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Focusing in Linear Ion Accelerators

Description: Abstract: "The results of the investigation of three methods of obtaining transverse stability in linear accelerators for ions are presented and discussed. For electric or magnetic quadrupole focusing the range of stable operation, oscillation amplitudes, and the operation of an actual grid is analyzed from measurements of the field distribution. Finally, the formulas applicable to focusing by axial magnetic lenses are presented."
Date: November 24, 1954
Creator: Smith, Lloyd & Gluckstern, Robert L.
Partner: UNT Libraries Government Documents Department

Aperture limitations for 2nd generation Nb3Sn LHC IR quadrupoles

Description: One of the straightforward ways towards the higher luminosity in the LHC is a replacement of the present 70-mm NbTi quadrupoles with Nb{sub 3}Sn quadrupoles which would provide the same field gradient but in a larger aperture. Conceptual designs of such quadrupoles with 90 mm aperture have been developed and studied. This paper discusses the possibilities and limitations of increasing the aperture of Nb{sub 3}Sn low-beta quadrupoles for a LHC luminosity upgrade up to 110 mm.
Date: June 2, 2003
Creator: Zlobin, Alexander V.; Kashikhin, Vadim V. & Strait, James B.
Partner: UNT Libraries Government Documents Department

Automatic component calibration and error diagnostics for model-based accelerator control. Phase I final report

Description: Phase I work studied the feasibility of developing software for automatic component calibration and error correction in beamline optics models. A prototype application was developed that corrects quadrupole field strength errors in beamline models.
Date: June 28, 1999
Creator: Stern, Dr. Carl & Lee, Dr. Martin
Partner: UNT Libraries Government Documents Department

Closed orbit response to quadrupole strength variation

Description: We derive two formulae relating the variation in closed orbit in a storage ring to variations in quadrupole strength, neglecting nonlinear and dispersive effects. These formulae correct results previously reported [1,2,3]. We compare the results of the formulae applied to the ATF with simulations using MAD, and consider their application to beam-based alignment.
Date: January 20, 2004
Creator: Wolski, Andrzej & Zimmermann, Frank
Partner: UNT Libraries Government Documents Department

Finite Element Model of Training in the superconducting quadrupole magnet SQ02

Description: This paper describes the use of 3D finite element models to study training in superconducting magnets. The simulations are used to examine coil displacements when the electromagnetic forces are cycled, and compute the frictional energy released during conductor motion with the resulting temperature rise. A computed training curve is then presented and discussed. The results from the numerical computations are compared with test results of the Nb{sub 3}Sn racetrack quadrupole magnet SQ02.
Date: November 1, 2007
Creator: Caspi, Shlomo & Ferracin, Paolo
Partner: UNT Libraries Government Documents Department

Efficient computation of matched solutions of the KV envelopeequation for periodic focusing lattices

Description: A new iterative method is developed to numerically calculate the periodic, matched beam envelope solution of the coupled Kapchinskij-Vladimirskij (KV) equations describing the transverse evolution of a beam in a periodic, linear focusing lattice of arbitrary complexity. Implementation of the method is straightforward. It is highly convergent and can be applied to all usual parameterizations of the matched envelope solutions. The method is applicable to all classes of linear focusing lattices without skew couplings, and also applies to parameters where the matched beam envelope is strongly unstable. Example applications are presented for periodic solenoidal and quadrupole focusing lattices. Convergence properties are summarized over a wide range of system parameters.
Date: January 3, 2006
Creator: Lund, Steven M.; Chilton, Sven H. & Lee, Edward P.
Partner: UNT Libraries Government Documents Department

Steering magnet design for a limited space

Description: We compare two extreme designs of steering magnets. The first one is a very thin steering magnet design which occupies only 6 mm in length and can be additionally installed as needed. The other is realized by applying extra coil windings to a quadrupole magnet and does not consume any length. The properties and the features of these steering magnets are discussed.
Date: May 4, 2009
Creator: Okamura,M.; Fite, J.; Lodestro, V.; Raparia, D. & Ritter, J.
Partner: UNT Libraries Government Documents Department

RF EXCITATION OF LINEAR AND CURVED SECTIONS OF THE CRFQ PROJECT.

Description: The design criteria of the linear and first curved sectors of the Circular Radiofrequency Quadrupole (CRFQ) proof of principle are presented in this paper. Radiofrequency measurements on a cold model of the linear sector and comparisons with numerical simulations are presented too.
Date: July 5, 2004
Creator: DAVINO,D.; CAMPAJOLA,L.; MASULLO,M. R. & RUGGIERO,A.
Partner: UNT Libraries Government Documents Department

MEASURING LOCAL GRADIENT AND SKEW QUADRUPOLE ERRORS IN RHIC IRS.

Description: The measurement of local linear errors at RHIC interaction regions using an ''action and phase'' analysis of difference orbits has already been presented. This paper evaluates the accuracy of this technique using difference orbits that were taken when known gradient errors and skew quadrupole errors were intentionally introduced. It also presents action and phase analysis of simulated orbits when controlled errors are intentionally placed in a RHIC simulation model.
Date: July 5, 2004
Creator: CARDONA,J.; PEGGS,S.; PILAT,R. & PTITSYN,V.
Partner: UNT Libraries Government Documents Department

MULTIOBJECTIVE DYNAMIC APERTURE OPTIMIZATION AT NSLS-II

Description: In this paper we present a multiobjective approach to the dynamic aperture (DA) optimization. Taking the NSLS-II lattice as an example, we have used both sextupoles and quadrupoles as tuning variables to optimize both on-momentum and off-momentum DA. The geometric and chromatic sextupoles are used for nonlinear properties while the tunes are independently varied by quadrupoles. The dispersion and emittance are fixed during tunes variation. The algorithms, procedures, performances and results of our optimization of DA will be discussed and they are found to be robust, general and easy to apply to similar problems.
Date: March 28, 2011
Creator: Yang, L.; Li, Y.; Guo, W. & Krinsky, S.
Partner: UNT Libraries Government Documents Department

The Brown-Servranckx matching transformer for simultaneous RFQ to DTL H{sup +} and H{sup {minus}} matching

Description: The issue involved in simultaneous matching of H{sup +} and H{sup -} beams between an RFQ and DTL lies in the fact that both beams experience the same electric-field forces at a given position in the RFQ. Hence, the two beams are focused to the same correlation. However, matching to a DTL requires correlation of the opposite sign. The Brown-Servranckx quarter-wave ({lambda}/4) matching transformer system, which requires four quadrupoles, provides a method to simultaneously match H{sup +} and H{sup -} beams between an RFQ and a DTL. The method requires the use of a special RFQ section to obtain the Twiss parameter conditions {beta}{sup x}={beta}{sup y} and {alpha}{sub x}={alpha}{sub y}=0 at the exit of the RFQ. This matching between the RFQ and DTL is described.
Date: September 1, 1996
Creator: Wadlinger, E.A. & Garnett, R.W.
Partner: UNT Libraries Government Documents Department

Vibrational stability of NLC linac and final focus components

Description: Vertical vibration of linac components (accelerating structures, girders and quadrupoles) in the NLC has been studied experimentally and analytically. Effects such as structural resonances and vibration caused by cooling water both in accelerating structures and quadrupoles have been considered. Experimental data has been compared with analytical predictions and simulations using ANSYS. A design, incorporating the proper decoupling of structure vibrations from the linac quadrupoles, is being pursued.
Date: February 6, 2003
Creator: al., F. Le Pimpec et
Partner: UNT Libraries Government Documents Department

MAGNETIC DESIGN OF A HIGH GRADIENT QUADRUPOLE FOR THE LHC LOW B INSERTIONS.

Description: Fermilab, Lawrence Berkeley National Laboratory and Brookhaven National Laboratory have formed a consortium to provide components for the Large Hadron Collider (LHC) to be built at CERN. The U.S. contribution includes half of the high gradient quadrupoles (HGQ) for the inner focusing triplets. In this paper a description of the HGQ magnetic design is given, including short sample limit for field gradient, sources and expected values of systematic and random field errors, and possible strategies for field quality correction.
Date: May 12, 1997
Creator: Sabbi, G.; Gourlay, S. A.; Kerby, J.; Lamm, M. J.; Limon, P. J.; Nobrega, F. et al.
Partner: UNT Libraries Government Documents Department

Fringe fields for the N channel permanent magnet array

Description: Analytical expressions are obtained for fringe field multipoles of an N channel permanent magnet quadrupole array. It is assumed that the system of magnetic wedges starts at some transverse (x, y) plane located at z = 0, and it continues to a magnet length z = l, where it stops. The iron yoke continues to z = {+-} {infinity}, but it will be shown that only a small overhang is actually required to maintain the quadrupole and translational symmetries. Recall the 2-d solution for the magnetic potential (H = {del}{phi}): {phi}{sub 2} = A [(x-x{sub i}){sup 2} - (y-y{sub i}){sub 2}], where A = -M{sub 0}/4b, M{sub 0} is the remnant field of the wedges, and (x{sub i}, y{sub i}) are the coordinates for the center of box (i). Boxes have dimensions 2b x 2b and alternate between vacuum fill (for beams) and magnetic wedge fill. The 2-d system looks like a portion of an infinite transverse lattice with periodicity lengthy = 4b in both the x and y directions. For the magnetic potential {phi}, the periodicity length is 2b.
Date: April 1, 1996
Creator: Lee, E.P.
Partner: UNT Libraries Government Documents Department

Alignment and steering scenarios for the APT linac

Description: The Accelerator for the Production of Tritium (APT) requires a very high proton beam current (100 mA cw). Requirement for hands-on maintenance limits the beam spill to less than 0.2 nA/m along most of the linac. To achieve this, it is important to understand the effects of fabrication, installation and operational errors, establish realistic tolerances, and develop techniques for mitigating their consequences. A new code, PARTREX, statistically evaluates the effects of alignment, quadrupole field, and rf phase and amplitude errors in the linac. This paper reviews the effects of quadrupole misalignments and present two steering algorithms that minimize the potential for particle loss from the beam halo. These algorithms were tested on the 8-to-20 MeV portion of the APT linac.
Date: September 1, 1996
Creator: Stovall, J.E.; Gray, E.R.; Nath, S.; Takeda, H.; Wood, R.L.; Young, L.M. et al.
Partner: UNT Libraries Government Documents Department

Magnetic design of a high gradient quadrupole for the LHC low-{beta} insertions

Description: Fermilab, Lawrence Berkeley National Laboratory and Brookhaven National Laboratory have formed a consortium to provide components for the Large Hadron Collider (LHC) to be built at CERN. The U.S. contribution includes half of the high gradient quadrupoles (HGQ) for the inner focusing triplets. In this paper a description of the HGQ magnetic design is given, including short sample limit for field gradient, sources and expected values of systematic and random field errors, and possible strategies for field quality correction.
Date: June 1, 1997
Creator: Sabbi, G.; Gourlay, S. A.; Kerby, J.; Limon, P. J.; Nobrega, F.; Novitski, I. et al.
Partner: UNT Libraries Government Documents Department

Design of a High Gradient Quadrupole for the LHC Interaction Regions

Description: A collaboration of Fermilab, Lawrence Berkeley National Laboratory and Brookhaven National Laboratory is currently engaged in the design of a high gradient quadrupole suitable for use in the LHC interaction regions. The cold iron design incorporates a two-shell, cos2{theta} coil geometry with a 70 mm aperture. This paper summarizes the progress on a magnetic and mechanical design that meets the requirements of maximum gradient {>=}250 T/m, operation at 1.8K, high field quality and provision for adequate cooling in a high radiation environment.
Date: March 1, 1997
Creator: Bossert, R.; Gourlay, S.A.; Heger, T.; Huang, Y.; Kerby, J.; Lamm, M.J. et al.
Partner: UNT Libraries Government Documents Department

An insertion to eliminate horizontal temperature of high energy electron beam

Description: High energy electron cooling with a circulated electron bunch could significantly increase the luminosity of hadron colliders. One of the significant obstacles is high horizontal temperature of electron bunches, suppressing dramatically calculated cooling rates. Recently, a transformation of betatron coordinates and angles for elimination of the radial temperature was found. In our paper, we present a simple scheme to make up this transformation by thin quadruples, drifts and a solenoid.
Date: March 16, 1998
Creator: Burov, A.V. & Danilov, V.V.
Partner: UNT Libraries Government Documents Department

Magnetic field strength and shape measurements of the Fermilab main injector quadrupoles

Description: All of the new quadrupoles for the Fermilab Main Injector ring have been built and measured. The magnets are 2.95 m and 2.54 m in length with a 41.7 mm bore. In operation, the magnets run from 1.61 T/m at 8. 9 GeV/c to 15.7 T/m at 120 GeV/c and 19.6 T/m at 150 GeV/c. These points correspond to injection, Main Injector fixed target physics and antiproton production, and extraction for transfer to the Tevatron. Good field uniformity is required to ensure a stable beam over the whole acceleration cycle. A significant octupole is included to assist in resonant extraction. The performance of these quadrupoles, in both integrated strength and field uniformity, is presented. All magnets produced meet the accelerator requirements.
Date: May 1, 1997
Creator: Harding, D.J.; Brown, B.C. & DiMarco, H.H.
Partner: UNT Libraries Government Documents Department