383 research outputs found
Effects of rf breakdown on the beam in the Compact Linear Collider prototype accelerator structure
Understanding the effects of RF breakdown in high-gradient accelerator
structures on the accelerated beam is an extremely relevant aspect in the
development of the Compact Linear Collider (CLIC) and is one of the main issues
addressed at the Two-beam Test Stand at the CLIC Test Facility 3 at CERN.
During a RF breakdown large electro-magnetic fields are generated and produce
parasitic magnetic fields which interact with the accelerated beam affecting
its orbit and energy. We discuss here measurements of such effects observed on
an electron beam accelerated in a CLIC prototype structure. Measurements of the
trajectory of bunch-trains on a nanosecond time-scale showed fast changes in
correspondence of breakdown which we compare with measurements of the relative
beam spots on a scintillating screen. We identify different breakdown scenarios
for which we offer an explanation based also on measurements of the power at
the input and output ports of the accelerator structure. Finally we present the
distribution of the magnitude of the observed changes in the beam orbit and we
discuss its correlation with RF power and breakdown location in the accelerator
structure.Comment: 10 pages, 8 figures. We replace the previous version of the article
with this one, in which we extend our discussion on the experimental set-up
and on the interpretation of our measurements, on the basis of the inputs
received during the review process for publication on Phys. Rev. Special
Topics - Accelerators and Beams. The essence of our conclusions remain
unchange
Achieving Zero Carbon in Sustainable Communities
Contemporary urban lifestyle emphasises green living and encourages people to estimate their environmental impact and to reduce their carbon footprint. It is important that carbon footprint of users and their demand is quantifiable and measured to create scenarios for design of buildings in various neighbourhoods forming clusters. This chapter presents an alternative approach for developing sustainable communities using activity-based design principles to quantify the energy demand per activity performed on a daily basis by members of various communities rather than making assumptions on space requirements using the traditional functional-based design approach. It starts with an overview of the key concepts and a set of principles for the development of sustainable communities based on achieving an equilibrium between local renewable resources (e.g. wind, water, solar) and users demand for alternative energy. Making smart use of renewable energy sources (e.g. solar, wind, water and utility grid) is becoming increasingly critical as the cost of electricity from conventional sources continues to rise sharply over the next years due to increase in global demand for energy and economic growth. The chapter discusses how energy demand consumption analysis per person based on different activities is used in evaluating overall energy need, space and land requirements in the community
Leptonic decays of the eta meson with the WASA detector at CELSIUS
Decay channels of the eta meson with at least one lepton pair in the final
state are discussed. Preliminary results on electron-positron pair production
from the pd->He eta reaction from the WASA experiment at CELSIUS are presented.Comment: 8 pages, 7 figures, prepared for Symposium on Meson Physics at
COSY-11 and WASA-at-COSY, Cracow, 17-22 June 200
The Use of Muscle Relaxants After Chemotherapy and Radiotherapy
Paweł Radkowski,1– 3 Michał Jacewicz,2 Iwona Podlińska,2 Maria Derkaczew2 1Department of Anaesthesiology and Intensive Care, Regional Specialist Hospital in Olsztyn, Olsztyn, Poland; 2Department of Anaesthesiology and Intensive Care, Faculty of Medicine, Collegium Medicum University of Warmia and Mazury in Olsztyn, Olsztyn, Poland; 3Department of Anaesthesiology and Intensive Care, Hospital zum Heiligen Geist in Fritzlar, Fritzlar, GermanyCorrespondence: Maria Derkaczew, Department of Anaesthesiology and Intensive Care, Faculty of Medicine, Collegium Medicum University of Warmia and Mazury in Olsztyn, Olsztyn, Poland, Email [email protected]: Patients after chemotherapy and radiotherapy while being operated can suffer from different systemic problems, which may complicate the anesthetic management. Some interactions between muscle relaxants and chemotherapeutics can occur.Aim: This article aims to present the use of muscle relaxants in cancer patients who have undergone chemotherapy and radiotherapy.Material and Methods: Our work is based on the available literature and the authors’ experience.Conclusion: Based on our observations and a thorough examination of the medical literature, it is advisable to exercise significant caution when employing muscle relaxants in individuals undergoing chemotherapy and radiotherapy. All muscle relaxants can behave differently after chemotherapy and radiotherapy, and for this reason, practitioners should familiarize themselves with the pharmacodynamics and pharmacokinetics of their chosen muscle relaxant.Keywords: muscle relaxant, chemotherapy, radiotherap
Status of the Cylindical-GEM project for the KLOE-2 Inner Tracker
The status of the R&D on the Cylindrical-GEM (CGEM) detector foreseen as
Inner Tracker for KLOE-2, the upgrade of the KLOE experiment at the DAFNE
phi-factory, will be presented. The R&D includes several activities: i) the
construction and complete characterization of the full-size CGEM prototype,
equipped with 650 microns pitch 1-D longitudinal strips; ii) the study of the
2-D readout with XV patterned strips and operation in magnetic field (up to
1.5T), performed with small planar prototypes in a dedicated test at the H4-SPS
beam facility; iii) the characterization of the single-mask GEM technology for
the realization of large-area GEM foils.Comment: 4 pages, 10 figures, Presented at Vienna Conference on
Instrumentation (Feb 15-20, 2010, Vienna, Austria). Submitted to the
Proceeding
RF-BREAKDOWN KICKS AT THE CTF3 TWO-BEAM TEST STAND
Abstract The measurement of the effects of RF-breakdown on the beam in CLIC prototype accelerator structures is one of the key aspects of the CLIC two-beam acceleration scheme being addressed at the Two-beam Test Stand (TBTS) at CTF3. RF-breakdown can randomly cause energy loss and transverse kicks to the beam. Transverse kicks have been measured by means of a screen intercepting the beam after the accelerator structure. In correspondence of a RFbreakdown we detect a double beam spot which we interpret as a sudden change of the beam trajectory within a single beam pulse. To time-resolve such effect, the TBTS has been equipped with five inductive Beam Position Monitors (BPMs) and a spectrometer line to measure both relative changes of the beam trajectory and energy losses. Here we discuss the methodology used and we present the latest results of such measurements
Anisotropy in the pion angular distribution of the reaction pp -> pp pi0 at 400 MeV
The reaction pp -> pp pi0 was studied with the WASA detector at the CELSIUS
storage ring. The center of mass angular distribution of the pi0 was obtained
by detection of the gamma decay products together with the two outgoing
protons, and found to be anisotropic with a negative second derivative slope,
in agreement with the theoretical predictions from a microscopic calculation.Comment: Revtex 4 style, 5 pages 7 figures, PACS numbers:13.60.Le, 13.75.Cs,
21.45.+v, 25.10.+
Exclusive Measurements of pp -> dpi+pi0: Double-Pionic Fusion without ABC Effect
Exclusive measurements of the reaction pp -> dpi+pi0 have been carried out at
T_p = 1.1 GeV at the CELSIUS storage ring using the WASA detector. The
isovector pi+pi0 channel exhibits no enhancement at low invariant pipi masses,
i. e. no ABC effect. The differential distributions are in agreement with the
conventional t-channel Delta-Delta excitation process, which also accounts for
the observed energy dependence of the total cross section. This is an update of
a previously published version -- see important note at the end of the article
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