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ABSTRACT: The 12 GeV Upgrade at Jefferson Lab requires a new particle spectrometer for precision Nuclear Physics studies at the highest electron momentum available. This new spectrometer the Super High Momentum Spectrometer (SHMS) operating at 11 GeV/c will be built in Hall C to work in coincidence with the present device, the 7.5 GeV/c High Momentum Spectrometer (HMS). The SHMS design requires five new SC magnets arranged as dipole, quad, quad, quad, dipole or dQQQD. The ldquodrdquo is a small 3.1 T, SC dipole providing an initial 3.5 degree bend which allows the SHMS to reach a 5.5 degree scattering angle and provide enough clearance for the other much larger magnets of the SHMS. The first SC quad is an upgraded version of the HMS Q1 quad running at 10.7 T/m in a 40 cm warm bore with a 1.86 m EFL. The second and third quads are a pair of a completely new design, 60 cm warm bore, 14.4 T/m, 1.6 m EFL cosine2Theta SC quadrupole. Finally, the main dipole is a 60 cm warm bore 4.5 T, 2.85 m EFL magnet that provides the momentum analysis for the SHMS. This project is on schedule for the start of commercial procurement beginning in FY2009 to support start of Physics with the SHMS in 2014. The final design details of these four unique magnets will be presented including the coil design, magnetic design, force collar, and cryostat.
IEEE Transactions on Appiled Superconductivity 07/2009; · 1.04 Impact Factor
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ABSTRACT: Trial coil winding of full size coils for the Q1 magnet of the Super High Momentum Spectrometer (SHMS) for JLAB Hall C has been performed under contract by Scientific Magnets Inc. This effort was required to demonstrate that the unique Q1 cold iron quadrupole shape can be executed with a Rutherford type SC cable. Details of the prototype winding tooling, conductor insulation scheme, coil former, the winding process including clamping and curing will be presented. Lessons learned from the initial set of windings were incorporated into the final trail windings of two complete full scale coils that can potentially be used in the actual magnet fabrication. The initial trial windings indicted that the coil end turns would benefit from additional support in the winding form and inclusion of a 5 degree shim along the first turn of the coil would be helpful in improving the fit up of the coils on the symmetry planes, leading to an improved end shape. These changes in coil shape were modeled in TOSCA and the resultant magnetic properties confirmed. The Q1 coils wound were tested for electrical properties, insulation effectiveness and dimensional consistency. Results from the three coils wound will be presented.
IEEE Transactions on Appiled Superconductivity 07/2009; · 1.04 Impact Factor
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ABSTRACT: The reference design for the first Quadrupole magnet of TJNAF's Super High Momentum Spectrometer (SHMS), Q1, is presented. The SHMS is a DQQQD design that will be capable of resolving particles up to 11 Gev/c in momentum. Q1 follows the successful design of the High Momentum Spectrometer's (HMS) Q1, that of an elliptically shaped super ferric yoke, conformal mapped window frame coil, and helium bath cooled coil design. The primary differences between the two designs is in the choice of superconducting cable and an overall longer magnet length. A single stack of surplus SSC Rutherford NbTi cable replaces the original four stack copper stabilized conductor used in the HMS's Q1. The SHMS Q1 will have a warm bore diameter of 400 mm and produce field gradients up to 9.1 T/m with an effective length of 2.14 m. Test coil windings progress will be given as well as reports on forces, conductor stability and energy margins.
IEEE Transactions on Appiled Superconductivity 07/2008; · 1.04 Impact Factor
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ABSTRACT: The Jefferson Lab 12 GeV/c upgrade involves building a new 12 GeV/c spectrometer for JLAB's Hall C called the super high momentum spectrometer (SHMS). This device achieves 4.5 mStr acceptance at bend angles for 5.5 to 40 by using five magnetic elements in a DQQQD configuration. The Q1 quadrupole is described elsewhere in this conference and is an evolution of a cold iron magnet used previously for the existing JLAB 7.5 GeV/c high momentum spectrometer (HMS). The pair of identical cosine two theta quads are an entirely new design with a large 60 cm warm bore and 13 T/m gradient. These 5 T Quads provide focusing for particles from 1 to 12 GeV/c and have an integral gradient strength of 23.5 (T/m)m. The magnetic design, including multipole strengths, will be presented. The quadrupole cold mass uses a stainless steel shrink fit force collar, titanium keys and a copper stabilized superconductor consisting of a 36 strand surplus SSC outer cable wave soldered to a copper extruded substrate. This combination provides for a very conservative magnet that can be assembled with little or no tooling and a high degree of stability. The force collar mechanical analysis will be presented as well as details of the magnet cryostat.
IEEE Transactions on Appiled Superconductivity 07/2008; · 1.04 Impact Factor
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[show abstract]
[hide abstract]
ABSTRACT: The Jefferson Lab 12 GeV upgrade involves building a new 12 GeV/c spectrometer for JLAB Hall C called the Super High Momentum Spectrometer (SHMS). This device achieves 4.5 mSr acceptance at bend angles from 5.5 degrees to 40 degrees by using five magnetic elements. The other magnetic elements of the SHMS, including the small SC dipole used to achieve the small 5.5 degree scattering angle, are described elsewhere in this conference. The 4.5 T SC dipole provides momentum analysis for particles from 1 to 12 GeV/c and has bend strength of 13.5 Tm. The magnetic design, including multipole strengths, will be presented. The dipole's cold mass uses a stainless steel shrink fit force collar, titanium keys and a copper stabilized super conductor consisting of a 36 strand surplus SSC outer cable wave soldered to a copper extruded substrate. This combination provides for a very conservative magnet that can be assembled with little or no tooling and has a high degree of stability. The force collar mechanical analysis will be presented as well as details of the magnet cryostat.
IEEE Transactions on Appiled Superconductivity 07/2008; · 1.04 Impact Factor
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ABSTRACT: We report on the design, fabrication, commissioning and operation of a large superconducting magnet system that is an important element of the 8 sector super conducting toroidal G0 Spectrometer located at Jefferson Lab (JLAB) in Newport News, VA. The purpose of the G0 experiment is the high precision measurement of polarized electron scattering by protons to isolate the strange quark content of normal baryonic matter by observing parity violation caused by the weak interaction. The G0 spectrometer has been operating for three years and first results are submitted for publication . The G0 SC torus is 4 meters long and 4 meters outside diameter and produces 3 Tesla in the 8 gaps that are accessible to particles. The realization of this 8 sector superconducting toroidal magnet required the development of a number of challenging large scale features including: large total open solid angle, high sector-sector field symmetry, the symmetry axis aligned perpendicular to gravity, the location of the liquid hydrogen (proton) target on axis in the magnet cryostat, and large surface area but thin titanium exit windows on one end of the cryostat. The cryostat consists of a super-alloy welded low permeability stainless steel shell (to minimize magnetization effects) and aluminum end caps. The 8 superconducting coils have unique characteristics including dry pancake wound copper stabilized NbTi conductors, encased in aluminum structure, mechanically preloaded and indirectly cooled by a set of parallel thermo siphon circuits. This magnet was built by BWXT under a fixed price performance contract that included fabrication to a defined ideal cold current spatial distribution. The commissioning and operations will be discussed
IEEE Transactions on Appiled Superconductivity 07/2006; · 1.04 Impact Factor
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ABSTRACT: The 12 GeV upgrade at Jefferson Lab has identified two new large spectrometers as Physics detectors for the project. The first is a 7.5 Gev/c 35 m-sr. spectrometer that requires a pair of identical Combined Function Superconducting Magnets (CFSM) that can simultaneously produce 1.5 T dipole fields and 4.5 T/m quadrupole fields inside a warm bore of 120cm. The second is an 11 GeV/c 2 m-sr. spectrometer that requires a CFSM that simultaneously produces a dipole field of 4.0 T and a quadruple field of 3.0 T/m in a 60 cm warm bore. Magnetic designs using TOSCA 3D have been performed to realize the magnetic requirements, provide 3d fields for optics analysis and produce field and force information for the engineering feasibility of the magnets. A two-sector cos(θ)/cos(2θ) design with a low nominal current density, warm bore and warm iron design has been selected and analyzed. These low current densities are consistent with the limits for a cryostable winding. The current paper will summarize the requirement definition of these two magnets. The conceptual design arrived at during the feasibility study involving the choice of conductors, thermal and structural analyses will be presented. A discussion of the manufacturing approach and challenges will be provided.
IEEE Transactions on Appiled Superconductivity 07/2005; · 1.04 Impact Factor
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ABSTRACT: An eight coil superconducting toroidal magnetic spectrometer has
been designed for the G0 experiment to be performed at Thomas Jefferson
National Accelerator Facility (TJNAF). The toroid is designed so that
the particle trajectories pass through the magnet insulating vacuum. The
magnet is made of aluminum structural components with a copper
stabilized indirectly cooled conductor. The toroid is 2 meters long, 4
meters outside diameter and is oriented with its major axis horizontal.
This orientation allows its use as an eight fold symmetric focusing
spectrometer. The SC magnet has a stored energy of 6.5 Mjoules. The
design and analysis of this device are presented. The plans and status
of magnet system procurement are presented
IEEE Transactions on Appiled Superconductivity 07/1997; · 1.04 Impact Factor
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P.D. Brindza,
M.J. Fowler,
R.T. Wines,
S.R. Lassiter,
S.R. Milward,
S. Pearmain,
J. Schouten,
N. Oda,
K. Tamura,
F. Ramsauer,
S. Wenger,
P. Bogensberger,
H. Sammer,
H. Dermoetz
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ABSTRACT: The High Momentum Spectrometer (HMS) became operational in June
1994 and is now in routine use as a nuclear physics spectrometer in Hall
C at TJNAF. The commissioning including installation, cooldown, initial
operation, testing and acceptance of the SC quadrupoles and SC dipole of
the HMS will be discussed. Results of measurements performed on the
magnets will be presented. The loss of a dipole current lead, failure
analysis and the repairs will be discussed. A brief discussion of the
Hall C SC magnet cryogenics will be included
IEEE Transactions on Appiled Superconductivity 07/1997; · 1.04 Impact Factor
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ABSTRACT: The cold iron, cryostable, superconducting, large aperture magnets
will operate over a decade of pole field excitation, from 0.2 T up to
2.1 T. The authors present a description of the modifications and
changes to these magnets that have occurred. The use of a
three-dimensional magnetostatic program, as a means of quality control
for these changes, and a description of the structural modifications to
the cryostat are included. The final expected magnetic performance as
modeled with the program is listed for the superconducting quadrupoles.
As modifications and manufacturing details have manifested, workable
solutions have been implemented that preserve both the magnetic and
mechanical specifications as well as keep to the delivery schedule. The
current status of the project is presented
IEEE Transactions on Appiled Superconductivity 04/1993; · 1.04 Impact Factor
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ABSTRACT: The current design for the Hall C High Momentum Spectrometer calls
for two large-aperture quadrupoles, each having the same physical
characteristics but operating at different field gradients. A cold-iron,
superconducting, laminated yoke magnet has been developed as the
reference design. The results of the two- and three-dimensional
magnetostatic studies are presented along with some details of the
conductor and cryostat design
IEEE Transactions on Magnetics 04/1991; · 1.36 Impact Factor
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ABSTRACT: The dipole for the Hall C High Momentum Spectrometer is a 470-ton,
superconducting, cryostable magnet. With a bend radius of 12.05625 m and
an effective length of 5.26 m, it is configured to achieve a 25°
bending angle for 6-GeV/c momentum particles over its 42-cm gap at a
central field excitation of 1.66 T. The thermal syphon cooled coil
consists of three double pancakes of 3-kA copper-stabilized conductor.
The cryostat consists of this cryostable coil wound directly onto a
stainless steel bobbin with G-10 support cylinders connected to the
bobbin to transfer loads produced during energization to the yoke iron,
and a stainless steel heat transfer panel cooled by LN<sub>2</sub> and a
stainless steel vacuum vessel. The coil assembly is suspended within the
vacuum vessel by eight tensioning support links
IEEE Transactions on Magnetics 04/1991; · 1.36 Impact Factor
