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Lengthwise field variation in CBA magnets

Description: The multipole content of the magnetic field in accelerator superconducting magnets built with a cos theta current distribution inside an iron yoke is determined by the placement of the individual current-carrying turns in the coil, by the location of the coil inside the iron yoke and by the amount of iron saturation at high field. Differences in these parameters cause the multipole content to vary from magnet to magnet leading to possible undesirable effects on beam behavior. Experience has shown that conductor placement errors, due to unavoidable size and placement differences in the conductor and current blocks, are the dominant cause of the observed variation in the multipole content of supposedly identical magnets. These variations were studied in existing magnets in order to see how similar variations might affect the performance of the SSC.
Date: January 1, 1984
Creator: Willen, E.
Partner: UNT Libraries Government Documents Department

Tables of particle fluxes

Description: The formula of F. Paige for secondary particle fluxes expected at ISABELLE has for convenience been tabulated over a range of momenta. The data are presented as flux/sec in 1 cm sq. areas. areas at various x, y positions (x = y = 0 is the intersection point) in a plane perpendicular to one of the colliding beams and located 1 meter from their intersection. The 1 cm sq. areas are taken as planes perpendicular to a vector connecting the area to the intersection point. Relevant parameters for each table are listed at the top of the table.
Date: January 1, 1977
Creator: Willen, E.H.
Partner: UNT Libraries Government Documents Department

Superconducting muon collider concepts

Description: High energy colliding beam machines for elementary particle research have grown so costly that funding for them has become problematical. The physics they would explore, however, remains compelling, so that new methods must be found to reach high energy if this physics is to be studied. One such new approach is the muon collider. This machine could reach multi-TeV collision energies with good luminosity at an affordable cost. The scenario for producing {mu}{sup +}{mu}{sup {minus}} collisions is shown schematically in a figure. A high intensity proton synchrotron delivers protons in sharply defined bunches onto a stationary target with an energy of 30 GeV. Many pions are produced that decay into muons; both are collected in a solenoid magnet system with useful energies in the range 0.1--1.0 GeV. The muons are then cooled, i.e. their transverse momentum as well as the spread in their longitudinal momentum is reduced. In this way, a bunch of protons is turned into a bunch of positive or negative muons suitable for acceleration and collision. The energy of the muons at this stage is only 0.02 GeV. Acceleration is accomplished in a series of recirculating linac accelerators, similar to the approach used in CEBAF. Upon reaching 2,000 GeV (2 TeV) of energy, the muons are transferred into a ring where positive and negative muons, transferred in successive bunches, collide and the collisions studied in a suitable detector. About 25% of the muons originally collected survive into the collider ring, and here they live for an average of {approximately} 1,000 revolutions. At this point, the surviving muons are dumped and new bunches are injected. This paper describes in abbreviated form the main features and parameters of the presently envisioned muon collider, most of it taken from the latter two reports.
Date: September 1, 1996
Creator: Willen, E.
Partner: UNT Libraries Government Documents Department

Effective mass trigger at the Brookhaven Multi-Particle Spectrometer (MPS)

Description: An effective mass trigger for use at the Brookhaven Multiparticle Spectrometer (MPS) is described. It is a microprocessor based device using extensive fast memory attached to proportional wire chambers in the MPS magnetic field. It will select kinematic quantities unique to the reaction being studied, thereby permitting higher sensitivities and a reduction in data-processing cost for MPS experiments. The principles of operation for this trigger, and the results of simulations to assess its performance, are presented.
Date: January 1, 1980
Creator: Willen, E H
Partner: UNT Libraries Government Documents Department

Superconducting magnets

Description: Superconducting dipole magnets for high energy colliders are discussed. As an example, the magnets recently built for the Relativistic Heavy Ion Collider at Brookhaven are reviewed. Their technical performance and the cost for the industry-built production dipoles are given. The cost data is generalized in order to extrapolate the cost of magnets for a new machine.
Date: December 31, 1996
Creator: Willen, E.
Partner: UNT Libraries Government Documents Department

Random errors in the magnetic field coefficients of superconducting magnets

Description: Random errors in the multipole magnetic coefficients of superconducting magnet have been of continuing interest in accelerator research. The Superconducting Super Collider (SSC) with its small magnetic aperture only emphasizes this aspect of magnet design, construction, and measurement. With this in mind, we present a magnet model which mirrors the structure of a typical superconducting magnet. By taking advantage of the basic symmetries of a dipole magnet, we use this model to fit the measured multipole rms widths. The fit parameters allow us then to predict the values of the rms multipole errors expected for the SSC dipole reference design D, SSC-C5. With the aid of first-order perturbation theory, we then give an estimate of the effect of these random errors on the emittance growth of a proton beam stored in an SSC. 10 refs., 6 figs., 2 tabs.
Date: January 1, 1985
Creator: Herrera, J.; Hogue, R.; Prodell, A.; Wanderer, P. & Willen, E.
Partner: UNT Libraries Government Documents Department

Magnetic field measurements of superconducting magnets for the colliding beam accelerator

Description: An important aspect of the development and production of superconducting magnets for the Colliding Beam Accelerator is the measurement of the magnetic field in the aperture of these magnets. The measurements have the three-fold purpose of determining the field quality as compared to the lattice requirements of the CBA, of obtaining the survey data necessary to position the magnets in the CBA tunnel, and lastly, of characterizing the magnetic fields for use in initial and future orbit studies of the CBA proton beams. Since for a superconducting storage accelerator it is necessary to carry out these detailed measurements on many (approx. 1000) magnets and at many current values (approx. 1000), we have chosen, in agreement with previous experience, to develop a system which Fourier analyses the voltages induced in a number of rotating windings and thereby obtains the multipole field components. The important point is that such a measuring system can be fast and precise. It has been used for horizontal measurements of the CBA ring dipoles.
Date: January 1, 1983
Creator: Herrera, J.; Kirk, H.; Prodell, A. & Willen, E.
Partner: UNT Libraries Government Documents Department

Measurement of the magnetic field coefficients of particle accelerator magnets

Description: An important aspect in the development of magnets to be used in particle accelerators is the measurement of the magnetic field in the beam aperture. In general it is necessary to measure the harmonic multipoles in the dipole, quadrupole, and sextupole magnets for a series of stationary currents (plateaus). This is the case for the Superconducting Super Collider (SSC) which will be ramped to high field over a long period (/approximately/1000 sec.) and then remain on the flat top for the duration of the particle collision phase. In contrast to this mode of operation, the Booster ring being constructed for the Brookhaven AGS, will have a fast ramp rate of approximately 10 Hz. The multipole fields for these Booster magnets must therefore be determined ''on the ramp.'' In this way the effect of eddy currents will be taken into account. The measurement system which we will describe in this paper is an outgrowth of that used for the SSC dipoles. It has the capability of measuring the field multipoles on both a plateau or during a fast ramp. In addition, the same basic coil assembly is used to obtain the magnetic multipoles in dipole, quadrupole, and sextupole magnets. 2 refs., 3 figs., 1 tab.
Date: January 1, 1989
Creator: Herrera, J.; Ganetis, G.; Hogue, R.; Rogers, E.; Wanderer, P. & Willen, E.
Partner: UNT Libraries Government Documents Department

Warm measurements of CBA superconducting magnets

Description: We present results on magnetic field measurements of CBA dipole magnets in the warm (normal conductor) and cryogenic (superconducting) states. We apply two methods for the warm measurements, a dc and ac method. We find a good correlation between warm and cryogenic measurements which lends itself to a reliable diagnosis of magnet field errors using warm measurements early in the magnet assembly process. We further find good agreement between the two warm measurement methods, both done at low currents.
Date: January 1, 1983
Creator: Engelmann, R.; Herrera, J.; Kahn, S.; Kirk, H.; Willen, E. & Yamin, P.
Partner: UNT Libraries Government Documents Department

Report of the subgroup on fast processing

Description: A study was made of the flow of data and the simultaneous processing needed to reduce the 10/sup 7/ to 10/sup 8/ triggers per second expected at ISABELLE to a number of events on the order of 10 to 100 per second which would be written on magnetic tape. It was assumed that within 100 ns of the event a fast pretrigger would have reduced the data rate to at most 10/sup 7/ per second. At that point, data from all sense elements in the experiment would be fed into a 1-..mu..s-long pipeline. Within the first 1 ..mu..s (while the data are in the first pipeline) another level of triggering would reduce the trigger rate to at most 10/sup 6/ per second. The data would then be fed into a second pipeline which is 50 ..mu..s long. During the 50 ..mu..s the data are in the second pipeline, a more sophisticated level of triggering (slow trigger) would reduce the trigger rate to a level that can be handled by standard data processing techniques (microprocessors or larger machines), i.e., 10/sup 2/ to 10/sup 3/ per second. The pipelines and the buffer between them, a sequential address memory, are described first, and then several alternative schemes for the pretrigger and slow trigger are presented. 10 figures.
Date: January 1, 1977
Creator: Gibbard, B.G.; Kirsch, L.E.; Moneti, G.; Plano, R.J.; Rabin, M.S.Z. & Willen, E.
Partner: UNT Libraries Government Documents Department

Superconducting RF cavities and magnets for a 4-TeV energy muon collider

Description: The accelerators must take the muon beams from {approximately} 100 MeV to 2 TeV energies within the muon lifetime for a 4 TeV energy muon collider. These constraints plus the muon decay heating seriously challenge the designs of the superconducting RF (SRF) cavities and magnets in the accelerators and collider ring. The multiple superconducting recirculation linac and the very rap8id-cycling superconducting synchrotron approach are both studied. The authors briefly introduce the technical considerations and preliminary designs of the SRF systems and magnets.
Date: November 1, 1997
Creator: Shu, Q.S.; Green, M.; Neuffer, D.; Summers, D.; Simrock, S. & Willen, E.
Partner: UNT Libraries Government Documents Department

CHANGE IN FIELD HARMONICS AFTER QUENCH AND THERMAL CYCLES IN SUPERCONDUCTING MAGNETS.

Description: A change in field harmonics after quench and thermal cycles has been observed in superconducting magnets for the Relativistic Heavy Ion Collider (RHIC). This paper presents the results of a systematic investigation of this effect in a number of RHIC dipole and quadrupole magnets. These changes in field harmonics may limit the ultimate field quality and its reproducibility in superconducting magnets. A change in pre-stress has also been observed after quench and thermal cycles. A possible link between these two changes is explored.
Date: May 12, 1997
Creator: GUPTA,R.; JAIN,A.; MURATORE,J.; WANDERER,P.; WILLEN,E. & WYSS,C.
Partner: UNT Libraries Government Documents Department

Coldmass for LHC Dipole Insertion Magnets

Description: Brookhaven National Laboratory (BNL) is building a number of magnets for the insertion regions of the Large Hadron Collider (LHC). This paper presents the magnetic design and the expected field quality in 2-in-1 dipole magnets. A unique feature of this cold mass design is the use of an oblate-shaped yoke. This concept permits a variety of BNL-built magnets to have a similar overall design and allows the LHC main dipole cryostat, post, etc., to be used in these magnets. The proposed oblate-shaped yoke also offers a way to reduce the overall cryostat size in future magnets. The dipoles will use the same 80 mm aperture coils as used in the Relativistic Heavy Ion Collider (RHIC) dipole magnets, but will use stainless steel collars. The design presented here is still evolving and the magnets may be built differently than described here.
Date: October 18, 1997
Creator: Gupta, R.; Alforque, R.; Anerella, M.; Kelly, E.; Plate, S.; Rufer, C. et al.
Partner: UNT Libraries Government Documents Department

MAGNETS FOR A MUON STORAGE RING.

Description: We present a new racetrack coil magnet design, with an open midplane gap, that keeps decay particles in a neutrino factory muon storage ring from directly hitting superconducting coils. The structure is very compact because coil ends overlap middle sections top and bottom for skew focusing optics. A large racetrack coil bend radius allows ''react and wind'' magnet technology to be used for brittle Nb{sub 3}Sn superconductors. We describe two versions: Design-A, a magnet presently under construction and Design-B, a further iterated concept that achieves the higher magnetic field quality specified in the neutrino factory feasibility Study-II report. For Design-B reverse polarity and identical end design of consecutive long and short coils offers theoretically perfect magnet end field error cancellation. These designs avoid the dead space penalty from coil ends and interconnect regions (a large fraction in machines with short length but large aperture magnets) and provide continuous bending or focusing without interruption. The coil support structure and cryostat are carefully optimized.
Date: June 18, 2002
Creator: PARKER, B.; ANERELLA, M.; GHOSH, A.; GUPTA, R.; HARRISON, M.; SCHMALZLE, J. et al.
Partner: UNT Libraries Government Documents Department

COLDMASS FOR LHC DIPOLE INSERTION MAGNETS.

Description: Brookhaven National Laboratory (BNL) is building a number of magnets for the insertion regions of the Large Hadron Collider (LHC). This paper presents the magnetic design and the expected field quality in 2-in-1 dipole magnets. A unique feature of this coldmass design is the use of an oblate-shaped yoke. This concept permits a variety of BNL-built magnets to have a similar overall design and allows the LHC main dipole cryostat, post, etc., to be used in these magnets. The proposed oblate-shaped yoke also offers a way to reduce the overall cryostat size in future magnets. The dipoles will use the same 80 mm aperture coils as used in the Relativistic Heavy Ion Collider (RHIC) dipole magnets, but will use stainless steel collars. The design presented here is still evolving and the magnets may be built differently than described here.
Date: October 20, 1997
Creator: GUPTA,R.; ALFORQUE,R.; ANERELLA,M.; KELLY,E.; PLATE,S.; RUFER,C. et al.
Partner: UNT Libraries Government Documents Department

FIELD QUALITY IMPROVEMENTS IN SUPERCONDUCTING MAGNETS FOR RHIC.

Description: A number of techniques have been developed and tested to improve the field quality in the superconducting dipole and quadrupole magnets to be used in the Relativistic Heavy Ion Collider (RHIC). These include adjustment in the coil midplane gap to compensate for the allowed and non-allowed harmonics, inclusion of holes and cutouts in the iron yoke to reduce the saturation-induced harmonics, and magnetic tuning shims to correct for the residual errors. We compare the measurements with the calculations to test the validity of these concepts.
Date: June 27, 1994
Creator: GUPTA,R.; JAIN,A.; KAHN,S.; MORGAN,G.; THOMPSON,P.; WANDERER,P. et al.
Partner: UNT Libraries Government Documents Department

MAGNETIC DESIGN OF A SUPERCONDUCTING AGS SNAKE.

Description: Brookhaven National Laboratory plans to build a partial helical snake for polarized proton acceleration in the AGS. It will be a 3 Tesla superconducting magnet having a magnetic length of 1.9 meter. AGS needs only one magnet and currently there is no plan to build a prototype. Therefore, the first magnet itself must function at the design operating field and provide the required field quality, spin rotation and deflections on the particle beam. New software have been developed that exchanges input/output between the OPERA3d field design program, the Pro-Engineering CAD model and the software that drives the machine to make slots in aluminum cylinders where blocks of 6-around-I NbTi wires are placed. This new software have been used to carry out a number of iterations to satisfy various design requirements and to assure that the profile that is used in making field computations is the same that is used in cutting metal. The optimized coil cross-section is based on a two layer design with both inner and outer layers having five current blocks per quadrant. The ends are based on a design concept that will be used for the first time in accelerator magnets.
Date: May 12, 2003
Creator: GUPTA,R.; LUCCIO,A.; MORGAN,G.; MACKAY,W.; POWER,K.; ROSER,T. et al.
Partner: UNT Libraries Government Documents Department

A HELICAL MAGNET DESIGN FOR RHIC.

Description: Helical dipole magnets are required in a project for the Relativistic Heavy Ion Collider (RHIC) to control and preserve the beam polarization in order to allow the collision of polarized proton beams. Specifications are for low current superconducting magnets with a 100 mm coil aperture and a 4 Tesla field in which the field rotates 360 degrees over a distance of 2.4 meters. A magnet meeting the requirements has been developed that uses a small diameter cable wound into helical grooves machined into a thick-walled aluminum cylinder.
Date: May 12, 1997
Creator: WILLEN,E.; GUPTA,R.; JAIN,A.; KELLY,E.; MORGAN,G.; MURATORE,J. et al.
Partner: UNT Libraries Government Documents Department