cluster-jet target of the CELSIUS storage ring. The magnetic lattice of the ring is such that the quadrant following the target can be used as a magnetic spectrometer with an acceptance cone of +/-0.6degrees, centred at 0degrees. A focal plane telescope, placed in the injection straight section. determined the excitation energy of the residual target nuclei. Data were taken for excitation energies between 15 and 35 MeV. The neutron decay was studied by the EDEN detector array positioned around the target, covering an angular range of 7-110degrees. In order to investigate a previously observ…
Burner backflow reduction in regeneration furnace
In the present case from the steel industry, waste hydrochloric acid from the pickling process is regenerated using spray roasting. The process is driven by four burners placed symmetrically along the periphery of the cylindrical main section of the reactor. Severe problems with gas backflow and sintering of iron oxide inside the burner chamber have led to a complete shut down of the process 1-2 times every week, which is a frequency which significantly affects the productivity. In this study the influence of a kick-out on the gas flow in the vicinity of the burner chamber is investigated numerically. It is shown that the kick-out geometry creates a vortical low pressure region preventing t…
Electromagnetic properties of low-spin states in102, 104Pd
Electromagnetic transitions from low-lying 0+, 2+, 4+ and 3− states in102, 104Pd have been studied using (p, 2n) and (p, p′) reactions and Coulomb excitation. TheE2 transition probabilities from the 0 3 + state in102Pd (13 W.u.) and from the 02/+ state in104Pd (14 W.u.) are somewhat low for two-phonon states. Generally, theE2 transition rates are reasonably well reproduced by the IBA-2 and by the boson-expansion description. The intruding 0 2 + state (t1/2=14.3 ns) in102Pd is connected to the 22/+ and 2 3 + states via strong E2 transitions: B(E2; 0 2 + → 2 2 + )=96±40 W.u.; B(E2; 2 3 + → 0 2 + =17±11 W.u.
Effects of mowing frequency on grassland flora and fauna: implications for the conservation of semi-natural grasslands in Europe
To maintain the high biodiversity and preserve the conservation value of semi-natural grasslands, management like grazing or mowing is necessary. Given the limited resources available for management, and few remaining areas, the best management method and intensity should be used. However, the evaluation and comparison of effects of different management intensities on a larger scale is often challenging, as most studies have a limited scope (e.g. only investigating effects in one grassland or for one type of organism). In view of this, we used meta-analysis methods to explore effects of different mowing intensities on biodiversity on a European scale, to reach more robust conclusions. We in…
Swedish monitoring data reveal negative effect of neo-nicotinoids on bumblebee abundance
Neo-nicotinioids are used as insecticides in a variety of crops, e.g. as seed-coating, but have also been found lethal to pollinating insects. In 2013, the European Union introduced a moratorium on some of these compounds. At the same time, the Swedish monitoring program NILS (National Inventory of Landscapes in Sweden) had completed its first round and today a second round has been completed. Thus, it is possible to analyze the effect of the moratorium on monitoring data on bumblebees in N=419 sites in southern Sweden. The presence of neo-nicotiniods was assessed using the official records of the type of crop grown on a field (Blockdatabasen), maintained by the Swedish board of Agriculture…