Author
Joseph DiMarco
Other affiliations: Lawrence Berkeley National Laboratory
Bio: Joseph DiMarco is an academic researcher from Fermilab. The author has contributed to research in topics: Superconducting magnet & Magnet. The author has an hindex of 17, co-authored 141 publications receiving 1197 citations. Previous affiliations of Joseph DiMarco include Lawrence Berkeley National Laboratory.
Papers published on a yearly basis
Papers
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TL;DR: Fermilab developed and investigated different high-field magnets (HFM) for present and future accelerators as discussed by the authors, including a series of 1-m long cos-theta dipole models based on the wind-and-react technique was fabricated and tested.
Abstract: Fermilab is developing and investigating different high-field magnets (HFM) for present and future accelerators. The HFM R&D program focused on the 10-12 T magnets based on Nb/sub 3/Sn superconductor and explored both basic magnet technologies for brittle superconductors-wind-and-react and react-and-wind. Magnet design studies in support of LHC upgrades and VLHC were conducted. A series of 1-m long cos-theta dipole models based on the wind-and-react technique was fabricated and tested. Three 1-m long flat racetracks and the common coil dipole model, based on a single-layer coil and react-and-wind technique, were also fabricated and tested. Extensive theoretical and experimental studies of electro-magnetic instabilities in Nb/sub 3/Sn strands, cables and magnets were performed and led to a successful 10 T dipole model. This paper presents the details of Fermilab's HFM program, reports its status and major results, and formulates the next steps for the program.
52 citations
TL;DR: In this article, the alignment of high-gradient superconducting quadrupole magnets is performed using a single stretched wire system with very long wire lengths, up to 20 m.
Abstract: High-gradient superconducting quadrupole magnets are being developed by the US LHC Accelerator Project for the Interaction Regions of the Large Hadron Collider. Determination of the magnetic axis for alignment of these magnets will be performed using a single stretched wire system. These measurements will be done both at room and cryogenic temperatures with very long wire lengths, up to 20 m. This paper reports on the stretched wire alignment methodology to be employed: and the results of recent room-temperature measurements on a 2 m model magnet with long wire lengths.
51 citations
TL;DR: This paper reports on application of printed-circuit board and fused-deposition modeling technologies, and what these offer to the fabrication of magnetic measurement probe systems.
Abstract: Rotating coil probes are essential for measuring harmonic multipole fields of accelerator magnets. A fundamental requirement of these probes is their accuracy, which typically implies that the probes need to be very stiff and straight, have highly accurate knowledge of the placement of windings, and an ability to buck the fundamental fields well in order to suppress the effects of vibrations. Ideally, for an R&D test environment, probe fabrication should also be easy and low-cost, so that probe parameters (type, length, number of turns, radius, etc.) can be customized to the magnet requiring test. Such facility allows measurement optimization for magnets of various multipolarity, aperture size, cable twist pitch, etc. The accuracy and construction flexibility aspects of probe development, however, are often at odds with each other. This paper reports on application of printed-circuit board and fused-deposition modeling technologies, and what these offer to the fabrication of magnetic measurement probe systems.
47 citations
TL;DR: The U.S. LHC Accelerator Research Program (LARP) and CERN combined their efforts in developing Nb3Sn magnets for the high-luminosity LHC upgrade.
Abstract: The U.S. LHC Accelerator Research Program (LARP) and CERN combined their efforts in developing Nb3Sn magnets for the high-luminosity LHC upgrade. The ultimate goal of this collaboration is to fabricate large aperture Nb 3Sn quadrupoles for the LHC interaction regions. These magnets will replace the present 70-mm-aperture NbTi quadrupole triplets for expected increase of the LHC peak luminosity up to 5 × 1034 cm –2s–1 or more. Over the past decade, LARP successfully fabricated and tested short and long models of 90 and 120-mm-aperture Nb3Sn quadrupoles. Recently, the first short model of 150-mm-diameter quadrupole MQXFS was built with coils fabricated both by LARP and CERN. The magnet performance was tested at Fermilab's vertical magnet test facility. This paper reports the test results, including the quench training at 1.9 K, ramp rate and temperature dependence, as well as protection heater studies.
37 citations
12 May 1997
TL;DR: The Fermilab's superconducting magnet R&D program has built a facility to test magnets in a vertical dewar of superfluid liquid helium as mentioned in this paper, with a temperature range of 1.8 K to 4.4 K and 1 atmosphere helium.
Abstract: Future high energy accelerators such as the Large Hadron Collider require accelerator magnets with the highest possible fields. For NbTi conductor magnets, this means operating at superfluid helium temperatures in the range of 1.8-1.9 K. As part of Fermilab's superconducting magnet R&D program, we have built a facility to test magnets in a vertical dewar of superfluid liquid helium. The dewar is designed for magnets up to 4 m length and 620 mm diameter, with a temperature range of 1.8 K to 4.4 K and 1 atmosphere helium. The power system consists of 10 kA and 8.8 kA power supplies operating in parallel, with a bus work and an extraction circuit that can accommodate up a 18 kA excitation current. A description of the facility as well as operational experience from the first magnet tests are presented.
35 citations
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TL;DR: In this article, the authors reviewed the last ten year of Nb3Sn accelerator magnet R&D and compared it to the needs of the upgrades and critically assessed the results of the Nb 3Sn and HTS technology and the planned R&DD programs also based on the inputs of first year of LHC operation.
Abstract: The Large Hadron Collider is working at about half its design value, limited by the defective splices of the magnet interconnections. While the full energy will be attained after the splice consolidation in 2014, CERN is preparing a plan for a Luminosity upgrade (High Luminosity LHC) around 2020 and has launched a pre-study for exploring an Energy upgrade (High Energy LHC) around 2030. Both upgrades strongly rely on advanced accelerator magnet technology, requiring dipoles and quadrupoles of accelerator quality and operating fields in the 11-13 T range for the luminosity upgrade and 16-20 T range for the energy upgrade. The paper will review the last ten year of Nb3Sn accelerator magnet R&D and compare it to the needs of the upgrades and will critically assess the results of the Nb3Sn and HTS technology and the planned R&D programs also based on the inputs of first year of LHC operation.
208 citations
TL;DR: The High Luminosity (HiLumi) Large Hadron Collider (LHC) project has, as the main objective, to increase the LHC peak luminosity by a factor five and the integrated luminosity, which will be achieved mainly with a new interaction region layout which will allow a stronger focusing of the colliding beams as discussed by the authors.
Abstract: The High Luminosity (HiLumi) Large Hadron Collider (LHC) project has, as the main objective, to increase the LHC peak luminosity by a factor five and the integrated luminosity by a factor ten. This goal will be achieved mainly with a new interaction region layout, which will allow a stronger focusing of the colliding beams. The target will be to reduce the beam size in the interaction points by a factor of two, which requires doubling the aperture of the low-β (or inner triplet) quadrupole magnets. The use of Nb3Sn superconducting material and, as a result, the possibility of operating at magnetic field levels in the windings higher than 11 T will limit the increase in length of these quadrupoles, called MQXF, to acceptable levels. After the initial design phase, where the key parameters were chosen and the magnet's conceptual design finalized, the MQXF project, a joint effort between the U.S. LHC Accelerator Research Program and the Conseil Europeen pour la Recherche Nucleaire (CERN), has now entered the construction and test phase of the short models. Concurrently, the preparation for the development of the full-length prototypes has been initiated. This paper will provide an overview of the project status, describing and reporting on the performance of the superconducting material, the lessons learnt during the fabrication of superconducting coils and support structure, and the fine tuning of the magnet design in view of the start of the prototyping phase.
121 citations
TL;DR: In this article, the authors present the HL-LHC low-β quadrupole design, based on the experience gathered by the US LARP program, and describe the support structure components to preload the coils, withstand the electro-magnetic forces, provide alignment and LHe containment, and integrate the cold mass in the LHC IRs.
Abstract: The high luminosity LHC (HL-LHC) project is aimed at studying and implementing the necessary changes in the LHC to increase its luminosity by a factor of five. Among the magnets that will be upgraded are the 16 superconducting low-β quadrupoles placed around the two high luminosity interaction regions (ATLAS and CMS experiments). In the current baseline scenario, these quadrupole magnets will have to generate a gradient of 140 T/m in a coil aperture of 150 mm. The resulting conductor peak field of more than 12 T will require the use of Nb3Sn superconducting coils. We present in this paper the HL-LHC low-β quadrupole design, based on the experience gathered by the US LARP program, and, in particular, we describe the support structure components to pre-load the coils, withstand the electro-magnetic forces, provide alignment and LHe containment, and integrate the cold mass in the LHC IRs.
99 citations
TL;DR: In this article, the authors summarize the status of Nb 3 Sn development in the USA and discuss low magnetic field instability in magnets that re-emerged through the use of very high current density Nb3 Sn wires, and solutions that address these stability problems.
89 citations
TL;DR: In this article, the microstructural and microchemical factors that are important for high critical current density Nb 3 Sn are reviewed and recent successful attempts to reduce the cost of alloying the Nb3 Sn for high field application are also examined and the potential for future improvements discussed.
82 citations