Volcanoes in Italy and the role of muon radiography D'Alessandro, Raffaello; Ambrosino, F; Baccani, G ...
Philosophical transactions of the Royal Society of London. Series A: Mathematical, physical, and engineering sciences,
12/2018, Letnik:
377, Številka:
2137
Journal Article
Recenzirano
Odprti dostop
Cosmic-ray muon radiography (muography), an imaging technique that can provide measurements of rock densities within the top few 100 m of a volcanic cone, has now achieved a spatial resolution of the ...order of 10 m in optimal detection conditions. Muography provides images of the top region of a volcano edifice with a resolution that is considerably better than that typically achieved with other conventional methods (i.e. gravimetric). We expect such precise measurements, to provide us with information on anomalies in the rock density distribution, which can be affected by dense lava conduits, low-density magma supply paths or the compression with the depth of the overlying soil. The MUon RAdiography of VESuvius (MURAVES) project is now in its final phase of construction and deployment. Up to four muon hodoscopes, each with a surface of roughly 1 m
, will be installed on the slope of Vesuvius and take data for at least 12 months. We will use the muographic profiles, combined with data from gravimetric and seismic measurement campaigns, to determine the stratigraphy of the lava plug at the bottom of the Vesuvius crater, in order to infer potential eruption pathways. While the MURAVES project unfolds, others are using emulsion detectors on Stromboli to study the lava conduits at the top of the volcano. These measurements are ongoing: they have completed two measurement campaigns and are now performing the first data analysis.This article is part of the Theo Murphy meeting issue 'Cosmic-ray muography'.
Lifetimes or lifetime limits of a small number of excited states of the sulfur isotopes with mass numbers A=35, 36, 37, and 38 have been measured using the differential recoil-distance method. The ...isotopes of sulfur were populated in binary grazing reactions initiated by a beam of 36S ions of energy 225 MeV incident on a thin 208Pb target which was mounted in the Cologne plunger apparatus. The combination of the PRISMA magnetic spectrometer and an early implementation of the AGATA γ-ray tracking array was used to detect γ rays in coincidence with projectile-like nuclear species. Lifetime measurements of populated states were measured within the range from about 1 to 100 ps. The number of states for which lifetime measurements or lifetime limits were possible was limited by statistics. For 35S, the lifetime was determined for the first 1/2+ state at 1572 keV; the result is compared with a previous published lifetime value. The lifetime of the 3− state of 36S at 4193 keV was determined and compared with earlier measurements. No previous lifetime information exists for the (6+) state at 6690 keV; a lifetime measurement with large associated error was made in the present work. For 37S, the states for which lifetime limits were established were those at 646 keV with Jπ=3/2− and at 2776 keV with Jπ=11/2−; there are no previously published lifetime values for excited states of 37S. Finally, a lifetime limit was established for the Jπ=(6+) state of 38S at 3675 keV; no lifetime information exists for this state in the literature. Measured lifetime values were compared with the results of state-of-the-art shell-model calculations based on the PSDPF, SDPF-U, and FSU effective interactions. In addition, nuclear magnetic-dipole and electric-quadrupole moments, branching ratios, mixing ratios, and electromagnetic transition rates, where available, have been compared with shell-model values. The current work suffers from poor statistics; nevertheless, lifetime values and limits have been possible, allowing a useful discussion of the ability of state-of-the-art shell-model calculations to reproduce the experimental results.
The Muon Imaging for Mining and Archaeology (MIMA) project aims at the development of a non-invasive technique for imaging dense structures or cavities, hidden in the underground or anyway surrounded ...by huge volumes of matter, based on Muon Absorption Radiography. Given its natural multidisciplinary, the final purpose is the validation of this methodology for applications in different fields, like Archaeology, Geology, mining, Civil Engineering and Civil Protection, in close cooperation with team in these fields. In this paper we report on the design, construction and performance of a compact and lightweight muon telescope designed mainly for archaeological investigation and geophysical prospections in general. The MIMA detector is also used currently as a test instrument to study different hardware solutions to optimize the global performance in these types of applications.
Muon radiography is a technique based on the measurement of absorption profiles of muons as they pass through matter. This measurement allows to obtain an image of the inner structure of large volume ...objects and is suitable to be applied in several fields, such as volcanology, archaeology and civil engeneering. One of the main applications concerns the study of volcanic structures; indeed it is possible to use this technique to measure the mass distribution inside the edifice of a volcano providing useful information to better understand the possible eruption mechanisms. The MURAVES (MUon RAdiography of VESuvius) project aims to the study of the summital cone of Mt. Vesuvius near Naples in Italy, one of the most dangerous active volcanoes in the world. The MURAVES apparatus is a modular, robust muon hodoscope system with a low power consumption, optimized to be used in inhospitable environments like the surroundings of volcanoes. The complete detection system is an array of identical tracking modules, each with an area of 1 m2, based on the use of plasic scintillators. The technologies, the status and the data analysis strategy of the experiment will be presented in this paper.
Lifetimes of states in the ground-state bands of (70)Se and (72)Se were measured using the recoil-distance Doppler shift method. The results deviate significantly from earlier measurements, requiring ...a revision of the conclusions drawn from a recent Coulomb excitation experiment concerning the shape of (70)Se. The new results lead to a coherent picture of shape coexistence in the neutron-deficient selenium and krypton isotopes. The coexistence and evolution of oblate and prolate shapes in this mass region is for the first time consistently described by new Hartree-Fock-Bogolyubov-based configuration-mixing calculations which were performed using the Gogny D1S interaction.
Muon Radiography or muography is based on the measurement of the absorption or scattering of cosmic muons, as they pass through the interior of large scale bodies, In particular, absorption muography ...has been applied to investigate the presence of hidden cavities inside the pyramids or underground, as well as the interior of volcanoes’ edifices. The MURAVES project has the challenging aim of investigating the density distribution inside the summit of Mt. Vesuvius. The information, together with that coming from gravimetric measurements, is useful as input to models, to predict how an eruption may develop. The MURAVES apparatus is a robust and low power consumption muon telescope consisting of an array of three identical and independent muon trackers, which provide in a modular way a total sensitive area of three square meters. Each tracker consists of four doublets of planes of plastic scintillator bars with orthogonal orientation, optically coupled to Silicon photomultipliers for the readout of the signal. The muon telescope has been installed on the slope of the volcano and has collected a first set of data, which are being analyzed.
A novel algorithm developed within muon radiography to localize objects or cavities hidden inside large material volumes was recently proposed by some of the authors (Bonechi
2015
, P02003 ...(doi:10.1088/1748-0221/10/02/P02003)). The algorithm, based on muon back projection, helps to estimate the three-dimensional position and the transverse extension of detected objects without the need for measurements from different points of view, which would be required to make a triangulation. This algorithm can now be tested owing to the availability of real data collected both in laboratory tests and from real-world measurements. The methodology and some test results are presented in this paper.This article is part of the Theo Murphy meeting issue 'Cosmic-ray muography'.
Lifetimes of excited states of the phosphorus isotopes 33 , 34 , 35 , 36 15 P have been measured by using the differential recoil-distance method. The isotopes of phosphorus were populated in binary ...grazing reactions initiated by a beam of 36 S ions of energy 225 MeV incident on a thin 208 Pb target mounted in the Cologne plunger apparatus. The combination of the PRISMA magnetic spectrometer and an early implementation of the AGATA γ -ray tracking array was used to detect γ rays in coincidence with projectile-like nuclear species. Lifetime measurements of populated states were made within the range from about 1 to 100 ps. The number of states for which lifetime measurements were possible was limited by statistics. For 33 P , lifetime limits were determined for the first 3/2+ and 5/2+ states at 1431 and 1848 keV, respectively; the results are compared with previous published lifetime values. The lifetime of the first 2+ state of 34 P at 429 keV was determined and compared with earlier measurements. For 35 P , the states for which lifetimes, or lifetime limits, were determined were those at 2386, 3860, 4101, and 4493 keV, with Jπ values of 3/2+, 5/2+, 7/2− 1 , and 7/2− 2 , respectively. There have been no previous published lifetimes for states in this nucleus. A lifetime was measured for the stretched π ( 1 f 7 / 2 ) ⊗ ν ( 1 f 7 / 2 ) J π = ( 7 + ) state of 36 P at 5212 keV and a lifetime limit was established for the stretched π ( 1 d 3 / 2 ) ⊗ ν ( 1 f 7 / 2 ) J π = ( 5 − ) state at 2030 keV. There are no previously published lifetimes for states of 36 P . Measured lifetime values were compared with the results of state-of-the-art shell-model calculations based on the PSDPF effective interaction. In addition, measured branching ratios, published mixing ratios, and electromagnetic transition rates, where available, have been compared with shell-model values. In general, there is good agreement between experiment and the shell model; however there is evidence that the shell-model values of the M1 transition rates for the 3/2+1→ 1 / 2 + (ground state) and 5/2+1→ 3 / 2 + 1 transitions in 33 P underestimate the experimental values by a factor between 5 and 10. In 35 P there are some disagreements between experimental and shell-model values of branching ratios for the first and second excited 7/2− states. In particular, there is a serious disagreement for the decay characteristics of the second 7/2− state at 4493 keV, for which the shell-model counterpart lies at 4754 keV. In this case, the shell-model competing electromagnetic decay branches are dominated by E1 and M1 transitions.
g factor of the 12+K-isomer in 174W Rocchini, M.; Nannini, A.; Benzoni, G. ...
The European physical journal. A, Hadrons and nuclei,
2020/11, Letnik:
56, Številka:
11
Journal Article
Recenzirano
The
g
factor of the
12
+
K
-isomer in
174
W has been measured by means of the time-differential perturbed angular distribution technique as
g
(
12
+
)
=
+
0.304
(
11
)
. In addition, the half-life of ...the isomer has been remeasured as
T
1
/
2
(
12
+
)
=
124
(
8
)
ns, in agreement with the literature value and confirming the anomalous hindrance
F
of the
E
2 transition to the
10
+
level of the ground state band with respect to the
γ
-tunnelling model prediction. The measured
g
factor has been compared with estimates based on experimental
g
factors from odd-mass isotopes in the same mass region and with Nilsson model calculations. The results establish unique features of the
12
+
K
-isomer in
174
W, which can possess a non-pure intrinsic configuration and/or can be characterised by values of the intrinsic quadrupole moment
Q
0
and the rotational
g
factor
g
R
significantly different with respect to the majority of
K
-isomers at mass
A
≈
180
.
Thick target yields for proton induced γ-ray emission (PIGE) on low-Z nuclei, namely B, N, Na, Al and Si, were measured for proton energies from 2.5 to 4.1MeV and emission angles of 0°, 45° and 90°, ...at the 3 MV Tandetron laboratory of INFN-LABEC in Florence. The studied reactions were: 10B(p,α′γ)7Be (Eγ=429keV), 10B(p,p′γ)10B (Eγ=718keV) and 11B(p,p′γ)11B (Eγ=2125keV) for boron; 14N(p,p′γ)14N (Eγ=2313keV) for nitrogen; 23Na(p,p′γ)23Na (Eγ=441 and 1636keV) and 23Na(p,α′γ)20Ne (Eγ=1634keV) for sodium; 27Al(p,p′γ)27Al (Eγ=844 and 1014keV) and 27Al(p,α′γ)24Mg (Eγ=1369keV) for aluminum; 28Si(p,p′γ)28Si (Eγ=1779keV) and 29Si(p,p′γ)29Si (Eγ=1273keV) for silicon. The PIGE thick target yields have been measured with an overall uncertainty typically better than 10%. The use of the measured thick target yield to benchmark and validate experimental cross sections available in the literature is demonstrated.
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