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Design and testing of the magnetic quadrupole for the Heavy Ion Fusion Program

Description: The Heavy Ion Fusion Program at the Lawrence Berkeley Laboratory is conducting experiments in the transport and acceleration of ``driverlike`` beams. The single beam coming from the four-to-one beam combiner will be transported in a lattice of pulsed magnetic quadrupoles. The present beam transport consists of high field, short aspect ratio magnetic quadrupoles to maximize the transportable current. This design could also be converted to be superconducting for future uses in a driver. The pulsed quadrupole will develop a maximum field of two Tesla and will be housed within the induction accelerator cells at the appropriate lattice period. Hardware implementation of the physics requirements and full parameter testing is described.
Date: April 1, 1995
Creator: Benjegerdes, R.; Faltens, A.; Fawley, W.; Peters, C.; Reginato, L. & Stuart, M.
Partner: UNT Libraries Government Documents Department

Quench antenna and fast-motion investigations during training of a 7T dipole magnet

Description: Equipment was installed to detect fast conductor motion and quench propagation in a 1 meter long superconducting dipole magnet (1) The fast-motion antenna, centered within the bore of the magnet, used three long dipole coils, mounted end-to-end to span the magnet length. Coil signals were nulled against a neighbor to produce low-ripple signals that were sensitive to local flux changes. A low-microphonic signal was used as an event trigger. (2) Nulling improvements were made for the magnet`s coil-imbalance signals for improved cross-correlation information. (3) A quench-propagation antenna was installed to observe current redistribution during quench propagation. It consisted of quadrupole/sextupole coil sets distributed at three axial locations within the bore of the magnet. Signals were interpreted in terms of the radius, angle, orientation, and rate of change of an equivalent dipole. The magnet was cooled to 1.8K to maximize the number of events. Twenty-four fast-motion events occurred before the first quench. The signals were correlated with the magnet-coil imbalance signals. The quench-propagation antenna was installed for all subsequent quenches. Ramp-rate triggered quenches produced adequate signals for analysis, but pole-turn quenches yielded such small signals that angular localization of a quench was not precise.
Date: October 17, 1994
Creator: Lietzke, A.F.; Benjegerdes, R.; Bish, P.; Krywinski, J.; Scanlan, R.; Schmidt, R. et al.
Partner: UNT Libraries Government Documents Department

Operating experience with a new accelerator control system based upon microprocessors

Description: This paper describes the design and operating experience with a high performance control system tailored to the requirements of the SuperHILAC accelerator. A large number (20) of the latest 16-bit microcomputer boards are used in a parallel-distributed manner to get a high system bandwidth. Because of the high bandwidth, software costs and complexity are significantly reduced. The system by its very nature and design is easily upgraded and repaired. Dynamically assigned and labeled knobs, together with touch-panels, allow a flexible and efficient operator interface. An X-Y vector graphics system provides for display and labeling of real-time signals as well as general plotting functions. This control system allows attachment of a powerful auxiliary computer for scientific processing with access to accelerator parameters.
Date: March 1, 1981
Creator: Magyary, S.; Lancaster, H.; Selph, F.; Fahmie, M.; Timossi, C.; Glatz, J. et al.
Partner: UNT Libraries Government Documents Department

High performance/low cost accelerator control system

Description: Implementation of a high performance computer control system tailored to the requirements of the SuperHILAC accelerator is described. This system uses a distributed (star-type) structure with fiber optic data links; multiple CPU's operate in parallel at each node. A large number (20) of the latest 16-bit microcomputer boards are used to get a significant processor bandwidth (exceeding that of many mini-computers) at a reasonable price. Because of the large CPU bandwidth, software costs and complexity are significantly reduced and programming can be less real-time critical. In addition all programming can be in a high level language. Dynamically assigned and labeled knobs together with touch-screens allow a flexible operator interface. An X-Y vector graphics system allows display and labeling of real-time signals as well as general plotting functions. Both the accelerator parameters and the graphics system can be driven from BASIC interactive programs in addition to the pre-canned user routines. This allows new applications to be developed quickly and efficiently by physicists, operators, etc. The system, by its very nature and design, is easily upgraded (via next generation of boards) and repaired (by swapping of boards) without a large hardware support group. This control system is now being tested on an existing beamline and is performing well. The techniques used in this system can be readily applied to industrial control systems.
Date: October 1, 1980
Creator: Magyary, S.; Glatz, J.; Lancaster, H.; Selph, F.; Fahmie, M.; Ritchie, A. et al.
Partner: UNT Libraries Government Documents Department

Design and testing of the 2 MV heavy ion injector for the Fusion Energy Research Program

Description: The Fusion Energy Research Group at the Lawrence Berkeley Laboratory has constructed and tested a pulsed 2 MV injector that produces a driver size beam of potassium ions. This paper describes the engineering aspects of this development which were generated in a closely coupled effort with the physics staff. Details of the ion source and beam transport physics are covered in another paper at this conference. This paper discusses the design details of the pulse generator, the ion source, the extractor, the diode column, and the electrostatic quadrupole column. Included will be the test results and operating experience of the complete injector.
Date: April 1, 1995
Creator: Abraham, W.; Benjegerdes, R.; Reginato, L.; Stoker, J.; Hipple, R.; Peters, C. et al.
Partner: UNT Libraries Government Documents Department

Magnetic field decay in model SSC dipoles

Description: We have observed that some of our model SSC dipoles have long time constant decays of the magnetic field harmonics with amplitudes large enough to result in significant beam loss, if they are not corrected. The magnets were run at constant current at the SSC injection field level of 0.3 tesla for one to three hours and changes in the magnetic field were observed. One explanation for the observed field decay is time dependent superconductor magnetization. Another explanation involves flux creep or flux flow. Data are presented on how the decay changes with previous flux history. Similar magnets with different Nb-Ti filament spacings and matrix materials have different long time field decay. A theoretical model using proximity coupling and flux creep for the observed field decay is discussed. 10 refs., 5 figs., 2 tabs.
Date: August 1, 1988
Creator: Gilbert, W.S.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Green, M.A.; Green, M.I. et al.
Partner: UNT Libraries Government Documents Department

Correction of magnetization sextupole in one-meter long dipole magnets using passing superconductor

Description: The generation of higher multipoles due to the magnetization of the superconductor in the dipoles of the SSC is a problem during injection of the beam into the machine. The use of passive superconductor was proposed some years ago to correct the magnetization sextupole in the dipole magnet. This paper presents the LBL test results in which the magnetization sextupole was greatly reduced in two one-meter long dipole magnets by the use of passive superconductor mounted on the magnet bore tube. The magnetization sextupole was reduced a factor of five on one magnet and a factor of eight on the other magnet using this technique. Magnetization decapole was also reduced by the passive superconductor. The passive superconductor method of correction also reduced the temperature dependence of the magnetization multipoles. In addition, the drift in the magnetization sextupole due to flux creep was also reduced. Passive superconductor correction appears to be a promising method of correcting out the effects of superconductor magnetization in SSC dipoles and quadrupoles. 10 refs., 6 figs.
Date: March 1, 1990
Creator: Green, M.A.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Gilbert, W.S.; Green, M.I. et al.
Partner: UNT Libraries Government Documents Department

Measurements of passive correction of magnetization higher multipoles in one meter long dipoles

Description: The use of passive superconductor to correct the magnetization sextupole and decapole in SSC dipoles appears to be promising. This paper presents the results of a series of experiments of passive superconductor correctors in one meter long dipole magnets. Reduction of the magnetization sextupole by a factor of five to ten has been achieved using the passive superconductor correctors. The magnetization decapole was also reduced. The passive superconductor correctors reduced the sextupole temperature sensitivity by an order of magnitude. Flux creep decay was partially compensated for by the correctors. 13 refs., 7 figs.
Date: September 1, 1990
Creator: Green, M.A.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Gilbert, W.S.; Green, M.I. et al.
Partner: UNT Libraries Government Documents Department

New measurements of magnetic field decay in 1 meter SSC-type dipoles

Description: Previous studies of magnetic field decay in model SSC dipoles due to changes in magnetization currents caused by flux creep have used the assumed SSC injection energy of 1 TeV, or 0.33 tesla central dipole field, and an excitation to the storage field of 6.6 tesla. More recently, it has been decided to inject at 2 TeV, or 0.66 tesla and so more recent tests have been carried out at the new injection field, or at both the new and old fields. Additionally, the effect of temperature changes and excitation cycles on the field decay have been studied. 6 refs., 11 figs., 2 tabs.
Date: September 1, 1990
Creator: Gilbert, W.S.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Green, M.A.; Green, M.I. et al.
Partner: UNT Libraries Government Documents Department

Training of LBL-SSC model dipole magnets at 1. 8 K

Description: We present the 1.8K training behavior of SSC Magnets, several of which have reached a peak current of 9400 A; a central field of 9 Tesla. For the SSC Project, more than 30 one meter long dipole magnets have been built and tested. The test results for the 4.3K operation have been presented previously. Magnet operation, primarily reaching design field without premature training, is expected to be superior in superfluid helium at 1.8K as compared with helium I at 4.3K. Not only is the critical current increased at the lower temperature, but the heat transfer is much improved. LBL has had an operating helium II facility for nine years and our standard test sequence has been to check for training in helium I at 4.3K and then cool the system down to 1.8K and train the magnet to its new, high limit. Because the mechanical forces are much greater at the higher currents and fields achieved at the lower temperature, information has been obtained on the adequacy of the mechanical design. Even for those magnets in which training quenches occurred in the inner layer at 4.3K, many of the quenches at 1.8K occurred in the outer layer. 10 refs., 8 figs.
Date: March 1, 1989
Creator: Gilbert, W.S.; Althaus, R.; Benjegerdes, R.; Caspi, S.; Peters, C.; Rechen, J. et al.
Partner: UNT Libraries Government Documents Department

Measurements of magnetization multipoles in four centimeter quadrupoles for the SSC

Description: Higher multipoles due to magnetization of the superconductor in superconducting dipole and quadrupole magnets has been observed in over twenty years. This report presents measurements of the 12 pole and 20 pole multipoles in a model one-meter long four-centimeter bore SSC type quadrupole built at the Lawrence Berkeley Laboratory (LBL). The measurements were compared with calculations of the field structure using magnetization theory. Good agreement was observed between the measured multipoles and the calculated multipoles. Under conditions equivalent to injection into the SSC at an energy of 2 TeV, about 1.0 unit of 12 pole was observed and 0.05 units of 20 pole was observed. (One unit of field error is a field error of one part in ten thousand). Magnetization multipole measurements were also done on the first full length (5 meter) SSC quadrupole prototype. Measurements of flux creep decay were made on three one meter quadrupoles and the first five meter long quadrupole. 7 refs., 9 figs.
Date: June 1, 1991
Creator: Green, M.A.; Barale, P.J.; Benjegerdes, R.W.; Gilbert, W.S.; Green, M.I.; Scanlan, R.M. et al.
Partner: UNT Libraries Government Documents Department

Quadrupole Magnets for the SSC Collider

Description: A 40 mm bore 211 T/m quadrupole magnet has been designed and tested at LBL. There are 8 coils of 30 strand cable arranged in 2 layers in a cos 2{theta} distribution, supported by 18 mm thick collars, preassembled into 146 mm long packs, and rigidly aligned in a cold-iron yoke. The design, construction details, and test results are given for three 1 m models and the first 5 m model.
Date: June 1, 1991
Creator: Taylor, C.E.; Barale, P.; Benjegerdes, R.; Caspi, S.; Dell'Orco, D.; Fritz, D. et al.
Partner: UNT Libraries Government Documents Department

Operational Characteristics, parameters, and history of a 13T Nb3Sn dipole

Description: The early design and test results have been previously reported. During the subsequent operation of 'D20' the accelerator prototype dipole has provided both additional and more detailed data as to its characteristics and performance. D20's use as a test facility for high field critical current measurements has provided operational experience and history pertammg to accelerator required characteristics. There has been recently obtained data related to field quality, operational reproducibility and reliability, which will be presented. This prototype 'D20' has attained the highest magnetic field of any accelerator prototype dipole constructed and tested to date. The magnet has continued to operate routinely.
Date: March 18, 1999
Creator: Benjegerdes, R.; Bish, P.; Caspi, S.; Chow, K.; Dietderich, D.; Hannaford, R. et al.
Partner: UNT Libraries Government Documents Department

SSC Quadrupole Magnet Performance at LBL

Description: Lawrence Berkeley Laboratory (LBL) contracted to design, construct, and test four short (1m) models and six full-size (5m) models of the Superconducting Super Collider (SSC) main-ring 5 meter focusing quadrupole magnet (211 Tesla/meter). The training performance of these magnets is summarized. Magnets were tested in a horizontal boiling helium (1 Atm) cryostat. The magnetic, strain-gage and training responses to two thermal cycles were measured. The quadrupole gradient, and relative multipole purity were determined from Fourier analysis of the rotating coil signals. Magnetic and strain-gage measurements were taken on-the-fly. The voltage-tap data was analyzed to determine quench-origin and propagation characteristics. Quench-training proceeded at 4.3K until a plateau was achieved or sub-cooling (2.5K) was used to accelerate the training process. The early short (1m) magnets were also trained at 1.8K (10kA) to help identify potential weak areas. The MIITs were calculated to compare various magnet protection methods. Except for modest training above the anticipated SSC operating point, the magnets performed very well and proved to be self-protecting. Some design flaws were identified and corrected. The last two 1 m models and all the 5m models have been reinstalled in cryostats at the SSC Laboratory, retested and used to achieve various milestones in their program.
Date: October 1, 1992
Creator: Lietzke, A.F.; Barale, P.; Benjegerdes, r.; Caspi, S.; Cortella, J.; Dell'Orco, D. et al.
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

The effect of flux creep on the magnetization field in the SSC diopole magnets

Description: The sextuple fields of model SSC dipole magnets have been observed to change with time when the magnets are held at constant current under conditions similar to injection into the SSC accelerator. The changes in the sextupole component have close to a linear log time dependence, and is felt to be caused by flux creep decay of the magnetization currents in the superconductor filaments. Measurements of this decay have been made under various conditions. The conditions include various central field inductions and changes of field prior to when the decay was measured. The measured field decay in the dipole's sextupole is proportional to the magnitude and sign of the sextupole due to magnetization which was measured at the start of the decay. This suggests that the decay is a bulk superconductivity flux creep. Proximity coupling appears to play only a minor role in the flux creep according to recent LBL measurements with a stable power supply. 4 refs., 6 figs., 3 tabs.
Date: June 1, 1989
Creator: Gilber, W.S.; Althaus, R.F.; Barale, P.J.; Benjegerdes, R.W.; Green, M.A.; Green, M.I. et al.
Partner: UNT Libraries Government Documents Department

Quadrupole magnets for the SSC

Description: At LBL, we have designed, constructed, and tested ten models (4-1meter, 6-5meter) of the Superconducting Super Collider (SSC) main-ring 5 meter focusing quadrupole magnet (211Tesla/meter). The results of this program are herein summarized.
Date: August 1, 1992
Creator: Lietzke, A.; Barale, P.; Benjegerdes, R.; Caspi, S.; Cortella, J.; Dell'Orco, D. et al.
Partner: UNT Libraries Government Documents Department

Test Results for a High Field (13T) Nb3Sn Dipole

Description: A Nb{sub 3}Sn dipole magnet (D20) has been designed, constructed, and tested at LBNL. Previously, they had reported test results from a hybrid design dipole which contained a similar inner Nb{sub 3}Sn and outer NbTi winding. This paper presents the final assembly characteristics and parameters which will be compared with those of the original magnet design. The actual winding size was determined and a secondary calibration of the assembly pre-load was done by pressure sensitive film. The actual azimuthal and radial D20 pre-loading was accomplished by a very controllable novel stretched wire technique. D20 reached 12.8T(4.4K) and 13.5T(1.8K) the highest dipole magnetic fields obtained to date in the world.
Date: December 1, 1996
Creator: McInturff, A.D.; Benjegerdes, R.; Bish, P.; Caspi, S.; Chow, K.; Ell'Orco, D. et al.
Partner: UNT Libraries Government Documents Department

Fabrication and test results of a high field, Nb3Sn superconducting racetrack dipole magnet

Description: The LBNL Superconducting Magnet Program is extending accelerator magnet technology to the highest possible fields. A 1 meter long, racetrack dipole magnet, utilizing state-of-the-art Nb{sub 3}Sn superconductor, has been built and tested. A record dipole filed of 14.7 Tesla has been achieved. Relevant features of the final assembly and tested results are discussed.
Date: June 15, 2001
Creator: Benjegerdes, R.; Bish, P.; Byford, D.; Caspi, S.; Dietderich, D.R.; Gourlay, S.A. et al.
Partner: UNT Libraries Government Documents Department

Superbend upgrade of the Advanced Light Source

Description: The Advanced Light Source (ALS) is a third generation synchrotron light source located at Lawrence Berkeley National Laboratory (LBNL). There was an increasing demand at the ALS for additional high brightness hard x-ray beamlines in the 7 to 40 keV range. In response to that demand, the ALS storage ring was modified in August 2001. Three 1.3 Tesla normal conducting bending magnets were removed and replaced with three 5 Tesla superconducting magnets (Superbends). The radiation produced by these Superbends is an order of magnitude higher in photon brightness and flux at 12 keV than that of the 1.3 Tesla bends, making them excellent sources of hard x-rays for protein crystallography and other hard x-ray applications. At the same time the Superbends did not compromise the performance of the facility in the VUV and soft x-ray regions of the spectrum. The Superbends will eventually feed 12 new beamlines greatly enhancing the facility's capability and capacity in the hard x-ray region. The Superbend project is the biggest upgrade to the ALS storage ring since it was commissioned in 1993. In this paper we present an overview of the Superbend project, its challenges and the resulting impact on the ALS.
Date: May 26, 2004
Creator: Robin, D.; Krupnick, J.; Schlueter, R.; Steier, C.; Marks, S.; Wang, B. et al.
Partner: UNT Libraries Government Documents Department

A dedicated storage ring for Far-IR coherent synchrotron radiation at the ALS

Description: We present the concepts for a storage ring dedicated to and optimized for the production of stable coherent synchrotron radiation (CSR) over the far-infrared wavelength range from about 200 microns to 1 mm.
Date: May 31, 2002
Creator: Barry, W.C.; Baptist, K.M.; Benjegerdes, R.J.; Biocca, A.K.; Byrd, J.M.; Byrne, W.E. et al.
Partner: UNT Libraries Government Documents Department