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8,400
Future Colliders
physics.acc-ph
The high energy physics advantages, disadvantages and luminosity requirements of hadrons, of leptons and photon-photon colliders are considered. Technical arguments for increased energy in each type of machine are presented. Their relative size, and the implications of size on cost are discussed.
physics
8,401
High Luminosity Muon Collider Design
physics.acc-ph
Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadrons and electron machines. They should be regarded as complementary. Parameters are given of a 4 TeV high luminosity muon-muon collider, and of a 0.5 TeV demonstration machine. We discuss the various systems in suc...
physics
8,402
On Stern-Gerlach forces allowed by special relativity and the special case of the classical spinning particle of Derbenev-Kondratenko
physics.acc-ph
This work is devoted to an examination of Stern-Gerlach forces consistent with special relativity and is motivated by recent interest in the relativistic Stern-Gerlach force acting on polarized protons in high-energy particle accelerators. The equations for the orbital and spin motion of a classical charged particle wi...
physics
8,403
Comparisons Between Modeling and Measured Performance of the BNL Linac
physics.acc-ph
Quite good agreement has been achieved between computer modeling and actual performance of the Brookhaven 200 MeV Linac. We will present comparisons between calculated and measured performance for the beam transport through the RFQ, the 6 meter transport from RFQ to the linac and meching and transport through the linac...
physics
8,404
New Expression for the Transverse Deflection of Relativistic Particle in High-Frequency Fields and Correlation with Panofsky- Wenzel Theorem
physics.acc-ph
It is shown that change in transverse momentum of a relativistic particle, crossing an accelerating cavity parallel to its axis, may be presented as an integral over trajectory, the integrand of which is proportional to the component of magnetic field parallel to this axis. The changes in two transversal components of ...
physics
8,405
Generator-Invertor-Dumper System of Electron (Positron) Bunches Moving in Cold plasma for Development of Strong Accelerating Electric Field
physics.acc-ph
It is shown that high accelerating gradient can be obtained in a specially constructed system of electron (positron) bunches, moving in cold plasma,with definite density. These combined bunch systems do not generate the wake fields behind them and can pass through the plasma column in a periodic sequence. The considera...
physics
8,406
One Dimensional Nonlinear Wake-fields Excited in a Cold Plasma by Charged Bunches
physics.acc-ph
One dimensional nonlinear plasma wake-fields excited by a single bunch and by series of bunches are considered. Essential differences are brought to light between negatively charged bunch case and positively one. The bunches with nonuniform distributions of density are investigated. The obtained results show dependence...
physics
8,407
High Energy Colliders
physics.acc-ph
We consider the high energy advantages, disadvantages and luminosity requirements of hadrons, leptons and photon-photon colliders. Technical problems in obtaining increased energy in each type of machine are presented. The machines relative size are also discussed.
physics
8,408
Muon-Muon and other High Energy Colliders
physics.acc-ph
Parameters are given of 4 TeV and 0.5 TeV (c-of-m) high luminosity muon-muon Colliders. We discuss the various systems, starting from the proton accelerator needed to generate the muons and proceeding through muon cooling, acceleartion and storage in a collider ring. Detector background, polarization are analyzed. We a...
physics
8,409
Wire scanners in low energy accelerators
physics.acc-ph
Fast wire scanners are today considered as part of standard instrumentation in high energy synchrotrons. The extension of their use to synchrotrons working at lower energies, where Coulomb scattering can be important and the transverse beam size is large, introduces new complications considering beam heating of the wir...
physics
8,410
Simulations of the Interaction Region in a Photon-Photon Collider
physics.acc-ph
The status and initial performance of a simulation program CAIN for interaction region of linear colliders is described. The program is developed to be applicable for e+e-, e-e-, e-gamma and gamma-gamma linear colliders. As an example of an application, simulation of a gamma-gamma collider option of NLC is reported.
physics
8,411
Stability and Halo Formation in Axisymmetric Intense Beams
physics.acc-ph
Beam stability and halo formation in high-intensity axisymmetric 2D beams in a uniform focusing channel are analyzed using particle-in-cell simulations. The tune depression - mismatch space is explored for the uniform (KV) distribution of the particle transverse-phase-space density, as well as for more realistic ones (...
physics
8,412
The ANKA Injector
physics.acc-ph
ANKA is a 2.5 GeV synchrotron radiation storage ring under construction at the Forschungszentrum Karlsruhe in Germany. The injector system will consist of a pre-injector with an end energy of 20 to 50 MeV and a 0.5 GeV booster synchrotron. In the following three different concepts for designing the booster synchrotron ...
physics
8,413
Conceptual and Experimental Feasibility Study of a Superconductive Micro-Undulator
physics.acc-ph
In this paper the concept and the first successful tests towards constructing a superconductive micro-undulator with a period length of 3.8 mm are described. The structures were built with a commercially available NbTi wire. A full 100 periods prototype is now under construction.
physics
8,414
The NSNS High Energy Beam Transport Line
physics.acc-ph
In the National Spallation Neutron Source (NSNS) design, a 180 meter long transport line connects the 1 GeV linac to an accumulator ring. The linac beam has a current of 28 mA, pulse length of 1 ms, and 60 Hz rep rate. The high energy transport line consists of sixteen 60 degrees FODO cells, and accommodates a 90 degre...
physics
8,415
The Algebraic Reconstruction Technique (ART)
physics.acc-ph
Projections of charged particle beam current density (profiles) are frequently used as a measure of beam position and size. In conventional practice only two projections, usually horizontal and vertical, are measured. This puts a severe limit on the detail of information that can be achieved. A third projection provide...
physics
8,416
A superconductive undulator with period length of 3.8 mm
physics.acc-ph
During the last years several attempts were undertaken to decrease the period length of undulators to the mm range. In this paper, a novel type of an in-vacuum undulator is described which is built with superconductive wires. The period length of this special device is 3.8 mm. In principle, it is possible to decrease t...
physics
8,417
Linac-Ring Type Colliders: Fourth Way To TeV Scale
physics.acc-ph
The present status of suggested linac-ring type ep and gamma-p colliders is reviewed. The main parameters of these machines as well as e-nucleus and gamma-nucleus colliders are considered. It is shown that sufficiently high luminosities may be achieved with a reasonable improvement of proton and electron beam parameter...
physics
8,418
Muon Dynamics in a Toroidal Sector Magnet
physics.acc-ph
We present a Hamiltonian formulation of muon dynamics in toroidal sector solenoids (bent solenoids)
physics
8,419
Two-dimensional Stationary Wake Fields in Vortexfree Cold Plasma. I
physics.acc-ph
Present paper is devoted to formulation of the system of the master equations of the problem and analytical considerations of the limiting cases, which have an exact solutions (transversal and longitudinal flat bunches, linear approxim- ation). Presented consideration gives some hints to the construction of proper algo...
physics
8,420
Muon Collider: Introduction and status
physics.acc-ph
Parameters are given of machines with center-of-mass (CoM) energies of 3 TeV and 400 GeV but, besides a comment on neutrino radiation, the paper concentrates on progress on the design of a machine to operate at a light Higgs mass, assumed, for this study, to be 100 GeV (CoM).
physics
8,421
Resonant Diffraction Radiation and Smith-Purcell Effect
physics.acc-ph
An approach has been developed where the Smith-Purcell radiation (SPR), i.e. emission of electrons moving close to a periodic structure, is treated as the resonant diffraction radiation. Simple formulas have been designed for the SPR intensity for a grating having perfectly conducting strips spaced by a vacuum gap. The...
physics
8,422
The Dynamic Aperture and the High Multipole Limit
physics.acc-ph
Tracking studies have indicated that for a lattice whose elements all have a single field multipole present, all having the same order k, the dynamic aperture approaches a non zero limit when k becomes very large. The dynamic aperture and other properties of the lattice, as k becomes large, will be called the high mult...
physics
8,423
Superconducting Superstructure for the TESLA Collider
physics.acc-ph
We discuss the new layout of a cavity chain (superstructure) allowing, we hope, significant cost reduction of the RF system of both linacs of the TESLA linear collider. The proposed scheme increases the fill factor and thus makes an effective gradient of an accelerator higher. We present mainly computations we have per...
physics
8,424
First experiments with a 100 period superconductive undulator with a period length of 3.8 mm
physics.acc-ph
A prototype of a novel superconductive undulator with a period length of 3.8 mm is described. The undulator is 100 periods long. In the first tests described in this paper the undulator was cooled in a helium bath and it was shown that it can be operated as expected with a maximum current of 1400 A. Afterwards the undu...
physics
8,425
Muon Collider Overview: Progress and Future Plans
physics.acc-ph
Besides continued work on the parameters of a 3-4 and 0.5 TeV CoM collider, many studies are now concentrating on a machine near 100 GeV that could be a factory for the s-channel production of Higgs particles. We mention the research on the various components in such muon colliders, starting from the proton accelerator...
physics
8,426
Wake Field Effect Analysis in APT Linac
physics.acc-ph
The 1.7-GeV 100-mA CW proton linac is now under design for the Accelerator Production of Tritium (APT) Project. The APT linac comprises both the normal conducting (below 211 MeV) and superconducting (SC) sections. The high current leads to stringent restrictions on allowable beam losses (<1 nA/m), that requires analyzi...
physics
8,427
Cavity Loss Factors For Non-Ultrarelativistic Beams
physics.acc-ph
Cavity loss factors can be easily computed for ultrarelativistic beams using time-domain codes like MAFIA or ABCI. However, for non-ultrarelativistic beams the problem is more complicated because of difficulties with its numerical formulation in the time domain. We calculate the loss factors of a non-ultrarelativistic ...
physics
8,428
Halo Formation in Spheroidal Bunches with Self-Consistent Stationary Distributions
physics.acc-ph
A new class of self-consistent 6-D phase space stationary distributions is constructed both analytically and numerically. The beam is then mismatched longitudinally and/or transversely, and we explore the beam stability and halo formation for the case of 3-D axisymmetric beam bunches using particle-in-cell simulations....
physics
8,429
Multi-Bunch Dynamics in RF Photoinjectors Through an Envelope Equation Approach
physics.acc-ph
Free Electron Lasers driven by Super-Conducting Linacs require the generation, acceleration and transport of trains of bunches with high charge, high repetition rate and low emittance. A numerical model already developed for the modeling of beam dynamics in SC Linacs has been now extended to treat RF guns with proper d...
physics
8,430
Multi-cell RF Injectors Driven by Thermoionic Cathodes
physics.acc-ph
We present the anticipated performances of a multi-cell RF injector operated either with a thermoionic cathode or with a gated photo-cathode. By means of a magnetic compression and a Coherent Spontaneous Emission seeded FEL radiating at 100 to 200 mm, the system produces a beam fully bunched with a 200 A peak current a...
physics
8,431
Thomson Scattering of Coherent Diffraction Radiation by an Electron Bunch
physics.acc-ph
The paper considers the process of Thomson scattering of coherent diffraction radiation (CDR) produced by the preceding bunch of the accelerator on one of the following bunches. It is shown that the yield of scattered hard photons is proportional to N$_e^3$, where N$_e$ is the number of electrons per bunch. A geometry ...
physics
8,432
Symplectic tracking using point magnets and a reference orbit made of circular arcs and straight lines
physics.acc-ph
Symplectic tracking of beam particles using point magnets is achieved using a reference orbit made of circular arcs and straight lines that join smoothly with each other. For this choice of the reference orbit, results are given for the transfer functions, transfer matrices, and the transit times of the magnets and dri...
physics
8,433
Measurement of colliding beam-beam parameters with wide-angle beamstrahlung
physics.acc-ph
The relation between beamstrahlung observables and beam-beam topologies is discussed.
physics
8,434
Large angle Beamstrahlung as a beam-beam monitoring tool
physics.acc-ph
A novel method to measure the beam-beam interaction in e+e- colliders is presented.
physics
8,435
Two-dimensional Cooling of Ion Beams in Storage Rings by Narrow Broad-Band Laser Beams
physics.acc-ph
A new scheme for the two-dimensional cooling of ion beams in storage rings is suggested in which ions interact with a counterpropagating broad-band laser beam. The interaction region in the direction of the ion movement is much less then the wavelength of the ion betatron oscillations. The laser beam in the orbit plane...
physics
8,436
Stochastic dynamics and Fokker-Planck equation in accelerator physics
physics.acc-ph
The aim of this contribution is to study the particle dynamics in a storage ring under the influence of noise. Some simplified stochastic beam dynamics problems are treated by solving the corresponding Fokker-Planck equations numerically.
physics
8,437
Status of Muon Collider Research and Development and Future Plans
physics.acc-ph
The status of the research on muon colliders is discussed and plans are outlined for future theoretical and experimental studies. Besides continued work on the parameters of a 3-4 and 0.5 TeV center-of-mass (CoM) energy collider, many studies are now concentrating on a machine near 0.1 TeV (CoM) that could be a factory...
physics
8,438
Vibrating Wire for Beam Profile Scanning
physics.acc-ph
The method for measurement of transverse profile (emittance) of the bunch by detecting of radiation arising scattering at of the bunch on the scanning wire is wide-spread. In this work the information about scattering bunch is proposed to measure using the oscillation frequency of the tightened scanning wire. In such w...
physics
8,439
Gravimetric Measurement of Magnetic Field Gradient Spatial Distribution
physics.acc-ph
Magnetic interaction between a weighing sample and an external magnetic field allows to measure characteristics of magnetic field (a sample with known magnetic characteristics), as well as the magnetic properties of a sample (a known magnetic field). Measurement of materials magnetic permeability is a well known applic...
physics
8,440
Physics Opportunities at a Muon Collider
physics.acc-ph
The case for a future high-energy collider based on muon beams is briefly reviewed.
physics
8,441
QuasiCerenkov Radiation of Relativistic Electrons in Crystals in the Presence of External Excitations
physics.acc-ph
The paper is devoted to the study of the influence of crystalline lattice distortions due to external excitations (acoustic vibrations, temperature gradient, etc.) on the Quasicerenkov radiation. Equations describing Quasicerenkov radiation of charged particles in distorted crystals are derived. These equations are sol...
physics
8,442
An Algorithm for Calculating the Spin Tune in Circular Accelerators
physics.acc-ph
A new algorithm for calculating the spin tune and the n-axis for circular accelerators is presented. The method resembles the one employed in the existing program code SODOM in that one-turn numerical spin maps at equally spaced orbit angle variables are used but it is more efficient than the latter. Furthermore, it is...
physics
8,443
Considerations on the Diffraction Limitations to the Spatial Resolution of Optical Transition Radiation
physics.acc-ph
The interest in using optical transition radiation (OTR) in high energy (multiGeV) beam diagnostics has motivated theoretical and experimental investigations on the limitations brought by diffraction on the attainable resolution. This paper presents calculations of the diffraction effects in an optical set-up using OTR...
physics
8,444
Hamiltonian Methods for the Study of Polarized Proton Beam Dynamics in Accelerators and Storage Rings
physics.acc-ph
The equations of classical spin-orbit motion can be extended to a Hamiltonian system in 9-dimensional phase space by introducing a coupled spin-orbit Poisson bracket and a Hamiltonian function. After this extension and by establishing connections between initial and extended systems it becomes possible to apply the met...
physics
8,445
Study of the Four-Rod RFQ Using the Normal Mode Theory of Transmission Lines
physics.acc-ph
The normal mode theory of the transmission lines is applied to the studies of the Four-Rod RFQ. This resonator consists of four quadrupole electrodes and stems. It can be simulated by the four-conductor shielded transmission line, which is loaded by sets of coaxial transmission lines corresponding to the support stems....
physics
8,446
Spectroscopy through the change of undulator parameters in dipole regime
physics.acc-ph
In this work a method of spectroscopy without monochromators for the undulator radiation (UR) source is proposed. This method is based of changing the magnetic field in the undulator. Different variations of field modulations and corresponding object reaction for the case of a dipole regime of UR exitation were conside...
physics
8,447
Compyter analysys of undulators with block-periodic structure
physics.acc-ph
Methods to detect the spectral sensitivity of an object using undulator radiation without monochromators or any other spectral devices are developed. The spectral transmission function of the object is calculated from its response to the spectrum-integral undulator radiation with the known spectral distribution. This r...
physics
8,448
Characteristics of synchrotron radiation of longitudinally polarized spinning particle in the pseudoclassical theory
physics.acc-ph
Spin dependencies of the intensity and polarization of the synchrotron radiation of the longitudinally polarized particle performing uniform circular motion in the magnetic field are investigated.
physics
8,449
Study of Multiple-Beam RFQ
physics.acc-ph
There are applications, which require MeV-range multiple-beams consisting of a large number of identical highly packed beamlets. The multiple-beam RFQ (MB-RFQ) arranged as a matrix array of longitudinal rod-electrodes is appropriate candidate. A configuration of MB-RFQ resonator should ensure identical quadrupole field...
physics
8,450
Linac-Ring Type phi Factory for Basic and Applied Researches
physics.acc-ph
In this paper, main parameters for linac-ring type collider desinged for producing $\phi $ particles copiously are estimated and potential of this machine in particle physics researches is investigated. Moreover, parameters for free electron laser and synchrotron radiation obtained from electron linac and positron ring...
physics
8,451
Resonant Diffraction Radiation from an Ultrarelativistic Particle Moving Close to a Tilted Grating
physics.acc-ph
A simple model for calculating the diffraction radiation characteristics from an ultrarelativistic charged particle moving close to a tilted ideally conducting strip is developed. Resonant diffraction radiation (RDR) is treated as a superposition of the radiation fields for periodically spaced strips. The RDR character...
physics
8,452
The Physics Opportunities and Technical Challenges of a Muon Collider
physics.acc-ph
We describe the physics opportunities and technical challenges of a muon collider as a tool for exploring high energy physics phenomena.
physics
8,453
Variable Field Bending Magnets for Recirculating Linacs
physics.acc-ph
A lattice of single aperture superconducting variable field bending magnets is proposed as a cheap and practical way to recirculate the beams in recirculating linear accelerators. It is shown that the VFBM's can be configured to provide strong focusing in both transverse planes for the full range of beam momenta transp...
physics
8,454
Multiple resonance compensation for betatron coupling and its equivalence with matrix method
physics.acc-ph
Analyses of betatron coupling can be broadly divided into two categories: the matrix approach that decouples the single-turn matrix to reveal the normal modes and the hamiltonian approach that evaluates the coupling in terms of the action of resonances in perturbation theory. The latter is often regarded as being less ...
physics
8,455
Discussion on Muon Collider Parameters at Center of Mass Energies from 0.1 TeV to 100 TeV
physics.acc-ph
Some of the potential capabilities and design challenges of muon colliders are illustrated using self-consistent collider parameter sets at center of mass energies ranging from 0.1 TeV to 100 TeV.
physics
8,456
Studies for Muon Colliders at Center-of-Mass Energies of 10 TeV and 100 TeV
physics.acc-ph
Parameter lists are presented for speculative muon colliders at center-of-mass energies of 10 TeV and 100 TeV. The technological advances required to achieve the given parameters are itemized and discussed, and a discussion is given of the design goals and constraints. An important constraint for multi-TeV muon collide...
physics
8,457
Concept of Powerful Multistage Coaxial Cyclotron for Pulsed and Continuous Beam Production
physics.acc-ph
The concept of large-radius multistage coaxial cyclotrons having separated orbits is described, to generate proton beams of 120-2000 MeV energy at tens of GW pulsed and hundreds of MW in continuous beam power operation. Accelerated beam losses must be less than 0.1 W/m for the intercepted average beam power linear dens...
physics
8,458
Beam extraction studies at 900 GeV using a channeling crystal
physics.acc-ph
Luminosity-driven channeling extraction has been observed for the first time in a 900 GeV study at the Fermilab Tevatron. This experiment, Fermilab E853, demonstrated that useful TeV level beams can be extracted from a superconducting accelerator during high luminosity collider operations without unduly affecting the b...
physics
8,459
Theory of the tune shift due to linear coupling
physics.acc-ph
The presence of skew quadrupole fields will linearly couple the x and y motions. The x and y motions can then be written as the sum of two normal modes >. This paper presents analytical perturbation theory results for the tunes of the normal modes. The results for the normal mode tunes are first found correct to lowest...
physics
8,460
Expression of Interest in R&D towards a Neutrino Factory Based on a Storage Ring and a Muon Collider
physics.acc-ph
We are exploring the feasibility of a neutrino factory based on a muon storage ring. In this, beams of nu_mu and nubar_e arise from the decay of mu- particles (or alternatively, nubar_mu and nu_e from mu+). The muons come from the decay of low-energy pions produced by a megawatt proton beam incident on a nuclear target...
physics
8,461
Single-Pass Lazer Polarization of Ultrarelativistic Positrons
physics.acc-ph
The new method for producing of the polarized relativistic positrons is suggested. A beam of unpolarized positrons accelerated up to a few GeV can be polarized during a head-on collision with an intense circularly polarized lazer wave. After a multiple Compton backscattering process the initial positrons may lose a sub...
physics
8,462
Beam Coupling Impedances of Small Discontinuities
physics.acc-ph
A general derivation of the beam coupling impedances produced by small discontinuities on the wall of the vacuum chamber of an accelerator is reviewed. A collection of analytical formulas for the impedances of small obstacles is presented.
physics
8,463
Simulation of Laser-Compton Cooling of Electron Beams
physics.acc-ph
We study a method of laser-Compton cooling of electron beams. Using a Monte Carlo code, we evaluate the effects of the laser-electron interaction for transverse cooling. The optics with and without chromatic correction for the cooling are examined. The laser-Compton cooling for JLC/NLC at E_0=2 GeV is considered.
physics
8,464
Feasibility of backward diffraction radiation for non-destructive diagnostics of relativistic charged particle beams
physics.acc-ph
The characteristics of backward diffraction radiation (BDR), i.e. radiation of the charged particle passing through a slit in the tilted screen, has been considered. The technique for non-destructive beam diagnostics based on the measurements of BDR yield for different tilted angles (theta-scan) is suggested.
physics
8,465
The Superconducting TESLA Cavities
physics.acc-ph
The conceptional design of the proposed linear electron-positron collider TESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with an accelerating gradient of Eacc >= 25 MV/m at a quality factor Q0 > 5E+9. The design goal for the cavities of the TESLA Test Facility (TTF) linac was set to the more moderate...
physics
8,466
Asynchronous accelerator with RFQ injection for active longitudinal compression of accelerated bunches
physics.acc-ph
An asynchronous accelerator is described, in which the principle of its operation permits the active longitudinal bunch compression of accelerated proton beams, to overcome the space charge limitation effects of intense bunches. It is shown that accelerated bunches from an RFQ linac can be adapted for Asynchronac injec...
physics
8,467
Diffraction Radiation Diagnostics for Moderate to High Energy Charged Particle Beams
physics.acc-ph
Diffraction radiation (DR) is produced when a charged particle passes through an aperture or near a discontinuity in the media in which it is traveling. DR is closely related to transition radiation (TR), which is produced when a charged particle traverses the boundary between media with different dielectric constants....
physics
8,468
Radiation from a Superluminal Source
physics.acc-ph
The sweep speed of an electron beam across the face of an oscilloscope can exceed the velocity of light, although of course the velocity of the electrons does not. Associated with this possibility there should be a kind of Cherenkov radiation, as if the oscilloscope trace were due to a charge moving with superluminal v...
physics
8,469
Classical "Dressing" of a Free Electron in a Plane Electromagnetic Wave
physics.acc-ph
The energy and momentum densities of the fields of a free electron in a plane electromagnetic wave include interference terms that are the classical version of the ``dressing'' of the electron the arises in a quantum analysis. The transverse mechanical momentum of the oscillating electron is balanced by the field momen...
physics
8,470
The Hawking-Unruh Temperature and Quantum Fluctuations in Particle Accelerators
physics.acc-ph
We wish to draw attention to a novel view of the effect of the quantum fluctuations during the radiation of accelerated particles, particularly those in storage rings. This view is inspired by the remarkable insight of Hawking that the effect of the strong gravitational field of a black hole on the quantum fluctuations...
physics
8,471
The Hawking-Unruh Temperature and Damping in a Linear Focusing Channel
physics.acc-ph
The Hawking-Unruh effective temperature, hbar a* / 2 pi c k, due to quantum fluctuations in the radiation of an accelerated charged-particle beam can be used to show that transverse oscillations of the beam in a practical linear focusing channel damp to the quantum-mechanical limit. A comparison is made between this be...
physics
8,472
Energy Balance in an Electrostatic Accelerator
physics.acc-ph
The principle of an electrostatic accelerator is that when a charge e escapes from a conducting plane that supports a uniform electric field of strength E_0, then the charge gains energy e E_0 d as it moves distance d from the plane. Where does this energy come from? We that the mechanical energy gain of the electron i...
physics
8,473
The Grating Accelerator
physics.acc-ph
In optics, a reflective grating is a conducting surface with a ripple. The typical use of such a grating involves an incident electromagnetic wave with wave vector k in the x-z plane, and interference effects lead to a discrete set of reflected waves also with wave vectors in the x-z plane. Consider, instead, an incide...
physics
8,474
The Laser-Driven Vacuum Photodiode
physics.acc-ph
A vacuum photodiode driven by a pulsed laser can sustain an average current very similar to that of a continous diode, where the latter is described by Child's law.
physics
8,475
The Helical Wiggler
physics.acc-ph
There is not a unique solution to the electro- or magnetostatic problem where the "boundary condition" is merely a specification of the fields along a line. As a practical example, we consider the case where it is desired to have a magnetic field that that traces a helix about the z axis.
physics
8,476
Temporary Acceleration of Electrons While Inside an Intense Electromagnetic Pulse
physics.acc-ph
A free electron can temporarily gain a very significant amount of energy if it is overrun by an intense electromagnetic wave. In principle, this process would permit large enhancements in the center-of-mass energy of electron-electron, electron-positron and electron-photon interactions if these take place in the presen...
physics
8,477
Novel approach for spin-flipping a stored polarized beam
physics.acc-ph
The traditional method of spin-flipping a stored polarized beam is based on slowly crossing an rf induced depolarizing resonance. This paper discusses a novel approach where the polarization reversal is achieved by trapping the beam polarization into a stable spin-flipping motion on top of the rf induced resonance at a...
physics
8,478
Test Results on the Silicon Pixel Detector for the TTF-FEL Beam Trajectory Monitor
physics.acc-ph
Test measurements on the silicon pixel detector for the beam trajectory monitor at the free electron laser of the TESLA test facility are presented. To determine the electronic noise of detector and read-out and to calibrate the signal amplitude of different pixels the 6 keV photons of the manganese K line are used. Tw...
physics
8,479
Design and Simulation of a High Frequency High Power Rf Extraction Device Using a Dielectric-Loaded Waveguide
physics.acc-ph
We consider the use of a dielectric-loaded structure to extract rf energy from a high current electron drive beam as a power source for a high energy two-beam accelerator. This represents an alternative technique which we show to have some significant advantages over the use of the currently proposed corrugated metal s...
physics
8,480
A Cupronickel Rotating Band Pion Production Target for Muon Colliders
physics.acc-ph
A conceptual design is presented for a high power cupronickel pion production target. It forms a circular band in a horizontal plane with approximate dimensions of: 2.5 meters radius, 6 cm high and 0.6 cm thick. The target is continuously rotated at 3 m/s to carry heat away from the production region to a water cooling...
physics
8,481
Rotating Band Pion Production Targets for Muon Colliders and Neutrino Factories
physics.acc-ph
An update is presented on a conceptual design for a pion production target station using a rotating cupronickel band and that was originally proposed for use at a muon collider facility with a 4 MW pulsed proton beam. After reviewing the salient design features and motivations for this target, ongoing studies are descr...
physics
8,482
Parameter Sets for 10 TeV and 100 TeV Muon Colliders, and their Study at the HEMC'99 Workshop
physics.acc-ph
A focal point for the HEMC'99 workshop was the evaluation of straw-man parameter sets for the acceleration and collider rings of muon colliders at center of mass energies of 10 TeV and 100 TeV. These self-consistent parameter sets are presented and discussed. The methods and assumptions used in their generation are des...
physics
8,483
Analytical treatment of the emittance growth in the main Linacs of future linear colliders
physics.acc-ph
In this paper the single and multibunch emittance growths in the main linac of a linear collider are analytically treated in analogy to the Brownian motion of a molecule, and the analytical formulae for the emittance growth due to accelerating structure misalignment errors are obtained by solving Langevin equation. The...
physics
8,484
Analytical estimation of the dynamic apertures of circular accelerators
physics.acc-ph
By considering delta function sextupole, octupole, and decapole perturbations and using difference action-angle variable equations, we find some useful analytical formulae for the estimation of the dynamic apertures of circular accelerators due to single sextupole, single octupole, single decapole (single 2$m$ pole in ...
physics
8,485
Polarized Protons in HERA
physics.acc-ph
Polarized proton beams at HERA can currently only be produced by extracting a beam from a polarized source and then accelerating it in the three synchrotrons at DESY. In this paper, the processes which can depolarize a proton beam in circular accelerators are explained, devices which could avoid this depolarization in ...
physics
8,486
Successive approximations for charged particle motion
physics.acc-ph
Single particle dynamics in electron microscopes, ion or electron lithographic instruments, particle accelerators, and particle spectrographs is described by weakly nonlinear ordinary differential equations. Therefore, the linear part of the equation of motion is usually solved and the nonlinear effects are then found ...
physics
8,487
First Observation of Self-Amplified Spontaneous Emission in a Free-Electron Laser at 109 nm Wavelength
physics.acc-ph
We present the first observation of Self-Amplified Spontaneous Emission (SASE) in a free-electron laser (FEL) in the Vacuum Ultraviolet regime at 109 nm wavelength (11 eV). The observed free-electron laser gain (approx. 3000) and the radiation characteristics, such as dependency on bunch charge, angular distribution, s...
physics
8,488
Upgrade of the PEP-II Low Beta Optics
physics.acc-ph
The successful commissioning and operation of the PEP-II asymmetric e+e- collider motivated further studies to increase luminosity. In this paper, we discuss a modification of the PEP-II lattice to reduce the vertical beta function at the Interaction Point (IP) from the design value of 1.5cm to 1.0cm. This could potent...
physics
8,489
Prediction of long term stability by extrapolation
physics.acc-ph
This paper studies the possibility of using the survival function to predict long term stability by extrapolation. The survival function is a function of the initial coordinates and is the number of turns a particle will survive for a given set of initial coordinates. To determine the difficulties in extrapolating the ...
physics
8,490
Beam Current Monitors in the Nlcta
physics.acc-ph
The current profile along the 126 ns, multi-bunch beam pulse in the Next Linear Collider Test Accelerator (NLCTA) is monitored with fast toroids (rise time ~1 ns). Inserted at several positions along the beam line, they allow us to track current transmission as a function of position along the bunch train. Various meas...
physics
8,491
Beam Profile Monitors in the Nlcta
physics.acc-ph
The transverse current profile in the Next Linear Collider Test Accelerator (NLCTA) electron beam can be monitored at several locations along the beam line by means of profile monitors. These consist of insertable phosphor screens, light collection and transport systems, CID cameras, a frame-grabber, and PC and VAX bas...
physics
8,492
The Proposed NLC Linac LLRF System
physics.acc-ph
The proposed Next Linear Collider (NLC) contains linac systems operating at L,S,C, and X band. This paper describes a wideband modular low-level RF (LLRF) system applicable for all NLC pulsed RF systems. High speed digital IF techniques are used for both arbitrary klystron drive modulation and accurate RF vector detect...
physics
8,493
Experience with the Pep-II RF System at High Beam Currents
physics.acc-ph
The PEP-II B Factory Low-Level RF System (LLRF) is a fully programmable VXI based design running under an EPICS control environment. Several RF feedback loops are used to control longitudinal coupled-bunch modes driven by the accelerating mode of the RF cavities. This paper updates the performance of the LLRF system as...
physics
8,494
New Design Study and Related Experimental Program for the LCLS RF Photoinjector
physics.acc-ph
We report the results of a recent beam dynamics study, motivated by the need to redesign the LCLS photoinjector, that lead to the discovery of a new effective working point for a split RF photoinjector. We consider the emittance compensation regime of a space charge beam: by increasing the solenoid strength, the emitta...
physics
8,495
Design Studies for a High Current Bunching System for CLIC Test Facility (CTF3) Drive Beam
physics.acc-ph
A bunching system is proposed for the initial stage of CTF3 which consists of one (two) 3 GHz prebunchers and one 3 GHz travelling wave (TW) buncher with variable phase velocities. The electron beam is emitted from a 140 KV DC gun. Since the macropulse beam current (3.5 A) at the exit of the TW buncher is rather high, ...
physics
8,496
Lattice Matching with a Quadrupole Missing
physics.acc-ph
The lattice for the present design of the TESLA Linear Collider with integrated X-Ray Laser Facility is basically a FODO structure with constant beta-function. There are more than 800 individually powered superconducting quadrupoles to focus the beam in the two main linear accelerators (each with a length of 15 km). Fo...
physics
8,497
Further Studies on the Prospects for Many-TeV Muon Colliders
physics.acc-ph
New self-consistent parameter sets are presented and discussed for muon collider rings at center-of-mass energies of 10, 30 and 100 TeV. All three parameter sets attain luminosities of 3 x 10^35 /cm^2/s. The parameter sets benefit from new insights gained at the HEMC'99 workshop that considered the feasibility of many-...
physics
8,498
Development of rebunching cavities at IAP
physics.acc-ph
A focus of work at IAP has been the development and optimization of spiral loaded cavities since the 1970s [A. Schempp et al, NIM 135, 409 (1976)]. These cavities feature a high efficiency, a compact design and a big variety of possible fields of application. They find use both as bunchers and post accelerators to vary...
physics
8,499
Measurement of the temporal response of ferroelectric cathodes
physics.acc-ph
Ferroelectric ceramics are tested as photocathodes at INFN Frascati Laboratories. In order to characterize them for use in linac injectors it is important to measure the temporal shape of the emitted current. With a duration of the laser pulse of 25 ps, the required resolution is a few ps. An apparatus has been set up ...
physics