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Magnets and Magnetic Measuring Techniques

Description: Preface: The existence of adequate experimental equipment, in particular the two operating cyclotrons of the Radiation Laboratory and the large 184-inch unit under construction, together with a nucleus of trained personnel, made it inevitable that work in connection with the war effort would be prosecuted vigorously at the University of California.
Date: June 1949
Creator: Wakerling, R. K. & Guthrie, Andrew
Partner: UNT Libraries Government Documents Department

Beta Magnet Current Stability

Description: Abstract: A TEC regulator amplifier driving an Eaterline-Angus recording meter was used to record magnet current variations. Tests were made to determine magnet current variations. Tests were made to determine magnet current stability for currents from 500 amperes to 4000 amperes. Changes were necessary in both the TEC and GE regulators before currents below 2500 amperes could be regulated. Regulation to 0.025 percent for and hour was obtained for currents of 1000 to 4000 amperes with the TEC and GE regulators, and regulation to 0.05 percent for 500 ampere currents.
Date: June 8, 1947
Creator: Hudson, E. D. & Becker, M. C.
Partner: UNT Libraries Government Documents Department

Ring Energy Selection and Extra Long Straight Sections for the Advanced Photon Source

Description: Recommended criteria are given for the performance of Advanced Photon Source (APS), taking into consideration undulator tunability criteria and their relationship to the storage ring energy and undulator gap, length of straight sections.
Date: April 1987
Creator: Brown, G.; Cho, Y.; Hastings, J.; Krinsky, S.; Moncton, D. E.; Shenoy, G. K. et al.
Partner: UNT Libraries Government Documents Department

Insertion Device and Beam Line Plans for the Advanced Photon Source : a Report and Recommendations by the Insertion Device and Beam Line Planning Committee

Description: In the 7-GeV Advanced Photon Source (APS) Conceptual Design Report (CDR), fifteen complete experimental beam lines were specified in order to establish a representative technical and cost base for the components involved. In order to optimize the composition of the insertion devices and the beam line, these funds are considered a ''Trust Fund.'' The present report evaluates the optimization for the distribution of these funds so that the short- and long-term research programs will be most productive, making the facility more attractive from the user's point of view. It is recommended that part of the "Trust Fund" be used for the construction of the insertion devices, the front-end components, and the first-optics, minimizing the cost to potential users of completing a beam line. In addition, the possibility of cost savings resulting from replication and standardization of high multiplicity components (such as IDs, front ends, and first-optics instrumentation) is addressed.
Date: February 1987
Creator: Boyce, R.; Hewitt, R.; Morrison, T. I.; Shenoy, G. K.; Thomlinson, W. & Viccaro, P. J.
Partner: UNT Libraries Government Documents Department

An Overview of the Characteristics of the 6-GeV Synchrotron Radiation : a Preliminary Guide for Users

Description: In this document we present the characteristics of the electromagnetic radiation from various types of sources on a 6-GeV storage ring. The sources include bending magnets, undulators and wigglers. The characteristics are compared with those of other synchrotron sources when operated at their design specifications. The influence of positron beam size on the brilliance is discussed, along with the power distribution from these sources. The goal of this document is to provide users with enough information on the behavior of radiation from a 6-GeV storage ring so that a dialogue can be established with the accelerator physicists and engineers to achieve an optimal design.
Date: October 1985
Creator: Shenoy, G. K. & Viccaro, P. J.
Partner: UNT Libraries Government Documents Department

Early operating and reliability experience with the CEBAF DC magnet power supplies

Description: The CEBAF accelerator is a five pass, recirculating, CW electron linear accelerator. There are a total of nine recirculation arcs connecting the two linacs. Three experimental halls are serviced by the accelerator through separate transport channels. The magnet powering system for CEBAF consists of approximately 2000 independent control channels. About 1850 of these channels are low current, trim magnet power supplies. There are 28 higher power supplies used to energize the major bending elements. Over one hundred, 20 amp, active shunts are used to vary current in selected magnets in the major dipole strings. The majority of the magnetic elements are concentrated in the arcs and transport channels. The correction dipoles, quadrupoles and sextupoles are each powered individually be a dedicated trim power supply channel. The arc and extraction channel dipoles are powered in series strings by the high powered supplies, known locally at CEBAF as `box power supplies'. Arc loads consist of some 30--40 magnets in series. Transport channel, path length control doglegs and septa box power supplies have loads ranging from 1 to 10 magnets. Shunts are installed on virtually all loads where two or more magnets are in series. At this time, 95% of the power supplies are installed and commissioned. In the past twelve months, beginning in May 1994, approximately 1200 trim magnet power supplies have been checked out. During this same period approximately 22 box power supplies and 100 shunts have been made operational. Full operation of the equipment has only been under way since early 1995. While this operation is only just beginning, much has been learned based on the reliability performance seen so far. The remainder of this paper describes the systems mentioned, their reliability problems, the fixes implemented to date, and some plans for the future. 6 refs., 3 tabs.
Date: August 1, 1996
Creator: Merz, W.; Flood, R.; Martin, E.J. & O'Sullivan, M.
Partner: UNT Libraries Government Documents Department

Overcoming weak intrinsic depolarizing resonances with energy-jump

Description: In the recent polarized proton runs in the AGS, a 5% partial snake was used successfully to overcome the imperfection depolarizing resonances. Polarized proton beam was accelerated up to the required RHIC injection energy of 25 GeV. However, significant amount of polarization was lost at 0+{nu}{sub y}, 12+{nu}{sub y} and 36+{nu}{sub y}, which is believed to be partially due to the coupling resonances. To overcome the coupling resonance, an energy-jump was generated by rapidly changing the beam circumference using the powerful AGS rf system. It clearly demonstrates that the novel energy-jump method can successfully overcome coupling resonances and weak intrinsic resonances.
Date: July 1, 1997
Creator: Huang, H.; Ahrens, L. & Alessi, J.G.
Partner: UNT Libraries Government Documents Department

Improved Magnetic Fusion Energy Economics via Massive Resistive Electromagnets

Description: Abandoning superconductors for magnetic fusion reactors and instead using resistive magnet designs based on cheap copper or aluminum conductor material operating at "room temperature" (300 K) can reduce the capital cost per unit fusion power and simplify plant operations. By increasing unit size well beyond that of present magnetic fusion energy conceptual designs using superconducting electromagnets, the recirculating power fraction needed to operate resistive electromagnets can be made as close to zero as needed for economy without requiring superconductors. Other advantages of larger fusion plant size, such as very long inductively driven pulses, may also help reduce the cost per unit fusion power.
Date: August 19, 1998
Creator: Woolley, R.D.
Partner: UNT Libraries Government Documents Department

Polarized proton experiment in the AGS with a partial snake

Description: In three polarized proton runs at the AGS it was recently shown that the imperfection depolarizing resonances in the AGS can be overcome with a 5% partial snake and the intrinsic depolarizing resonances could be jumped with the pulsed tune-jump quadrupoles even in the presence of the partial snake. For the first time polarized proton beam was accelerated up to the required RHIC injection energy of 25 GeV. No polarization was lost due to the imperfection resonances and the depolarization from most intrinsic resonances was avoided with the tune-jump quadrupoles. However, significant amount of polarization was lost at 0+{nu}{sub y}, 12+{nu}{sub y} and 36+{nu}{sub y}, which is believed to be partially due to coupling resonances. A novel energy-jump method and other new schemes to overcome the coupling and intrinsic resonances are discussed.
Date: December 1, 1996
Creator: Huang, H.; Ahrens, L. & Alessi, J.G.
Partner: UNT Libraries Government Documents Department

Experimental results of a single emittance compensation solenoidal magnet

Description: A new iron dominated single emittance compensation solenoidal magnet was designed to be integrated with the BNL/SLAC/UCLA 1.6 cell S-Band Photocathode rf Gun. This emittance compensated photoinjector is now in operation at the Brookhaven Accelerator Test Facility. It has produced a 0.329 {+-} 0.012 pC, {tau}{sub 95%} = 10.9 psec electron bunches with a normalized rms transverse emittance of {epsilon}{sub n,rms} = 1.17 {+-} 0.16 {pi} mm mrad. POISSON field maps were used with PARMELA to optimize the emittance compensation solenoidal magnet design. Magnetic field measurements show that at the cathode plane B{sub z} {le} 10 G for a peak magnetic field of B{sub z,max} = 3 kG. Which is in agreement with POISSON simulation. A single emittance compensation solenoidal magnet will produces an initial angular momentum of the electron bunch that manifests itself in a initial magnetic emittance term that cannot be eliminated. This magnetic emittance {epsilon}{sub n,rms}{sup mag} scales as 0.010 {pi} mm mrad/G as the cathode, which is in agreement with PARMELA simulations. Experimental beam dynamics results are presented that shows relative angular rotation and spot size as a function of cathode magnetic field. These results are compared to theory.
Date: July 1997
Creator: Palmer, D. T.; Miller, R. H.; Wang, X. J.; Ben-Zvi, I. & Skaritka, J.
Partner: UNT Libraries Government Documents Department

Design of the Source Development Lab bunch compressor

Description: The accelerator at the Source Development Lab at BNL consists of a 1.6 cell RF photocathode electron gun followed by a 230 MeV SLAC-type linac that includes a magnetic chicane bunch compressor. The nominal specifications call for a 10 ps FWHM bunch of 2nC charge to be compressed in time by a factor of 25 at an energy of 85 MeV. The design of the compressor magnets and the beam dynamics from the gun through the magnetic chicane are described.
Date: December 31, 1997
Creator: Graves, W.S.; Ben-Zvi, I.; Johnson, E.D.; Krinsky, S.; Skaritka, J.; Woodle, M.H. et al.
Partner: UNT Libraries Government Documents Department

Emittance studies of the BNL/SLAC/UCLA 1.6 cell photocathode rf gun

Description: The symmetrized 1.6 cell S-band photocathode gun developed by the BNL/SLAC/UCLA collaboration is in operation at the Brookhaven Accelerator Test Facility (ATF). A novel emittance compensation solenoid magnet has also been designed, built and is in operation at the ATF. These two subsystems form an emittance compensated photoinjector used for beam dynamics, advanced acceleration and free electron laser experiments at the ATF. The highest acceleration field achieved on the copper cathode is 150 MV/m, and the guns normal operating field is 130 MV/m. The maximum rf pulse length is 3 {micro}s. The transverse emittance of the photoelectron beam were measured for various injection parameters. The 1 nC emittance results are presented along with electron bunch length measurements that indicated that at above the 400 pC, space charge bunch lengthening is occurring. The thermal emittance, {epsilon}{sub o}, of the copper cathode has been measured.
Date: July 1997
Creator: Palmer, D. T.; Miller, R. H. & Wang, X. J.
Partner: UNT Libraries Government Documents Department

Specification of multipole tolerances for the APS quadrupole magnet

Description: This note will address a proposed method for specifying the multipole tolerance for the design and production of APS quadrupole magnets. The tolerances for the multipole components for the quadrupole magnets will be set to that level which reduces the dynamic aperture by about 10--15% from the ideal machine dynamic aperture (as specified in CDR-87). This level may appear rather stringent, especially compared to the 50--60% reduction resulting from quad placement errors. However, when all tolerances are taken together, the residual dynamic aperture would be prohibitively small and commissioning would be difficult if these tolerances were at twice this level. The dynamic aperture was determined using the numerical tracking program RACETRACK.
Date: August 1, 1988
Creator: Kramer, S. L.
Partner: UNT Libraries Government Documents Department

Survey, alignment, and beam stability at the Advanced Light Source

Description: This paper describes survey and alignment at the Lawrence Berkeley Laboratories Advanced Light Source (ALS) accelerators from 1993 to 1997. The ALS is a third generation light source requiring magnet alignment to within 150 microns. To accomplish this, a network of monuments was established and maintained. Monthly elevation surveys show the movement of the floor over time. Inclinometers have recently been employed to give real time information about magnet, vacuum tank and magnet girder motion in the ALS storage ring.
Date: October 1, 1997
Creator: Krebs, G.F.
Partner: UNT Libraries Government Documents Department

Hysteresis study techniques and results for accelerator magnets with unipolar current excitation

Description: Using an automated magnet measurement system employing a variety of current excitation ramps, extensive studies of the hysteretic behavior of magnet strength have been carried out. An analytic description which is accurate at better than 0.1% has been achieved. Prescriptions for setting field strength using these formulas will be adequate for multi-energy operation of the Fermilab Main Injector, for deceleration in the Main Injector and Accumulator and for multi-energy operation of various beamline magnets. An overview of this work is provided. Important regularities of the magnet behavior are identified.
Date: April 23, 1999
Creator: Brown, Bruce C.
Partner: UNT Libraries Government Documents Department

Polarized neutrons in RHIC

Description: There does not appear to be any obvious way to accelerate neutrons, polarized or otherwise, to high energies by themselves. To investigate the behavior of polarized neutrons the authors therefore have to obtain them by accelerating them as components of heavier nuclei, and then sorting out the contribution of the neutrons in the analysis of the reactions produced by the heavy ion beams. The best neutron carriers for this purpose are probably {sup 3}He nuclei and deuterons. A polarized deuteron is primarily a combination of a proton and a neutron with their spins pointing in the same direction; in the {sup 3}He nucleus the spins of the two protons are opposite and the net spin (and magnetic moment) is almost the same as that of a free neutron. Polarized ions other than protons may be accelerated, stored and collided in a ring such as RHIC provided the techniques proposed for polarized proton operation can be adapted (or replaced by other strategies) for these ions. This paper discusses techniques for accelerating polarized {sup 3}He nuclei and deuterons.
Date: April 20, 1998
Creator: Courant, E.D.
Partner: UNT Libraries Government Documents Department

Muon dynamics in a toroidal sector magnet

Description: The present scenario for the cooling channel in a high brightness muon collider calls for a quasi-continuous solenoidal focusing channel. The beam line consists of a periodic array of rf cavities and approximately 2 cm long LiH absorbers immersed in a solenoid with alternating focusing field (FOFO). The authors present a Hamiltonian formulation of muon dynamics in toroidal sector solenoids (bent solenoid).
Date: September 17, 1997
Creator: Gallardo, J.C.; Fernow, R. & Palmer, R.B.
Partner: UNT Libraries Government Documents Department