131 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
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
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
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
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
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
The second production of RSD (AC-LGAD) at FBK
In this contribution we describe the second run of RSD (Resistive AC-Coupled
Silicon Detectors) designed at INFN Torino and produced by Fondazione Bruno
Kessler (FBK), Trento. RSD are n-in-p detectors intended for 4D particle
tracking based on the LGAD technology that get rid of any segmentation implant
in order to achieve the 100% fill-factor. They are characterized by three
key-elements, (i) a continuous gain implant, (ii) a resistive n-cathode and
(iii) a dielectric coupling layer deposited on top, guaranteeing a good spatial
reconstruction of the hit position while benefiting from the good timing
properties of LGADs. We will start from the very promising results of our RSD1
batch in terms of tracking performances and then we will move to the
description of the design of the RSD2 run. In particular, the principles
driving the sensor design and the specific AC-electrode layout adopted to
optimize the signal confinement will be addressed
High-Precision 4D Tracking with Large Pixels using Thin Resistive Silicon Detectors
The basic principle of operation of silicon sensors with resistive read-out
is built-in charge sharing. Resistive Silicon Detectors (RSD, also known as
AC-LGAD), exploiting the signals seen on the electrodes surrounding the impact
point, achieve excellent space and time resolutions even with very large
pixels. In this paper, a TCT system using a 1064 nm picosecond laser is used to
characterize sensors from the second RSD production at the Fondazione Bruno
Kessler. The paper first introduces the parametrization of the errors in the
determination of the position and time coordinates in RSD, then outlines the
reconstruction method, and finally presents the results. Three different pixel
sizes are used in the analysis: 200 x 340, 450 x 450, and 1300 x 1300
microns^2. At gain = 30, the 450 x 450 microns^2 pixel achieves a time jitter
of 20 ps and a spatial resolution of 15 microns concurrently, while the 1300 x
1300 microns^2 pixel achieves 30 ps and 30 micron, respectively. The
implementation of cross-shaped electrodes improves considerably the response
uniformity over the pixel surface.Comment: 28 pages, 23 figures submitted to NIM
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