Business models to assure availability of advanced superconductors for the accelerator sector and promote stewardship of superconducting magnet technology for the US economy

Stakeholders representing concerns of national and global leadership, industries that use superconducting magnets in products, manufacturers of superconducting wires and tapes that supply to industries, and innovation generators from small businesses and universities came together to address stewardship of superconducting magnet technology and assurance of supply of advanced superconductors to the accelerator sector. This report outlines potential public-private partnerships that develop and enhance domestic capabilities to meet the needs of science facilities in the accelerator systems sector and in the broader commercial ecosystem.Comment: 28 pages not including appendices, 6 figures. arXiv admin note: substantial text overlap with arXiv:2208.1237

Energy deposition studies for the High-Luminosity Large Hadron Collider inner triplet magnets

A detailed model of the High Luminosity LHC inner triplet region with new large-aperture Nb3Sn magnets, field maps, corrector packages, and segmented tungsten inner absorbers was built and implemented into the FLUKA and MARS15 codes. In the optimized configuration, the peak power density averaged over the magnet inner cable width is safely below the quench limit. For the integrated luminosity of 3000 fb-1, the peak dose in the innermost magnet insulator ranges from 20 to 35 MGy. Dynamic heat loads to the triplet magnet cold mass are calculated to evaluate the cryogenic capability. In general, FLUKA and MARS results are in a very good agreement.Comment: 24 p

Progress in high field accelerator magnet development by the US LHC Accelerator Research Program

The maximum magnetic field available to guide and focus the proton beams will be the most important factor driving the design of the High Energy LHC. The US LHC Accelerator Research Program (LARP) is a collaboration of US National Laboratories aiming at demonstrating the feasibility of Nb3Sn magnet technology for application to future colliders. While LARP is primarily focused on the requirements of the High-Luminosity LHC (HL-LHC), it is also directly relevant to the High-Energy LHC (HE-LHC). Program results and future directions will be discussed.Comment: 7 pages, contribution to the EuCARD-AccNet-EuroLumi Workshop: The High-Energy Large Hadron Collider, Malta, 14 -- 16 Oct 2010; CERN Yellow Report CERN-2011-003, pp. 30-3

Dipole magnets above 20 tesla: Research needs for a path via high-temperature superconducting rebco conductors

To enable the physics research that continues to deepen our understanding of the Universe, future circular colliders will require a critical and unique instrument—magnets that can generate a dipole field of 20 T and above. However, today’s maturing magnet technology for low-temperature superconductors (Nb-Ti and Nb3 Sn) can lead to a maximum dipole field of around 16 T. High-temperature superconductors such as REBCO can, in principle, generate higher dipole fields but significant challenges exist for both conductor and magnet technology. To address these challenges, several critical research needs, including direct needs on instrumentation and measurements, are identified to push for the maximum dipole fields a REBCO accelerator magnet can generate. We discuss the research needs by reviewing the current results and outlining the perspectives for future technology development, followed by a brief update on the status of the technology development at Lawrence Berkeley National Laboratory. We present a roadmap for the next decade to develop 20 T-class REBCO accelerator magnets as an enabling instrument for future energy-frontier accelerator complex

Damage mechanisms in superconductors due to the impact of high energy proton beams and radiation tolerance of cryogenic diodes used in particle accelerator magnet systems

High energy hadron accelerators such as the Large Hadron Collider (LHC) at CERN and its planned upgrade to achieve higher luminosity, the High Luminosity Large Hadron Collider (HL-LHC), require superconducting magnets to provide strong magnetic fields, needed to steer and focus the particle beams at these high energies. During operation the superconducting magnets and their components are exposed to radiation resulting from primary and secondary particles from two main sources of beam losses. During normal operation, steady state losses resulting from interaction of the particle beams with residual gas molecules or from particle debris in interaction points affect the accelerator magnets and their components along the machine. In case of failures, significant parts of the beam can be lost in a short time, resulting in localized damage due to heating from energy deposition, which in turn causes thermo-mechanical stresses and strains. In the HL-LHC, novel focusing superconducting quadrupole magnets will be installed, based on Nb$_3$Sn and located close to the interaction points. Furthermore, the beam intensity will be doubled. Both, steady state losses and the severity of losses due to fast failures scale with the beam intensity. In this thesis, effects of beam losses on accelerator magnet components were studied. Firstly, the effects of high intensity and high energy proton beam impact on the low temperature superconductors (LTS) Nb-Ti, Nb$_3$Sn and tapes based on the high temperature superconductor (HTS) YBCO were studied. An experiment was performed where beam was directed on superconductors in a cryogenic environment in CERN’s HiRadMat facility. The performance of the superconductors was afterwards analyzed for their critical transport current, critical field and temperature, as well as inspected with optical and electron microscopic methods. The experimental setup, the observed damage mechanisms and the subsequent analysis are discussed. Secondly, the powering layout of the magnet circuits foresees the use of cryogenic power diodes, connected in parallel to each magnet, serving as passive protection in case of a quench. The diodes are located in close proximity to the beam axis and are affected by the enhanced radiation levels close to the interaction points. To identify a diode type that can be safely operated during the lifetime of HL-LHC, the radiation hardness of existing LHC-type diodes and prototype diodes, that are expected to be more radiation tolerant were tested. An experiment was set up, which allowed the irradiation and in situ measurements of three different types of diodes at cryogenic temperatures. All prototypes were analyzed for forward and reverse bias voltage characteristics and the temperature dependence while warming up. Their thermal annealing potential could also be evaluated. The experimental setup, the in situ measurements and the subsequent analysis are discussed

The future prospects of muon colliders and neutrino factories

The potential of muon beams for high energy physics applications is described along with the challenges of producing high quality muon beams. Two proposed approaches for delivering high intensity muon beams, a proton driver source and a positron driver source, are described and compared. The proton driver concepts are based on the studies from the Muon Accelerator Program (MAP). The MAP effort focused on a path to deliver muon-based facilities, ranging from neutrino factories to muon colliders, that could span research needs at both the intensity and energy frontiers. The Low EMittance Muon Accelerator (LEMMA) concept, which uses a positron-driven source, provides an attractive path to very high energy lepton colliders with improved particle backgrounds. The recent study of a 14 TeV muon collider in the LHC tunnel, which could leverage the existing CERN injectors and infrastructure and provide physics reach comparable to the 100 TeV FCC-hh, at lower cost and with cleaner physics conditions, is also discussed. The present status of the design and R&D efforts towards each of these sources is described. A summary of important R&D required to establish a facility path for each concept is also presented.Comment: 29 pages, 17 figure

Conceptual design of a nonscaling fixed field alternating gradient accelerator for protons and carbon ions for charged particle therapy

Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.The conceptual design for a nonscaling fixed field alternating gradient accelerator suitable for charged particle therapy (the use of protons and other light ions to treat some forms of cancer) is described.EPSR