Manned space missions towards Moon and Mars planned in the next decades require a reliable radiation risk assessment considering the long time exposure of astronauts (up to years) to different ...radiation fields. The radiation environment inside a human space habitat, generated by the interaction of the Galactic Cosmic Rays and occasionally of Solar Particle Events with the spacecraft hull, is peculiar due to its composition (ions from Hydrogen to Iron, knock out neutrons) and the large kinetic energy range of the particles. For this reason the risk assessment approach used for astronauts in space is quite different from the one used on Earth. In this approach the risk for astronauts is evaluated calculating factors which score the risk in function of physical characteristics of the single particle, like the quality factor Q (related to the radiation ionizing power) or the squared ratio between the charge (Z) and velocity (β) of the particle (Z2/β2). LIDAL-ALTEA (Light Ion Detector for ALTEA - Anomalous Long Term Effects on Astronauts) is an experimental apparatus which will allow to evaluate for the first time in the field the Z2/β2 risk factor of the single detected particle on-board the International Space Station. The LIDAL system is a Time-Of-Flight detector designed to work paired to three Silicon Detector Units of the ALTEA, which will measure the deposited energy of the passing particle. The velocity of the particle (β), calculated from the Time-Of-Flight measurement performed by LIDAL, allows to evaluate the particle electric charge once related to the deposited energy measured by ALTEA. A first LIDAL prototype has been developed by the University of Rome "Tor Vergata" and tested at TIFPA (Trento Insistute for Fundamental Physics Applications) proton beam line, in order to evaluate the timing performances of the detector. Results are briefly presented and the current status of the apparatus production is discussed in view of the launch scheduled for 2019.
ABSTRACT The nature of particle acceleration at the Sun, whether through flare reconnection processes or through shocks driven by coronal mass ejections, is still under scrutiny despite decades of ...research. The measured properties of solar energetic particles (SEPs) have long been modeled in different particle-acceleration scenarios. The challenge has been to disentangle the effects of transport from those of acceleration. The Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) instrument enables unique observations of SEPs including the composition and angular distribution of the particles about the magnetic field, i.e., pitch angle distribution, over a broad energy range (>80 MeV)-bridging a critical gap between space-based and ground-based measurements. We present high-energy SEP data from PAMELA acquired during the 2012 May 17 SEP event. These data exhibit differential anisotropies and thus transport features over the instrument rigidity range. SEP protons exhibit two distinct pitch angle distributions: a low-energy population that extends to 90° and a population that is beamed at high energies (>1 GeV), consistent with neutron monitor measurements. To explain a low-energy SEP population that exhibits significant scattering or redistribution accompanied by a high-energy population that reaches the Earth relatively unaffected by dispersive transport effects, we postulate that the scattering or redistribution takes place locally. We believe that these are the first comprehensive measurements of the effects of solar energetic particle transport in the Earth's magnetosheath.
The LIDAL (Light Ion Detector for ALTEA) is a device designed to work paired with three silicon detector units of ALTEA (Anomalous Long Term Effects on Astronauts) in order to improve the particle ...identification capabilities of ALTEA on the International Space Station also providing Time-of-Flight measurements. The LIDAL-ALTEA goal is to measure ions from protons up to iron in real time. The improved measurements of the radiation environment inside ISS will be very valuable for radiation risk assessment and mitigation. It is necessary to have a detailed simulation of the apparatus response to cosmic ray nuclei in order to assess the detector response, its observational capabilities and to set the relevant parameters of the device. Here a new Monte Carlo simulation of the LIDAL-ALTEA setup and physics processes, in the framework of FLUKA, is presented. A comparison between Monte Carlo simulations and calibration data is also shown.
The new generation of particle physics experiments at current and future colliders demands more and more robust detectors. A proposed solution to the stringent requirements are the Small-pad ...Resistive Micormegas. This technology is being developed during recent years, in the framework of the new R&D project RHUM. Different resistive schemes have been implemented. The different behaviours of the embedded resistor layout and the Diamond-Like Carbon (DLC) uniform layers scheme have been studied. Results at very high rate are shown. HV stability studies with two different gases are reported.
ABSTRACT The Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA) detector was launched on board the Russian Resurs-DK1 satellite on 2006 June 15. The data collected ...during the first four years have been used to search for large-scale anisotropies in the arrival directions of cosmic ray positrons. The PAMELA experiment allows for a full sky investigation, with sensitivity to global anisotropies in any angular window of the celestial sphere. Data samples of positrons in the rigidity range of 10 GV R 200 GV were analyzed. This article discusses the method and the results of the search for possible local sources through the analysis of anisotropy in positron data compared to the proton background. The resulting distributions of arrival directions are found to be isotropic. Starting from the angular power spectrum, a dipole anisotropy upper limit of δ = 0.076 at the 95% confidence level is determined. An additional search is carried out around the Sun. No evidence of an excess correlated with that direction was found.
In the ATLAS computing model Grid resources are managed by PanDA, the system designed for production and distributed analysis, and data are stored under various formats in ROOT files. End-user ...physicists have the choice to use either the ATHENA framework or directly ROOT, that provides users the possibility to use PROOF to exploit the computing power of multi-core machines or to dynamically manage analysis facilities. Since analysis facilities are, in general, not dedicated to PROOF only, PROOF-on-Demand (PoD) is used to enable PROOF on top of an existing resource management system. In a previous work we investigated the usage of PoD to enable PROOF-based analysis on Tier-2 facilities using the PoD/gLite plug-in interface. In this paper we present the status of our investigations using the recently developed PoD/PanDA plug-in to enable PROOF and a real end-user ATLAS physics analysis as payload. For this work, data were accessed using two different protocols: XRootD and file protocol. The former in the site where the SRM interface is Disk Pool Manager (DPM) and the latter where the SRM interface is StoRM with GPFS file system. We will first describe the results of some benchmark tests we run on the ATLAS Italian Tier-1 and Tier-2s sites and at CERN. Then, we will compare the results of different types of analysis, comparing performances accessing data in relation to different types of SRM interfaces and accessing data with XRootD in the LAN and in the WAN using the ATLAS XROOTD storage federation infrastructure.
A useful parametrization of the energy spectrum of galactic cosmic rays (GCR) near Earth is offered by the so-called force-field model which describes the shape of the entire spectrum with a single ...parameter, the modulation potential. While the usefulness of the force-field approximation has been confirmed for regular periods of solar modulation, it was not tested explicitly for disturbed periods, when GCR are locally modulated by strong interplanetary transients. Here we use direct measurements of protons and α-particles performed by the PAMELA space-borne instrument during December 2006, including a major Forbush decrease, in order to directly test the validity of the force-field parameterization. We conclude that (1) The force-field parametrization works very well in describing the energy spectra of protons and α-particles directly measured by PAMELA outside the Earths atmosphere; (2) The energy spectrum of GCR can be well parameterized by the force-field model also during a strong Forbush decrease; (3) The estimate of the GCR modulation parameter, obtained using data from the world-wide neutron monitor network, is in good agreement with the spectra directly measured by PAMELA during the studied interval. This result is obtained on the basis of a single event analysis, more events need to be analyzed.
Data handling, reconstruction, and simulation for the KLOE experiment Ambrosino, F.; Antonelli, A.; Antonelli, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Letnik:
534, Številka:
3
Journal Article
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The broad physics program of the KLOE experiment is based on the high event rate at the Frascati φ
factory, and calls for an up-to-date system for data acquisition and processing. In this review of ...the KLOE offline environment, the architecture of the data-processing system and the programs developed for data reconstruction and Monte Carlo simulation are described, as well as the various procedures used for data handling and transfer between the different components of the system.
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