Engineering Design and Prototype Fabrication of HOM Couplers for HL-LHC Crab Cavities

The High-Luminosity upgrade for the LHC relies on a set of RF Crab Cavities for reaching its goals. Two parallel concepts, the Double Quarter Wave (DQW) and the RF Dipole (RFD), are going through a comprehensive design process along with preparation of fabrication in view of extensive tests with beam in SPS. High Order Modes (HOM) couplers are critical in providing damping in RF cavities for operation in accelerators. HOM prototyping and fabrication have recently started at CERN. In this paper, an overview of the final shape is provided along with an insight in the mechanical and thermal analyses performed to validate the design of these critical components. Emphasis is also given to test campaigns, material selection, prototyping and initial fabrication that are aimed at fulfilling the highly demanding tolerances of the couplers

Crab Cavity and Cryomodule Development for HL-LHC

The HL-LHC project aims at increasing the LHC luminosity by a factor 10 beyond the design value. The installation of a set of RF Crab Cavities to increase bunch crossing angle is one of the key upgrades of the program. Two concepts, Double Quarter Wave (DQW) and RF Dipole (RFD) have been proposed and are being produced in parallel for test in the SPS beam before the next long shutdown of CERN accelerator’s complex. In the retained concept, two cavities are hosted in one single cryomodule, providing thermal insulation and interfacing with RF coupling, tuning, cryogenics and beam vacuum. This paper overviews the main design choices for the cryomodule and its different components, which have the goal of optimizing the structural, thermal and electro-magnetic behavior of the system, while respecting the existing constraints in terms of integration in the accelerator environment. Prototyping and testing of the most critical components, manufacturing, preparation and installation strategies are also described

Design of Dressed Crab Cavities for the HL-LHC Upgrade

The HL-LHC upgrade relies on a set of RF crab cavities for reaching its goals. Two parallel concepts, the Double Quarter Wave (DQW) and the RF Dipole (RFD), are going through a comprehensive design process along with preparation of fabrication in view of extensive tests with beam in SPS. High Order Modes (HOM) couplers are critical in providing damping in RF cavities for operation in accelerators. HOM prototyping and fabrication have recently started at CERN. In this paper, an overview of the final geometry is provided along with an insight in the mechanical and thermal analyses performed to validate the design of this critical component. Emphasis is also given to material selection, prototyping, initial fabrication and test campaigns that are aimed at fulfilling the highly demanding tolerances of the couplers

Chiaramonti, Scipione

Italian philosopher and astronomer, Scipione Chiaramonti (1565–1652) was one of the last defenders of the Aristotelian orthodoxy in its entireness and in particular in regard of the traditional cosmological view, openly arguing with intellectual personalities of his time such as Tycho Brahe, Johannes Kepler and Galileo Galilei and their new discoveries

Diabetes or hypertension as risk indicators for missing teeth experience: An exploratory study in a sample of Mexican adults

Background: To determine an exploratory estimation of the strength of type 2 diabetes mellitus (T2DM) and hypertension diagnoses as risk indicators for missing teeth in a sample of Mexican adults.Materials and Methods: A comparative cross‑sectional study of sixty adult patients in a health center in Mexico included as dependent variable, the number of missing teeth (and having a functional dentition) and as independent variables, diagnoses for diabetes or hypertension, age, sex, maximum level of schooling, and tobacco use. Of the 60 participants, 20 were diagnosed with T2DM, 13 with hypertension, and 27 were  otherwise diagnosed as healthy in their most recent medical checkup. A negative binomial regression (NBR) model was generated. Results: Mean age was 50.7 ± 16.2 and 50.0% were women. Mean number of missing teeth was 4.98 ± 4.17. In the multivariate NBR model, we observed that individuals with T2DM had higher risk of more missing teeth (incidence rate ratios [IRRs] = 3.13; 95% confidence interval [CI] = 2.09–4.69), followed by those with hypertension (IRRs = 2.63; 95% CI = 1.77–3.90). In addition, participants with current tobacco use were significantly more likely to have suffered tooth loss (P < 0.05) than those who were never smokers or former smokers, just like older  participants (P < 0.05). Conclusions: T2DM and hypertension are independently associated with higher experience of missing teeth in an open adult population in Mexico. Future studies with a more sophisticated epidemiological design and encompassing a more detailed landscape of chronic diseases, type and length of use of long‑term medications, and patterns of dental care use are needed to better delineate these associations.Keywords: Adult, hypertension, Mexico, tooth loss, type 2 diabete