Report on the Production Magnet Measurement System for the Fermilab Energy Saver Superconducting Dipoles and Quadrupoles
TL;DR: The measurement system and procedures used to test more than 900 superconducting dipole magnets and more than 275 superconducted quadrupole magnets for the Fermilab Energy Saver are described in this article.
Abstract: The measurement system and procedures used to test more than 900 superconducting dipole magnets and more than 275 superconducting quadrupole magnets for the Fermilab Energy Saver are described. The system is designed to measure nearly all parameters relevant to the use of the magnets in the accelerator including maximum field capability and precision field measurements. The performance of the instrumentation with regard to precision, reliability, and operational needs for high volume testing will be described. Previous reports have described the measurement system used during development of the Saver magnets from which this system has evolved.
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TL;DR: In this paper, the time variation in the magnetic field of a model Tevatron dipole magnet at constant excitation current has been studied and it has been observed that variations in symmetry allowed harmonic components over long time ranges show a log t behavior indicative of "flux creep".
Abstract: The time variation in the magnetic field of a model Tevatron dipole magnet at constant excitation current has been studied. Variations in symmetry allowed harmonic components over long time ranges show a log t behavior indicative of 'flux creep'. Both short-time-range and long-time-range behavior depend on the excitation history. Similar effects are seen in the remnant fields present in full-scale Tevatron dipoles following current ramping. Both magnitudes and time dependences are observed to depend on details such as ramp rate, flattop duration, and number of ramps. In a few magnets, variations are also seen in symmetry-disallowed harmonics. >
32Â citations
CERN1
TL;DR: In this paper, the problems encountered and solved at the Tevatron are described and used as an introduction to the many challenges posed by the use of superconducting magnet technology.
Abstract: Superconducting magnets have played a key role in advancing the energy reach of proton synchrotrons and enabling them to play a major role in defining the Standard Model. The problems encountered and solved at the Tevatron are described and used as an introduction to the many challenges posed by the use of this technology. The LHC is being prepared to answer the many questions beyond the Standard Model and in itself is at the cutting edge of technology. A description of its magnets and their properties is given to illustrate the advances that have been made in the use of superconducting magnets over the past 30 years.
29Â citations
TL;DR: In this article, the authors present magnetic field data from Fermilab's production line for the fabrication of 901 21 foot long superconducting dipoles for use in the Energy Saver/Doubler, showing that the mechanical design permits substantial reduction of the magnitudes of the normal and skew quadrupole harmonic coefficients.
Abstract: At Fermilab we have operated a production line for the fabrication of 901 21 foot long superconducting dipoles for use in the Energy Saver/Doubler. At any one time 772 of these dipoles are installed in the accelerator and 62 in beamlines; the remainder are spares. Magnetic field data are now available for most of these dipoles; in this paper we present some of these data which show that we have been able to maintain the necessary consistency in field quality throughout the production process. Specifically we report harmonic field coefficients, showing that the mechanical design permits substantial reduction of the magnitudes of the normal and skew quadrupole harmonic coefficients; field shape profiles; integral field data; and field angle data. Details of the measurement apparatus and procedures are described elsewhere.
26Â citations
TL;DR: In this article, data on the persistent current residual fields in Tevatron dipoles and quadrupoles are presented and compared to the doublet theory of persistent current fields and an estimate is given for the multipole fields expected in the Superconducting Super Collider (SSC) dipole proposed by Fermilab.
Abstract: Data on the persistent current residual fields in Tevatron dipoles and quadrupoles are presented. The data are compared to the doublet theory of persistent current fields and an estimate is given for the multipole fields expected in the Superconducting Super Collider (SSC) dipole proposed by Fermilab.
10Â citations
TL;DR: The Fermilab Energy Saver/Doubler (Tevatron) accelerator contains 216 superconducting quadrupole magnets before installation in the Tevatron ring.
Abstract: The Fermilab Energy Saver/Doubler (Tevatron) accelerator contains 216 superconducting quadrupole magnets Before installation in the Tevatron ring, these magnets plus an additional number of spares were extensively tested at the Fermilab Magnet Test Facility (MTF) Details on the results of the tests are presented here
6Â citations
References
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TL;DR: In this article, a computerized ac loss measurement system was developed and more than 50 magnets were measured, and a statistical correlation between quench current and ac loss was shown, from the measurements of magnets made of different kinds of cables, most of the eddy current loss was found to be in the inner coil of the double layer structure.
Abstract: A computerized ac loss measurement system was developed and more than 50 magnets were measured. The ac losses were very much dependent on various factors such as conductor surface and pressure applied to coil windings. Statistical correlation between quench current and ac loss will be shown. From the measurements of magnets made of different kinds of cables, most of the eddy current loss was found to be in the inner coil of the double layer structure. Among the three kinds of eddy current loops, the one which comes from the interconnection between crossing strands was proved to be the major part of the eddy current loss. Such an eddy current can be almost eliminated, by the use of a copper oxide resistive layer between strands. Thus, the Energy Doubler/Saver magnets, will be operated up to 4.5T with a loss of about 450J/cycle per each dipole magnet. To estimate real time power loss instead of total loss throughout whole cycle, a new method was tried and successful results were obtained.
34Â citations
TL;DR: In this article, the authors present magnetic field data from Fermilab's production line for the fabrication of 901 21 foot long superconducting dipoles for use in the Energy Saver/Doubler, showing that the mechanical design permits substantial reduction of the magnitudes of the normal and skew quadrupole harmonic coefficients.
Abstract: At Fermilab we have operated a production line for the fabrication of 901 21 foot long superconducting dipoles for use in the Energy Saver/Doubler. At any one time 772 of these dipoles are installed in the accelerator and 62 in beamlines; the remainder are spares. Magnetic field data are now available for most of these dipoles; in this paper we present some of these data which show that we have been able to maintain the necessary consistency in field quality throughout the production process. Specifically we report harmonic field coefficients, showing that the mechanical design permits substantial reduction of the magnitudes of the normal and skew quadrupole harmonic coefficients; field shape profiles; integral field data; and field angle data. Details of the measurement apparatus and procedures are described elsewhere.
26Â citations
TL;DR: In this paper, the authors measured 50 Energy Doubler dipoles and 6 quadrupoles using a facility which currently averages complete measurements of 5 magnets a week (Fig. 1).
Abstract: We have measured in recent months 50 Energy Doubler dipoles and 6 quadrupoles using a facility which currently averages complete measurements of 5 magnets a week (Fig. 1). Dipoles are 22 feet long with 3 inch diameter beam bore and produce a full field of 4.5T at 4500A. Quadrupoles are 7 feet long and produce a field gradient of 99T/m (Fig. 2). In the Energy Doubler, 4.23T corresponds to 1000 GeV. Magnets are measured individually for quench behavior, training, a.c. loss, harmonic content, integral field (gradient) length, vertical plane, longitudinal field homogeneity.
7Â citations
TL;DR: The Fermilab Energy Saver/Doubler (Tevatron) accelerator contains 216 superconducting quadrupole magnets before installation in the Tevatron ring.
Abstract: The Fermilab Energy Saver/Doubler (Tevatron) accelerator contains 216 superconducting quadrupole magnets Before installation in the Tevatron ring, these magnets plus an additional number of spares were extensively tested at the Fermilab Magnet Test Facility (MTF) Details on the results of the tests are presented here
6Â citations
TL;DR: The Fermilab Magnet Test Facility has been used to provide cooling for the testting of approximately 1200 Energy Saver superconducting magnets as mentioned in this paper, which has been in operation for about 32000 hours.
Abstract: The cryogenic system of the Fermilab Magnet Test Facility has been used to provide cooling for the testting of approximately 1200 Energy Saver superconducting magnets. The system provides liquid helium, liquid nitrogen, gas purification, and vacuum support for six magnet test stands. It provides for simultaneous high current testing of two superconducting magnets and non-high current cold testing of two additional magnets. The cryogenic system has been in operation for about 32000 hours. The 1200 magnets have taken slightly more than three years to test.
6Â citations