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Arbitrary function generator for APS injector synchrotron correction magnets

Description: The APS injector synchrotron ring measures about 368 m in circumference. In order to obtain the precision of the magnetic field required for the positron acceleration from 450 Mev to 7.7 Gev with low beam loss, eighty correction magnets are distributed around its circumference. These magnets provide the vernier field changes required for beam orbit correction during the acceleration phase of the injector synchrotron cycle. Because of mechanical imperfections in the construction, as well as installation of real dipole and multi-pole magnets, the exact field correction required at each correction magnet location is not known until a beam is actually accelerated. It is therefore essential that a means is provided to generate a correction field that is a function of the beam energy from injection until extraction for each correction magnet. The fairly large number of correction magnets in the system requires that the arbitrary function generator design be as simple as possible yet provide the required performance. An important, required performance feature is that the function can be changed or modified ``on the fly``, to provide the operator with a real-time feel during the tune up process. The arbitrary function generator described in this report satisfies these requirements.
Date: November 7, 1990
Creator: Despe, O.D.
Partner: UNT Libraries Government Documents Department

ARF1 Frequency and Amplitude Curve Calibration

Description: ARF1 was calibrated and checked on 4/18/01. The technique used was to set the start/stop timers (A:R1LLT1 and A:R1LLT2) for duration of 200 msec. Driving the cavities for longer than 200 msec at full voltage could put some stress on the Hipotronics anode supply. The Camac curve generator card was substituted with a precision DC voltage source. Data for both amplitude and frequency were taken with the DC source. A HP 8563A spectrum analyzer in zero span with resolution bandwidth of 1 MHz at a center frequency of 52.818 MHz was used to take the amplitude data. The dynamic curve was a triangle waveform provided by a triggered HP3213A function generator. Frequency was measured on the Fluke frequency counter mounted in the rack in AP50 (with the high level RF off). The attached data and graph contain the current calibration. ARF1-1 is slightly lower voltage than ARF1-2, but well within spec. The calibration was made with the Anode supply at 9 Kvolts, the bend busses were off due to an access that was in progress. Due to the unregulated Anode supply, the voltage levels observed may be slightly higher than with bend busses on. The dynamic performance with the triangle waveform looks correct. The peak voltages measured for ARF1-1 and ARF1-2 were 27.1 KV and 32.9 KV respectively. The calibration for the fanback is 22 Kvolts per volt for ARF1-1&2, and 66 Kvolts per volt for ARF1 Sum. ARF1 has historically run with a flat top voltage duration of 160 msec. The current curve generator has lengthened that time considerably. The curve generator should take full advantage of the 65 dB dynamic range measured.
Date: April 20, 2001
Creator: Pasquinelli, Ralph J.
Partner: UNT Libraries Government Documents Department

Architecture and Performance of the PEP-II Low-Level RF System

Description: Heavy beam loading in the PEP-II B Factory along with large ring circumferences places unique requirements upon the low-level rf (LLRF) system. RF feedback loops must reduce the impedance observed by the beam while ignoring the cavity transients caused by the ion clearing gap. Special attention must be placed on the cavity tuner loops to allow matching the ion clearing gap transients in the high energy ring and the low energy ring. A wideband fiber optic connection to the longitudinal feedback system allows a rf station to operate as a powerful ''sub-woofer'' to damp residual low order coupled bunch motion. This paper describes the design and performance of the VXI based, EPICS controlled, PEP-II low-level rf system(s). Baseband in-phase and quadrature (IQ) signal processing using both analog and modern digital techniques are used throughout the system. A family of digital down converters provide extremely accurate measurements of many rf signals throughout the system. Each system incorporates a built-in network analyzer and arbitrary rf function generator which interface with Matlab to provide a wide range of functions ranging from automated configuration of each feedback loop to cavity FM processing. EPICS based sequences make the entire system a turn-key operation requiring minimal operator intervention. In the event of a fault, fast history buffers throughout the system write selected rf signals to disk files which can be viewed later to help diagnose problems. Actual data from commissioning runs of PEP-II is presented.
Date: April 14, 1999
Creator: Corredoura, Paul L.
Partner: UNT Libraries Government Documents Department

Subpicosecond high-brightness uv laser system

Description: A laser system that produces intense subpicosecond pulses of 248 nm light is under development. Ultrashort pulses are generated in the visible in a synchronously-pumped mode-locked dye oscillator, heterodyned into the uv by two KDP crystals, and amplified in a chain of KrF* amplifiers. Front end output of 5 ..mu..J is amplified to 20 mJ and focused to peak intensities of order 10/sup 17/ W cm/sup -2/. Additional amplification is expected to permit experiments at intensities >10/sup 20/ W cm/sup -2/.
Date: January 1, 1986
Creator: Gibson, R.B.
Partner: UNT Libraries Government Documents Department

Basic principles governing the design of magnetic switches

Description: The idea of using saturable reactors as the basis of high power pulse generators is not a new concept, but there have been few recent applications of this technology. Here the principle of magnetic pulse generation is briefly described and some of the basic guidelines used to design these circuits are discussed. A demonstration of the principles by a small scale pulse amplifier is presented, and finally there is an extrapolation to a large scale system.
Date: November 18, 1980
Creator: Birx, D.L.; Lauer, E.J.; Reginato, L.L.; Schmidt, J. & Smith, M.
Partner: UNT Libraries Government Documents Department

AGS tune jump system to cross horizontal depolarization resonances overview

Description: Two partial snakes overcome the vertical depolarizing resonances in the AGS. But a new type of depolarizing intrinsic resonance from horizontal motion appeared. We reduce these using horizontal tune jumps timed to these resonances. We gain a factor of six in crossing rate with a tune jump of 0.05 in 100 {micro}s. Two quadrapoles, we described in 2009, pulse 42 times, the current matching beam energy. The power supplies for these quads are described in detail elsewhere in this conference. The controls for the Jump Quad system is based on a BNL designed Quad Function Generator. Two modules are used; one for timing, and one to supply reference voltages. Synchronization is provided by a proprietary serial bus, the Event Link. The AgsTuneJump application predicts the times of the resonances during the AGS cycle and calculates the power supply trigger times from externally collected tune and energy versus time data and the Low and High PS voltage functions from a voltage to current model of the power supply. The system was commissioned during runs 09 & 10 and is operational. Many beam effects are described elsewhere. The TuneJump system has worked well and has caused little trouble save for the perturbations in the lattice having such a large effect due to our need to run with the vertical tune within a few thousandths of the integer tune. As these problems were mostly sorted out by correcting the 6th harmonic orbit distortions which caused a large 18 theta beta wave. Also running with minimal chromaticity reduces emittance growth. There are still small beta waves which are being addressed. The timing of the pulses is still being investigated, but as each crossing causes minimal polarization loss, this is a lengthy process.
Date: March 28, 2011
Creator: Glenn, J.W.; Ahrens, L.; Fu, W.; Mi, J.L.; Rosas, P.; Schoefer, V. et al.
Partner: UNT Libraries Government Documents Department

Compressed magnetic flux amplifier with capacitive load

Description: A first-order analysis is presented for a compressed magnetic flux (CMF) current amplifier working into a load with a capacitive component. Since the purpose of the investigation was to gain a general understanding of the arrangement, a number of approximations and limitations were accepted. The inductance of the transducer varies with time; the inductance/resistance/capacitance (LRC) circuit therefore is parametric and solutions are different for the stable regime (high C), the oscillation regime (low C), and the transition case. Solutions and performance depend strongly on circuit boundary conditions, i.e., energization of the circuit by either an injected current or by an applied capacitor charge. The behavior of current and energy amplification for the various cases are discussed in detail. A number of experiments with small CMF devices showed that the first-order theory presented predicts transducer performance well in the linear regime.
Date: March 1, 1980
Creator: Stuetzer, O.M.
Partner: UNT Libraries Government Documents Department

Orbit compensation for the time-varying elliptically polarized wiggler with switching frequency at 100 hz

Description: In October 1996, the elliptically polarized wiggler, installed in the X13 straight section of the NSLS X-ray ring, was commissioned at an operating frequency of 100 hz. This wiggler generates circularly polarized photons in the energy range of 0.1 to 10 keV with AC modulation of polarization helicity. The vertical magnetic field is produced by a hybrid permanent magnet structure, and the horizontal magnetic field is generated by an electromagnet capable of switching at frequencies up to 100 hz. Here, the authors discuss the compensation of the residual vertical and horizontal orbit motion utilizing a time-domain algorithm employing a function generator to drive trim coils at the wiggler ends, and the wideband high precision orbit measurement system of the X-ray ring. The residual orbit motion has been reduced to a level below 1 micron, and the device has been run in regular operations with no negative effect on other users.
Date: July 1, 1997
Creator: Singh, O. & Krinsky, S.
Partner: UNT Libraries Government Documents Department

Lecture 4: transmission lines and capacitors

Description: The topic of this lecture is pulse forming networks. The first item of discussion will be transmission lines because they are so prevalent, even if only in the form of coaxial cable. From there the subject will proceed to pulse-forming networks: the practical problems encountered with them, their advantages, and disadvantages. Capacitors will be our final topic, as they are the limiting factor in lumped transmission elements.
Date: January 1, 1980
Creator: Butcher, R.R.
Partner: UNT Libraries Government Documents Department

Pulse voltage circuits

Description: The problems associated with very high voltages may be avoided in part by a variety of pulse-multiplication techniques. These methods are quite varied but share two features, the use of modest dc voltages and the use of switching techniques, to produce in some manner a vectorial transient addition of voltages. Many such methods exist, but only the Marx blank, spiral generator, inversion generator, and Blumlein will be addressed here in detail. Two other methods will be given a brief discussion as matters of interest.
Date: January 1, 1980
Creator: Willis, W.L.
Partner: UNT Libraries Government Documents Department

Numerically controlled oscillator for the Fermilab booster

Description: In order to improve the stability of the Fermilab Booster low level rf system, a numerically controlled oscillator system is being constructed. Although the system has not been implemented to date, the design is outlined in this paper. The heart of the new system consists of a numerically synthesized frequency generator manufactured by the Sciteq Company. The 3 Ghz/sec rate and 30 to 53 MHz range of the Booster frequency program required the design of a CAMAC based, fast-cycling (1 MHz), 65K X 32 bit, digital function generator. A 1 MHz digital adder and 12 bit analog to digital converter will be used to correct small program errors by phase locking the oscillator to the beam. 6 refs., 1 fig.
Date: April 1, 1989
Creator: Crisp, J.L. & Ducar, R.J.
Partner: UNT Libraries Government Documents Department

Magnetic switches and circuits

Description: This report outlines the use of saturable inductors as switches in lumped-element, magnetic-pulse compression circuits is discussed and the characteristic use of each is defined. In addition, the geometric constraints and magnetic pulse compression circuits used in short-pulse, low-inductance systems are considered. The scaling of presaturation leakage currents, magnetic energy losses, and switching times with geometrical and material parameters are developed to aid in evaluating magnetic pulse compression systems in a particular application. Finally, a scheme for increasing the couping coefficient in saturable stripline transformers is proposed to enable their use in the short-pulse, high-voltage regime.
Date: May 1, 1982
Creator: Nunnally, W.C.
Partner: UNT Libraries Government Documents Department

Development of a 50 Hz, 250 kV, 500 ns, 500 KW average power pulser

Description: This paper describes the development of a 50 Hz research pulser with per shot specifications of 250 kV, 500 ns FWHM, 10 kJ. It is designed for burst mode service. The pulser is a two element Guillemin Type C pulse forming network with two parallel Marx generators serving as the first element and a single Marx generator serving as the second element. This paper will consider the two Marx generators of the first element only and will outline the important ongoing developmental areas.
Date: January 1, 1980
Creator: Buttram, M.T.
Partner: UNT Libraries Government Documents Department

Rf power saving in large storage rings

Description: This note considers the application of CARTOP, constant amplitude rf to pulse converter, to obtain average and peak power gains in large e/sup + -/ rings. CARTOP is a scheme where energy storage and modulation converts a continuous radio frequency (rf) wave into periodic rf pulses. A system with CARTOP is shown. The modulated rf goes through an energy storing network (ESN) that contains at least one energy storing cavity (ESC), which acts as a flywheel. Between pulses, it takes energy from the klystron and during the pulse it delivers energy to an accelerating cavity (AC).
Date: May 15, 1979
Creator: Farkas, Z.D.
Partner: UNT Libraries Government Documents Department

Stripline magnetic modulators for lasers and accelerators

Description: The basics of magnetic modulators including magnetic element and circuit considerations as applied to accelerators and lasers requiring repetitive (1 to 10 kHz), high voltage (50 to 500 kV), short pulse (50 to 100 ns) are discussed. The scaling of energy losses and switching parameters with material are included.
Date: January 1, 1981
Creator: Nunnally, W.C.
Partner: UNT Libraries Government Documents Department

A battery-powered flux compression generator system

Description: Flux compression generators (FCGs) are primarily used as energy amplifiers. While a FCG can be made small, typically the ''seed'' energy that the FCG amplifies comes from a capacitator bank much larger and heavier than the FCG. If seed energy was supplied by a compact device, FCGs could be used as portable power supplies. One application of interest is to combine a compact seed source with a FCG and transformer. The result would be a self-contained power supply capable of producing a microsecond long, megavolt pulse. The objective of the work described in this paper was to make a seed source capable of energizing a standard Los Alamos plate FCG. The power supply was to be relatively small, light weight, and able to deliver at least 100-kJ to a 280-nH inductive load, e.g., plate FCG. 4 figs., 2 tabs.
Date: January 1, 1989
Creator: Vorthman, J.E.; Fowler, C.M.; Hoeberling, R.F. & Fazio, M.V.
Partner: UNT Libraries Government Documents Department

Magnetic switching

Description: The paper discusses the development program in magnetic switching which was aimed at solving the rep-rate and reliability limitations of the ATA spark gaps. The end result has been a prototype physically very similar to the present Advanced Test Accelerator (ATA) pulse power unit but vastly superior in performance. This prototype, which is easily adaptable to the existing systems, has achieved a burst rep-rate of 20 kHz and an output voltage of 500 kV. A one-on-one substitution of the existing pulse power module would result in a 100 MeV accelerator. Furthermore, the high efficiency of the magnetic pulse compression stages has allowed CW operation of the prototype at one kilohertz opening up other applications for the pulse power. Performance and design details will be described.
Date: June 1, 1983
Creator: Birx, D.; Cook, E.; Hawkins, S.; Poor, S.; Reginato, L.; Schmidt, J. et al.
Partner: UNT Libraries Government Documents Department

Design of a 20-MJ coaxial generator

Description: A design is presented for an explosive-driven sweeping-wave coaxial generator. The generator is required to deliver 20 MJ to a 10-nH load with a final current-doubling time of 10 ..mu..s. A simple model of the armature motion takes into account both the explosive drive and the back pressure of the magnetic field. Shock and diffusion losses are combined in a self-consistent manner with the armature dynamics to give a circuit model for the generator. The scaling of this design to higher energies is discussed.
Date: January 1, 1983
Creator: Felber, F.S.; Caird, R.S.; Fowler, C.M.; Erickson, D.J.; Freeman, B.L. & Coforth, J.H.
Partner: UNT Libraries Government Documents Department

Conceptual design for a short-pulse explosive-driven generator

Description: A design is described for a short-pulse explosive-driven generator. The initial flux is provided by a side-fed one-turn coil that is crow-barred at peak field. This field is then compressed by the axially uniform expansion of a cylindrical armature inside the coil. A multistrand helical coil is used to convert the changing flux to voltage at the coaxial output. The circuit is completed by the impact of the armsture against contact rings connected to the helical coil and output. An approximate circuit model is derived. The analysis indicates that several megajoules can be delivered to an inductive load in 0.5 to 5.0 ..mu..s.
Date: January 1, 1986
Creator: Caird, R.S. & Fowler, C.M.
Partner: UNT Libraries Government Documents Department

Weapons Evaluation Test Laboratory at Pantex: Testing and data handling capabilities of Sandia National Laboratories at the Pantex Plant, Amarillo, Texas

Description: The Weapons Evaluation Test Laboratory (WETL), operated by Sandia Laboratories at the Pantex Plant in Amarillo, Texas, is engaged primarily in the testing of weapon systems in the stockpile or of newly produced weapon systems for the Sandia Surety Assessment Center. However, the WETL`s unique testing equipment and data-handling facilities are frequently used to serve other organizations. Service to other organizations includes performing special tests on weapon components, subassemblies, and systems for purposes such as basic development and specific problem investigation. The WETL staff also sends equipment to other laboratories for specific tests that cannot be performed at Pantex. For example, we modified and sent equipment to Brookhaven National Laboratory for testing with their Neutral Particle Beam. WETL supplied the engineering expertise to accomplish the needed modifications to the equipment and the technicians to help perform many special tests at Brookhaven. A variety of testing is possible within the WETL, including: Accelerometer, decelerometer, and G-switch g-level/closure testing; Neutron generator performance testing; weapon systems developmental tests; weapon system component testing; weapon system failure-mode-duplication tests; simultaneity measurements; environmental extreme testing; parachute deployment testing; permissive action link (PAL) testing and trajectory-sensing signal generator (TSSG) testing. WETL`s existing equipment configurations do not restrict the testing performed at the WETL. Equipment and facilities are adapted to specific requirements. The WETL`s facilities can often eliminate the need to build or acquire new test equipment, thereby saving time and expense.
Date: August 1, 1993
Creator: Peters, W. R.
Partner: UNT Libraries Government Documents Department

Neutrino horn power supply operational experience

Description: The operational experiences required to run the 300 kA pulsed power supply at Brookhaven National Laboratory are given. Various interlocks and monitoring circuits are described and the impact on system reliability are discussed. The initial conditioning process of the power supply during startup is described.
Date: January 1, 1987
Creator: Stillman, P.; Sandberg, J.; Carroll, A.S.; Leonhardt, W.; Monaghan, R.; Pearson, C. et al.
Partner: UNT Libraries Government Documents Department

Design of pulse transformers for PFL charging

Description: Air core pulse transformers powered by low voltage capacitor banks can be simple efficient systems for charging high-voltage (0.5 to 3 MV), pulse forming transmission lines (PFL) such as those used in electron and ion beam accelerators. In these applications pulse transformers must have the combined capability of high voltage endurance and high energy transfer efficiency, particularly in repetitive pulse systems where these features are of primary importance. The design of shielded, high-voltage, spiral, strip transformers which fulfill these requirements is described in this paper. Transformers of this type have been tested in three systems which operate with greater than 90% transfer efficiency and have not failed in over 10/sup 7/ shots.
Date: January 1, 1979
Creator: Rohwein, G.J.
Partner: UNT Libraries Government Documents Department