203 research outputs found
Design and development of the Control Board for the LHCb Silicon Tracker
This note is intended to give a detailed definition of the Silicon Tracker Control Board (CB) design and use. This electronic card is composed of several elements and it is the hardware part of the Silicon Tracker (ST) that will fulfil both the ST ECS (Experiment Control System) and TFC (Timing and Fast Control) tasks next to the detector. A description of the CB functionalities will be shown as well as a detailed description of its design and development
Novel reaction force for ultra-relativistic dynamics of a classical point charge
The problem of the electromagnetic radiation of an accelerated charged
particle is one of the most controversial issues in Physics since the beginning
of the last century, representing one of the most popular unsolved problems of
the Modern Physics. Different equations of motion have been proposed throughout
history for a point charge including the electromagnetic radiation emitted, but
all these expressions show some limitations. An equation based on the principle
of conservation of energy is proposed in this work for the ultra-relativistic
motion. Different examples are analyzed showing that the energy lost by the
charge agrees with the Li\'enard formula. This proposed equation has been
compared with the Landau-Lifshitz equation obtaining a good agreement in the
range of application of the Landau-Lifshitz formula.Comment: 9 pages, 10 figure
Relativistic particle motion of a charge including the radiation reaction
The problem of the electromagnetic radiation of an accelerated charged particle is one of the
most controversial issues in Physics since the beginning of the last century representing one of
the most popular unsolved problems of the Modern Physics. Different equations of motion for
a point charge including the electromagnetic radiation emitted have been proposed throughout
history, but all these expressions show some limitations. An equation based on the principle of
conservation of energy is proposed for the ultra-relativistic motion. Different examples are
analyzed showing that the energy lost by the charge agrees with the relativistic generalization
of the Larmor formula. This proposed equation has been compared with the Landau-Lifshitz
equation obtaining a good agreement in the range of application of the Landau-Lifshitz formula.
Finally, it is discussed a possible variation of the typical relativistic particle integrators (e.g. Boris,
Vay or Higuera-Cary methods) in order to include the radiation reaction
Numerical study of dark current dynamics in a high-gradient backward travelling wave accelerating cavity using the electromagnetic simulation software CST studio.
High-Gradient accelerating cavities are one of the main research lines in the development of
compact linear colliders. However, the operation of such cavities is currently limited by nonlinear
effects that are intensified at high electric fields, such as dark currents and radiation
emission or RF breakdowns.
A new normal-conducting High-Gradient S-band Backward Travelling Wave accelerating
cavity for medical application (v=0.38c) designed and constructed at Conseil Européen pour la
Recherche NuclĂ©aire (CERN) is being tested at Instituto de FĂsica Corpuscular (IFIC) High Power
RF Laboratory. The objective consists of studying its viability in the development of compact
linear accelerators for hadrontherapy treatments in hospitals.
Due to the high surface electric field in the cavity, electrons are emitted following Fowler-
Nordheim equation, also known as dark currents. The emission and dynamic of these
electrons are of fundamental importance on different phenomena such as RF Breakdowns or
radiation dose emission.
In this work, 3D electromagnetic numerical simulations have been performed using the
computer simulation technology software CST Studio Suite. Then, the resulting EM field maps
are used to study the emission and electron dynamics inside the cavity. The simulation results
are compared with experimental data and first conclusions discussed
Tolcapone, a potent aggregation inhibitor for the treatment of familial leptomeningeal amyloidosis
Hereditary transthyretin amyloidosis (ATTR) is a disease characterized by the extracellular deposition of transthyretin (TTR) amyloid fibrils. Highly destabilizing TTR mutations cause leptomeningeal amyloidosis, a rare, but fatal, disorder in which TTR aggregates in the brain. The disease remains intractable, since liver transplantation, the reference therapy for systemic ATTR, does not stop mutant TTR production in the brain. In addition, despite current pharmacological strategies have shown to be effective against in vivo TTR aggregation by stabilizing the tetramer native structure and precluding its dissociation, they display low brain permeability. Recently, we have repurposed tolcapone as a molecule to treat systemic ATTR. Crystal structures and biophysical analysis converge to demonstrate that tolcapone binds with high affinity and specificity to three unstable leptomeningeal TTR variants, stabilizing them and, consequently, inhibiting their aggregation. Because tolcapone is an FDA-approved drug that crosses the blood-brain barrier, our results suggest that it can translate into a first disease-modifying therapy for leptomeningeal amyloidosis. Databases PDB codes for A25T-TTR, V30G-TTR, and Y114C-TTR bound to tolcapone are 6TXV, 6TXW, and 6XTK, respectively
Study of the RF pulse heating phenomenon in high gradient accelerating devices by means of analytical approximations
The main objective of this work is to present a
simple method, based on analytical expressions, for obtaining
a quick approximation of the temperature rise due to the Joule
effect inside the metallic walls of an RF accelerating device. This
proposal relies on solving the 1D heat-transfer equation for a
thick wall, where the heat sources inside the wall are the ohmic
losses produced by the RF electromagnetic fields penetrating
the metal with finite electrical conductivity. Furthermore, it is
discussed how the theoretical expressions of this method can be
applied to obtain an approximation to the temperature increase
in realistic 3D RF accelerating structures, taking as an example
the cavity of an RF electron gun. These theoretical results have
been benchmarked with numerical simulations carried out with
commercial finite-element method codes, finding good agreement
among them
Two-dimensional simulation of the electron transport in a photomultiplier tube
Photomultiplier tubes are widely used in experimental physics because they convert small light
signals into a measurable electric current. Although their working principle is well known, it is
very difficult to find simulations of the electron transport in these devices. For this reason, the
electron transport in the Hamamatsu R13408-100 photomultiplier tube has been simulated in
2D. The software SUPERFISH is used for calculating the electrostatic fields and the Boris method
for the effective electron dynamics. The secondary electron emission in the dynodes is
implemented using an effective electron model and the modified Vaughanâs model. Some
figures of merit for photomultiplier tubes (e.g. the gain, the electron transit time or the transit
time spread) in function of the supply voltage and an external magnetic field have been studied
obtaining a good qualitative accordance with the Hamamatsu datasheet. In further studies, we
are going to compare our simulations with experimental measurements
Compactlight design study
H2020 CompactLight Project aims at designing the next generation of compact hard X-Rays Free-Electron Lasers, relying on very high accelerating gradients and on novel undulator concepts. CompactLight intends to design a compact Hard X-ray FEL facility based on very high-gradient acceleration in the X band of frequencies, on a very bright photo injector, and on short-period/superconductive undulators to enable smaller electron beam energy. If compared to existing facilities, the proposed facility will benefit from a lower electron beam energy, due to the enhanced undulators performance, be significantly more compact, as a consequence both of the lower energy and of the high-gradient X-band structures, have lower electrical power demand and a smaller footprint. CompactLight is a consortium of 24 institutes (21 European + 3 extra Europeans), gathering the world-leading experts both in the domains of X-band acceleration and undulator design
Opposite-side flavour tagging of B mesons at the LHCb experiment
The calibration and performance of the oppositeside
flavour tagging algorithms used for the measurements
of time-dependent asymmetries at the LHCb experiment
are described. The algorithms have been developed using
simulated events and optimized and calibrated with
B
+ âJ/ÏK
+, B0 âJ/ÏK
â0 and B0 âD
ââ
Ό
+
ΜΌ decay
modes with 0.37 fbâ1 of data collected in pp collisions
at
â
s = 7 TeV during the 2011 physics run. The oppositeside
tagging power is determined in the B
+ â J/ÏK
+
channel to be (2.10 ± 0.08 ± 0.24) %, where the first uncertainty
is statistical and the second is systematic
- âŠ