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Stability of bunched beams against high order nonlinear resonances

Description: For a given tune, beams can be made stable against the effects of isolated high order resonances. However, in a system whose betatron tune is changing, there exists a mechanism for beam loss. This mechanism is discussed and applied to the case of bunched beams, where the synchrotron motion introduces a time variation of tune. A stability criterion for a system with varying tune is presented, together with a set of suggested parameter values. The basic constraint is that the linear tune spread in the bunches (arising through the chromaticity) be smaller than the nonlinear tune spread (arising from the nonlinearities of magnetic field as well as the beam-beam interaction). This can be achieved with a small chromaticity and a relatively large nonlinear term causing a tune spread with betatron amplitude. Specific values for chromaticity and nonlinearity are suggested. A limit on the resonance excitation strength is also given. Since the beam-beam interaction introduces a tune spread with amplitude, then in some range it is found to have a stabilizing influence insofar as isolated high order nonlinear resonances are concerned. This point is discussed together with a brief discussion on the onset of stochastic phenomena, which are due to the interaction of many resonances. It is concluded that with the given set of parameters, bunched beams stable against high order nonlinear resonances can be achieved. (auth)
Date: December 1, 1973
Creator: Month, M.
Partner: UNT Libraries Government Documents Department

BPERM version 3.0: A 2-D wakepotential/impedance code

Description: BPERM 3.0 is an improved version of a previous release. The main purpose of this version is to make it more user friendly. Following a simple 1-2-3 procedure, one obtains both text and graphical output of the wakepotential and impedance for a given geometry. The calculation is based on a boundary perturbation method, which is significantly faster than numerical simulations. It is accurate when the discontinuities are small. In particular, it works well for tapered structures. 5 refs., 3 figs.
Date: October 1, 1996
Creator: Barts, T. & Chou, W.
Partner: UNT Libraries Government Documents Department

Longitudinal wake field corrections in circular machines

Description: In computations of longitudinal particle motions in accelerators and storage rings, the fields produced by the interactions of the beam with the cavity in which it circulates are usually calculated by multiplying Fourier components of the beam current by the appropriate impedances. This procedure neglects the slow variation with time of the Fourier coefficients and of the beam revolution frequency. When there are cavity elements with decay times that are comparable with or larger than the time during which changes in the beam parameters occur, these changes can not be neglected. Corrections for this effect have been worked out in terms of the response functions of elements in the ring. The result is expressed as a correction to the impedance which depends on the way in which the beam parameters are changing. A method is presented for correcting a numerical simulation by keeping track of the steady state and transient terms in the response of a cavity.
Date: October 1, 1996
Creator: Symon, K.R.
Partner: UNT Libraries Government Documents Department

Workshop on physics at the first muon collider and front-end of a muon collider: A brief summary

Description: In November 1997 a workshop was held at Fermilab to explore the physics potential of the first muon collider, and the physics potential of the accelerator complex at the `front-end` of the collider. An extensive physics program emerged from the workshop. This paper attempts to summarize this physics program and to identify the main conclusions from the workshop. 14 refs., 1 fig., 5 tabs.
Date: February 1, 1998
Creator: Geer, S.
Partner: UNT Libraries Government Documents Department

Ion effects in future circular and linear accelerators

Description: In this paper, the author discusses ion effects relevant to future storage rings and linear colliders. The author first reviews the conventional ion effects observed in present storage rings and then discusses how these effects will differ in the next generation of rings and linacs. These future accelerators operate in a new regime because of the high current long bunch trains and the very small transverse beam emittances. Usually, storage rings are designed with ion clearing gaps to prevent ion trapping between bunch trains or beam revolutions. Regardless, ions generated within a single bunch train can have significant effects. The same is true in transport lines and linacs, where typical vacuum pressures are relatively high. Amongst other effects, the author addresses the tune spreads due to the ions and the resulting filamentation which can severely limit emittance correction techniques in future linear colliders, the bunch-to-bunch coupling due to the ions which can cause a multi-bunch instability with fast growth rates, and the betatron coupling and beam halo creation which limit the vertical emittance and beam lifetimes.
Date: May 1, 1995
Creator: Raubenheimer, T.O.
Partner: UNT Libraries Government Documents Department

On the feasibility of tracking with differential-algebra maps in long-term stability studies for large hadron colliders

Description: A time-saving alternative to conventional element-by-element tracking in long-term stability studies is the use of truncated Taylor maps. This report discusses how the non-symplecticity of a moderately high-order truncated Taylor map affects its reliability when the map is used for tracking over several thousand turns. Various machines and two different map-constructing programs are compared. It is found that the discrepancies between the Taylor map results and those obtained by direct tracking grow with amplitude. Thus, such maps are not guaranteed to be sufficient for long-term tracking over millions of turns without suitable symplectification.
Date: January 1, 1992
Creator: Kleiss, R.; Schmidt, F. & Yan, Y.
Partner: UNT Libraries Government Documents Department

Accelerator waveform synthesis and longitudinal beam dynamics in a small induction recirculator

Description: A recirculating induction accelerator requires accelerating waveforms that produce current amplification and provide bunch length control throughout the acceleration process. Current amplification occurs because of both an increase in the beam velocity and a shortening of the length of the beam bunch. The pulsed acceleration and control waveforms seen by the beam change in time as the pulse duration shortens. For one acceleration cycle of the small recirculator, each accelerating gap is driven by a burst of 15 pulses. As the beam gains velocity, the time interval between pulses shortens from approximately 20 to 10 {mu}sec. A zero-dimensional design code REC is used to develop the accelerator wave forms. An envelope/fluid code CIRCE and a 3-D particle code WARP3d are used to confirm the REC design and study the effects of errors. The authors find that acceleration errors can lead to space-charge waves launched at the bunch ends that strongly affect or even destroy the current pulse shape. The relation between the rate of longitudinal compression and the velocity of space charge waves is studied.
Date: April 1995
Creator: Fessenden, T.J.; Grote, D.P. & Sharp, W.M.
Partner: UNT Libraries Government Documents Department

QA (Quality Assurance) role in advanced energy activities: Towards an /open quotes/orthodox/close quotes/ Quality Program: Canonizing the traditions at Fermilab

Description: After a brief description of the goal of Fermi National Accelerator Laboratory (Fermilab) this paper poses and answers three questions related to Quality Assurance (QA) at the Laboratory. First, what is the difference between 'orthodox' and 'unorthodox' QA and is there a place for 'orthodox' QA at a laboratory like Fermilab. Second, are the deeper philosophical and cultural frameworks of high-energy physics acommodating or antagonistic to an 'orthodox' QA Program. Finally, faced with the task of developing an institutional QA program for Fermilab where does one begin. The paper is based on experience with the on-going development and implementation of an institutional QA Program at Fermilab. 10 refs.
Date: February 1, 1988
Creator: Bodnarczuk, M.W.
Partner: UNT Libraries Government Documents Department

Evolution of the racetrack microtron control system

Description: Ultimately, the true measure of a control system lies in how well initial decisions allow for exigencies, as the overall machine evolves and requirements solidify. Recognizing that advances in electronic technology virtually guarantee that any system will be technologically out of date by the time it is operational, the criteria really do not involve the state of the technological advancement, but instead legitimately ask whether the control-system design can adjust to the inevitable machine-design changes, whether the operators can use it to control the machine in a reasonable manner, whether it was built within budget constraints, or - in short - whether it works. On these bases, our initial decisions on the racetrack microtron (RTM) control system have been increasingly vindicated as the system has evolved, and we feel that our experiences have shed some light on just which criteria are of real importance, and which are merely a part of the lore of popular misinformation. Unless the basic requirements are met, technical elegance is no virtue, and when they are met, design simplicity is no vice.
Date: January 1, 1981
Creator: Martin, E.R.; Schneider, C.M.; Martinez, V.A.; Trout, R.E. & Gritzo, R.E.
Partner: UNT Libraries Government Documents Department

CP violation and flavor-changing-currents at {mu}{sup +}{mu}{sup minus} colliders

Description: Production and decay (CP) asymmetries at {mu}{sup +}{mu}{sup {minus}} collider, in extensions of the Standard Model (SM) are reported. Production asymmetries appear to be very promising for a large range of parameters, decays are less effective. Importance of flavor- changing scalar currents involving the top are emphasized. At lepton colliders, the top-anticharm final state is uniquely suited for such searches. At a muon collider there is the novel possibility of tree level {mu}{sup +}{mu}{sup {minus}} {r_arrow} t{ovr c}. This talk is based on works done in collaboration with David Atwood and Laura Reina. 10 refs., 8 figs.
Date: April 2, 1996
Creator: Soni, A.
Partner: UNT Libraries Government Documents Department

Muon collider design

Description: The possibility of muon colliders was introduced by Skrinsky et al., Neuffer, and others. More recently, several workshops and collaboration meetings have greatly increased the level of discussion. In this paper we present scenarios for 4 TeV and 0.5 TeV colliders based on an optimally designed proton source, and for a lower luminosity 0.5 TeV demonstration based on an upgraded version of the AGS. It is assumed that a demonstration version based on upgrades of the FERMILAB machines would also be possible. 53 refs., 25 figs., 8 tabs.
Date: March 1, 1996
Creator: Palmer, R.; Sessler, A. & Skrinsky, A.
Partner: UNT Libraries Government Documents Department

Experience with the NEG (nonevaporable getter) strips at the Brookhaven heavy ion transport line

Description: The AGS and the Tandem Van de Graaff, two valuable physics assets, are now jointed together by a transport line of 700 m in length. This line allows heavy ions from the Tandem, up to a fully striped silicon (M = 28) to be injected into the AGS and accelerated to energies of approximately 15 GeVamu. New areas of physics research at very high nuclear densities can now be studied using some of the extensive experimental facilities already existing at the AGS. With the addition of a booster synchrotron between the Tandem and the AGS, all heavier ions up to gold can also be accelerated. To minimize the beam loss due to charge exchange between the partially stripped heaviest ions (i.e. Au + 33 at 1 MeVamu) and the residual gas molecules, a vacuum of 10 /sup /minus/8/ Torr is required for this transport line. To achieve this vacuum, we have opted to use the combination of small ion pumps (20 1s diode type) and simple geometry was implemented which offers low cost (<$200m), easy installation and maintenance. Pressures of 10 /sup /minus/10/ and low 10 /sup /minus/9/ Torr have been maintained over the last two years following the initial activation. This paper describes the NEG strip system, and the experience obtained during the installation and the operation of this 700m heavy ion transport line (HITL).
Date: January 1, 1988
Creator: Hseuh, H.C.; Benjamin, J.; Stattel, P.; Feigenbaum, I. & Manni, M.
Partner: UNT Libraries Government Documents Department

Costs to build Fermilab in 1984 dollars

Description: It is of current interest to examine the costs incurred to date to build Fermi National Accelerator Laboratory and to determine what those costs are when stated in FY 1984 constant dollars. The appended tables are in support of this exercise and are based on all costs for Equipment items (reduced by obsolescence) and all Plant Projects which have been appropriated through FY 1984. Also included are non-plant costs which are required to complete the Energy Saver, Tevatron I and II projects (i.e., Equipment and R and D in support of Construction). This study makes the assumption that all funding through FY 1984 will have been costed by the end of FY 1986. Those costs incurred in FY 1985 and FY 1986 have been deflated to FY 1984 dollars. See Appendix A for the DOE inflation factors used in the conversion to FY 1984 dollars. The costs are identified in three categories. The Accelerator Facilities include all accelerator components, the buildings which enclose them and utilities which support them. The Experimental Facilities include all beam lines, enclosures, utilities and experimental equipment which are usable in current experimental programs. The Support Facilities include lab and office space, shops, assembly facilities, roads, grounds and the utilities which do not specifically support the Accelerator or Experimental Facilities, etc.
Date: February 1, 1984
Creator: Jordan, N.G. & Livdahl, P.V.
Partner: UNT Libraries Government Documents Department

Synchrotrons for heavy ions: Bevalac experience

Description: The Bevalac should be viewed not as a model of accelerator hardware - a modern heavy ion complex will look quite different, but as a model for an operating versatile multifaceted, multiuser heavy ion facility. Of value to the planning of a new accelerator such as MARIA is the knowledge of operating modes peculiar to heavy ions and specific hardware requirements to carry out its mission with the mandated flexibility and reliability. This paper starts with a discussion of parameters and machine characteristics most suitable for medical and nuclear science applications. It then covers experience in interleaving these two research programs, and finally, concentrates on accelerator configuratin questions; injectors, repetition rate, vacuum systems and cost criteria which will be relevant to the design of MARIA.
Date: October 1, 1980
Creator: Grunder, H.A.; Gough, R.A. & Alonso, J.R.
Partner: UNT Libraries Government Documents Department

Accelerators for research and applications

Description: The newest particle accelerators are almost always built for extending the frontiers of research, at the cutting edge of science and technology. Once these machines are operating and these technologies mature, new applications are always found, many of which touch our lives in profound ways. The evolution of accelerator technologies will be discussed, with descriptions of accelerator types and characteristics. The wide range of applications of accelerators will be discussed, in fields such as nuclear science, medicine, astrophysics and space-sciences, power generation, airport security, materials processing and microcircuit fabrication. 13 figs.
Date: June 1, 1990
Creator: Alonso, J.R.
Partner: UNT Libraries Government Documents Department

The Delta-t tuneup procedure for the Fermilab Linac

Description: The delta-t procedure provides a means of monitoring and setting to design values the phase and amplitude of fields within a linear accelerator. Deviations from design values of energy entering an accelerator module can also be determined. The procedure will be used to tune the upgraded linac under construction at Fermilab. Results of preliminary tests of the technique on the existing 200 MeV linac show qualitative trends in agreement with analysis. Quantitative comparisons show some differences. 4 refs., 6 figs.
Date: October 1, 1990
Creator: Owens, T.L. & McCrory, E.S.
Partner: UNT Libraries Government Documents Department

Control system for the NBS microtron accelerator

Description: As various subsystems of the National Bureau of Standards/Los Alamos racetrack microtron accelerator are being brought on-line, we are gaining experience with some of the innovations implemented in the control system. Foremost among these are the joystick-based operator controls, the hierarchical distribution of control system intelligence, and the independent secondary stations, permitting sectional stand-alone operation. The result of the distributed database philosophy and parallel data links has been very fast data updates, permitting joystick interaction with system elements. The software development was greatly simplified by using the hardware arbitration of several parallel processors in the Multibus system to split the software tasks into independent modules.
Date: January 1, 1985
Creator: Martin, E.R.; Trout, R.E.; Wilson, B.L.; Ayres, R.L. & Yoder, N.R.
Partner: UNT Libraries Government Documents Department

Multiple gas analyzer sample test points

Description: Fermi National Accelerator Laboratory (Fermilab) is now beginning to depend upon dedicated gas analyzers in their collider and large fixed target experiment areas. In the past one or two gas samples were taken and sent off to Argonne National Laboratory for gas analysis, for even a basic check of ratios for Ar (Argon) C{sub 2}H{sub 6} (Ethane) 50/50% mixtures. This paper discusses the measuring techniques.
Date: October 21, 1988
Creator: Sellberg, G.
Partner: UNT Libraries Government Documents Department

Spool piece aperture: warm to cold temperature position changes

Description: In an effort to determine the position of the correction coil system contained in the spool piece in operation, a series of experiments were done in Lab 2 during the cryogenic testing of the spools. A special turn-around box was constructed which had a window through which a sighting could be made of the aperture of the coil packages. A set of four survey monuments were constructed with three point suspension, which were back-lighted by placing a small bulb behind each target which could be turned on individually external to the spool string while under vacuum and at any temperature. The targets were located at the ends of each correction coil package in their beam tube.
Date: December 1, 1982
Creator: McInturff, A.D.
Partner: UNT Libraries Government Documents Department

Brief summary of staffing levels at Fermilab during initial construction years

Description: This paper very briefly summarizes the work of the various groups that were involved from the beginning through the end of the initial construction phase of the Fermilab project (defined here to be July 1, 1972) and the final construction or completion phase which is here defined as December 31, 1973. The numbers in this report have been gathered by examining the personnel records of Fermilab with the research being done by Chuck Marofske, the Head of Laboratory Services and his staff and by assembling information from the memories of people still with the laboratory in 1983. Since there was much mobility within the laboratory during the construction years and frequent reorganizations were the norm, the numbers presented herein can not be considered to be more accurate than about +- 5%.
Date: November 1, 1983
Creator: Livdahl, P.V.
Partner: UNT Libraries Government Documents Department

Review of ion accelerators

Description: The field of ion acceleration to higher energies has grown rapidly in the last years. Many new facilities as well as substantial upgrades of existing facilities have extended the mass and energy range of available beams. Perhaps more significant for the long-term development of the field has been the expansion in the applications of these beams, and the building of facilities dedicated to areas outside of nuclear physics. This review will cover many of these new developments. Emphasis will be placed on accelerators with final energies above 50 MeV/amu. Facilities such as superconducting cyclotrons and storage rings are adequately covered in other review papers, and so will not be covered here.
Date: June 1, 1990
Creator: Alonso, J.
Partner: UNT Libraries Government Documents Department

Bevalac versatility: Operations achievements in the multi-tasking mode

Description: Demand for relativistic heavy ion beams at the Bevalac has increased dramatically in the past two years. To keep pace, the Bevalac make use of five injectors, precise guide field control, preset beam transport line tunes, nine nuclear science target areas, and three biology/radiotherapy areas, along with elegant control computer algorithms, to achieve high operating efficiency. Routine operation includes as many as ten ion/energy/beamline changes per day, 15 major nuclear science experiments each year, radiotherapy on nearly a daily basis, with biology experiments operating biweekly. High operating efficiency and low failure rates combine to produce high annual research hours. 12 refs., 2 figs.
Date: March 1, 1989
Creator: Lothrop, F.; Alonso, J.; Miller, R. & Tekawa, M.
Partner: UNT Libraries Government Documents Department