177 research outputs found
First results with the {ANET} Compact Thermal Neutron Collimator
This paper presents the first determination of the spatial resolution of the
ANET Compact Neutron Collimator, obtained with a measuring campaign at the LENA
Mark-II TRIGA reactor in Pavia. This novel collimator consists of a sequence of
collimating and absorbing channels organised in a chessboard-like geometry. It
has a scalable structure both in length and in the field of view. It is
characterized by an elevated collimation power within a limited length. Its
scalability and compactness are added values with respect to traditional
collimating system. The prototype tested in this article is composed of 4
concatenated stages, each 100mm long, with a channel width of 2.5mm, delivering
a nominal L/D factor of 160. This measuring campaign illustrates the use of the
ANET collimator and its potential application in neutron imaging for facilities
with small or medium size neutron sources.Comment: 9 pages, 8 figures, prepared for submission to JINS
First experimental results of the spatial resolution of RSD pad arrays read out with a 16-ch board
Resistive Silicon Detectors (RSD, also known as AC-LGAD) are innovative silicon sensors, based on the LGAD technology, characterized by a continuous gain layer that spreads across the whole sensor active area. RSDs are very promising tracking detectors, thanks to the combination of the built-in signal sharing with the internal charge multiplication, which allows large signals to be seen over multiple read-out channels. This work presents the first experimental results obtained from a 34 array with 200~\mum~pitch, coming from the RSD2 production manufactured by FBK, read out with a 16-ch digitizer. A machine learning model has been trained, with experimental data taken with a precise TCT laser setup, and then used to predict the laser shot positions, finding a spatial resolution of ~ 5.5 um
Design of a novel compact neutron collimator
In this work the concept of a novel slow neutron collimator and the way to
operate it are presented. The idea is based on the possibility to decouple the
device field-of-view from its collimation power. A multi-channel geometry is
proposed consisting of a chess-board structure where highly neutron-absorbing
channels are alternated to air channels. A borated polymer was purposely
developed to produce the attenuating components in the form of square-sectioned
long rods. A scalable structure consisting of multiple collimation sectors can
be arranged. The geometrical parameter LD, corresponding to the ratio between
the length of a channel and its width, defines the collimation power. Several
sectors can be arranged one after the other to reach relevant collimation
powers. Each sector, 100 mm long, is composed by several channels with D = 2.5
mm corresponding to an L/D coefficient of 40. The target field of view is 50x50
mm2. This novel collimator, developed inside the INFN-ANET collaboration, due
to its intrinsic compactness, will be of great importance to enhance the
neutron imaging capability of small to medium-size neutron sources.Comment: 8 pages, 5 figures, accepted for publication to JINS
On some aspects of the geometry of differential equations in physics
In this review paper, we consider three kinds of systems of differential
equations, which are relevant in physics, control theory and other applications
in engineering and applied mathematics; namely: Hamilton equations, singular
differential equations, and partial differential equations in field theories.
The geometric structures underlying these systems are presented and commented.
The main results concerning these structures are stated and discussed, as well
as their influence on the study of the differential equations with which they
are related. Furthermore, research to be developed in these areas is also
commented.Comment: 21 page
Singular lagrangians: some geometric structures along the Legendre map
New geometric structures that relate the lagrangian and hamiltonian
formalisms defined upon a singular lagrangian are presented. Several vector
fields are constructed in velocity space that give new and precise answers to
several topics like the projectability of a vector field to a hamiltonian
vector field, the computation of the kernel of the presymplectic form of
lagrangian formalism, the construction of the lagrangian dynamical vector
fields, and the characterisation of dynamical symmetries.Comment: 27 pages; minor changes, a reference update
The Tulczyjew triple for classical fields
The geometrical structure known as the Tulczyjew triple has proved to be very
useful in describing mechanical systems, even those with singular Lagrangians
or subject to constraints. Starting from basic concepts of variational
calculus, we construct the Tulczyjew triple for first-order Field Theory. The
important feature of our approach is that we do not postulate {\it ad hoc} the
ingredients of the theory, but obtain them as unavoidable consequences of the
variational calculus. This picture of Field Theory is covariant and complete,
containing not only the Lagrangian formalism and Euler-Lagrange equations but
also the phase space, the phase dynamics and the Hamiltonian formalism. Since
the configuration space turns out to be an affine bundle, we have to use affine
geometry, in particular the notion of the affine duality. In our formulation,
the two maps and which constitute the Tulczyjew triple are
morphisms of double structures of affine-vector bundles. We discuss also the
Legendre transformation, i.e. the transition between the Lagrangian and the
Hamiltonian formulation of the first-order field theor
Development of gamma insensitive silicon carbide diagnostics to qualify intense thermal and epithermal neutron fields
The e_LiBANS project aims at creating accelerator based compact neutron
facilities for diverse interdisciplinary applications. After the successful
setting up and characterization of a thermal neutron source based on a medical
electron LINAC, a similar assembly for epithermal neutrons has been developed.
The project is based on an Elekta 18 MV LINAC coupled with a
photoconverter-moderator system which deploys the ({\gamma},n) photonuclear
reaction to convert a bremsstrahlung photon beam into a neutron field. This
communication describes the development of novel diagnostics to qualify the
thermal and epithermal neutron fields that have been produced. In particular, a
proof of concept for the use of silicon carbide photodiodes as a thermal
neutron rate detector is presented.Comment: 10 pages, 10 figures, accepted for publication to JINST on the 17th
April 202
A new Low Gain Avalanche Diode concept: the double-LGAD
This paper describes the new concept of the double-LGAD. The goal is to
increase the charge at the input of the electronics, keeping a time resolution
equal or better than a standard (single) LGAD; this has been realized by adding
the charges of two coupled LGADs while still using a single front-end
electronics. The study here reported has been done starting from single LGAD
with a thickness of 25 \textmu{m}, 35 \textmu{m} and 50 \textmu{m}.Comment: arXiv admin note: text overlap with arXiv:2208.0571
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