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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

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

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

Radiation and Thermal Analysis of Superconducting Quadrupoles in the Interaction Region of Linear Collider

Description: Radiation heat deposition in the superconducting magnets of the Interaction Region (IR) of a linear collider can be a serious issue that limits the magnet operating margins and shortens the material lifetime. Radiation and thermal analyses of the IR quadrupoles in the incoming and extraction beam lines of the ILC are performed in order to determine the magnet limits. This paper presents an analysis of the radial, azimuthal and longitudinal distributions of heat deposition in the incoming and disrupted beam doublets. Operation margins of the magnets based on NbTi superconductor are calculated and compared. The radiation and thermal analysis of the ILC IR quadrupoles based on Rutherford type cables was performed. It was found that the peak radiation heat deposition takes place in the second extraction quadrupole QFEX2. The maximum power density in the coil is {approx}17mW/g. This is rather high, comparing to the proton machines (LHC). However, the fast radial decay of the heat deposition together with the high thermal conductivity of the Rutherford type cable limits the coil temperatures to a moderate level. It was determined that both 2-layer and 4-layer QFEX2 magnet designs have thermal margins of a factor of {approx}4 at the nominal gradient of 31.3 T/m. Because of the large margins, these magnets can easily accommodate possible changes in the IR optics and heat deposition levels.
Date: October 14, 2011
Creator: Drozhdin, A. I.; Kashikhin, V. V.; Kashikhin, V. S.; Lopes, M. L.; Mokhov, N. V.; Zlobin, A. V. et al.
Partner: UNT Libraries Government Documents Department

Radiation and thermal analysis of superconducting quadrupoles in the interaction region of linear collider

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: Drozhdin, A.I.; Kashikhin, V.V.; Kashikhin, V.S.; Lopes, M.L.; Mokhov, N.V.; Zlobin, A.V. et al.
Partner: UNT Libraries Government Documents Department

Experimental studies of helical solenoid model based on YBCO tape-bridge joints

Description: Helical solenoids that provide solenoid, helical dipole and helical gradient field components are designed for a helical cooling channel (HCC) proposed for cooling of muon beams in a muon collider. The high temperature superconductor (HTS), 12 mm wide and 0.1 mm thick YBCO tape, is used as the conductor for the highest-field section of HCC due to certain advantages, such as its electrical and mechanical properties. To study and address the design, and technological and performance issues related to magnets based on YBCO tapes, a short helical solenoid model based on double-pancake coils was designed, fabricated and tested at Fermilab. Splicing joints were made with Sn-Pb solder as the power leads and the connection between coils, which is the most critical element in the magnet that can limit the performance significantly. This paper summarizes the test results of YBCO tape and double-pancake coils in liquid nitrogen and liquid helium, and then focuses on the study of YBCO splices, including the soldering temperatures and pressures, and splice bending test.
Date: June 1, 2011
Creator: Yu, M.; Lombardo, V.; Turrioni, D.; Zlobin, A.V.; /Fermilab; Flangan, G. et al.
Partner: UNT Libraries Government Documents Department

Helical Muon Beam Cooling Channel Engineering Design

Description: The Helical Cooling Channel (HCC), a novel technique for six-dimensional (6D) ionization cooling of muon beams, has shown considerable promise based on analytic and simulation studies. However, the implementation of this revolutionary method of muon cooling requires new techniques for the integration of hydrogen-pressurized, high-power RF cavities into the low-temperature superconducting magnets of the HCC. We present the progress toward a conceptual design for the integration of 805 MHz RF cavities into a 10 T Nb{sub 3}Sn based HCC test section. We include discussions on the pressure and thermal barriers needed within the cryostat to maintain operation of the magnet at 4.2 K while operating the RF and energy absorber at a higher temperature. Additionally, we include progress on the Nb{sub 3}Sn helical solenoid design.
Date: May 1, 2012
Creator: Kashikhin, V.S.; Lopes, M.L.; Romanov, G.V.; Tartaglia, M.A.; Yonehara, K.; Yu, M. et al.
Partner: UNT Libraries Government Documents Department

Mechanical analysis and test results of 4-coil superconducting helical solenoid model

Description: Novel configurations of helical superconducting magnets for muon beam 6D phase space cooling channels and demonstration experiments are being designed at Fermilab. Operating as needed for the beam cooling in a cryogenic environment, the helical solenoid generates longitudinal and transverse magnetic fields; meanwhile, large Lorentz forces are produced, so rigid coil support structures need to be designed. A short model of a helical solenoid (HS), consisting of four coils and supporting structures, was designed, built and tested at Fermilab. The magnetic and mechanical designs were analyzed using TOSCA and ANSYS. The supporting structures were fabricated and assembled using SSC NbTi cable. Strain gauges were utilized to monitor the deformation of the structures due to both thermal contraction and Lorentz forces. The superconducting coils were trained during the test. The model should prove the design concept, fabrication technology, and the magnet system performance.
Date: January 1, 2010
Creator: Yu, M.; Andreev, N.; Chlachidze, G.; /Fermilab; Johnson, R.P.; /MUONS Inc., Batavia et al.
Partner: UNT Libraries Government Documents Department

Design Studies of Magnet Systems for Muon Helical Cooling Channels

Description: Helical cooling channels with superimposed solenoid and helical dipole and quadrupole coils, and a pressurized gas absorber in the aperture offer high efficiency of 6D muon beam cooling. In this paper, we continue design studies and comparison of two basic concepts of magnet system proposed for a helical cooling channel focusing on the high field sections. The results of magnetic analysis and Lorentz force calculations as well as the superconductor choice are presented and discussed.
Date: June 25, 2008
Creator: Kashikhin, V.; Kashikhin, V.S.; Lamm, M.J.; Lopes, M.L.; Zlobin, A.V.; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

Modeling the high-field section of a muon helical cooling channel

Description: This paper describes the conceptual design and parameters of a short model of a high-field helical solenoid for muon beam cooling. Structural materials choices, fabrication techniques and first test results are discussed.
Date: May 1, 2010
Creator: Zlobin, A.V.; Barzi, E.; Kashikhin, V.S.; Lamm, M.J.; Lombardo, V.; Lopes, M.L. et al.
Partner: UNT Libraries Government Documents Department