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Modifications in the AUTOMESH and other POISSON Group Codes

Description: Improvements in the POISSON Group Codes are discussed. These improvements allow one to compute magnetic field to an accuracy of a few parts in 100,000 in quite complicated geometries with a reduced requirement on computational time and computer memory. This can be accomplished mainly by making the mesh dense at some places and sparse at other places. AUTOMESH has been modified so that one can use variable mesh size conveniently and efficiently at a number of places. We will present an example to illustrate these techniques. Several other improvements in the codes AUTOMESH, LATTICE and POISSON will also be discussed.
Date: January 1, 1986
Creator: Gupta, R.C.
Partner: UNT Libraries Government Documents Department

Improved mesh generator for the POISSON Group Codes

Description: This paper describes the improved mesh generator of the POISSON Group Codes. These improvements enable one to have full control over the way the mesh is generated and in particular the way the mesh density is distributed throughout this model. A higher mesh density in certain regions coupled with a successively lower mesh density in others keeps the accuracy of the field computation high and the requirements on the computer time and computer memory low. The mesh is generated with the help of codes AUTOMESH and LATTICE; both have gone through a major upgrade. Modifications have also been made in the POISSON part of these codes. We shall present an example of a superconducting dipole magnet to explain how to use this code. The results of field computations are found to be reliable within a few parts in a hundred thousand even in such complex geometries.
Date: March 16, 1987
Creator: Gupta, R.C.
Partner: UNT Libraries Government Documents Department

Collarless, close-in, shaped iron aperture designs for the SSC (Superconducting Super Collider) dipole

Description: The nominal-design SSC (Superconducting Super Collider) dipole encloses the coil in an iron yoke having a circular aperture. The radial gap between the coil and the iron is about 15 mm to provide space for a strong annular collar around the coil, and also to reduce the effects of iron saturation on central field harmonics. The 15 mm gap also reduces the desirable dipole field contributed by the iron. The present paper gives a coil and aperture configuration in which the gap is reduced to 5 mm at the midplane, in which the aperture is shaped to reduce the unwanted effects of iron saturation. The transfer function is increased about 5% at 6.6 Tesla and the unwanted harmonics are within SSC tolerances at all field levels. These designs would require that the yoke and containment vessel absorb the stresses due to assembly and magnetic forces. A short magnet is being built with a close-in shaped iron aperture and existing coil geometry to assess the benefits of this concept. 7 refs., 3 figs., 6 tabs.
Date: January 1, 1989
Creator: Gupta, R.C. & Morgan, G.H.
Partner: UNT Libraries Government Documents Department

Design for a high field combined function superferric magnet

Description: A combined function superferric magnet option has been investigated for the Relativistic Heavy Ion Collider (RHIC). The option requires the maximum value of the field in the magnet to be much higher than that achieved in any existing combined function accelerator magnet. A model is presented here in which a good field quality can be maintained up to 2T. It is done by carefully designing the yoke structure and positioning the coils in such a way that the iron poles tend to saturate evenly across the gap. A cold iron model might be necessary for this magnet. 4 refs., 2 figs., 1 tab.
Date: January 1, 1985
Creator: Gupta, R.C. & Morgan, G.H.
Partner: UNT Libraries Government Documents Department

Correcting field harmonics after design in superconducting magnets

Description: For a variety of reasons the actual field harmonics, as measured, in the superconducting magnets come out to be somewhat different than what were intended at the time of design. In this paper we shall discuss the schemes which can be used to correct them in the magnets. We shall discuss them for both the allowed and non-allowed harmonics. Since the deviation in field harmonics from their design value is mainly related to the mechanical properties of the coil cross section, in order for a scheme to work as planned, the mechanical configuration of the coil should not be changed significantly while this correction is being implemented.
Date: January 1, 1992
Creator: Gupta, R.C.
Partner: UNT Libraries Government Documents Department

Improving the design and analysis of superconducting magnets for particle accelerators

Description: High energy particle accelerators are now the primary means of discovering the basic building blocks of matter and understanding the forces between them. In order to minimize the cost of building these machines, superconducting magnets are used in essentially all present day high energy proton and heavy ion colliders. The cost of superconducting magnets is typically in the range of 20--30% of the total cost of building such machines. The circulating particle beam goes through these magnets a large number of times (over hundreds of millions). The luminosity performance and life time of the beam in these machines depends significantly on the field quality in these magnets. Therefore, even a small error in the magnetic field shape may create a large cumulative effect in the beam trajectory to throw the particles of the magnet aperture. The superconducting accelerator magnets must, therefore, be designed and constructed so that these errors are small. In this thesis the research and development work will be described 3which has resulted in significant improvements in the field quality of the superconducting magnets for the Relativistic Heavy Ion Collider (RHIC). The design and the field quality improvements in the prototype of the main collider dipole magnet for the Superconducting Super Collider (SSC) will also be presented. RHIC will accelerate and collide two counter rotating beams of heavy ions up to 100 GeV/u and protons up to 250 GeV. It is expected that RHIC will create a hot, dense quark-gluon plasma and the conditions which, according to the Big Bang theory, existed in the early universe.
Date: November 1, 1996
Creator: Gupta, R.C.
Partner: UNT Libraries Government Documents Department

IMPROVING THE DESIGN AND ANALYSIS OF SUPERCONDUCTING MAGNETS FOR PARTICLE ACCELERATORS

Description: The field quality in superconducting magnets has been improved to a level that it does not appear to be a limiting factor on the performance of RHIC. The many methods developed, improved and adopted during the course of this work have contributed significantly to that performance. One can not only design and construct magnets with better field quality than in one made before but can also improve on that quality after construction. The relative field error ({Delta}B/B) can now be made as low as a few parts in 10{sup {minus}5} at 2/3 of the coil radius. This is about an order of magnitude better than what is generally expected for superconducting magnets. This extra high field quality is crucial to the luminosity performance of RHIC. The research work described here covers a number of areas which all must be addressed to build the production magnets with a high field quality. The work has been limited to the magnetic design of the cross section which in most cases essentially determines the field quality performance of the whole magnet since these magnets are generally long. Though the conclusions to be presented in this chapter have been discussed at the end of each chapter, a summary of them might be useful to present a complete picture. The lessons learned from these experiences may be useful in the design of new magnets. The possibilities of future improvements will also be presented.
Date: November 1, 1996
Creator: GUPTA,R.C.
Partner: UNT Libraries Government Documents Department

A single layer coil superconducting magnet for SSC (Superconducting Super Collider)

Description: The superconducting magnet under consideration for the proposed Superconducting Super Collider (SSC) uses a two layer coil geometry and is optimized for 6.6 T central field. In this paper we assess if it is possible to design a dipole having a realistic single layer coil configuration, using a cable having the same size as that used in the present SSC outer layer coil, can achieve a central field of about 6 T. The affirmative answer assumes a superconductor current density approaching the best achieved thus far in production, close-coupled cold iron with at most a very thin collar, a high but not unreasonable current density in copper at quench, and operation below 4.2 K. The performance under other operating conditions will also be discussed. We shall first describe the cable used in this design. We shall discuss the optimization procedure of the iron shape, particularly in the aperture region to minimize the effects of iron saturation. We shall outline the design of a realistic single layer coil geometry. Finally we shall discuss various operating parameters from the quench protection point of view.
Date: 1987
Creator: Gupta, R. C.; Morgan, G. H. & Thompson, P. A.
Partner: UNT Libraries Government Documents Department

A comparison of calculations and measurements of the magnetic characteristics of the SSC (Superconducting Super Collider) design D dipole

Description: Measurements on two 4.5 m long design D dipoles are compared with computer calculations of their harmonics. These two magnets were tested at high fields, up to about 7.5 T, by subcooling.
Date: January 1, 1987
Creator: Gupta, R.C.; Morgan, G.H. & Wanderer, P.
Partner: UNT Libraries Government Documents Department

Coil and iron design for SSC 50 mm magnet

Description: In this paper we present the design of the two dimensional coil and iron cross section, referred to as DSX201/W6733, for the 50 mm aperture dipole magnet being built at the Brookhaven National Laboratory for the Superconducting Super Collider (SSC). The computed values of the allowed field harmonics as a function of current, the quench performance predictions, the stored energy calculations, the effect of random errors on the coil placement and the Lorentz forces on the coil will be presented. The yoke has been optimized to reduce iron saturation effects on the field harmonics. We shall present the summary of this design which will include the expected overall performance of this cross section. 4 refs., 8 figs., 12 tabs.
Date: January 1, 1990
Creator: Gupta, R.C.; Kahn, S.A. & Morgan, G.H.
Partner: UNT Libraries Government Documents Department

SSC 50 mm dipole cross section

Description: In this paper we present the magnetic design of the two dimensional coil and iron cross section, referred to as DSX201/W6733, for the 50 mm aperture main ring dipole magnet for the Superconducting Super Collider (SSC). The computed values of the allowed field harmonics as a function of current, the quench performance predictions, the stored energy calculations, the effect of random errors on the coil placement and the Lorentz forces on the coil will be presented. The yoke has been optimized to reduce iron saturation effects on the field harmonics. We shall present the summary of this design which will include the expected overall performance of this cross section. Prototypes of these dipoles are being built at the Brookhaven National Laboratory (BNL) and at the Fermi National Accelerator Laboratory (FNAL). There are slight differences between the cross sections at the two laboratories. 7 refs., 6 figs., 11 tabs.
Date: January 1, 1991
Creator: Gupta, R.C.; Kahn, S.A. & Morgan, G.H.
Partner: UNT Libraries Government Documents Department

Beam transfer lines for the AGS (Alternating Gradient Synchrotron) Booster

Description: The injection lines for the proton and heavy ion beam injection into the Booster and a beam transfer line from the Booster to the Alternating Gradient Synchrotron (AGS) are described here. The proton injection line is from the 200 MeV linac and the heavy ion injection line is from the present beam transport line of the Tandem Van de Graaff. The beam transfer line is for transporting the accelerated beam from the Booster to the AGS. Also included in the discussion is a method of extraction from the Booster and injection into the AGS.
Date: January 1, 1987
Creator: Gupta, R.C.; Lee, S.Y.; Lee, Y.Y. & Zhao, X.F.
Partner: UNT Libraries Government Documents Department

The Effect of Axial Stress on YBCO Coils

Description: The large aspect ratio of typical YBCO conductors makes them ideal for constructing solenoids from pancake style coils. An advantage of this method is that each subunit can be tested before assembly into the finished magnet. The fact that conductors are available in relatively short lengths is another reason for using such a fabrication technique. The principal drawback is the large number of joints required to connect the coils together. When very high field solenoids such as those contemplated for the muon collider are built in this way the magnetic forces between pancakes can be very large. Extensive measurements have been made on the effect of stress on short lengths of conductor, but there is little or no data on the effect of intercoil loading. The experiment described in this paper was designed to test the ability of YBCO coils to withstand these forces. A spiral wound 'pancake' coil made from YBCO coated conductor has been stressed to a pressure of 100MPa in the axial direction at 77K. In this case axial refers to the coil so that the force is applied to the edge of the conductor. The effect on the critical current was small and completely reversible. Repeatedly cycling the pressure had no measureable permanent effect on the coil. The small current change observed exhibited a slight hysteretic behaviour during the loading cycle.
Date: March 28, 2011
Creator: Sampson, W.; Anerella, M.; Cozzolino, J.P.; Gupta, R.C.; Shiroyanagi, Y. & Evangelou, E.
Partner: UNT Libraries Government Documents Department

Nb3Sn Magnets for a Muon Collider

Description: High field dipole and quadrupole magnet designs with racetrack coils are investigated. The design option is particularly attractive for a muon collider dipole magnet using the Nb{sub 3}Sn superconductor. A conceptual design of {approx} 15 T single aperture dipole magnet is presented where the coils maintain a simple 2-d structure through the ends. The use of racetrack coils in quadrupole magnets is also discussed. It appears that the racetrack coils are less attractive for high gradient quadrupole magnets.
Date: June 20, 1998
Creator: Gupta, R.C.; Green, M.A.; Scanlan, R.M. & Palmer, R.
Partner: UNT Libraries Government Documents Department

Nb{sub 3}Sn magnets for a muon collider

Description: High field dipole and quadrupole magnet designs with racetrack coils are investigated. The design option is particularly attractive for a muon collider dipole magnet using the Nb{sub 3}Sn superconductor. A conceptual design of {approximately}15 T single aperture dipole magnet is presented where the coils maintain a simple 2-d structure through the ends. The use of racetrack coils in quadrupole magnets is also discussed. It appears that the racetrack coils are less attractive for high gradient quadrupole magnets.
Date: July 1998
Creator: Gupta, R. C.; Green, M. A.; Scanlan, R. M. & Palmer, R.
Partner: UNT Libraries Government Documents Department

A comparison of calculations and measurements of the field harmonics as a function of current in the SSC dipole magnets

Description: A large number of short and long superconducting dipole magnets for the Superconducting Super Collider (SSC) have been constructed and measured for their magnetic field properties at Brookhaven National Laboratory (BNL). In this paper we compare the calculations and measurements for the variation of field harmonics as a function of current in 40 mm aperture and 50 mm aperture dipole magnets. The primary purpose of this paper is to examine the iron saturation effects on the field harmonics. The field harmonics also change due to the persistent current in the superconducting wires and due to the deformation of the coil shape because of Lorentz forces. We discuss the variation in the sextupole harmonics (b{sub 2}) with current and explain the differences between the calculations and measurements. We also discuss the skew quadrupole harmonic at high field in the long dipole magnets. 3 refs., 3 figs., 1 tab.
Date: January 1, 1991
Creator: Gupta, R.C.; Cottingham, J.G.; Kahn, S.A.; Morgan, G.H. & Wanderer, P.
Partner: UNT Libraries Government Documents Department

Field quality evaluation of the superconducting magnets of the relativistic heavy ion collider

Description: In this paper, the authors first present the procedure established to evaluate the field quality, quench performance, and alignment of the superconducting magnets manufactured for the Relativistic Heavy Ion Collider (RHIC), and then discuss the strategies used to improve the field quality and to minimize undesirable effects by sorting the magnets. The field quality of the various RHIC magnets is briefly summarized.
Date: May 1, 1995
Creator: Wei, J.; Gupta, R.C.; Jain, A.; Peggs, S.G.; Trahern, C.G.; Trbojevic, D. et al.
Partner: UNT Libraries Government Documents Department

Iron saturation control in RHIC dipole magnets

Description: The Relativistic Heavy Ion Collider (RHIC) will require 360 dipoles of 80 mm bore. This paper discusses the field perturbations produced by the saturation of the yoke iron. Changes have been made to the yoke to reduce these perturbations, in particular, decapole < 10{sup {minus}4}. Measurements and calculations for 6 series of dipole magnets are presented. 2 refs., 2 figs., 1 tab.
Date: January 1, 1991
Creator: Thompson, P.A.; Gupta, R.C.; Kahn, S.A.; Hahn, H.; Morgan, G.H.; Wanderer, P.J. et al.
Partner: UNT Libraries Government Documents Department

Revised cross section for RHIC dipole magnets

Description: Using the experience gained in designing and building Relativistic Heavy Ion Collider (RHIC) dipole prototype magnets an improved cross section has been developed. Significant features of this design include the use of only three wedges for field shaping and wedge cross sections which are sectors of an annulus. To aid in the understanding of the actual magnets, one has been sectioned, and detailed mechanical and photographic measurements made of the wire positions. The comparison of these measurements with the magnetic field measurements will is presented. 2 refs, 3 figs., 2 tabs.
Date: January 1, 1991
Creator: Thompson, P.A.; Gupta, R.C.; Kahn, S.A.; Hahn, H.; Morgan, G.H.; Wanderer, P.J. et al.
Partner: UNT Libraries Government Documents Department

The AGS-Booster lattice

Description: The AGS Booster has three objectives. They are to increase the space charge limit of the AGS, to increase the intensity of the polarized proton beam by accumulating many linac pulses (since the intensity is limited by the polarized ion source), and to reaccelerate heavy ions from the BNL Tandem Van de Graaff before injection into the AGS. The machine is capable of accelerating protons at 7.5 Hertz from 200 MeV to 1.5 GeV or to lower final energies at faster repetition rates. The machine will also be able to accelerate heavy ions from as low as 1 MeV/nucleon to a magnetic rigidity as high as 17.6 Tesla-meters with a one second repetition rate. As an accumulator for polarized protons, the Booster should be able to store the protons at 200 MeV for several seconds. We expect that the Booster will increase the AGS proton intensity by a factor of four, polarized proton intensity by a factor of twenty to thirty, and will also enable the AGS to accelerate all species of heavy ions (at present the AGS heavy ion program is limited to the elements lighter than sulfur because it can only accelerate fully stripped ions). The construction project started in FY 1985 and is expected to be completed in 1989. The purpose of this paper is to provide a future reference for the AGS Booster lattice.
Date: January 1, 1987
Creator: Lee, Y.Y.; Barton, D.S.; Claus, J.; Cottingham, J.G.; Courant, E.D.; Danby, G.T. et al.
Partner: UNT Libraries Government Documents Department

HIGH FIELD SOLENOID FOR MUON COOLING.

Description: Magnets made with high-temperature superconducting (HTS) coils operating at low temperatures have the potential to produce extremely high fields for use in accelerators and beam lines. The specific application of interest that we are proposing is to use a very high field (of the order of 50 Tesla) solenoid to provide a very small beta region for the final stages of cooling for a muon collider. With the commercial availability of HTS conductor based on BSCCO technology with high current carrying capacity at 4.2 K, very high field solenoid magnets should be possible. In this paper we will evaluate the technical issues associated with building this magnet. In particular we address how to mitigate the high Lorentz stresses associated with this high field magnet.
Date: June 26, 2006
Creator: KAHN, S.A.; ALSHARO'A, M.; HANLET, P.; JOHNSON, R.P.; KUCHNIR, M.; NEWSHAM, F. et al.
Partner: UNT Libraries Government Documents Department

Status of RHIC head-on beam-beam compensation project

Description: Two electron lenses are under construction for RHIC to partially compensate the head-on beam-beam effect in order to increase both the peak and average luminosities. The final design of the overall system is reported as well as the status of the component design, acquisition, and manufacturing. An overview of the RHIC head-on beam-beam compensation project is given in [1], and more details in [2]. With 2 head-on beam-beam interactions in IP6 and IP8, a third interaction with a low-energy electron beam is added near IP10 to partially compensate the the head-on beam-beam effect. Two electron lenses are under construction, one for each ring. Both will be located in a region common to both beams, but each lens will act only on one beam. With head-on beam-beam compensation up to a factor of two improvement in luminosity is expected together with a polarized source upgrade. The current RHIC polarized proton performance is documented in Ref. [4]. An electron lens (Fig. 1) consists of an DC electron gun, warm solenoids to focus the electron beam during transport, a superconducting main solenoid in which the interaction with the proton beam occurs, steering magnets, a collector, and instrumentation. The main developments in the last year are given below. The experimental program for polarized program at 100 GeV was expected to be finished by the time the electron lenses are commissioned. However, decadal plans by the RHIC experiments STAR and PHENIX show a continuing interest at both 100 GeV and 250 GeV, and a larger proton beam size has been accommodated in the design (Tab. 1). Over the last year beam and lattice parameters were optimized, and RHIC proton lattices are under development for optimized electron lens performance. The effect of the electron lens magnetic structure on the proton beam was evaluated, and found to ...
Date: March 28, 2011
Creator: Fischer, W.; Anerella, M.; Beebe, E.; Bruno, D.; Gassner, D.M.; Gu, X. et al.
Partner: UNT Libraries Government Documents Department

LARP Long Nb3Sn Racetrack Coil Program

Description: Development of high-performance Nb{sub 3}Sn quadrupoles is one of the major goals of the LHC Accelerator Research Program (LARP). As part of this program, long racetrack magnets are being made in order to check that the change in coil length that takes place during reaction is correctly accounted for in the quadrupole design and to check for length effects in implementing the 'shell' method of coil support. To check the racetrack magnet manufacturing plan, a short racetrack magnet is being made. This magnet will be the first to use restack-rod process Nb{sub 3}Sn, making it a 'long sample' test vehicle for this new material. The paper reports the reaction and characterization of the Nb{sub 3}Sn, and construction features and test results from the short racetrack magnet. The paper also reports on the status of the construction of the first long racetrack magnet.
Date: June 1, 2007
Creator: Wanderer, P.; Ambrosio, G.; Anerella, M.; Barzi, E.; Bossert, R.; Cheng, D. et al.
Partner: UNT Libraries Government Documents Department