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Resolution depths for some transmitter receiverconfigurations

Description: Away from a conductive body, secondary magnetic fields due to currents induced in the body by a time varying external magnetic field are approximated by (equivalent) magnetic dipole fields. Approximating the external magnetic field by its value at the location of the equivalent magnetic dipoles, the equivalent magnetic dipoles' strengths are linearly proportional to the external magnetic field, for a given time dependence of external magnetic field, and are given by the equivalent dipole polarizability matrix. The polarizability matrix and its associated equivalent dipole location is estimated from magnetic field measurements made with at least three linearly independent polarizations of external magnetic fields at the body. Uncertainties in the polarizability matrix elements and its equivalent dipole location are obtained from analysis of a linearized inversion for polarizability and dipole location. Polarizability matrix uncertainties are independent of the scale of the polarizability matrix. Dipole location uncertainties scale inversely with the scale of the polarizability matrix. Uncertainties in principal polarizabilities and directions are obtained from the sensitivities of eigenvectors and eigenvalues to perturbations of a symmetric matrix. In application to synthetic data from a magnetic conducting sphere and to synthetic data from an axially symmetric elliptic conducting body, the estimated polarizability matrices, equivalent dipole locations and principal polarizabilities and directions are consistent with their estimated uncertainties.
Date: August 28, 2002
Creator: Smith, J. Torquil; Morrison, H. Frank & Becker, Alex
Partner: UNT Libraries Government Documents Department

Measurements of the persistent current decay and snapback effect in Nb3Sn Fermilab-built accelerator prototype magnets

Description: In recent years, Fermilab has been performing an intensive R an D program on Nb{sub 3}Sn accelerator magnets. This program has included dipole and quadrupole magnets for different programs and projects, including LARP and VLHC. A systematic study of the persistent current decay and snapback effect in the fields of these magnets was executed at the Fermilab Magnet Test Facility. The decay and snapback were measured under a range of conditions including variations of the current ramp parameters and flattop and injection plateau durations. This study has mostly focused on the dynamic behavior of the normal sextupole and dodecapole components in dipole and quadrupole magnets respectively. The paper summarizes the recent measurements and presents a comparison with previously measured NbTi magnets.
Date: May 1, 2012
Creator: Velev, G. V.; Chlachidze, G.; DiMarco, J. & Kashikhin, V. V.
Partner: UNT Libraries Government Documents Department

The Search for the CP-violating emission of an E1 photon from the K(L) ---> pi+ pi- gamma decay

Description: A search for the CP-violating electric dipole (E1) direct emission contribution to the K{sub L} {yields} {pi}{sup +}{pi}{sup -}{gamma} decay is performed using data from the 1997 KTeV/E832 experiment. Because the K{sub L} {yields} {pi}{sup +}{pi}{sup -}{gamma} decay mode is massively dominated by the CP-violating inner bremsstrahlung (IB) and the CP-conserving magnetic dipole (M1) direct emission processes, previous analyses have neglected the E1 contribution. Therefore, this measurement is the first attempt to directly quantify the size of the E1 decay process. This E1 transition is one of the very few CP-violating processes that is accessible to experiment and, in principle, will produce new insights into the structure of the neutral kaon. The result of this analysis is that the E1 contribution is below the threshold of sensitivity, and therefore an upper bound of |g{sub E1}| < 0.14 (90% CL) is reported. In the process of obtaining this upper limit, high resolution measurements of fit parameters ({tilde g}{sub M1} and a{sub 1}/a{sub 2}) associated with the size and shape of the M1 direct emission peak are also extracted. The fit results for these parameters: {tilde g}{sub M1} = 1.229 {+-} 0.035 (stat) {+-} 0.087 (syst); a{sub 1}/a{sub 2} = -0.733 {+-} 0.007 (stat) {+-} 0.014 (syst) are in strong agreement with previous measurements.
Date: January 1, 2005
Creator: Shields, John Michael & U., /Virginia
Partner: UNT Libraries Government Documents Department

Use beam steering dipoles to minimize aberrations associated with off-centered transit through the induction bunching module. Design an improved NDCX-I drift compression section to make best use of the new bunching module to optimize planned initial NDCX-I target experiments

Description: This milestone has been met by: (1) calculating steering solutions and implementing them in the experiment using the three pairs of crossed magnetic dipoles installed in between the matching solenoids, S1-S4. We have demonstrated the ability to center the beam position and angle to<1 mm and<1 mrad upstream of the induction bunching module (IBM) gap, compared to uncorrected beam offsets of several millimeters and milli-radians. (2) Based on LSP and analytic study, the new IBM, which has twice the volt-seconds of our first IBM, should be accompanied by a longer drift compression section in order to achieve a predicted doubling of the energy deposition on future warm-dense matter targets. This will be accomplished by constructing a longer ferro-electric plasma source. (3) Because the bunched current is a function of the longitudinal phase space and emittance of the beam entering the IBM we have characterized the longitudinal phase space with a high-resolution energy analyzer.
Date: March 28, 2008
Creator: HIFS-VNL; Seidl, Peter; Seidl, P.; Barnard, J.; Bieniosek, F.; Coleman, J. et al.
Partner: UNT Libraries Government Documents Department

TERMINATION OF IDEAL COS m phi WINDING

Description: Configurations are proposed, and illustrated, for terminating the 'cosine {phi}' windings of an ideal iron-free dipole magnet so as to preserve the quality of the internal field integrated (vs. z) through the entire magnet. The end windings are placed on a surface of the same radius as that on which the conductors lie in the central (2-D) portion of the structure. The desired pure dipole quality of the integrated field then is assured by requiring that the z-component of current, after projection onto the y-z plane, shall have in that plane a density distribution whose integral is independent of y. As a result of the analysis, end-winding configurations that satisfy this requirement are proposed in which each conductor filament follows through the transition region a locus whose y-z projection is of the form z(y;Y{sub 0}) = f(y{sub 0}) - f(y-y{sub 0}), with f(0) = 0, wherein Y{sub 0} serves as an index to identify the location of the filament in the central (2-D) portion of the structure. Simple solutions of this nature are indicated in which the function f has the form f(y-y{sub 0}) = k (y-y{sub 0}{sup p}/a) for windings on the surface of a cylinder of radius {und a}, with p < 1 (and preferably p {le} 1/2) to ensure a smooth transition into the end region. The straightforward extension of these results to configurations for the production of integrated fields of higher multipolarity also is indicated.
Date: April 1, 1986
Creator: Laslett, L.J.; Caspi, S. & Helm, M.
Partner: UNT Libraries Government Documents Department

Multi-transmitter multi-receiver null coupled systems forinductive detection and characterization of metallic objects

Description: Equivalent dipole polarizabilities are a succinct way tosummarize the inductive response of an isolated conductive body atdistances greater than the scale of the body. Their estimation requiresmeasurement of secondary magnetic fields due to currents induced in thebody by time varying magnetic fields in at least three linearlyindependent (e.g., orthogonal) directions. Secondary fields due to anobject are typically orders of magnitude smaller than the primaryinducing fields near the primary field sources (transmitters). Receivercoils may be oriented orthogonal to primary fields from one or twotransmitters, nulling their response to those fields, but simultaneouslynulling to fields of additional transmitters is problematic. Iftransmitter coils are constructed symmetrically with respect to inversionin a point, their magnetic fields are symmetric with respect to thatpoint. If receiver coils are operated in pairs symmetric with respect toinversion in the same point, then their differenced output is insensitiveto the primary fields of any symmetrically constructed transmitters,allowing nulling to three (or more) transmitters. With a sufficientnumber of receivers pairs, object equivalent dipole polarizabilities canbe estimated in situ from measurements at a single instrument sitting,eliminating effects of inaccurate instrument location on polarizabilityestimates. The method is illustrated with data from a multi-transmittermulti-receiver system with primary field nulling through differencedreceiver pairs, interpreted in terms of principal equivalent dipolepolarizabilities as a function of time.
Date: October 17, 2005
Creator: Smith, J. Torquil; Morrison, H. Frank; Doolittle, Lawrence R. & Tseng, Hung-Wen
Partner: UNT Libraries Government Documents Department

Global and Local Coupling Compensation Experiments in Rhic Using Ac Dipoles.

Description: Compensation of transverse coupling during the RHIC energy ramp has been proven to be non-trivial and tedious. The lack of accurate knowledge of the coupling sources has initiated several efforts to develop fast techniques using turn-by-turn BPM data to identify and compensate these sources. This paper aims to summarize the beam experiments performed to measure the coupling, matrix and resonance driving terms with the aid of RHIC ac dipoles at injection energy.
Date: June 26, 2006
Creator: Calaga, R. & Franchi, A. (Gsi), Tomas, R.(Cern)
Partner: UNT Libraries Government Documents Department

Comparison of Total Cooling Provided to the Energy Released After Low Current Quenches of SSC Dipoles in MAGCOOL

Description: The performance of the MAGCOOL cryogenic system after low current strip heater quenches of SSC dipole has been investigated. For quench currents between 2000 and 4000 amperes, the loop pressure after a quench does not exceed the set pressure for venting. Excellent agreement between total cooling and the magnetic stored energy is found for each of the several values of quench current. The results indicate that the measurements are accurate and he method of calculation appropriate.
Date: April 14, 1992
Creator: Wu, K. C.
Partner: UNT Libraries Government Documents Department

Applications of the RHIC AC Dipoles and Their Expected Performance

Description: Two AC dipoles with horizontal and vertical oscillating magnetic fields will be installed in RHIC. They will provide coherent oscillations for beam dynamic studies and betatron function measurements. The AC dipole with horizontal magnetic field will also be used to induce a full spin flip for RHIC polarized proton experiments. This note discusses the applications of the AC dipoles in RHIC and their expected parameters
Date: June 18, 1999
Creator: M., Bai; Parker, B.; Meth, M.; Peggs, S.; Roser, T. & Trbojevic, D.
Partner: UNT Libraries Government Documents Department

6. 4 Tesla dipole magnet for the SSC

Description: A design is presented for a dipole magnet suitable for the proposed SSC facility. Test results are given for model magnets of this design 1 m long and 4.5 m long. Flattened wedge-shaped cables (''keystoned'') are used in a graded, two-layer ''cos theta'' configuration with three wedges to provide sufficient field uniformity and mechanical rigidity. Stainless steel collars 15 mm wide, fastened with rectangular keys, provide structural support, and there is a ''cold'' iron flux return. The outer-layer cable has 30 strands of 0.0255 in. dia NbTi multifilamentary wire with Cu/S.C. = 1.8, and the inner has 23 strands of .0318 in. dia wire with Cu/S.C. = 1.3. Performance data is given including training behavior, winding stresses, collar deformation, and field uniformity.
Date: May 1, 1985
Creator: Taylor, C.E.; Caspi, S.; Gilbert, W.; Meuser, R.; Mirk, K.; Peters, C. et al.
Partner: UNT Libraries Government Documents Department

Initial results from 50mm short SSC dipoles at Fermilab

Description: Several short model SSC 50 mm bore dipoles are being built and tested at Fermilab. Mechanical design of these magnets has been determined from experience involved in the construction and testing of 40 mm dipoles. Construction experience includes coil winding, curing and measuring, coil end part design and fabrication, ground insulation, instrumentation, collaring and yoke assembly. Fabrication techniques are explained and construction problems are discussed. Similarities and differences from the 40 mm dipole tooling and management components are outlined. Test results from the first models are presented. 19 refs., 12 figs.
Date: March 1, 1991
Creator: Bossert, R.C.; Brandt, J.S.; Carson, J.A.; Coulter, K.; Delchamps, S.; Ewald, K.D. et al.
Partner: UNT Libraries Government Documents Department

Superconductor imaging surface magnetometry: Principles and applications

Description: We present in this paper the principles of superconductor imaging surface magnetometry. This new method should permit MEG and other weak field measurements without the necessity of an expensive magnetically shielded room. We report results showing signal to noise rejection ratios of 1/333,000 with simple apparatus. The goal of 1/1,000,000, seldom achieved by second order gradiometers, should be readily attainable in improved imaging magnetometers. 3 refs., 2 figs.
Date: January 1, 1990
Creator: Overton, W.C. Jr. & van Hulsteyn, D.B.
Partner: UNT Libraries Government Documents Department

Optimizing receiver configurations for resolution of equivalent dipole polarizabilities in situ

Description: Equivalent dipole polarizabilities are a succinct way to summarize the inductive response of an isolated conductive body at distances greater than the scale of the body. At any time lag or frequency, an equivalent dipole polarizability response is comprised of 9 parameters; six specifying an equivalent dipole polarizability matrix (which is symmetric) and three specifying the apparent location of the body center. Smith and Morrison (2002) give equations for calculating uncertainties in equivalent dipole polarizability and position based on analysis of an iterative linearized inversion. Here, the root mean squared uncertainty in polarizability is weighted and summed over a number of control points and minimized using an evolutionary algorithm for a number of instrument designs. Three families of designs are presented: single transmitter systems for use on a 2-D grid of positions with negligible error in relative instrument location, two transmitter systems for use on a line of positions with negligible error in relative instrument location, and three transmitter systems for stand alone use. Results for the one and two transmitter systems are strongly degraded by errors in instrument position, whereas the three transmitter systems are insensitive to instrument positioning errors.
Date: February 12, 2004
Creator: Smith, J. Torquil & Morrison, H. Frank
Partner: UNT Libraries Government Documents Department

A Model for Determining Dipole, Quadrupole, and Combined Function Magnet Costs.

Description: One of the most important considerations in designing large accelerators is cost. This paper describes a model for estimating accelerator magnet costs, including their dependences on length, radius, and field. The reasoning behind the cost model is explained, and the parameters of the model are chosen so as to correctly give the costs of a few selected magnets. A comparison is made with earlier formulae. Estimates are also given for other costs linearly dependent on length, and for 200 MHz superconducting RF.
Date: September 14, 2004
Creator: Palmer, R. B. & Berg, S. J.
Partner: UNT Libraries Government Documents Department

Test Results on Nb3Sn Dipole Magnets

Description: A cosine theta type dipole magnet using Nb{sub 3}Sn conductor have been designed, built and tested. D19H is a two-layer dipole magnet with a Nb{sub 3}Sn inner layer and a NbTi outer layer. Coil-pairs are connected with two of the four Nb{sub 3}Sn splices in a high field region, and compressed by a ring and collet system. It trained well at 4.4K, but poorly at 1.8K. Strain gages revealed that the coil-ends were not loaded well enough for high field operation (after cool-down), so another thermal cycle is planned. The low end-load is believed to be the cause of several mysteries observed during operation. Except for the outer-layer 1.8 K training difficulty, the magnet's operation was encouraging.
Date: December 12, 1996
Creator: Lietzke, A. F.; Benjegerdes, R.; Caspi, S.; Dell'Orco, D.; Harnden, W.; McInturff, A. D. et al.
Partner: UNT Libraries Government Documents Department

Fabrication and Test Results of a Nb3Sn Superconducting Racetrack Dipole Magnet

Description: A 'proof-of-principle' Nb{sub 3}Sn superconducting dual-bore dipole magnet was built from racetrack coils, as a first step in a program to develop an economical, 15 Tesla, accelerator-quality magnet. The mechanical design and magnet fabrication procedures are discussed. No training was required to achieve temperature-dependent plateau currents, despite several thermal cycles that involved partial magnet disassembly and substantial pre-load variations. Subsequent magnets are expected to approach 15 Tesla with substantially improved conductor.
Date: February 6, 2000
Creator: Chow, K.; Dietderich, D. R.; Gourlay, S. A.; Gupta, R.; Harnden, W.; Lietzke, A. F. et al.
Partner: UNT Libraries Government Documents Department

Universality of Unintegrated Gluon Distributions at small x

Description: We systematically study dijet production in various processes in the small-x limit and establish an effective kt-factorization for hard processes in a system with dilute probes scattering on a dense target. In the large-Nc limit, the unintegrated gluon distributions involved in different processes are shown to be related to two widely proposed ones: the Weizsacker-Williams gluon distribution and the dipole gluon distribution.
Date: January 4, 2011
Creator: Dominguez, Fabio; Marquet, Cyrille; Xiao, Bowen & Yuan, Feng
Partner: UNT Libraries Government Documents Department

Fabrication and Test Results of a Nb3Sn Superconducting Racetrack Dipole Magnet

Description: A 'proof-of-principle' Nb{sub 3}Sn superconducting dual-bore dipole magnet was built from racetrack coils, as a first step in a program to develop an economical, 15 Tesla, accelerator-quality magnet. The mechanical design and magnet fabrication procedures are discussed. No training was required to achieve temperature-dependent plateau currents, despite several thermal cycles that involved partial magnet disassembly and substantial pre-load variations. Subsequent magnets are expected to approach 15 Tesla with substantially improved conductor.
Date: March 22, 1999
Creator: Chow, K.; Dietderich, D. R.; Gourlay, S. A.; Gupta, R.; Harnden, W.; Lietzke, A. F. et al.
Partner: UNT Libraries Government Documents Department

Combining multipole data

Description: The problem of combining the information from three sets of magnetic field data for dipole magnets is addressed. Three methods for combining multipole data are described which may be useful under possibly different assumptions: multipole feeddown, expansion in orthogonal functions, and fictitious sources. The methods of multipole feeddown and sources were both tried on the magnet data, with the result that the method of sources worked well. (LEW)
Date: March 1, 1987
Creator: Michelotti, L.
Partner: UNT Libraries Government Documents Department

The design and manufacture of the Fermilab Main Injector Dipole Magnet

Description: Fermilab's new Main Injector Ring (MIR) will replace the currently operating Main Ring to provide 150 GeV Proton and Antiproton beams for Tevetron injection, and rapid cycling, high intensity, 120 GeV Proton beams for Antiproton production. To produce and maintain the required high beam quality, high intensity, and high repetition rate, conventional dipole magnets with laminated iron core and water cooled copper conductor were chosen as the bending magnet. A new magnet design having low inductance, large copper cross section, and field uniformity sufficient for high intensity injection and efficient slow resonant extraction, is required to obtain the needed geometric aperture, dynamic aperture, and operational reliability. The current Main Injector Ring lattice design requires the use of 344 of these magnets. 216 of these magnets are to be 6 m long, and 128 are to be 4 m long.
Date: March 1, 1992
Creator: Brown, B. C.; Chester, N. S.; Harding, D. J. & Martin, P. S.
Partner: UNT Libraries Government Documents Department

Status of magnet system for RHIC

Description: A Relativistic Heavy Ion Colliding beam accelerator (RHIC) has been proposed at Brookhaven National Laboratory. The machine would generate colliding beams of energies up to 100 GeV/amu of ions as heavy as /sup 197/Au. The facilities necessary to accelerate these ions up to 11 GeV/amu are either already operational or under construction at BNL. This paper will discuss the magnet system for the actual collider ring itself, which will further accelerate the particles to beam energies of between 7 and 100 GeV/amu, store them, and provide interaction regions. This magnet system will consist of two rings of superconducting magnets placed in an existing 3.8 km tunnel.
Date: January 1, 1986
Creator: Thompson, P.A.; Cottingham, J.; Dahl, P.; Fernow, R.; Garber, M.; Ghosh, A. et al.
Partner: UNT Libraries Government Documents Department
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