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Wake field produced by a particle in the presence of conductive plates: a vehicle for the excitation of the coupled betatron-synchrotron instabilities

Description: Beam instabilities observed in ADONE were studied. The interaction of a single particle betatron oscillation with conductive plates was analyzed. First, Fourier analysis of the field source was performed, then the usual approach to determine the plate response was used by treating the plates as transmission lines. Finally, with a process of anti-transformation the total response to the oscillation of a single particle was constructed. The wake field decays over a distance which is of the order of magnitude of the length of the plates themselves. Nevertheless, the shape of the wake field depends on the terminating independence. Several cases, for instance matched, open and shorted plates are considered. (auth)
Date: May 22, 1973
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Comparison between theoretical predictions and tracking

Description: The beam-beam interaction in a proton-antiproton collider has been an outstanding issue for a long time. Several theoretical predictions have been made in the past which range from the appearance of single beam-beam driven resonances to the onset of stochasticity and Arnold diffusion and the presence of chaotic trajectories. All these effects would cause a limit on the maximum strength of the beam-beam interaction, the so called beam-beam tune-shift, and speculative values have been offered ranging from as low as 0.0005 to as large as a fraction of unit. The lower limit could be caused in a more complicated situation where the external focussing forces which keep the two beams in the same storage ring are also modulated in time. These theoretical predictions have been compared with extensive computer tracking where the motion of the particles is followed turn after turn over very long periods of time. Though it is indeed possible to observe the formation of several resonances, nevertheless the onset of connected stochasticity seems to occur at too large beam-beam tune-shift to be of any practical relevance. Moreover no Arnold diffusion has been observed to have any practical significance. Chaotic trajectories have been found to embed the phase space in disconnected regions of appreciable extension. They increase in numbers considerably when time modulation of external focussing forces is added. 15 refs., 18 figs.
Date: January 1, 1985
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Wakeatron: acceleration of electrons on the wake field of a proton bunch

Description: We explore in this note the idea of accelerating a low intensity electron or positron bunch, travelling through a linear rf structure, following at a short distance an intense proton bunch which leaves behind a wake field. This device acts like a transformer where two beams are involved: one made of protons at high current and low energy, the other made of either electrons or positrons, at low current and high energy. The two beams are coupled electromagnetically to each other by a specially designed rf structure made of a long sequence of cavities.
Date: January 1, 1985
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Review of heavy ion collider proposals

Description: In this paper we review proposals for heavy-ion colliders generated during the last few years for several national laboratories. The proposals span over a large range of energy and luminosity to accommodate the experimental needs of both the nuclear and the high-energy physicists. We report also briefly efforts in the same field happening in Europe.
Date: January 1, 1985
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Acceleration of electrons by the wake field of proton bunches

Description: This paper discusses a novel idea to accelerate low-intensity bunches of electrons (or positrons) by the wake field of intense proton bunches travelling along the axis of a cylindrical rf structure. Accelerating gradients in excess of 100 MeV/m and large ''transformer ratios'', which allow for acceleration of electrons to energies in the TeV range, are calculated. A possible application of the method is an electron-positron linear collider with luminosity of 10/sup 33/ cm/sup -2/ s/sup -1/. The relatively low cost and power consumption of the method is emphasized.
Date: January 1, 1986
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Scenario for the relativistic heavy ion collider (RHIC) for Brookhaven National Laboratory

Description: In this note we describe a scheme to obtain a high performance relativistic heavy ion collider (RHIC) sized to fit within the CBA tunnel at BNL. The project has two parts: the Source of heavy ions and the Collider itself. We keep these two parts separated since a different analysis is done for each. It is obvious that the performance of the total facility depends crucially on the performance of both.
Date: May 1, 1984
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Summary of the workshop

Description: The Workshop on the ''RHIC'' Performance was held at the Collider Center, Brookhaven National Laboratory, from March 21 to 26, 1988. The Workshop had three major goals: To check the validity and soundness of the methods described in the Conceptual Design Report (CDR, May 1986), in order to ensure the performance proposed there. To initiate and study techniques that increase the luminosity in the second stage of RHIC by a factor of twenty beyond the CDR values, and to reduce the interactive region to a rms length of less than 20 cm. To investigate possible limits on beam intensity and dimensions, and their impact on RHIC hardware. Conclusions and recommendations on these topics are discussed in this paper. 5 tabs.
Date: January 1, 1988
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Interaction of a coasting beam and a bunched beam with frequency slip

Description: Collisions between a coasting beam and a bunched beam can be so arranged that a particle in the coasting beam collides with the bunched beam only intermittently. A particle thus interacts with a bunch for a given number of revolutions, say q, and then slips away into the interbunch space. The process, with each cycle taking say, n revolutions, then continues. The possible effects of this intermittient type force are considered. The linear stopbands introduced are dealt with in detail. Growth rates are obtained as a function of q, assuming a Gaussian fall-off in the force. The stabilizing influence of an azimuthally constant octupole field component is demonstrated. Isolated nonlinear resonances excited by the intermittent force are discussed. No quantitative treatment is given as far as concerns the stochastic nature of highly nonlinear systems. Also, the influence of feeding mechanisms, such as a time variation of the tune is neglected. If the number of revolutions between kicks, ~n is large, then there is the possibility of loss of correlation betveen kicks. The resulting diffusion is analyzed and diffusion rates are estimated. It was concluded that: (1) growth due to linear instabilities are effectively damped by making q large enough. The perturbation is turned on and off adiabatically and leaves no record of itself from cycle to cycle. The growth rate is linear in DELTA the beam-- beam linear tune shift per interaction and per revolution; (2) the diffusion induced by random processes causing the kicks to be uncorrelated produces a bearm growth rate which is quadratic in DELTA nu . Although it is smaller than the gradient stopband growth (for low q), it is essentially independent of tune (and so occurs for all particles) and it has no drop-off with q. In fact, for large q, it increases like q/sup ...
Date: January 1, 1973
Creator: Month, M. & Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Closed orbit analysis for RHIC

Description: We examine the effects of four types of errors in the RHIC dipoles and quadrupoles on the on-momentum closed orbit in the machine. We use PATRIS both to handle statistically the effects of kick-modeled errors and to check the performance of the Fermilab correcting scheme in a framework of a more realistic modeling. On the basis of the accepted rms values of the lattice errors, we conclude that in about 40% of all studied cases the lattice must be to some extent pre-corrected in the framework of the so-called ''first turn around strategy,'' in order to get a closed orbit within the aperture limitations at all and, furthermore, for approximately 2/3 of the remaining cases we find that a single pass algorithm of the Fermilab scheme is not sufficient to bring closed orbit distortions down to acceptable levels. We have modified the scheme and have allowed repeated applications of the otherwise unchanged three bump method and in doing so we have been able to correct the orbit in a satisfactory manner. 4 refs., 2 figs., 3 tabs.
Date: January 1, 1989
Creator: Milutinovic, J. & Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Comparison of accelerator codes for a RHIC (Relativistic Heavy Ion Collider) lattice

Description: We present the results of comparison of performances of several tracking or/and analysis codes. The basic purpose of this program was to assess reliability and accuracy of these codes, i.e., to determine the so-called ''error bars'' for the predicted values of tunes and other lattice functions as a minimum and, if possible, to discover potential difficulties with underlying physical models in these codes, inadequate algorithms, residual bugs and the like. Not only have we been able to determine the error bars, which for instance for the tunes at dp/p = +1% are ..delta nu../sub xi/ = 0.0027, ..delta nu../sub y/ = 0.0010, but also our program has brought about improvements of several codes. 8 refs., 3 figs., 2 tabs.
Date: January 1, 1989
Creator: Milutinovic, J. & Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Momentum precooling in the Debuncher ring for the Fermilab Tevatron-I project

Description: The design of the antiproton source for the Fermilab Tevatron-I project (TeV-I) incorporates two separate rings. The Accumulator Ring uses a stochastic cooling/stacking system to accumulate a sufficient number of antiprotons for use in the Tevatron collider. The Debuncher Ring rotates buckets and debunches antiproton pulses from the production target. This requires, in the Debuncher, a choice of lattice transition energy very near the beam energy, resulting in very narrow spread in the circulation frequency. If the energy spread could be further reduced in the Debuncher before the beam is transferred to the Accumulator, operational improvements would result in: (1) the reduction of stochastic cooling power in the Accumulator; (2) the acceptance of a larger momentum bite of antiprotons in the Debuncher (thus more antiprotons); and (3) the reduction of momentum aperture in the Accumulator. This note describes a quick investigation of the feasibility of precooling within the framework of technically achievable parameters.
Date: March 1, 1983
Creator: Ruggiero, A.G. & Simpson, J.
Partner: UNT Libraries Government Documents Department

Collective effects in short bunches: Summary of the Working Group on Proton Bunches

Description: This report discusses the following topics on proton beam bunching: space charge, a collective but incoherent effect; a very short proton bunch; long proton bunches; transition energy crossing; intrabeam scattering; vacuum related effects; and the issue of mode-coupling for proton bunches. (LSP)
Date: October 10, 1990
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

AN ALTERNATIVE SCHEME FOR THE NEUTRINO FACTORY WITH A HIGH POWER PROTON DRIVER.

Description: We describe a scheme to produce an intense and collimated beam of neutrinos for the neutrino-oscillation experiment. The scheme feature is the presence of a Proton Driver that generates a proton beam at very large power (10mA x 15GeV), considerably higher than that proposed elsewhere for this application. With this scheme, because of the high intensity of the proton beam, to produce neutrinos at the same required rates, it is sufficient to collect {pi} and {mu} mesons only around a small angle and at reduced momentum spreads. This eliminates the need for the difficult longitudinal manipulations of the protons and mesons, and of the ionization cooling that still needs to be demonstrated. It is also shown, at the end of the paper, that the Neutrino Factory here proposed can also be used as an injector for a 1 x 1 TeV{sup 2} {mu}{sup +} - {mu}{sup -} collider at large luminosity.
Date: June 30, 2001
Creator: RUGGIERO,A.G.
Partner: UNT Libraries Government Documents Department

The transport line between the main ring and the energy doubler

Description: In this paper we describe the transport line between the main ring (MR) and the energy doubler (ED). The transport line is designed on the basis of the following three assumptions: (1) The ED is located at the apex of the same tunnel which encloses the MR. The relative locations of the two rings are shown in Fig. 1. The ED line is 3 feet to the inside and 4 feet above with respect to the MR line. Watching Fig. 1 the beam moves toward the page and the center of the rings is to the right. The continuous outer curve is the cross section of the tunnel in a typical long-straight section, the dashed inner curve is the cross section of the tunnel in the bent section. (2) The beam has to be extracted from one long-straight section of the MR (BO) and injected in the next medium-straight section of the ED (B17). The two rings are assumed to have the same identical lattice structure. (3) To keep the aisle-way in the tunnel as clear as we can it is advisable to extract the beam horizontally but displaced first vertically upward and second horizontally inward. The beam is then injected vertically. To avoid problems associated with trapped flux at low fields, it is advisable to inject at an energy substantially higher than 100 GeV. On the other hand, the last two assumptions limit the maximum energy to about 200 GeV. For higher energy one has, at the same time, to transfer the beam from one long-straight section to the next long-straight section and to obstruct a good fraction of the tunnel with Ragnets. Thus, the transport line we are going to describe here, has been designed for the transfer energy of 200 GeV. The transport line is divided in ...
Date: July 1, 1974
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Negative-ion injection by charge exchange at 2.4 GeV

Description: The present technical note describes multi-turn injection by charge exchange of 2.4-GeV negative ions in a Accumulator Ring used as an intense Pulsed Spallation Neutron Source. The major concern of beam loss due to magnetic stripping of the negative ions is addressed. It is demonstrated that, despite the high energy of the ions and the limitation on the magnitude of the magnetic field, it is possible to control the amount of beam losses to a fractional value of better than 10{sup {minus}5}, as it is required to avoid latent activation of the accelerator components. The injection magnet system which accomplish this is described. The paper addresses also the concern of beam loss due to the same effect in the 2.4-GeV injector linear accelerator, and in the transport from the Linac to the Accumulator Ring.
Date: September 1, 1995
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Multiple-linac approach for tritium production and other applications

Description: This report describes an approach to tritium production based on the use of multiple proton linear accelerators. Features of a single APTT Linac as proposed by the Los Alamos National Laboratory are presented and discussed. An alternative approach to the attainment of the same total proton beam power of 200 MW with several lower-performance superconducting Linacs is proposed and discussed. Although each of these accelerators are considerable extrapolations of present technology, the latter can nevertheless be built at less technical risk when compared to the single high-current APT Linac, particularly concerning the design and the performance of the low-energy front-end. The use of superconducting cavities is also proposed as a way of optimizing the accelerating gradient, the overall length, and the operational costs. The superconducting technology has already been successfully demonstrated in a number of large-size projects and should be seriously considered for the acceleration of intense low-energy beams of protons. Finally, each linear accelerator would represent an ideal source of very intense beams of protons for a variety of applications, such as: weapons and waste actinide transmutation processes, isotopes for medical application, spallation neutron sources, and the generation of intense beams of neutrinos and muons for nuclear and high-energy physics research. The research community at large has obviously an interest in providing expertise for, and in having access to, the demonstration, the construction, the operation, and the exploitation of these top-performance accelerators.
Date: January 10, 1995
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Design considerations on a proton superconducting linac

Description: The authors analyze the longitudinal motion of a single proton in a superconducting linear accelerator. They derive the linearized equations of motion, and develop a matrix formalism to represent the progress of motion. The goal is to provide a tool which can be easily included in a computer code for the design of superconducting proton linacs. In particular they determine the stability conditions, and the amount of motion mismatch resulting from the presence of drift insertions, and from the rate of acceleration. Space-charge effects have not been included in the analysis. They complement the analysis with considerations of the rf and cryogenic power requirements, of the pulsed mode of operation, and of the beam transverse confinement. They conclude with an example of a Spallation Neutron Source.
Date: August 1, 1995
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Power excitation by the use of a rf wiggler

Description: It is well-known that there are difficulties to obtain rf power sources of significant amount for frequencies larger than 3 GHz. Yet, rf sources in the centimeter/millimeter wavelength range would be very useful to drive, for example, high-gradient accelerating linacs for electron-positron linear colliders. We would like to propose an alternative method to produce such radiation. It makes use of a short electron bunch traveling along the axis of a waveguide which is at the same time excited by a TM propagating electromagnetic wave. It is well known that radiation can be obtained by wiggling the motion of the electrons in a direction perpendicular to the main one. The wiggling action can be included by electromagnetic fields in a fashion similar to the one caused by wiggler magnets. We found that an interesting mode of operation is to drive the waveguide with an excitation frequency very close to the cut off. For such excitation, the corresponding e.m. wave travels with a very large phase velocity which in turn has the effect to increase the wiggling action on the electron bunch. Our method, to be effective, relies also on the coherence of the radiation; that is the bunch length is taken to be considerably shorter than the radiated wavelength. In this case, the total power radiated should be proportional to the square of the total number of electrons in the bunch. The paper concludes with possible modes of operation, a list of performance parameters and a proposed experimental set-up.
Date: January 1, 1992
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Tandems as injectors for synchrotrons

Description: This is a review on the use of Tandem electrostatic accelerators for injection and filling of synchrotrons to accelerate intense beams of heavy-ions to relativistic energies. The paper emphasizes the need of operating the Tandems in pulsed mode for this application. It has been experimentally demonstrated that at the present this type of accelerators still provides the most reliable and best performance.
Date: January 1, 1992
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Beam position monitor analysis

Description: A large proportion of devices used to interact with charged-particle beams in accelerator or storage rings can be classified as pick-ups or kickers. These devices extract information about the particle motion or affect a change in the motion. One device used frequently as pick-up or kicker is made with two little plates with one or more terminations per plate. In this paper the structure with one termination per plate is examined. The azimuthal dependence is taken into account in circular geometry for one plate of given dimensions. The charges and currents induced on the plates are studied using azimuthal and frequency harmonic expansions. The potential equations are derived and developed in the frequency domain in order to give the close expression of the output voltage. And finally, the numerical results are discussed. 9 refs., 4 figs.
Date: March 1, 1989
Creator: Di Massa, G. & Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

General analysis of beam position monitors

Description: A large proportion of devices used to interact with charged-particle beams in accelerator or storage rings can be classified as pick-ups or kickers. These devices extract information about the particle motion or affect a change in the motion. One device used frequently as pick-up or kicker is made with two little plates with one or more terminations per plate. In this paper the structure with one termination per plate is examined. 3 refs., 3 figs.
Date: January 1, 1989
Creator: Di Massa, G. & Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Exact analysis to any order of the linear coupling problem in the thin lens model

Description: In this report we attempt the exact solution of the motion of a charged particle in a circular accelerator under the effects of skew quadrupole errors. We adopt the model of error distributions, lumped in locations with zero extensions. This thin-lens approximation provides an analytical insight to the problem to any order. The total solution is expressed in terms of driving terms which are actually correlation factors to several order. An application follows on the calculation and correction of tune-splitting and on the estimate of the role the higher-order terms play in the correction method.
Date: January 1, 1991
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department