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I. Novitski

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Papers by I. Novitski

MDPCT1 Quench Data and Performance Analysis

IEEE Transactions on Applied Superconductivity, 2022

MDPCT1 is a four-layer cos-theta Nb3Sn dipole demonstrator developed and tested at FNAL in the fr... more MDPCT1 is a four-layer cos-theta Nb3Sn dipole demonstrator developed and tested at FNAL in the framework of the U.S. Magnet Development Program. The magnet reached record fields for accelerator magnets of 14.1 T at 4.5 K in the first test and 14.5 T at 1.9 K in the second test and then showed large degradation. While its inner coils performed exceptionally well with only two quenches up to 14.5 T and no evidence of degradation, the outer coils degraded over the course of testing. By adopting new measurement and analysis techniques at FNAL we are discussing in detail what happened. Both success and failure in our diagnostics are discussed. The evolution of techniques over the course of two tests (and three thermal cycles) shows the path to address challenges brought by the first four-layer magnet tested at FNAL. This paper presents the analysis of quench data along with diagnostic features and complementary measurements taken in support of the magnet performance analysis.

Development of a 120-mm Aperture Nb3Sn Dipole Coil With Stress Management

IEEE Transactions on Applied Superconductivity

This paper describes a 120-mm aperture 2-layer dipole coil with stress management (SM) developed ... more This paper describes a 120-mm aperture 2-layer dipole coil with stress management (SM) developed at Fermilab based on cos-theta coil geometry. A model of the coil support structure made of plastic was printed using additive manufacturing technology and used for practice coil winding. The real coil support structure was printed using the 316 stainless steel. The results of the SM structure size control and the key coil fabrication steps are reported in the paper. The design of coil SM structure and the coil FEA in the dipole mirror test configurations are presented and discussed.  Index Terms-Accelerator magnet, magnetic field, mechanical structure, Nb 3 Sn Rutherford cable, stress management.

Mechanical Utility Structure for Testing High Field Superconducting Dipole Magnets

IEEE Transactions on Applied Superconductivity, 2019

The U.S. Magnet Development Program (MDP) collaboration is designing a utility mechanical structu... more The U.S. Magnet Development Program (MDP) collaboration is designing a utility mechanical structure for testing various high-field superconducting dipole coils. The design uses a shell-based structure concept, which allows applying preload in two steps: during a room temperature assembly and during a cool down to a cryogenic temperature. The structure is designed to accommodate various coil designs-including Nb3Sn Cosine Theta (CT) and Canted CT magnets as well as hybrid magnets with high temperature superconductor cables. Superconducting coils, enclosed by bolted pads to form an octagonal coil pack, will be inserted into a reusable yoke-shell subassembly and precisely preloaded during the assembly using a bladder-and-key technology. Due to a differential thermal contraction between an external aluminum shell and the magnet core, the coil preload increases during the cool down up to level required for 17-T excitation. Such a reusable structure will serve as a testing fixture supporting goals of the MDP program, decreasing cost and simplifying coil performance testing at different preload levels. We present a finite-element analysis of the structure preloading various coil designs and examine the predicted coil stress at each step of the magnet assembly and excitation.

120 mm Superconducting Quadrupole for Interaction Regions of Hadron Colliders

Magnetic and mechanical designs of a superconducting quadrupole magnet with 120-mm aperture suita... more Magnetic and mechanical designs of a superconducting quadrupole magnet with 120-mm aperture suitable for interaction regions of hadron colliders are presented. The magnet is based on a two-layer shell-type coil and a cold iron yoke. Special spacers made of a low-Z material are implemented in the coil midplanes to reduce the level of radiation heat deposition in the coil. The quadrupole mechanical structure is based on a thick aluminum collar supported by the iron yoke and stainless steel skin. Magnet parameters including maximum field gradient, field quality and temperature margin for NbTi or Nb₃Sn coils at the operating temperatures of 1.9 K and 4.5 K are reported. The level and distribution of radiation heat deposition in the coil and other magnet components are discussed.

DEVELOPMENT AND TEST OF COLLARING METHODS FOR Nb[sub 3]SN QUADRUPOLE MAGNETS

Fermilab is developing Nb3Sn quadrupole magnets for the planned upgrade of interaction regions of... more Fermilab is developing Nb3Sn quadrupole magnets for the planned upgrade of interaction regions of the Large Hadron Collider (LHC). Several 90-mm quadrupole models using a collar-based mechanical structure have been fabricated and tested within the framework of the US-LHC Accelerator Research Program (LARP) . Two distinctly different approaches have been employed, one using quadrupole-symmetric and one using dipole-symmetric collar laminations. This paper describes the design features of both collar types, collaring techniques for brittle Nb 3 Sn coils, and compares the advantages and disadvantages of the two approaches. Results of mechanical analysis for quadrupoles based on dipole-type and quadrupole-type collars are presented. Magnet construction issues and test results are reported. Test results include coil and component strain and magnetic measurements during construction. Plans for the completion and test of the first dipole-symmetric assembly are described.

A conceptual design of the 2+ MW LBNE beam absorber

The Long Baseline Neutrino Experiment (LBNE) will utilize a neutrino beamline facility located at... more The Long Baseline Neutrino Experiment (LBNE) will utilize a neutrino beamline facility located at Fermilab. The facility will aim a beam of neutrinos, produced by 60-120 GeV protons from the Fermilab Main Injector, toward a detector placed at the Deep Underground Science and Engineering Laboratory (DUSEL) in South Dakota. Secondary particles that do not decay into muons and neutrinos as well as any residual proton beam must be stopped at the end of the decay region to reduce noise/damage in the downstream muon monitors and reduce activation in the surrounding rock. This goal is achieved by placing an absorber structure at the end of the decay region. The requirements and conceptual design of such an absorber, capable of operating at 2+ MW primary proton beam power, is described.

Quench performance and mechanical behavior of 1 m model magnet for the LHC low-beta quadrupoles at KEK

IEEE Transactions on Appiled Superconductivity, 2001

Two 1-m model magnets for the LHC low-beta insertion quadrupole have been developed. One was fabr... more Two 1-m model magnets for the LHC low-beta insertion quadrupole have been developed. One was fabricated by KEK to confirm the magnet performance with the final cross section. Another model that was identically designed was built at Toshiba to confirm the technical transfer. In the curing process, the coil size was controlled by the optimised curing shim thickness. These magnets were connected in series and simultaneously tested at 1.9 K. Quench history of the present models showed better performance than the previous model and the magnets were verified to reach the LHC operational current without a quench after a thermal cycle. The R&D phase of the LHC insertion quadrupole will move to development of 6-m long prototype.

Quench performance of Fermilab model magnets for the LHC inner triplet quadrupoles

IEEE Transactions on Appiled Superconductivity, 2001

... H. Glass, J. Kerby, MJ L am , A. Makarov, AD McInturff, A. Nobrega, I. Novitski, T. Ogitsu, D... more

Design of a 2 Tesla transmission line magnet for the VLHC

IEEE Transactions on Appiled Superconductivity, 2000

Ahstrcl-A prototypc of tlic transmission linc magnct for thc Very Large Hadron Collldcr is bcing ... more

$Research paper thumbnail of Quench Protection Study of a Single-Aperture 11 T <formula formulatype="inline"><tex Notation="TeX">$ \hbox{Nb}_{3}\hbox{Sn}$</tex></formula> Demonstrator Dipole for LHC Upgrades$

Quench Protection Study of a Single-Aperture 11 T <formula formulatype="inline"><tex Notation="TeX">$ \hbox{Nb}_{3}\hbox{Sn}$</tex></formula> Demonstrator Dipole for LHC Upgrades

IEEE Transactions on Applied Superconductivity, 2013

The planned upgrade of the Large Hadron Collider (LHC) collimation system will include installati... more The planned upgrade of the Large Hadron Collider (LHC) collimation system will include installation of additional collimators in the dispersion suppressor areas. The longitudinal space for the collimators could be provided by replacing 15-m-long 8.33 T NbTi LHC main dipoles with shorter 11 T Nb 3 Sn dipoles compatible with the LHC lattice and main systems. FNAL and CERN have started a joint program with the goal of building a 5.5-m-long twin-aperture Nb 3 Sn dipole prototype suitable for installation in the LHC. The first step of this program is the development of a 2-m-long single-aperture demonstrator dipole with a nominal field of 11 T at the LHC nominal current of 11.85 kA. This paper summarizes the results of quench protection studies of 11 T dipoles performed using the single-aperture Nb 3 Sn demonstrator.

$Research paper thumbnail of Field Quality Measurements in a Single-Aperture 11 T <formula formulatype="inline"><tex Notation="TeX">$ \hbox{Nb}_{3}\hbox{Sn}$</tex> </formula> Demonstrator Dipole for LHC Upgrades$

Field Quality Measurements in a Single-Aperture 11 T <formula formulatype="inline"><tex Notation="TeX">$ \hbox{Nb}_{3}\hbox{Sn}$</tex> </formula> Demonstrator Dipole for LHC Upgrades

IEEE Transactions on Applied Superconductivity, 2013

The upgrade of the LHC collimation system foresees additional collimators in the LHC dispersion s... more The upgrade of the LHC collimation system foresees additional collimators in the LHC dispersion suppressor areas. The longitudinal space for the collimators could be provided by replacing some NbTi LHC main dipoles with shorter 11 T Nb 3 Sn dipoles. To demonstrate this possibility Fermilab and CERN have started a joint program to develop a Nb 3 Sn dipole prototype suitable for installation in the LHC. The first step of this program is the development of a 2 m long, 60 mm bore, singleaperture demonstrator dipole with the nominal field of 11 T at the LHC operational current of 11.85 kA. This paper presents the results of magnetic measurements of the single-aperture Nb 3 Sn demonstrator dipole including geometrical harmonics, coil magnetization and iron saturation effects. The experimental data are compared with the magnetic calculations.

Superconducting Magnet System for Muon Beam Cooling

IEEE Transactions on Applied Superconductivity, 2007

A helical cooling channel has been proposed to quickly reduce the six-dimensional phase space of ... more A helical cooling channel has been proposed to quickly reduce the six-dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. A novel superconducting magnet system for a muon beam cooling experiment is being designed at Fermilab. The inner volume of the cooling channel is filled with liquid helium where passing muon beam can be decelerated and cooled in a process of ionization energy loss. The magnet parameters are optimized to match the momentum of the beam as it slows down. The results of 3D magnetic analysis for two designs of magnet system, mechanical and quench protection considerations are discussed.

Superconducting Magnet System for Muon Beam Cooling

IEEE Transactions on Applied Superconductivity, 2007

A helical cooling channel has been proposed to quickly reduce the six-dimensional phase space of ... more A helical cooling channel has been proposed to quickly reduce the six-dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. A novel superconducting magnet system for a muon beam cooling experiment is being designed at Fermilab. The inner volume of the cooling channel is filled with liquid helium where passing muon beam can be decelerated and cooled in a process of ionization energy loss. The magnet parameters are optimized to match the momentum of the beam as it slows down. The results of 3D magnetic analysis for two designs of magnet system, mechanical and quench protection considerations are discussed.

Conceptual Designs of Dipole Magnet for Muon Collider Storage Ring

IEEE Transactions on Applied Superconductivity, 2011

Conceptual designs of a superconducting dipole magnet for a Storage Ring of a Muon Collider with ... more Conceptual designs of a superconducting dipole magnet for a Storage Ring of a Muon Collider with a 1.5 TeV center of mass (c.o.m.) energy and an average luminosity of 10 34 cm-2 s-1 are presented. In contrast to proton machines, the dipoles for the Muon Collider should be able to handle ~0.5 kW/m of dynamic heat load from the muon beam decays. The magnets are based on Nb 3 Sn superconductor and designed to provide an operating field of 10 T in the 20-mm aperture with the critical current margin required for reliable machine operation. The magnet cross-sections were optimized to achieve the best possible field quality in the aperture occupied by beams. The developed mechanical structures provide adequate coil prestress and support at the maximum level of Lorentz forces in the coil. Magnet parameters are reported and compared with the requirements.

$Research paper thumbnail of The Study of Single <formula formulatype="inline"> <tex Notation="TeX">${\rm Nb}_{3}{\rm Sn}$</tex></formula> Quadrupole Coils Using a Magnetic Mirror Structure$

The Study of Single <formula formulatype="inline"> <tex Notation="TeX">${\rm Nb}_{3}{\rm Sn}$</tex></formula> Quadrupole Coils Using a Magnetic Mirror Structure

IEEE Transactions on Applied Superconductivity, 2011

ABSTRACT Several 90-mm quadrupole coils made of 0.7-mm Nb3Sn strand based on the “Restack Rod Pro... more ABSTRACT Several 90-mm quadrupole coils made of 0.7-mm Nb3Sn strand based on the “Restack Rod Process” (RRP) of 108/127 design, with cored and non-cored cables and different cable insulation, were fabricated and individually tested at Fermi National Accelerator Laboratory (Fermilab) using a test structure designed to provide a quadrupole magnetic field environment. The coils were instrumented with voltage taps and strain gauges to study quench performance and mechanical properties. The Nb3Sn strand and cable parameters, the coil fabrication details, the mirror model assembly procedure and test results at temperatures from 4.5 K to 1.9 K are reported and discussed.

Field quality in Fermilab-built models of quadrupole magnets for the LHC interaction region

IEEE Transactions on Appiled Superconductivity, 2001

Superconducting quadrupole magnets for the interaction regions of the Large Hadron Collider are b... more Superconducting quadrupole magnets for the interaction regions of the Large Hadron Collider are being developed by the US-LHC Accelerator Project. These 70 mm bore quadrupole magnets are intended to operate in superfluid helium at 1.9 K with a nominal field gradient of 215 T/m. A series of 2 m model magnets has been built and cold tested at Fermilab to optimize their design and construction and to study the performance of the magnets. Field measurements of the 8 model magnets and comparisons with the required field quality are reported in this paper.

DEVELOPMENT OF A 15 T Nb3Sn ACCELERATOR DIPOLE DEMONSTRATOR AT FERMILAB

IEEE Transactions on Applied Superconductivity, 2016

A 100 TeV scale Hadron Collider (HC) with a nominal operation field of at least 15 T is being con... more A 100 TeV scale Hadron Collider (HC) with a nominal operation field of at least 15 T is being considered for the post-LHC era, which requires using the Nb3Sn technology. Practical demonstration of this field level in an accelerator-quality magnet and substantial reduction of the magnet costs are important requirements for realization of such a machine. Fermilab has started the development of a 15 T Nb3Sn dipole demonstrator for a 100 TeV scale HC. The magnet design is based on optimized 60-mm aperture 4-layer shell-type coils, graded between the inner and outer layers to maximize the performance and reduce the cost. The experience gained during the Nb3Sn magnet R&D is applied to various aspects of the magnet design. This paper describes the magnetic and structural designs and parameters of the 15 T Nb3Sn dipole demonstrator and the steps towards its fabrication.

Status of the 11 T Nb3Sn Dipole Project for the LHC

IEEE Transactions on Applied Superconductivity, 2014

The planned upgrade of the LHC collimation system includes additional collimators in the LHC latt... more The planned upgrade of the LHC collimation system includes additional collimators in the LHC lattice. The longitudinal space for the collimators could be obtained by replacing some LHC main dipoles with shorter but stronger dipoles compatible with the LHC lattice and main systems. A joint development program with the goal of building a 5.5 m long two-in-one aperture Nb 3 Sn dipole prototype suitable for installation in the LHC is being conducted by FNAL and CERN magnet groups. As part of the first phase of the program, 1 m long and 2 m long single aperture models are being built and tested, and the collared coils from these magnets will be assembled and tested in two-in-one configuration in both laboratories. In parallel with the short model magnet activities, the work has started on the production line in view of the scaleup to 5.5 m long prototype magnet. The development of the final cryo-assembly comprising two 5.5 m long 11T dipole cold masses and the warm collimator in the middle, fully compatible with the LHC main systems and the existing machine interfaces, has also started at CERN. This paper summarizes the progress made at CERN and FNAL towards the construction of 5.5 m long 11 T Nb 3 Sn dipole prototype and the present status of the activities related to the integration of the 11 T dipole and collimator in the LHC.

Test of Optimized 120-mm LARP Nb 3 Sn Quadrupole Coil Using Magnetic Mirror Structure

The US LHC accelerator research program (LARP) is developing a new generation of large-aperture h... more The US LHC accelerator research program (LARP) is developing a new generation of large-aperture high-field quadrupoles based on Nb3Sn conductor for the High luminosity upgrade of Large Hadron Collider (HiLumi-LHC). Tests of the first series of 120-mm aperture HQ coils revealed the necessity for further optimization of the coil design and fabrication process. Modifications in coil design were gradually implemented in two HQ coils previously tested at Fermi National Accelerator Laboratory (Fermilab) using a magnetic mirror structure (HQM01 and HQM02). This paper describes the construction and test of an HQ mirror model with a coil of optimized design and with an interlayer resistive core in the conductor. The cable for this coil was made of a smaller diameter strand, providing more room for coil expansion during reaction. The 0.8-mm strand, used in all previous HQ coils was replaced with a 0.778-mm Nb3Sn strand of RRP 108/127 sub-element design. The coil was instrumented with voltage ...

Development and First Test of the 15 T $Nb_3Sn$ Dipole Demonstrator MDFCT1

Fermilab in the framework of the U.S. Magnet Development Program (US-MDP) has developed and fabri... more