Search results for "Trap"
showing 10 items of 2144 documents
Production of pure samples of 131mXe and 135Xe
2011
Pure samples of (131m)Xe, (133m)Xe, (133)Xe and (135)Xe facilitate the calibration and testing of noble gas sampler stations and related laboratory instrumentation. We have earlier reported a Penning trap-based production method for pure (133m)Xe and (133)Xe samples. Here we complete the work by reporting the successful production of pure (131m)Xe and (135)Xe samples using the same technique. In addition, we present data on xenon release from graphite.
Penning trap for isobaric mass separation at IGISOL
2003
Abstract A cylindrical Penning trap has been built at the ion guide isotope separator facility IGISOL of the University of Jyvaskyla. The main goal of the Penning trap application is to purify low-energy radioactive ion beams. The aim is to make isobarically pure beams. The technical description is presented.
Ultrapotassic volcanism from the waning stage of the Neotethyan subduction: a key study from the Izmir-Ankara-Erzincan suture belt, central northern …
2016
Upper Cretaceous volcano-sedimentary successions in the Central Pontides of Turkey, related to the closure of the Tethys Ocean, include a variety of alkaline ultrapotassic igneous rocks that have been classified as leucititic, lamprophyric and trachytic based on their mineral paragenesis. Although the ultrapotassic rocks display a range of K 2 O contents (0·9–8·4 wt %) that may partly reflect alteration processes, they display subduction-related trace element signatures characterized by significant enrichment of large ion lithophile elements and light rare earth elements relative to high field strength elements and heavy rare earth elements and depletion of Nb and Ta. However, their initial…
Radionuclide fluxes in the Arabian Sea: the role of particle composition
2005
We investigated the influence of the composition of the vertical particle flux on the removal of particle reactive natural radionuclides (Th-230 and Pa-231) from the water column to the sediments. Radionuclide concentrations determined in sediment traps moored in the western, central and eastern Arabian Sea were related to the major components (carbonate, particulate organic matter (POC), opal, lithogenic material) of the particle flux. These data were combined with sediment trap data previously published from the Southern Ocean, Equatorial Pacific and North Atlantic [Z. Chase, R.F. Anderson, M.Q. Fleisher, P.W. Kubik, The influence of particle composition and particle flux on scavenging of…
Electronic effects in the production of smali dianionic gold clusters by electron attachment on to stored Au-n, n = 12-28
1999
Abstract Single charged gold clusters Au n -, 12 n 28, are stored in a Penning trap, size selected and transformed into dianions, Au2- n by the application of an electron beam. At the onset of dianion production, that is that range of cluster sizes n where the smallest doubly charged clusters are observed, the measured intensity ratio of the dianions to their precursors is not a continuous function of cluster size. Instead, there is a strong odd-even effect and a comparatively intense signal of Au2-18 The observed structures are very reminiscent of similar phenomena in the abundance spectra of metal clusters as observed by Knight et al. (1984, Phys. Rev. Lett., 52, 2141), which gave ris…
Interpretation of capacitance spectra and transit times of single carrier space-charge limited transport in organic layers with field-dependent mobil…
2007
The ac impedance characteristics of a single carrier with space-charge limited current (SCLC) transport in organic layers with field-dependent mobility is analyzed, indicating the similarities as well as the differences to the constant mobility case. The model provides capacitance spectra and transit times from different calculation methods, in relation to the electric field distribution in the SCLC regime. It is found that the low frequency capacitance lies in the range 3Cg/4 < Cif < Cg, with respect to the geometric capacitance Cg. An approximated expression for the variation of the transit time with applied bias is derived, in good agreement with exact calculations. Experimental results …
First Observation of Doubly Charged Negative Gold Cluster Ions
1999
Singly charged gold cluster anions in the size range n = 16–30 have been captured, stored and size selected in a Penning trap. After application of an electron beam doubly charged gold cluster anions have been observed for 20 ≤ n ≤ 30. To our knowledge this is the first observation of metal cluster dianions. The threshold appearance size is in good agreement with a simple charged sphere model. The application of argon gas pulses simultaneously with the electron beam is found to increase the production rate by an order of magnitude.
External-ion accumulation in a Penning trap with quadrupole excitation assisted buffer gas cooling
1994
Abstract A pulsed ion beam from an external source is injected into a Penning trap and accumulated by repeatedly lowering during ion capture to prevent the ions already captured from escaping. For the same reason the newly captured ions have to be cooled, which achieved by buffer gas collisions. To prevent radial on loss, the ions are exposed to azimuthal quadrupole excitation. By choosing the appropriate frequency (range) this method (selective quadrupole excitation assisted capture and centering (SQUEACE) allows a mass selection during the capture process and leads to a centering of those ions in the Penning trap. The multiple ion bunch capture results in a significant improvement in sign…
Chapter 7 HITRAP: A Facility at GSI for Highly Charged Ions
2008
Abstract An overview and status report of the new trapping facility for highly charged ions at the Gesellschaft fur Schwerionenforschung is presented. The construction of this facility started in 2005 and is expected to be completed in 2008. Once operational, highly charged ions will be loaded from the experimental storage ring ESR into the HITRAP facility, where they are decelerated and cooled. The kinetic energy of the initially fast ions is reduced by more than fourteen orders of magnitude and their thermal energy is cooled to cryogenic temperatures. The cold ions are then delivered to a broad range of atomic physics experiments.
La rappresentazione dei caratteri della città mediterranea nella storia: il caso di Trapani e del suo territorio
2020
Decifrare la città e la sua evoluzione storica attraverso l’analisi delle sue rappresentazioni è ad oggi, almeno per Trapani, una modalità d’indagine mai perseguita. Quelle che ad una prima osservazione appaiono graficamente come sproporzioni, imprecisioni, approssimazioni o addirittura irrazionalità potrebbero invece essere utili a suggerirci nuove traiettorie di ricerca, sia sulle vere e proprie trasformazioni fisiche che sul contesto socio-culturale entro il quale queste si sono svolte. Deciphering the city and its historical evolution through the analysis of its representations is today, at least for Trapani, a method of investigation never pursued. Those that at a first observation app…