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Study of 2-in1 large-aperture Nb3Sn IR quadrupoles for the LHC luminosity upgrade

Description: Double-aperture Nb{sub 3}Sn quadrupoles with asymmetric coils and with cold and warm iron yokes were studied for the dipole-first upgrade scenario of the LHC Interaction Regions (IR). This paper describes the magnet design concepts and discusses their performance parameters, including field gradient and field quality limitations.
Date: June 1, 2006
Creator: Kashikhin, V. V. & Zlobin, A. V.
Partner: UNT Libraries Government Documents Department

Study of YBCO tape anisotropy as a function of field, field orientation and operating temperature

Description: Superconducting magnets with magnetic fields above 20 T will be needed for a Muon Collider and possible LHC energy upgrade. This field level exceeds the possibilities of traditional Low Temperature Superconductors (LTS) such as Nb{sub 3}Sn and Nb{sub 3}Al. Presently the use of high field high temperature superconductors (HTS) is the only option available for achieving such field levels. Commercially available YBCO comes in tapes and shows noticeable anisotropy with respect to field orientation, which needs to be accounted for during magnet design. In the present work, critical current test results are presented for YBCO tape manufactured by Bruker. Short sample measurements results are presented up to 14 T, assessing the level of anisotropy as a function of field, field orientation and operating temperature.
Date: June 1, 2011
Creator: Lombardo, v.; Barzi, E.; Turrioni, D. & Zlobin, A.V.
Partner: UNT Libraries Government Documents Department

Insert Coil Test for HEP High Field Magnets Using YBCO Coated Conductor Tapes

Description: The final beam cooling stages of a Muon Collider may require DC solenoid magnets with magnetic fields of 30-50 T. In this paper we present progress in insert coil development using commercially available YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} Coated Conductor. Technological aspects covered in the development, including coil geometry, insulation, manufacturing process and testing are summarized and discussed. Test results of double pancake coils operated in liquid nitrogen and liquid helium are presented and compared with the performance of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} tape short samples.
Date: June 15, 2011
Creator: Lombardo, V.; Barzi, E.; Turrioni, D.; Zlobin, A.V. & /Fermilab
Partner: UNT Libraries Government Documents Department

120-mm supercondcting quadrupole for interaction regions of hadron colliders

Description: Magnetic and mechanical designs of a Nb{sub 3}Sn 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 mid-planes to reduce the level of radiation heat deposition and radiation dose in the coil. The quadrupole mechanical structure is based on aluminum collars supported by an iron yoke and a stainless steel skin. Magnet parameters including maximum field gradient and field harmonics, Nb3Sn coil pre-stress and protection at the operating temperatures of 4.5 and 1.9 K are reported. The level and distribution of radiation heat deposition in the coil and other magnet components are discussed.
Date: May 1, 2010
Creator: Zlobin, A.V.; Kashikhin, V.V.; Mokhov, N.V.; Novitski, I. & /Fermilab
Partner: UNT Libraries Government Documents Department

Critical currents of YBCO tapes and Bi-2212 wires at different temperatures and magnetic fields

Description: Design studies for the cooling channel of a Muon Collider call for straight and helical solenoids generating field well in excess of the critical fields of state of the art Low Temperature Superconductors (LTS) such as Nb{sub 3}Sn or NbTi. Therefore, High Temperature Superconductors (HTS) will need to be used for the manufacturing of all or certain sections of such magnets to be able to generate and withstand the field levels at the cryogenic temperatures required by the new machine. In this work, two major High Temperature Superconductors - Bi2212 round wires and YBCO coated conductor tapes - are investigated to understand how critical current density of such conductors scales as a function of external field and operating temperature. This is vital information to make conductor choices depending on the application and to proceed with the design of such magnets.
Date: August 1, 2010
Creator: Lombardo, V.; Barzi, e.; Turrioni, D.; Zlobin, A.V. & /Fermilab
Partner: UNT Libraries Government Documents Department

Studies of high-field sections of a muon helical cooling channel with coil separation

Description: The Helical Cooling Channel (HCC) was proposed for 6D cooling of muon beams required for muon collider and some other applications. HCC uses a continuous absorber inside superconducting magnets which produce solenoidal field superimposed with transverse helical dipole and helical gradient fields. HCC is usually divided into several sections each with progressively stronger fields, smaller aperture and shorter helix period to achieve the optimal muon cooling rate. This paper presents the design issues of the high field section of HCC with coil separation. The effect of coil spacing on the longitudinal and transverse field components is presented and its impact on the muon cooling discussed. The paper also describes methods for field corrections and their practical limits. The magnetic performance of the helical solenoid with coil separation was discussed in this work. The separation could be done in three different ways and the performances could be very different which is important and should be carefully described during the beam cooling simulations. The design that is currently being considered is the one that has the poorest magnetic performance because it presents ripples in all three components, in particular in the helical gradient which could be quite large. Moreover, the average gradient could be off, which could affect the cooling performance. This work summarized methods to tune the gradient regarding the average value and the ripple. The coil longitudinal thickness and the helix period can be used to tune G. Thinner coils tend to reduce the ripples and also bring G to its target value. However, this technique reduces dramatically the operational margin. Wider coils can also reduce the ripple (not as much as thinner coils) and also tune the gradient to its target value. Longer helix periods reduce ripple and correct the gradient to the target value.
Date: March 1, 2011
Creator: Lopes, M.L.; Kashikhin, V.S.; Yonehara, K.; Yu, M.; Zlobin, A.V. & /Fermilab
Partner: UNT Libraries Government Documents Department

Radiation effects in a muon collider ring and dipole magnet protection

Description: The requirements and operating conditions for a Muon Collider Storage Ring (MCSR) pose significant challenges to superconducting magnets. The dipole magnets should provide a high magnetic field to reduce the ring circumference and thus maximize the number of muon collisions during their lifetime. One third of the beam energy is continuously deposited along the lattice by the decay electrons at the rate of 0.5 kW/m for a 1.5-TeV c.o.m. and a luminosity of 10{sup 34} cm{sup -2}s{sup -1}. Unlike dipoles in proton machines, the MCSR dipoles should allow this dynamic heat load to escape the magnet helium volume in the horizontal plane, predominantly towards the ring center. This paper presents the analysis and comparison of radiation effects in MCSR based on two dipole magnets designs. Tungsten masks in the interconnect regions are used in both cases to mitigate the unprecedented dynamic heat deposition and radiation in the magnet coils.
Date: March 1, 2011
Creator: Mokhov, N.V.; Kashikhin, V.V.; Novitski, I.; Zlobin, A.V. & /Fermilab
Partner: UNT Libraries Government Documents Department

Compact IR Quadrupoles for Linear Colliders Based on Rutherford-type Cable

Description: The upcoming and disrupted beams in the interaction region (IR) of a linear collider are focused by doublets consisting of two small-aperture superconducting quadrupoles. These magnets need an effective compact magnetic shielding to minimize magnetic coupling between the two channels and sufficient temperature margin to withstand radiation-induced heat depositions in the coil. This paper presents conceptual designs of IR quadrupoles for linear colliders based on NbTi and Nb{sub 3}Sn Rutherford-type cables.
Date: August 1, 2008
Creator: Lopes, M.L.; Kashikhin, V.S.; Kashikhin, V.V.; Zlobin, A.V. & /Fermilab
Partner: UNT Libraries Government Documents Department

Modular test facility for HTS insert coils

Description: The final beam cooling stages of a Muon Collider may require DC solenoid magnets with magnetic fields in the range of 40-50 T. In this paper we will present a modular test facility developed for the purpose of investigating very high field levels with available 2G HTS superconducting materials. Performance of available conductors is presented, together with magnetic calculations and evaluation of Lorentz forces distribution on the HTS coils. Finally a test of a double pancake coil is presented.
Date: October 1, 2009
Creator: Lombardo, V; Bartalesi, A.; Barzi, E.; Lamm, M.; Turrioni, D.; Zlobin, A.V. et al.
Partner: UNT Libraries Government Documents Department

Study of HTS Wires at High Magnetic Fields

Description: Fermilab is working on the development of high field magnet systems for ionization cooling of muon beams. The use of high temperature superconducting (HTS) materials is being considered for these magnets using Helium refrigeration. Critical current (I{sub c}) measurements of HTS conductors were performed at FNAL and at NIMS up to 28 T under magnetic fields at zero to 90 degree with respect to the sample face. A description of the test setups and results on a BSCCO-2223 tape and second generation (2G) coated conductors are presented.
Date: January 1, 2009
Creator: Turrioni, D.; Barzi, E.; Lamm, M.J.; Yamada, R.; Zlobin, A.V.; Kikuchi, A. et al.
Partner: UNT Libraries Government Documents Department

Quench margin measurement in Nb3Sn quadrupole magnet

Description: One of the possible practical applications of the Nb{sub 3}Sn accelerator magnets is the LHC luminosity upgrade that involves replacing the present NbTi focusing quadrupoles in two high-luminosity interaction regions (IR). The IR magnets are exposed to strong radiation from the interaction point that requires a detailed investigation of the magnet operating margins under the expected radiation-induced heat depositions. This paper presents the results of simulation and measurement of quench limits and temperature margins for a Nb{sub 3}Sn model magnet using a special midplane strip heater.
Date: August 1, 2008
Creator: Kashikhin, V.V.; Bossert, R.; Chlachidze, G.; Lamm, M.; Novitski, I.; Zlobin, A.V. et al.
Partner: UNT Libraries Government Documents Department

Optics implications of implementing Nb3Sn magnets in the LHC phase 1 upgrade

Description: CERN has encouraged the US-LARP collaboration to participate in Phase I of the LHC luminosity upgrade by analyzing the benefits gained by using Nb3Sn technology to replace the functionality of select NbTi magnets that CERN is committed to construct. Early studies have shown that the much higher gradients (shorter magnetic lengths) and temperature margins (quench stability) of Nb3Sn magnets compared to their NbTi counterparts is favorable--allowing the insertion of additional absorbers between Q1 and Q2, for example. This paper discusses the relative merits of the NbTi and Nb3Sn options.
Date: June 1, 2008
Creator: Johnstone, J.A.; Kashikhin, V.V.; Mokhov, N.V.; Zlobin, A.V. & /Fermilab
Partner: UNT Libraries Government Documents Department

Fabrication, qualification and test of high Jc ROEBEL YBCO coated conductor cable for HEP magnets

Description: The ROEBEL cable concept allows for a high critical current cable assembled using commercially available YBa{sub 2}Cu{sub 3}O{sub 7-{Delta}} coated conductors. this approach to cable design leads to several technological improvements if applied to the manufacture process of next generation low inductance, high current density HTS coils. A reduction in inductance proves to be extremely important when it comes to protection of coils capable of generating fields in the range of 40-50T, such as the ones needed in the last stage of the cooling channel of a muon collider. In this work several aspects are presented including the qualification and minimum requirements for YBa{sub 2}Cu{sub 3}O{sub 7-{Delta}}coated conductor in terms of 2D current density uniformity and the manufacturing process of ROEBEL cables. Test results achieved using a superconducting transformer for critical current measurements in liquid helium are shown, discussed and compared to the performance of a single YBa{sub 2}Cu{sub 3}O{sub 7-{Delta}} coated conductor tape.
Date: August 1, 2010
Creator: Lombardo, V.; Barzi, E.; Turrioni, D.; Zlobin, A.V.; /Fermilab; Long, N.J. et al.
Partner: UNT Libraries Government Documents Department

Magnet designs for muon collider ring and interactions regions

Description: Conceptual designs of superconducting magnets for the storage ring of a Muon Collider with a 1.5 TeV c.o.m. energy and an average luminosity of 10{sup 34} cm{sup -2}s{sup -1} are presented. All magnets are based on Nb{sub 3}Sn superconductor and designed to provide an adequate operating field/field gradient in the aperture with the critical current margin required for reliable magnet operation in the machine. Magnet cross-sections were optimized to achieve the accelerator field quality in the magnet aperture occupied with beams. The magnets and corresponding protective measures are designed to handle about 0.5 kW/m of dynamic heat load from the muon beam decays. Magnet parameters are reported and compared with the requirements.
Date: May 1, 2010
Creator: Zlobin, A.V.; Alexahin, Y.I.; Kashikhin, V.V.; Mokhov, N.V. & /Fermilab
Partner: UNT Libraries Government Documents Department

Fabrication and test of short helical solenoid model based on YBCO tape

Description: A helical cooling channel (HCC) is a new technique proposed for six-dimensional (6D) cooling of muon beams. To achieve the optimal cooling rate, the high field section of HCC need to be developed, which suggests using High Temperature Superconductors (HTS). This paper updates the parameters of a YBCO based helical solenoid (HS) model, describes the fabrication of HS segments (double-pancake units) and the assembly of six-coil short HS model with two dummy cavity insertions. Three HS segments and the six-coil short model were tested. The results are presented and discussed.
Date: March 1, 2011
Creator: Yu, M.; Lombardo, V.; Lopes, M. L.; Turrioni, D.; Zlobin, A. V.; Flanagan, G. et al.
Partner: UNT Libraries Government Documents Department

Muon Collider interaction region and machine-detector interface design

Description: One of the key systems of a Muon Collider (MC) - seen as the most exciting option for the energy frontier machine in the post-LHC era - is its interaction region (IR). Designs of its optics, magnets and machine-detector interface are strongly interlaced and iterative. As a result of recent comprehensive studies, consistent solutions for the 1.5-TeV c.o.m. MC IR have been found and are described here. To provide the required momentum acceptance, dynamic aperture and chromaticity, an innovative approach was used for the IR optics. Conceptual designs of large-aperture high-field dipole and high-gradient quadrupole magnets based on Nb{sub 3}Sn superconductor were developed and analyzed in terms of the operating margin, field quality, mechanics, coil cooling and quench protection. Shadow masks in the interconnect regions and liners inside the magnets are used to mitigate the unprecedented dynamic heat deposition due to muon decays ({approx}0.5 kW/m). It is shown that an appropriately designed machine-detector interface (MDI) with sophisticated shielding in the detector has a potential to substantially suppress the background rates in the MC detector.
Date: March 1, 2011
Creator: Mokhov, N.V.; Alexahin, Y.I.; Kashikhin, V.V.; Striganov, S.I.; Zlobin, A.V. & /Fermilab
Partner: UNT Libraries Government Documents Department

Development and Fabrication of Nb3Sn Rutherford Cable for the 11 T DS Dipole Demonstration Model

Description: Fermilab and CERN started the development of 11 T 11-m long Nb{sub 3}Sn dipoles to replace few regular LHC NbTi dipoles and free space for cold collimators in LHC DS areas. An important step in the design of these magnets is the development of the high aspect ratio Nb{sub 3}Sn cable to achieve the nominal field of 11 T at the nominal LHC operating current of 11.85 kA with 20% margin. The keystoned cables 14.7 mm wide with and without a stainless steel core were made out of hard Cu wires and Nb{sub 3}Sn RRP strand 0.7 mm nominal diameter. The cable optimization process was aimed at achieving both mechanical stability and minimal damage to the delicate internal architecture of the Restacked-Rod-Process (RRP) Nb{sub 3}Sn strands with 127 restack design to be used in the magnet short models. Each cable was characterized electrically for transport properties degradation at high field and for low field stability, and metallographically for internal damage.
Date: November 30, 2011
Creator: Barzi, E.; Lombardo, V.; Nobrega, F.; Turrioni, D.; Yamada, R.; Zlobin, A.V. et al.
Partner: UNT Libraries Government Documents Department