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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

Magnets for RHIC (Relativistic Heavy Ion Collider)

Description: The magnet system for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven is briefly described. The basic layout of the RHIC and a regular arc cell are shown, and the layout of the magnets to bring the beams into collision is described. The characteristics of the dipole and quadrupole magnets required for the arcs and intersection regions are given. The research and development effort has focused on the arc dipoles, and the current dipole design is shown. Magnet performance characteristics are reported. The arc quadrupole design and characteristics are given. (LEW)
Date: January 1, 1986
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

End fields of CBA superconducting magnets

Description: Measurements of the two dimensional harmonic content of the end fields generated by the Brookhaven CBA dipole and quadrupole superconducting magnets are presented. Both the local longitudinal structure and the integrated end effects are examined.
Date: January 1, 1983
Creator: Kirk, H.G.; Herrera, J. & Willen, E.
Partner: UNT Libraries Government Documents Department

Superconducting magnets

Description: This report provides a self-consistent description of a magnetic field in the aperture of a superconducting magnet and details how this field can be calculated in a magnet with cos theta current distribution in the coils. A description of an apparatus that can be used to measure the field uniformity in the aperture has been given. Finally, a detailed description of the magnet being developed for use in the Superconducting Super Collider is given. When this machine is built, it will be by far the largest application of superconductivity to date and promises to make possible the experimental discoveries needed to understand the basic laws of nature governing the world in which we live.
Date: January 1, 1985
Creator: Willen, E.; Dahl, P. & Herrera, J.
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

Quench performance of six similar 17 m-long, 40 mm-aperture SSC model dipoles

Description: The quench performance of the final six 17 m-long, 40 mm-aperture SSC model dipoles made at Brookhaven National Laboratory is presented in summary form. The six magnets are of similar construction, except for two features (1) the copper-to-superconductor ratio of the inner cable (either 1.3:1 or 1.5:1) and (2) the axial Preload at 4.35K. The inner coil quench performance does not appear to be correlated with the copper-to-superconductor ratio. There does appear to be a correlation between the outer coil quench performance and the cold axial preload.
Date: January 1, 1992
Creator: Wanderer, P. & Willen, E.
Partner: UNT Libraries Government Documents Department

Performance of R and D sextupole trim coils for SSC (Superconducting Super Collider) dipoles

Description: For the proposed Superconducting Super Collider (SSC), trim coils placed inside the main coils of the dipoles are needed to correct for field nonuniformities due to superconducting magnetization, iron saturation, and systematic construction errors. Four 4.5 m superconducting sextupole trim coils have been made using methods adapted from printed circuit technology and suitable for mass production. This paper presents measurements of the multipoles and quench currents and compares them with SSC requirements. Based on these results, this type of trim coil (''Multiwire'') looks quite promising for use in the SSC.
Date: January 1, 1987
Creator: Wanderer, P.; Herrera, J.; Thompson, P. & 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

Field measuring probe for SSC (Superconducting Super Collider) magnets

Description: The field probe developed for measuring the field in SSC dipole magnets is an adaptation of the rotating tangential coil system in use at Brookhaven for several years. Also known as the MOLE, it is a self-contained room-temperature mechanism that is pulled through the aperture of the magnet with regular stops to measure the local field. Several minutes are required to measure the field at each point. The probe measures the multipole components of the field as well as the field angle relative to gravity. The sensitivity of the coil and electronics is such that the field up to the full 6.6 T excitation of the magnet as well as the field when warm with only 0.01 T excitation can be measured. Tethers are attached to both ends of the probe to carry electrical connections and to supply dry nitrogen to the air motors that rotate the tangential windings as well as the gravity sensor. A small computer is attached to the probe for control and for data collection, analysis and storage. Digital voltmeters are used to digitize the voltages from the rotating coil and several custom circuits control motor speeds in the probe. The overall diameter of the probe is approximately 2 cm and its length is 2.4 m; the field sensitive windings are 0.6 m in length.
Date: March 1, 1987
Creator: Ganetis, G.; Herrera, J.; Hogue, R.; Skaritka, J.; Wanderer, P. & Willen, E.
Partner: UNT Libraries Government Documents Department

Magnetic field properties of the ISABELLE Project superconducting dipole magnets

Description: A series of prototype superconducting dipole magnets have been constructed and tested as part of the ISABELLE Project research and development program. Results of magnetic field measurements are presented with emphasis placed on the DC and AC components of the main field. Magnetization and the effects of the magnetic fields at the ends of the magnet are displayed.
Date: January 1, 1981
Creator: Kirk, H.G.; Engelmann, R.; Herrera, J.; Jaeger, K.; Robins, K. & Willen, E.
Partner: UNT Libraries Government Documents Department

Random errors in the magnetic field coefficients of superconducting quadrupole magnets

Description: The random multipole errors of superconducting quadrupoles are studied. For analyzing the multipoles which arise due to random variations in the size and locations of the current blocks, a model is outlined which gives the fractional field coefficients from the current distributions. With this approach, based on the symmetries of the quadrupole magnet, estimates are obtained of the random multipole errors for the arc quadrupoles envisioned for the Relativistic Heavy Ion Collider and for a single-layer quadrupole proposed for the Superconducting Super Collider. (LEW)
Date: January 1, 1987
Creator: Herrera, J.; Hogue, R.; Prodell, A.; Thompson, P.; Wanderer, P. & Willen, E.
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

Development of the SSC (Superconducting Super Collider) trim coil beam tube assembly

Description: The Superconducting Super Collider uses approx. =9600 dipole magnets. The magnets have been carefully designed to exhibit minimal magnetic field harmonics. However, because of superconductor magnetization effects, iron saturation and conductor/coil positioning errors, certain harmonic errors are possible and must be corrected by use of multipole correctors called trim coils. For the most efficient use of axial space in the magnet, and lowest possible current, a distributed internal correction coil design is planned. The trim coil assembly is secured to the beam tube, a uhv tube with special strength, size, conductivity and vacuum. The report details the SSC trim coil/beam tube assembly specifications, history, and ongoing development.
Date: January 1, 1987
Creator: Skaritka, J.; Kelly, E.; Schneider, W.; Shutt, R.; Thompson, P.; Wanderer, P. et al.
Partner: UNT Libraries Government Documents Department

Field quality aspects of CBA superconducting magnets

Description: A series of superconducting dipole magnets for the BNL Colliding Beam Accelerator which were manufactured to have the proper field quality characteristics has been tested. This report presents the analysis of the field harmonics of these magnets.
Date: 1983
Creator: Kahn, S.; Engelmann, R.; Fernow, R.; Greene, A. F.; Herrera, J.; Kirk, H. et al.
Partner: UNT Libraries Government Documents Department