2,637 research outputs found
Micro-beam and pulsed laser beam techniques for the micro-fabrication of diamond surface and bulk structures
Micro-fabrication in diamond is involved in a wide set of emerging
technologies, exploiting the exceptional characteristics of diamond for
application in bio-physics, photonics, radiation detection. Micro ion-beam
irradiation and pulsed laser irradiation are complementary techniques, which
permit the implementation of complex geometries, by modification and
functionalization of surface and/or bulk material, modifying the optical,
electrical and mechanical characteristics of the material. In this article we
summarize the work done in Florence (Italy) concerning ion beam and pulsed
laser beam micro-fabrication in diamond.Comment: 14 pages, 5 figure
Probing the statistical decay and alpha-clustering effects in 12c+12c and 14n+10b reactions
An experimental campaign has been undertaken at INFN Laboratori Nazionali di
Legnaro, Italy, in order to progress in our understanding of the statistical
properties of light nuclei at excitation energies above particle emission
threshold, by measuring exclusive data from fusion-evaporation reactions. A
first reaction 12C+12C at 7.9 AMeV beam energy has been measured, using the
GARFIELD+Ring Counter experimental setup. Fusion-evaporation events have been
exclusively selected. The comparison to a dedicated Hauser-Feshbach calculation
allows us to give constraints on the nuclear level density at high excitation
energy for light systems ranging from C up to Mg. Out-of-equilibrium emission
has been evidenced and attributed both to entrance channel effects favoured by
the cluster nature of reaction partners and, in more dissipative events, to the
persistence of cluster correlations well above the 24Mg threshold for 6 alphas
decay. The 24Mg compound nucleus has been studied with a new measurement 14N +
10B at 5.7 AMeV. The comparison between the two datasets would allow us to
further constrain the level density of light nuclei. Deviations from a
statistical behaviour can be analyzed to get information on nuclear clustering.Comment: 4 pages, 2 figures, Contribution to conference proceedings of the
25th International Nuclear Physics Conference (INPC 2013
Usefulness of panoramic 344°-viewing in Crohn's disease capsule endoscopy : a proof of concept pilot study with the novel PillCam™ Crohn's system
Background: A new capsule endoscopy (CE) system featuring two advanced optics for 344\ub0-viewing and a prolonged operative time has been recently developed for Crohn's disease (CD) patients. Hence, we evaluated, for the first time, the performance of this novel CE and the add-on value of the 344\ub0-viewing in a multi-center real-life setting. Methods: Consecutive patients with suspected or established CD received the PillCam\u2122 Crohn's System as supplementary diagnostic work-up focused on the small-bowel between June 2017 and June 2018. Technical and clinical data, including the panenteric CE diagnostic yield, the Lewis score and the impact of small-bowel findings on clinical management during a 6-months follow-up (new diagnosis, staging or treatment upgrade) were collected, thereby evaluating the added value of the 344\ub0 panoramic-view (lesions detected by camera A and B) over the standard 172\ub0-view (lesions detected by one camera only). Results: Among 41 patients (aged 43 \ub1 20 years), 73% underwent CE for suspected CD and 27% for established CD. The rate of complete enteroscopy was 90%. No technical failure or retention occurred. Compared to the standard 172\ub0 view, the panoramic 344\ub0-view revealed a greater number of patients with a relevant lesion (56.1% vs. 39.0%; P = 0.023), resulting in higher Lewis score (222,8 vs. 185.7; P = 0.031), and improved clinical management (48.8% vs. 31.7%, P = 0.023). Conclusions: The panoramic 344\ub0-view increases small-bowel CE accuracy, thereby improving the clinical management of CD patients with mild small-bowel active disease. This system should be regarded as a new standard for both small-bowel diagnosis and monitoring in inflammatory bowel diseases
An IMU and USBL-aided buoy for underwater localization
Autonomous underwater navigation remains, as of today, a challenging task. The
marine environment limits the number of sensors available for precise localization, hence Au-
tonomous Underwater Vehicles (AUVs) usually rely on inertial and velocity sensors to obtain an
estimate of their position either through dead reckoning or by means of more sophisticated
navigation filters (such as Kalman filters and its extensions [1]). On the other hand, acoustic
localization makes possible the determination of a reliable vehicles pose estimate exploiting suit-
able acoustic modems [3]; such estimate can even be integrated within the navigation filter of the
vehicle in order to increase its accuracy. In this paper, the authors discuss the development and
the performance of an Ultra-Short BaseLine (USBL)-aided buoy to improve the localization of
underwater vehicles. At first, the components and the physical realization of the buoy will be
discussed; then, the procedure to compute the position of the target will be analyzed. The
following part of the paper will be focused on the development of a recursive state estimation
algorithm to process the measurements computed by the buoy; specifically, Extended Kalman Filter
[4] has been adopted to deal with the nonlinearities of the sensors housed on the buoy. A
validation of the measurement filtering through experimental tests is also proposed
An IMU and USBL-aided buoy for underwater localization
Autonomous underwater navigation remains, as of today, a challenging task. The
marine environment limits the number of sensors available for precise localization, hence Au-
tonomous Underwater Vehicles (AUVs) usually rely on inertial and velocity sensors to obtain an
estimate of their position either through dead reckoning or by means of more sophisticated
navigation filters (such as Kalman filters and its extensions [1]). On the other hand, acoustic
localization makes possible the determination of a reliable vehicles pose estimate exploiting suit-
able acoustic modems [3]; such estimate can even be integrated within the navigation filter of the
vehicle in order to increase its accuracy. In this paper, the authors discuss the development and
the performance of an Ultra-Short BaseLine (USBL)-aided buoy to improve the localization of
underwater vehicles. At first, the components and the physical realization of the buoy will be
discussed; then, the procedure to compute the position of the target will be analyzed. The
following part of the paper will be focused on the development of a recursive state estimation
algorithm to process the measurements computed by the buoy; specifically, Extended Kalman Filter
[4] has been adopted to deal with the nonlinearities of the sensors housed on the buoy. A
validation of the measurement filtering through experimental tests is also proposed
Response of microchannel plates in ionization mode to single particles and electromagnetic showers
Hundreds of concurrent collisions per bunch crossing are expected at future
hadron colliders. Precision timing calorimetry has been advocated as a way to
mitigate the pileup effects and, thanks to their excellent time resolution,
microchannel plates (MCPs) are good candidate detectors for this goal. We
report on the response of MCPs, used as secondary emission detectors, to single
relativistic particles and to electromagnetic showers. Several prototypes, with
different geometries and characteristics, were exposed to particle beams at the
INFN-LNF Beam Test Facility and at CERN. Their time resolution and efficiency
are measured for single particles and as a function of the multiplicity of
particles. Efficiencies between 50% and 90% to single relativistic particles
are reached, and up to 100% in presence of a large number of particles. Time
resolutions between 20ps and 30ps are obtained.Comment: 20 pages, 9 figures. Paper submitted to NIM
Response of microchannel plates to single particles and to electromagnetic showers
We report on the response of microchannel plates (MCPs) to single
relativistic particles and to electromagnetic showers. Particle detection by
means of secondary emission of electrons at the MCP surface has long been
proposed and is used extensively in ion time-of-flight mass spectrometers. What
has not been investigated in depth is their use to detect the ionizing
component of showers. The time resolution of MCPs exceeds anything that has
been previously used in calorimeters and, if exploited effectively, could aid
in the event reconstruction at high luminosity colliders. Several prototypes of
photodetectors with the amplification stage based on MCPs were exposed to
cosmic rays and to 491 MeV electrons at the INFN-LNF Beam-Test Facility. The
time resolution and the efficiency of the MCPs are measured as a function of
the particle multiplicity, and the results used to model the response to
high-energy showers.Comment: Paper submitted to NIM
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