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Baldini, M.

Publications and source records attributed to Baldini, M..

Development and Test of a Large Aperture $Nb_3Sn$ Cos-Theta Dipole Coil with Stress Management

An innovative stress-management (SM) concept for cos-theta (CT) coils (SMCT coil concept) has been proposed at Fermilab. A large-aperture two-layer Nb3Sn SMCT dipole coil was designed and manufactured to validate and test the SM concept including coil design, fabrication technology, and performance. The first large-aperture SMCT coil (SMCT1) was fabricated and assembled with a small-aperture Nb3Sn coil inside a dipole mirror magnet. SMCT1 coil tests in a dipole mirror structure was performed in two configurations - SMCTM1a with only powered two-layer SMCT1 coil and SMCTM1b with the SMCT coil connected in series with an inner two-layer dipole coil. The test goals are to prove the SMCT coil concept in two-layer and four-layer mirror configurations; demonstrate that the magnet can reach the targeted quench current at the established preload; study magnet training, training memory after thermal cycle, ramp rate and temperature dependences of the magnet quench current; and test the SMCT1 coil quench protection parameters. This paper summarizes the SMCT1 coil design and parameters, the coil main fabrication steps, its assembly in the dipole mirror structure. The results of the SMCTM1a/b mirror test are presented and discussed.

43 PARTICLE ACCELERATORS↗

First results of AUP Nb3Sn quadrupole horizontal tests

The Large Hadron Collider will soon undergo an upgrade to increase its luminosity by a factor of ~10 [1]. A crucial part of this upgrade will be replacement of the NbTi focusing magnets with Nb3Sn magnets that achieve a ~50% increase in the field strength. This will be the first ever large-scale implementation of Nb3Sn magnets in a particle accelerator. The High-Luminosity LHC Upgrade, HL-LHC is a CERN project with a world-wide collaboration. It is under construction and utilizes Nb3Sn Magnets (named MQXF) as key ingredients to increase tenfold the integrated luminosity delivered to the CMS and ATLAS experiments in the next decade. The HL-LHC AUP is the US effort to contribute approximately 50% of the low-beta focusing magnets and crab cavities for the HL-LHC. This paper will present the program to fabricate the Nb3Sn superconducting magnets. We are reporting the status of the HL-LHC AUP project present the results from horizontal tests of the first fully assembled cryo-assembly.

43 PARTICLE ACCELERATORS↗

AUP First Pre-Series Cryo-Assembly Design Production and Test Overview

New high field and large-aperture quadrupole magnets for the low-beta inner triplets (Q1, Q2, Q3) have been built and tested as part of the high-luminosity upgrade of the Large Hadron Collider (HL-LHC). These new quadrupole magnets are based on Nb3Sn superconducting technology. The US Accelerator Upgrade Project (US-AUP) is producing the Q1 and Q3 Cryo-Assemblies: a pair of ~5 m long magnet structures installed in a stainless-steel helium vessel (Cold Mass) and surrounded by cryostat shields, piping, and a vacuum vessel. In conclusion, this paper gives an overview of the design, production, and the results of the horizontal test of the first pre-series Q1/Q3 Cryo-Assembly.

43 PARTICLE ACCELERATORS↗

Quench Performance of the First Pre-series AUP Cryo-assembly

The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN will include eight cryo-assemblies that are expected to be fabricated and delivered to CERN by the US HL-LHC Accelerator Upgrade Project (AUP) as part of the U.S. contributions to the HL-LHC. These cryostat assemblies are the quadrupole magnetic components of the HL-LHC Q1 and Q3 inner triplet optical elements in front of the two interaction points. Each cryo-assembly consists of two 4.2 m long Nb 3 Sn quadrupole magnets with aperture 150 mm and operating gradient 132.6 T/m. The first pre-series cryo-assembly has been fabricated and successfully tested at the horizontal test facility at Fermi National Accelerator Laboratory. Here in this manuscript we report the quench test results of the LQXFA/B-01 cryo-assembly. The primary objective of the horizontal test is full cryo-assembly qualification and validation of the performance requirements.

43 PARTICLE ACCELERATORS↗

Development and Test of a Large-aperture Nb3Sn Cos-theta Dipole Coil with Stress Management

The design concept of the Electron Ion Collider (EIC), which is under construction at BNL, considers adding a 2nd Interaction Region (IR) and detector to the machine after completion of the present EIC project. Recent progress with development and fabrication of large-aperture high-field magnets based on the Nb3Sn technology for the HL-LHC makes this technology interesting for the 2nd EIC IR. This paper summarizes the results of feasibility studies of large-aperture high-field Nb3Sn dipoles and quadrupoles for the 2nd EIC IR.

43 PARTICLE ACCELERATORS↗

Magnetic Measurements and Alignment Results of LQXFA/B Cold Mass Assemblies at Fermilab

MQXFA production series quadrupole magnets are being built for the Hi-Lumi (HL) LHC upgrade by the U.S. Accelerator Upgrade Project (US-HL-LHC AUP). These magnets are being placed in pairs, as a cold mass, within cryostats at Fermilab, and are being tested to assess alignment and magnetic performance at Fermilab's horizontal test stand facility. The ~10 m - long assembly must meet stringent specifications for quadrupole strength and harmonic field integrals determination, magnetic axis position, and for magnet variations in positioning and local field profile. Here this paper describes the results of the magnetic and alignment measurements which characterize the first LQXFA/B assembly.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Analysis of the MQXFA Low Beta Quadrupoles for HL-LHC after 50% magnet assembly complete +

The US HL-LHC Accelerator Upgrade Project (AUP) is fabricating the MQXFA magnets to be used in the Q1 and Q3 Inner Triplet elements of the High Luminosity LHC (HL-LHC). This is the first production of Nb3Sn magnets for a particle accelerator, together with the MQXFB magnets for Q2a and Q2b. Here we show status and some results of MQXFA magnets fabrication and vertical test.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Commissioning, Performance, and Effect of the Quench Current-Boosting Device on a Dedicated Superconducting Magnet

Superconducting magnet training is one of the accelerator related issues attracting attention due to significant operational costs and time budget associated to it. It is especially worrisome that magnets based on the “next-generation” Nb 3 Sn technology are affected by long training. While various efforts are underway to better understand and resolve the problem a parallel path could also be investigated, a path bypassing the issue. Following the concept of fast induced over-current during magnet powering, FNAL has developed an upgradable capacitor-based device to discharge through a superconducting magnet at quench detection or operator chosen time. The 0.4 F/1 kV device has been tested on a 1-m-long dipole-coil in a “mirror” magnet configuration and conclusive results on magnet training elimination have been observed. Here in this paper we discuss the main characteristics of the device, compare simulated response and actual performance, elaborate on test drivers and outcomes. Next steps and perspectives for future use are debated.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Status and Challenges of the Interaction Region Magnets for HL-LHC

About one hundred magnets of six different types shall be installed in the High Luminosity LHC (HL-LHC) in the years 2026-2028 at CERN. The magnets design, construction and test are based on CERN collaborations with institutes and industrial partners in USA, Spain, Italy, Japan and China. Three types of correctors are based on Nb-Ti technology and feature conductor peak fields in the 2 to 4 T range: for all of them the prototype phase has been successfully completed. The production is well advanced for the superferric correctors, and is starting for the canted cosine theta correctors and for the nested correctors. The separation and recombination Nb-Ti dipoles D1 and D2, with a 4.5-6 T bore field range, are both in the prototype phase after the completion of the short model program. The most challenging magnet, the Nb 3 Sn quadrupole with conductor peak field above 11 T, is in the prototype phase at CERN and halfway through the production phase in the USA. In this paper we will give, for each type of magnet, an overview of the main achievements obtained so far and we will outline the technical points still needing validation from the prototype program.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

US HL-LHC Accelerator Upgrade Project: MQXFA11 shipping incident report

The truck transporting the MQXFA11 magnet from LBNL to BNL was involved in an accident on 7/20/22. It was rear ended by another truck. Drivers were not injured. The main hit took place on the right back corner. The truck with the MQXFA11 magnet was towed to a tow yard in Rockdale, IL (~50 min drive from Fermilab). Subsequently, it was moved on another truck and moved to Fermilab. Fermilab employees added 3 accelerometers on the crate before it was moved on the new truck and attended all loading/unloading operations at the tow yard and at FNAL. The magnet arrived at FNAL on July 28 th . Upon arrival a visual inspection was performed. Accelerometers were removed and shock data were analyzed. Electrical checkout and a metrology survey were carried out. Strain data were also collected from the fiber optics installed on two coils and compared with data obtained before shipment. This report presents a summary of results. More pictures and details can be found at: https://indico.fnal.gov/event/55698/

43 PARTICLE ACCELERATORS↗

MQXFA11 shipping incident report

The truck transporting the MQXFA11 magnet from LBNL to BNL was involved in an accident on 7/20/22. It was rear ended by another truck. The magnet arrived at FNAL on July 28th. Upon arrival a visual inspection was performed. Accelerometers were removed and shock data were analyzed. Electrical checkout and a metrology survey were carried out. Strain data were also collected from the fiber optics installed on two coils and compared with data obtained before shipment. This report presents a summary of results.

43 PARTICLE ACCELERATORS↗

Magnetic Measurements of $\mathrm{HL-LHC AUP}$ Cryo-Assemblies at Fermilab

LQXFA/B production series cryogenic assemblies are being built for the LHC upgrade by the HL-LHC Accelerator Upgrade Project (AUP). These contain a pair of MQXFA quadrupole magnets combined as a cold mass within a vacuum vessel, and are to be installed in the IR regions of the LHC. The LQXFA/B are being tested at 1.9 K to assess alignment and magnetic performance at Fermilab's horizontal test facility. The ~10 m long assembly must meet stringent specifications for quadrupole strength and harmonic field integrals determination, magnetic axis location, and for variations in axis position and local field profiles. A multi-probe, PCB-based rotating coil and a Single Stretched Wire system are employed for these measurements. To accurately determine rotating coil location and angles within the cold mass, a laser tracker is utilized to record multiple targets at one end of the probe. Here this paper describes the measurements, probes/equipment, and techniques used to perform the necessary characterization of the cold mass.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Advancing Superconducting Magnet Diagnostics for Future Colliders

Future colliders will operate at increasingly high magnetic fields pushing limits of electromagnetic and mechanical stress on the conductor [1]. Understanding factors affecting superconducting (SC) magnet performance in challenging conditions of high mechanical stress and cryogenic temperatures is only possible with the use of advanced magnet diagnostics. Diagnostics provide a unique observation window into mechanical and electromagnetic processes associated with magnet operation, and give essential feedback to magnet design, simulations and material research activities. Development of novel diagnostic capabilities is therefore an integral part of next-generation magnet development. In this paper, we summarize diagnostics development needs from a prospective of the US Magnet Development Program (MDP), and define main research directions that could shape this field in the near future.

43 PARTICLE ACCELERATORS↗

Magnetic Measurements of HL-LHC AUP Cryo-Assemblies at Fermilab

LQXFA/B production series cryogenic assemblies are being built for the LHC upgrade by the HL-LHC Accelerator Upgrade Project (AUP). These contain a pair of MQXFA quadrupole magnets combined as a cold mass within a vacuum vessel, and are to be installed in the IR regions of the LHC. The LQXFA/B are being tested at 1.9 K to assess alignment and magnetic performance at Fermilab's horizontal test facility. The ~10 m - long assembly must meet stringent specifications for quadrupole strength and harmonic field integrals determination, magnetic axis location, and for variations in axis position and local field profile. A multi-probe, PCB-based rotating coil and Single Stretched Wire system are employed for these measurements. To accurately determine rotating coil location and angles within the cold mass, a laser tracker is utilized to record multiple targets at one end of the probe. This paper describes the measurements, probes/equipment, and techniques used to perform the necessary characterization of the cold mass.

43 PARTICLE ACCELERATORS↗