Search results for "amber"
showing 10 items of 419 documents
Volcano seismicity and ground deformation unveil the gravity-driven magma discharge dynamics of a volcanic eruption.
2015
Effusive eruptions are explained as the mechanism by which volcanoes restore the equilibrium perturbed by magma rising in a chamber deep in the crust. Seismic, ground deformation and topographic measurements are compared with effusion rate during the 2007 Stromboli eruption, drawing an eruptive scenario that shifts our attention from the interior of the crust to the surface. The eruption is modelled as a gravity-driven drainage of magma stored in the volcanic edifice with a minor contribution of magma supplied at a steady rate from a deep reservoir. Here we show that the discharge rate can be predicted by the contraction of the volcano edifice and that the very-long-period seismicity migrat…
Biogas from municipal solid waste landfills: A simplified mathematical model
2018
AbstractMunicipal solid waste (MSW) landfills now represent one of the most important issues related to the waste management cycle. Knowledge of biogas production is a key aspect for the proper exploitation of this energy source, even in the post-closure period. In the present study, a simple mathematical model was proposed for the simulation of biogas production. The model is based on first-order biodegradation kinetics and also takes into account the temperature variation in time and depth as well as landfill settlement. The model was applied to an operating landfill located in Sicily, in Italy, and the first results obtained are promising. Indeed, the results showed a good fit between me…
The n2EDM experiment at the Paul Scherrer Institute
2018
We present the new spectrometer for the neutron electric dipole moment (nEDM) search at the Paul Scherrer Institute (PSI), called n2EDM. The setup is at room temperature in vacuum using ultracold neutrons. n2EDM features a large UCN double storage chamber design with neutron transport adapted to the PSI UCN source. The design builds on experience gained from the previous apparatus operated at PSI until 2017. An order of magnitude increase in sensitivity is calculated for the new baseline setup based on scalable results from the previous apparatus, and the UCN source performance achieved in 2016.
The FURIOS laser ion source at IGISOL-4
2013
Abstract The FURIOS laser ion source at the Accelerator Laboratory of the University of Jyvaskyla has been moved to a new location as a part of the IGISOL-4 facility. The laser ion source project had a high priority which allowed the transport of laser light to be optimized during the design phase. The laser resonators have been upgraded with a dual etalon configuration leading to greatly reduced laser linewidth. The transport efficiency of the dual-chamber gas cell has been determined using an alpha recoil source, with efficiencies ranging from a few percent in the beam interaction chamber to nearly 20% in the ionization chamber. In addition, we present recent results from the re-commissio…
Management and Control of the Read Out Processors (tpps) of the Aleph Time Projection Chamber
1989
The readout of the Aleph time projection chamber (TPC) relies on a set of 72 time projection processors (TPPs), which are based on a Motorola 68020 microprocessor running a real-time operating system. The advanced processing capabilities of the TPPs allow them to perform in parallel a number of tasks, both during and outside of data acquisition, which are outlined. The management and control of such a large number of intelligent devices is presented. The discussion covers the hardware configuration of the TPPs; the software running the TPPs; their management, status, and control; exception handling and message logging; and the TPP monitoring tasks. >
Dosimetry for electron Intra-Operative RadioTherapy: Comparison of output factors obtained through alanine/EPR pellets, ionization chamber and Monte …
2015
Abstract In this work a comparison between the response of alanine and Markus ionization chamber was carried out for measurements of the output factors (OF) of electron beams produced by a linear accelerator used for Intra-Operative Radiation Therapy (IORT). Output factors (OF) for conventional high-energy electron beams are normally measured using ionization chamber according to international dosimetry protocols. However, the electron beams used in IORT have characteristics of dose per pulse, energy spectrum and angular distribution quite different from beams usually used in external radiotherapy, so the direct application of international dosimetry protocols may introduce additional uncer…
A Time Projection Chamber with GEM-Based Readout
2016
For the International Large Detector concept at the planned International Linear Collider, the use of time projection chambers (TPC) with micro-pattern gas detector readout as the main tracking detector is investigated. In this paper, results from a prototype TPC, placed in a 1 T solenoidal field and read out with three independent GEM-based readout modules, are reported. The TPC was exposed to a 6 GeV electron beam at the DESY II synchrotron. The efficiency for reconstructing hits, the measurement of the drift velocity, the space point resolution and the control of field inhomogeneities are presented.
Production of a magnesium ion beam using the MIVOC method
1996
Abstract We report the successful production of multiply charged Mg ion beams at the Jyvaskyla ECRIS using a magnesium compound, magnesocene. The compound was placed in a separate vacuum chamber connected to the second stage of the 6.4 GHz JYFL-ECRIS. From there the vapour of the compound was allowed to diffuse into the source at room temperature. After a brief optimizing procedure the intensity of the 24 Mg 5+ beam was measured to be 11.8 eμA.
The FIRST experiment at GSI
2012
The FIRST (Fragmentation of Ions Relevant for Space and Therapy) experiment at the SIS accelerator of GSI laboratory in Darmstadt has been designed for the measurement of ion fragmentation cross-sections at different angles and energies between 100 and 1000 MeV/nucleon. Nuclear fragmentation processes are relevant in several fields of basic research and applied physics and are of particular interest for tumor therapy and for space radiation protection applications. The start of the scientific program of the FIRST experiment was on summer 2011 and was focused on the measurement of 400 MeV/nucleon 12C beam fragmentation on thin (8 mm) graphite target. The detector is partly based on an alread…
Large-angle production of charged pions with 3-12.9 GeV/c incident protons on nuclear targets
2008
Measurements of the double-differential pi(+/-) production cross section in the momentum range 100 <= p <= 800 MeV/c and angle range 0.35 <= theta <= 2.15 rad in proton-beryllium, proton-carbon, proton-aluminium, proton-copper, proton-tin, proton-tantalum, and proton-lead collisions are presented. The data were taken with the large-acceptance HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3 to 12.9 GeV/c hitting a target with a thickness of 5% of a nuclear interaction length. Tracking and identification of the produced particles was performed by using a small-radius cylindrical Time Projection Chamber (TPC) placed inside a …