Specifications, quality control, manufacturing, and testing of accelerator magnets

The performance of the magnets plays an important role in the functioning of an accelerator. Most of the magnets are designed at the accelerator laboratory and built by industry. The link between the laboratory and the manufacturer is the contract containing the Technical Specifications of the magnets. For an overview of the contents of the Technical Specifications, the specifications for the magnets of ALBA (bending, quadrupole, and sextupole) are described in this paper. The basic rules of magnet design are reviewed in Appendix A.Comment: 41 pages, presented at the CERN Accelerator School CAS 2009: Specialised Course on Magnets, Bruges, 16-25 June 200

Implementation of Peer Support and Shared Decision-Making Aids for the Transcatheter Aortic Valve Replacement Population

Background: Patients at a community hospital verbalized fear, stress and anxiety about transcatheter aortic valve replacement (TAVR). Patients with aortic stenosis eligible for TAVR may experience low self-efficacy and anxiety while considering valve replacement which may lead to poor quality of life, interfere with understanding information from medical providers, and other health complications. Methods: All patients eligible for TAVR between June and August of 2019 were invited to participate in a pilot project using peer support and use of shared decision-making (SDM) aids. Former TAVR patients were trained to be Mended Hearts TAVR peer volunteers. Participants were connected by telephone with a peer by the valve coordinator and SDM aids from the American College of Cardiology were initiated and reviewed during appointments. Patients’ anxiety and self-efficacy were measured before and after peer support using the General Anxiety Disorder-7 and the Cardiac Self-Efficacy scales. Patients evaluated the helpfulness of the SDM aids using the Preparation for Decision-Making scale and open-ended questions were used to gather additional information beyond questionnaire scale questions. Results: Eleven TAVR patients evaluated anxiety and CSE and twelve patients evaluated the SDM aids. Post-GAD-7 scores showed four patients had a decrease in anxiety, five had no change, and two had an increased anxiety score. Post CSE scores showed increases in confidence for 58% of patients in one or more areas of self-efficacy and all patients rated the SDM aids as ‘somewhat to a great deal helpful’. All patients responded positively during interviews, stating that even if they felt confident before the interventions, they felt even greater confidence afterward. Conclusion: The interventions empowered patients to discuss their health and procedural concerns and personal values with their medical team. Patients feel more confident with their decisions regarding TAVR after receiving peer support and the shared decision-making aids

SESAME, a third generation synchrotron light source for the Middle East region

Developed under the auspices of UNESCO, SESAME is being established as an autonomous international research centre in the Middle East/Mediterranean region. It will have as its centrepiece a 2.5 GeV third Generation synchrotron light source with 13 straight sections for insertion devices and an emittance of 26.6 nm-rad. It will provide intense radiation from the IR to hard X-rays to a community that is expected to exceed 1000 users a few years after the start of operation in 2008

The incompatibility of Nudge and Co-Design as tools for policymaking

The use of nudge theory to inform policy interventions in response to COVID-19 has re-opened debates over the politically paternalistic nature of governing by ‘nudges’ and has given momentum to calls to include the more participatory elements of co-design into policymaking. Emma Blomkamp and Colette Einfeld suggest in seeking to combine mutually exclusive elements of each practice, academics and policymakers risk blurring lines of authority and public trust in policymaking

First multi-bend achromat lattice consideration.

By the beginning of 1990, three third-generation synchrotron light sources had been successfully commissioned in Grenoble, Berkeley and Trieste (ESRF, ALS and ELETTRA). Each of these new machines reached their target specifications without any significant problems. In parallel, already at that time discussions were underway regarding the next generation, the `diffraction-limited light source (DLSR)', which featured sub-nm rad electron beam emittance, photon beam brilliance exceeding 10(22) and the potential to emit coherent radiation. Also, at about that time, a first design for a 3 GeV DLSR was developed, based on a modified multiple-bend achromat (MBA) design leading to a lattice with normalized emittance of ℇx = 0.5 nm rad. The novel feature of the MBA lattice was the use of seven vertically focusing bend magnets with different bending angles throughout the achromat cell to keep the radiation integrals and resulting beam emittance low. The baseline design called for a 400 m ring circumference with 12 straight sections of 6 m length. The dynamic aperture behaviour of the DLSR lattice was estimated to produce > 5 h beam lifetime at 100 mA stored beam current

Transient analysis of RF cavities under beam loading

The conventional electrical model analogy of a RF cavity is a shunt RLC circuit supplied by two current sources representing the RF amplifier and the beam. In the literature, the impedance of the cavity is often calculated in the Fourier domain. This type of cavity modelling has two drawbacks: First, it assumes a perfect matching between the cavity and the amplifier therefore it neglects the reflected voltage. And, second, it does not provide any information about the cavity transient response, for example at start-up or upon beam arrival, while this information can be very important for the design of the regulation loops. In this work we will remove these drawbacks by calculating the cavity impedance in Laplace domain taking the reflected voltage into account. We will then modify our model so that it also includes the influence of the beam on the cavity. For transient RF simulations, though, a typical problem is the long simulation time due to the relatively slow transient response compared to the RF period. To overcome this problem, finally, we will use a mathematical method to map the cavity frequency response from RF to baseband to reduce the simulation time significantly.Peer ReviewedPostprint (author’s final draft

ASD intervention research in real world contexts: Refining single case designs

Abstract: There is a pressing need for intervention research that reflects real world practice to support evidence based decision making for families, professionals and administrators who support children with ASD. Some of the challenges confronting intervention research are explored, with solutions offered based on single case design methodology. Challenges with single case designs are also outlined and contemporary solutions that are applicable in real world contexts are illustrated in a study by the authors. Research utilizing these strategies may assist with facilitating practitioners to engage in practice-based research to bridge the research to practice gap in intervention with young children with ASD

Glass bead size and morphology characteristics in support of Crystal Mist field experiments

One of the tasks of the Lethality Group within US Army Space and Strategic Defense Command (USASSDC) is the development of a capability to simulate various missile intercept scenarios using computer codes. Currently under development within USASSDC and its various contractor organizations is a group of codes collected under a master code called PEGEM for Post Event Ground Effects Model. Among the various components of the code are modules which are used to predict atmospheric dispersion and transport of particles or droplets following release at the altitude specified in the missile intercept scenario. The atmospheric transport code takes into account various source term data from the intercept such as: initial cloud size; droplet or particle size distribution; and, total mass of agent released. An ongoing USASSDC experimental program termed Crystal Mist involved release of precision glass beads under various altitude and meteorological conditions to assist in validation and refinement of various codes that are components of PEGEM used to predict particle atmospheric transport and diffusion following a missile intercept. Here, soda-lime glass beads used in the Crystal Mist series of atmospheric transport and diffusion tests were characterized by scanning electron microscopy and automated image processing routines in order to fully define their size distributions and morphology. Four bead size classifications ranging from a median count diameter of 45 to 200 micrometers were found to be approximately spherical and to fall within the supplier`s sizing specifications. Log-normal functions fit to the measured size distributions resulted in geometric standard deviations ranging from 1.08 to 1.12, thereby fulfilling the field trial requirements for a relatively narrow bead size distribution