Multipole Field Effects for the Superconducting Parallel-Bar/RF-Dipole Deflecting/Crabbing Cavities

The superconducting parallel-bar deflecting/crabbing cavity is currently being considered as one of the design options in rf separation for the Jefferson Lab 12 GeV upgrade and for the crabbing cavity for the proposed LHC luminosity upgrade. Knowledge of multipole field effects is important for accurate beam dynamics study of rf structures. The multipole components can be accurately determined numerically using the electromagnetic surface field data in the rf structure. This paper discusses the detailed analysis of those components for the fundamental deflecting/crabbing mode and higher order modes in the parallel-bar deflecting/crabbing cavity

Design Evolution and Properties of Superconducting Parallel-Bar rf-Dipole Detecting and Crabbing Cavities

Deflecting/crabbing cavities serve a variety of purposes in different accelerator applications, primarily in separating a single beam into multiple beams and in rotating bunches for head-on collisions at the interaction point in particle colliders. Deflecting/crabbing cavities are also used for transverse and longitudinal emittance exchange in beams, x-ray pulse compression, and for beam diagnostics. Compact superconducting deflecting/crabbing cavities are under development due to strict dimensional constraints and requirements for higher field gradients with low surface losses. The TEM-like superconducting parallel-bar cavity supports low operating frequencies, thus making the design favorable for many of the deflecting/crabbing cavity applications. The design of the parallel-bar cavity based on cylindrical straight loading elements and rectangular outer conductors has evolved and been adapted to improve the design properties by modifying the design geometry. The improved design with trapezoidal-shaped loading elements and cylindrical outer conductor has attractive properties such as low and well-balanced peak surface fields and high transverse shunt impedance. Additionally, the wide separation of modes in the higher-order mode spectrum and the absence of lower-order mode are advantageous in high current applications. The evolution of the parallel-bar geometry into an rf-dipole geometry is presented with a detailed analysis of the properties for each design

Fabrication, Processing, and RF Test of RF-Dipole Prototype Crabbing Cavity for LHC High Luminosity Upgrade

The superconducting rf-dipole crabbing cavity is one of two crabbing cavity designs proposed for the LHC high luminosity upgrade. The proof-of-principle rf-dipole cavity operating at 400 MHz has demonstrated excellent performance exceeding the design specifications. The prototype cavity for SPS beam test has been designed to include the fundamental power coupler, HOM couplers, and all the ancillary components intended to meet the design requirements. A crabbing cavity system is expected to be installed in the SPS beam line and tested prior to the installation in LHC; this will be the first crabbing cavity operation on a proton beam. The fabrication of two prototype rf-dipole cavities is currently being completed at Jefferson Lab. This paper presents the details on cavity processing and cryogenic test results of the rf-dipole cavities

Ocorrência de Banisia myrsusalis (Walker, 1895) atacando sapotizeiro na Região dos Tabuleiros Costeiros do Estado do Piauí.

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Ocorrência de Zamagiria laidion (Lepidoptera: Pyralidae) atacando sapotizeiros na Região dos Tabuleiros Costeiros do Piauí.

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Mechanical Analysis of the 400 MHz RF-Dipole Crabbing Cavity Prototype for LHC High Luminosity Upgrade

The proposed LHC high luminosity upgrade requires two crabbing systems in increasing the peak luminosity, operating both vertically and horizontally at two interaction points of IP1 and IP5. The required system has tight dimensional constraints and needs to achieve higher operational gradients. A proof-of-principle 400 MHz crabbing cavity design has been successfully tested and has proven to be an ideal candidate for the crabbing system. The cylindrical proof-of-principle rf-dipole design has been adapted in to a square shaped design to further meet the dimensional requirements. The new rf-dipole design has been optimized in meeting the requirements in rf-properties, higher order mode damping, and multipole components. A crabbing system in a cryomodule is expected to be tested on the SPS beam line prior to the test at LHC. The new prototype is required to achieve the mechanical and thermal specifications of the SPS test followed by the test at LHC. This paper discusses the detailed mechanical and thermal analysis in minimizing Lorentz force detuning and sensitivity to liquid He pressure fluctuations

Accessibility and Usage of Digital Technologies among Academics for Research: A Case of Selected Humanities and Social Sciences Faculties in Sri Lankan Universities

The Humanities and Social Sciences (HSS) involve understanding the human experience and the relationships between individuals and groups in society. The adoption of digital technologies has challenged the discipline of HSS, creating an entirely new environment for the study of human activities. This research aims to explore the employment of digital tools, resources and services in HSS research. Further, the use of digital methods (DM) throughout the research process; the impact of COVID-19 on the use of DM in research; the constraints of using DM in research were tested. Both quantitative and qualitative data were collected from Colombo, Kelaniya and Sri Jayewardenepura universities targeting academics in Economics, English, English Language Teaching, Geography, History and Archeology, Buddhist Studies, Political Science, Sinhala, and Sociology. Considering the digital infrastructure facilities, most of the academics rated email (45.6%) and LMS services (46.7%) as excellent but maintenance provided by the institute was not adequate. Most academics rated good on access to data storage (37.9%); reference management software (27.5%); plagiarism detection software (29.1%); institutional repository (35.2%); and support to online publications (39.6%) provided by their institutes. 55.7% of surveyed academics in SS often use digital data collection methods while in the Humanities it was 43.4%. Online publishing was most often used by SS (50.9%) and only 39.5% by the Humanities. 53.8% of SS academics and 43.4% of humanities academics often use cloud storage. Findings confirmed the expansion of using digital research methods during the pandemic compared to the early pandemic situation. Collaborative research works, virtual conferences, citation databases and digital indexing were identified as popular trends. DOI: http://doi.org/10.31357/fhss/vjhss.v08i02.0

Shifted loops and coercivity from field imprinted high energy barriers in ferritin and ferrihydrite nanoparticles

We show that the coercive field in ferritin and ferrihydrite depends on the maximum magnetic field in a hysteresis loop and that coercivity and loop shifts depend both on the maximum and cooling fields. In the case of ferritin we show that the time dependence of the magnetization also depends on the maximum and previous cooling fields. This behavior is associated to changes in the intra-particle energy barriers imprinted by these fields. Accordingly, the dependence of the coercive and loop shift fields with the maximum field in ferritin and ferrihydrite can be described within the frame of a uniform-rotation model considering a dependence of the energy barrier with the maximum and the cooling fields.Comment: 8 pages, 5 figures. Accepted for publication in Phys. Rev. B. Final version with improved writing and figure

Anemia infecciosa equina: epizootiologia, prevencao e controle no Pantanal.

Os equideos sao ferramentas de trabalho essenciais a mais importante atividade economica do Pantanal - a pecuaria de corte, a qual e desenvolvida extensivamente na regiao. A Anemia Infecciosa Equina (AIE), conhecida mundialmente como Febre-do-pantano, e considerada uma das principais doencas que acometem equideos no Pantanal. Durante seis anos, entre 1990 e 1995, a Embrapa Pantanal conduziu pesquisas sobre a AIE na regiao, as quais envolveram 28 fazendas e 3.285 equinos. Estudos epizootiologicos permitiram a obtencao de um perfil de prevalencia da AIE em equinos, em relacao ao sexo, idade e manejo. Tambem, estudos sobre vetores (mutucas) incluiram o levantamento e sazonalidade de especies, definicao das epocas de maior risco de transmissao e aspectos da interacao vetor-hospedeiro. Tais estudos originaram um Programa de Prevencao e Controle da AIE efetivamente adequado a realidade do Pantanal. De forma resumida, esse Programa baseia-se no diagnostico inicial e monitoramento periodico dos animais da propriedade, separacao e manejo adequado de animais positivos e negativos e obtencao de potros negativos a partir de femeas positivas. A validacao dessa tecnologia foi realizada com sucesso em propriedades da regiao; em uma das fazendas acompanhadas, uma prevalencia inicial de 42,7% foi reduzida a zero, em tres anos.bitstream/item/37568/1/CT29.pd