471 research outputs found
Beam Dynamics Studies for the CLIC Main Linac
The implications of long-range wakefields on the beam quality are
investigated through a detailed beam dynamics study. Injection offsets are
considered and the resulting emittance dilution recorded, including systematic
sources of error. These simulations have been conducted for damped and detuned
structures (DDS) and for waveguide damped structures-both for the CLIC
collider.Comment: 3 pages, 6 figures, IPAC1
The synthesis of optimal controls for linear problems with retarded controls
Synthesis of optimal controls for linear systems with retarded control
Alignment of the CLIC BDS
Aligning the CLIC Beam Delivery System faces two major challenges, the tight tolerances for the emittance preservation and its strong non-linear beam dynamics. For these reasons conventional beam-based alignment techniques, like dispersion free steering, are only partially successful and need to be followed by optimization algorithms based on other observables, like beam sizes
Evaluation of Psychometric and Linguistic Properties of the Italian Adolescent Pain Assessment Scales: A Systematic Review
Introduction: Adolescents’ pain experiences
are complex and multidimensional, and evaluating
pain only from a sensory and affective
point of view may be in many instances limiting
and inadequate; this is the reason why it is
of paramount importance to identify the tools
which can better assess the pain experienced by
young patients. A person-oriented approach is
highly encouraged, as it may better investigate
the cognitive and behavioral development typical
of this age group. The aim of this review
paper is to describe the available tools which are
able to adequately assess pain intensity in adolescents,
in particular those validated in Italian.
Methods: We conducted a systematic review
using four databases: CINAHL, PsycINFO,
PubMed and Cochrane, and selected all the
articles published between January 1970 and
November 2017. We selected all the papers
reporting the validation process of pain assessment
tools specifically tailored for adolescent
patients (age range 10–18 years) and based on
psychometric and linguistic parameters, and
focused especially on the tools available in
Italian and able to measure acute and chronic
pain.
Results: The results of our investigation have
revealed the existence of 40 eligible tools, 17 of
which are monodimensional and the remaining
23 multidimensional, more specifically tailored
to assess both acute and chronic pain. Some of
the instruments (26) were self-reports while
others were classified as behavioral (13) and/or
mixed. Only one tool turned out to be suitable
for fragile adolescents, while six adopted a
person-oriented approach that better emphasized
the cognitive and behavioral process typical
of the adolescent population. None of them
has ever been validated in Italian.
Conclusion: Valid and reliable psychometric
tools specifically organized to provide a cultural
and linguistic evaluation of the patient are
indeed the most recommended instruments to
assess the intensity of the pain experienced by
the patient, as they may provide useful information to implement a health policy
aimed at identifying the best assistance
programs
Feedback Studies
Dynamic imperfections in future linear colliders can lead to a significant luminosity loss. We discuss different orbit feedback strategies in the main linac that can mitigate the emittance dilution and compare their efficiency. We also address the impact of ground motion in the beam delivery system and the potential cures
A primary electron beam facility at CERN
This paper describes the concept of a primary electron beam facility at CERN,
to be used for dark gauge force and light dark matter searches. The electron
beam is produced in three stages: A Linac accelerates electrons from a
photo-cathode up to 3.5 GeV. This beam is injected into the Super Proton
Synchrotron, SPS, and accelerated up to a maximum energy of 16 GeV. Finally,
the accelerated beam is slowly extracted to an experiment, possibly followed by
a fast dump of the remaining electrons to another beamline. The beam parameters
are optimized using the requirements of the Light Dark Matter eXperiment (LDMX)
as benchmark.Comment: 3 pages, 3 figure
Beam Dynamics Issues in the CLIC Long Transfer Line
Both the main and the drive beam of the CLIC project must be transported from the central production site to the head of the main linacs over more than twenty kilometers. Over such distances chromatic error may be substantial. With long distances and large beam currents, ion-induced detuning and instabilities and multi-bunch resistive wall effects must also be considered. These effects are quantified and simulated. Based on these results, a baseline design has been established
Recent Improvements in the Tracking Code Placet
The tracking code Placet has recently undergone several improvements. A redesign of its internal data structures and a new user interface based on the mathematical toolbox Octave considerably expanded its simulation capabilities. Several new lattice elements, optimization algorithms and physics processes were added to allow for more complete start-to-end simulations. Finally, the use of the AML language and the Universal Parser Library have extended its interfacing capability. A review of these new features is presented in this paper
EUPRAXIA@SPARC_LAB: Beam Dynamics studies for the X-band Linac
In the framework of the Eupraxia Design Study an advanced accelerator
facility EUPRAXIA@SPARC_LAB has been proposed to be realized at Frascati
(Italy) Laboratories of INFN. Two advanced acceleration schemes will be
applied, namely an ultimate high gradient 1 GeV X-band linac together with a
plasma acceleration stage to provide accelerating gradients of the GeV/m order.
A FEL scheme is foreseen to produce X-ray beams within 3-10 nm range. A 500-TW
Laser system is also foreseen for electron and ion production experiments and a
Compton backscattering Interaction is planned together with extraction
beamlines at intermediate electron beam energy for neutron beams and THz
radiation production. The electron beam dynamics studies in the linac are here
presented together with the preliminary machine layout.Comment: 5 pages, 3 figures, NIM-A proceedings of EAAC201
TRADITIONAL FINAL FOCUS SYSTEM FOR CLIC
Abstract A traditional Final Focus System based on dedicated chromaticity correction sections is presented as an alternative for CLIC Final Focus. The Scheme of the lattice is shown and tha luminosity bandwidth is calculated. A systematic tuning using Beam Based Alignment and sectupole knobs is perdormed. The complete comparison to the Local Chromaticity correction scheme is presented
- …