1,721,539 research outputs found
Measuring the antihydrogen fall
No full textTheAEg ̄ISexperiment(AntimatterExperiment:Gravity,Interferometry, Spectroscopy (Drobychev et al., 2007)), aims at directly measuring the gravitational
acceleration g on a beam of cold antihydrogen (H). After production, the H atoms will be driven to fly horizontally with a velocity of a few 100 m/s for a path length of about 1 meter. The small deflection, few tens of μm, will be measured using two material gratings coupled to a position-sensitive detector working as a Moiré deflectometer similarly to what has been done with atoms (Oberthaler et al., Phys
Rev A 54:3165, 1996). Details about the detection of the H annihilation point at the end of the flight path with a position-sensitive microstrip detector and a silicon tracker system will be discussed
Light hypernuclei in FINUDA
No full textThe FINUDA experiment produces L-hypernuclei stopping in thin targets the K’s coming from the decay of the F particle inside the DAFNE eþ-e collider machine. The L-hypernucleus formation is detected by measur- ing the momentum of the outgoing coming from the strangeness-exchange reaction (K;) inside the targets. Experimental results related to few-body issues, such as hypernuclear spectroscopy, hypernuclear decays, and neutron- rich hypernuclei will be presented
Hypernuclei formation probability as a function of the atomic mass number A
No full textThe creation of a hypernucleus [2], that is a nucleus in which a nucleon is replaced by an hyperon, requires the injection of strangeness into the nucleus. This is possible in different ways [3], mainly using π+ or K− beams on nuclear targets; recently, also electron beams have been used. The FINUDA experiment at the DAΦNE Φ factory of the INFN “Laboratori Nazionali di Frascati” produced Λ-hypernuclei by stopping, in thin nuclear targets (0.1-0.2 g/cm2), the negative kaons originating from the Φ decay through the strangeness-exchange reaction K−st o p +A Z →AΛ Z + π − , where A Z indicates
the target nucleus and AΛZ the Λ hypernucleus in which a Λ particle replaced a neutron. FINUDA, an unconventional and
innovative apparatus, allowed the positioning of 8 different target modules around the interaction region. In this way different
targets could be studied contemporaneously, with the same apparatus and with the same analysis technique, allowing for a
direct comparison between different nuclei. In particular FINUDA could study the production of Λ-hypernuclei on 7Li, 9Be,
12C, 13C and 16O targets. Both the Λ binding energy and the hypernuclei production probabilities have been measured [1].
The new measurements on 7 Li, 9 Be, 13C and 16O, along with previous measurements on 12C, allowed for a meaningful study
ΛΛΛΛ Λ
of the formation of p-shell hypernuclei from the two-body capture of K− at rest, giving for the first time the possibility of disentangling the effects due to atomic wave-function of the captured K− from those due to the pion optical nuclear potential and from those due to the specific hypernuclear states [4]
Progettazione della struttura di un portale per tomografia muonica di rottami di ferro
No full textLa fusione metallurgica di sorgenti radioattive all'interno di impianti di recupero di rottami di ferro è
estremamente pericolosa sia per gli operatori che per l’ambiente e la salute degli abitanti in una vasta
area attorno all’impianto stesso. Sulla base di incidenti passati, ed i conseguenti danni socioambientali,
le acciaierie sono state attrezzate con sistemi di rilevamento radioattivo in modo da
scongiurare il più possibile delle contaminazioni su larga scala. Si è cercato quindi di limitare le
conseguenze di un eventuale incidente all’interno delle acciaierie stesse, le quali sono comunque
estremamente sensibili all’argomento sia per la salvaguardia della salute dei propri dipendenti sia per
le pesanti conseguenze economiche che una contaminazione radioattiva comporta.
Particolare attenzione viene data all’identificazione preventiva delle sorgenti radioattive prima che
entrino nei processi di fusione con la conseguente compromissione dell’impianto. Le acciaierie che
sfruttano rottami di ferro, infatti, sono già attrezzate con strumenti in grado di rilevare la presenza di
radiazioni, se non schermate, ma sono completamente indifese se la sorgente radioattiva è ben
confinata all'interno di un involucro di materiale appropriato quale ad esempio il piombo. Un gruppo
di lavoro interdisciplinare composto da ingegneri e fisici si è occupato, insieme a due aziende, della
progettazione di un portale dedicato alla scansione di mezzi pesanti carichi di rottame di ferro: il
principio utilizzato per la rilevazione dei rifiuti radioattivi é la tecnologia della radiografia muonica.
Nel presente articolo si descrive il progetto e l'attività svolta dal gruppo di lavoro
Radiological risks from irradiation of cargo contents with EURITRACK neutron inspection systems
No full textThe radiological risk for the population related to the neutron irradiation of cargo containers with a tagged neutron inspection system has been studied. Two possible effects on the public health have been assessed: the modification of the nutritional and organoleptic properties of the irradiated materials, in particular foodstuff, and the neutron activation of consumer products (i.e. food and pharmaceuticals). The result of this study is that irradiation of food and foodstuff, pharmaceutical and medical devices in container cargoes would neither modify the properties of the irradiated material nor produce effective doses of concern for public health. Furthermore, the dose received by possible stowaways present inside the container during the inspection is less than the annual effective dose limit defined by European Legislation for the public
Design Requirements Assessment in the COMMAND (COmpact Multi-purpose Muon and Neutron Detector) Project
No full textProgetti europei per la sicurezza civile EURITRACK ed Eritr@C: valutazione di rischio radiologico e operazioni di licenza
No full textBiological shielding assessment and dose rate calculation for a neutron inspection portal
No full textWith reference to the prototype of neutron inspection portal built and successfully tested in the Rijeka seaport (Croatia) within the EURITRACK (EURopean Illicit Trafficking Countermeasures Kit) project, an assessment of the biological shielding in different set-up configurations of a future portal has been calculated with MCNP Monte Carlo code in the frame of the Eritr@C (European Riposte against Illicit TR@ffiCking) project. In the configurations analyzed the compliance with the dose limits for workers and the population stated by the European legislation is provided by appropriate shielding of the neutron sources and by the delimitation of a controlled area
Coulomb corrections to low energy antiproton annihilation cross sections on protons and nuclei
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