Comparison of 2-D Magnetic Designs of Selected Coil Configurations for the Next European Dipole (NED)

The Next European Dipole (NED) activity is developing a high-performance Nb$_{3}$Sn wire (aiming at a non-copper critical current density of 1500 A/mm2 at 4.2 K and 15 T), within the framework of the Coordinated Accelerator Research in Europe (CARE) project. This activity is expected to lead to the fabrication of a large aperture, high field dipole magnet. In preparation for this phase, a Working Group on Magnet Design and Optimization (MDO) has been established to propose an optimal design. Other parallel Work Packages are concentrating on relevant topics, such as quench propagation simulation, innovative insulation techniques, and heat transfer measurements. In a first stage, the MDO Working Group has selected a number of coil configurations to be studied, together with salient parameters and features to be considered during the evaluation: the field quality, the superconductor efficiency, the conductor peak field, the stored magnetic energy, the Lorentz Forces and the fabrication difficulties. 2-D magnetic calculations have been performed, and the results of this comparison between the different topologies are presented in this paper. The 2-D mechanical computations are ongoing and the final stage will be 3-D magnetic and mechanical studies

European Strategy for Particle Physics -- Accelerator R&D Roadmap

The 2020 update of the European Strategy for Particle Physics emphasised the importance of an intensified and well-coordinated programme of accelerator R&D, supporting the design and delivery of future particle accelerators in a timely, affordable and sustainable way. This report sets out a roadmap for European accelerator R&D for the next five to ten years, covering five topical areas identified in the Strategy update. The R&D objectives include: improvement of the performance and cost-performance of magnet and radio-frequency acceleration systems; investigations of the potential of laser / plasma acceleration and energy-recovery linac techniques; and development of new concepts for muon beams and muon colliders. The goal of the roadmap is to document the collective view of the field on the next steps for the R&D programme, and to provide the evidence base to support subsequent decisions on prioritisation, resourcing and implementation.Comment: 270 pages, 58 figures. Editor: N. Mounet. LDG chair: D. Newbold. Panel chairs: P. V\'edrine (HFM), S. Bousson (RF), R. Assmann (plasma), D. Schulte (muon), M. Klein (ERL). Panel editors: B. Baudouy (HFM), L. Bottura (HFM), S. Bousson (RF), G. Burt (RF), R. Assmann (plasma), E. Gschwendtner (plasma), R. Ischebeck (plasma), C. Rogers (muon), D. Schulte (muon), M. Klein (ERL

Joint 3D inversion of nearshore and land MT and CSEM data in coastal areas of volcanic islands: application to the Bouillante geothermal field

International audienceA large-scale magnetotelluric (MT) and controlled-source electromagnetic (CSEM) acquisition campaign was conducted around the exploited Bouillante geothermal field in Guadeloupe in the Lesser Antilles, supplemented by a regional airborne transient electromagnetic survey (AEM). The target is the characterization of the geothermal reservoir and the associated clay cap, generally identified by its highly conductive electrical signature, typical of a conventional volcanic geothermal system in an andesite-type geological environment. MT allows targeting the deepest parts of the subsurface, but the natural signal on which it relies is on average weak at low latitudes and can be much weaker than anthropogenic noise, making its use with dense acquisition challenging close to inhabited areas. CSEM allows completing and densifying the data coverage in the most urbanized areas thanks to the use of high power active current sources and less demanding measurement systems. Moreover, MT and CSEM 3D modeling, as well as inversion, in the coastal areas of volcanic islands can be challenging due to numerical errors induced by the presence of the sea/land interface and large variations in nearshore bathymetry and topography. These errors must be estimated and corrected to best invert the field data. Here we present the workflow and results of the 3D CSEM and MT modeling and inversion independently. The resistivity model obtained with CSEM is consistent with the known geology and the 3D MT model, but provides improved resolution as well as new information on the extension of the reservoir nearshore. We also discuss the complementarity between MT and CSEM in this context, and how to perform their joint inversion in order to benefit from the high resolution and sensitivity of CSEM on the first 2 km and the ability of MT to provide deeper information

The mid-Capitanian (Middle Permian) mass extinction and carbon isotope record of South China

Conodont, C isotope and fossil and facies data are presented for the Capitanian (Middle Permian)mass extinction record seen in platform carbonates (Maokou and Wuchiaping formations) of South China, where limestones interdigitate with the volcanic succession of the Emeishan large igneous province. The Maokou Formation provides an extinction recordmarked by the loss of keriothecal-walled fusulinaceans and a turnover incalcareous algae. In sections within the Emeishanprovince this crisis occurs at the base of the oldest record of volcanismfrom the Jinogondolella altudaensis conodont zone (of mid-Capitanian age). Around the periphery of the Emeishan province this extinction level lies within the upper part of the Maokou Formation at a level where platform carbonate deposition was frequently interrupted by thick volcanic ash depositional events. The assemblages of the uppermost Maokou Formation are characterised by typical “Late Permian” taxa although these levels still lie within theMiddle Permian (Guadalupian Series). “Disaster” taxa, such as Earlandia and Diplosphaerina are locally prolifically abundant in the aftermath of the mass extinction. The crisis is particularly noteworthy amongst photosynthetic taxa such as calcareous algae and fusulinaceans that probably harboured photosymbionts. Therefore, a kill mechanism involving cooling from explosive volcanism and potentially acid rain from sulphate aerosols appears appropriate. A composite δ13Ccarb curve, calibrated against a high-resolution conodont biostratigraphy reveals a major intra-Capitanian negative excursion (of >5‰) superimposed on typically heavy (4–5‰)Middle Permian values. This curve can also be recognised in Panthalassan seamount carbonates of Japan although this requires reassignment of apparently Upper Permian limestones to the Middle Permian. In both China and Japan the Capitanian mass extinction occurs during the early stage of this major, intra-Capitanian negative excursion. Assuming typical platform carbonate accumulation rates, the records of the Maokou Formation suggest δ13Ccarb values fell at ~0.01‰/kyr suggesting a catastrophic origin (such as gas hydrate destabilisation) is unlikely, although a volcanic source is possible

Inhibition of neural precursor cell proliferation by the oligodendrocyte myelin glycoprotein (OMgp)

National audienc