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Preliminary studies of an infrared free-electron laser oscillator at the ATF(BNL)

Description: In this report, I present results of a theoretical 1-D model discussed by G. Dattoli, A. Reniere and myself. The validity of a steady-state analysis is discussed and some estimates are given of the effects introduced by the ''lethargy'' of the laser pulse due to the finite length of the e/sup /minus// pulse. Also, I present analytical expressions for the laser pulse in terms of supermodes (wave-packets of cavity modes), their evolution, physical width as well as the associated frequency spectrum. Next, I present results obtained with a 3-D code for the single pass, small-signal gain. In the appendix, I summarize the symbols used in this report. 2 refs., 6 figs., 3 tabs.
Date: October 19, 1988
Creator: Gallardo, J.C.
Partner: UNT Libraries Government Documents Department

3-D numerical analysis of a high-gain free-electron laser

Description: We present a novel approach to the 3-dimensional high-gain free- electron laser amplifier problem. The method allows us to write the laser field as an integral equation which can be efficiently and accurately evaluated on a small computer. The model is general enough to allow the inclusion of various initial electron beam distributions to study the gain reduction mechanism and its dependence on the physical parameters. 16 refs., 8 figs., 1 tab.
Date: October 19, 1988
Creator: Gallardo, J.C.
Partner: UNT Libraries Government Documents Department

Control of non-linear space-charge emittance growth

Description: A simple analytical model of the space-charge (self-fields) of a few picosecond electron pulse in a RF photocathode electron gun is presented. The model permits a search for the optimal laser distribution (transverse and longitudinal) that will result in an electron beam with minimum transverse emittance. It is concluded that electron distributions with sharp edges in the transverse dimension and parabolic (inverted) in the longitudinal direction are best to minimize the emittance. These effects have been confirmed with extensive simulations using the numerical code PARMELA. 9 refs., 5 figs., 1 tab.
Date: January 1, 1990
Creator: Gallardo, J.C.
Partner: UNT Libraries Government Documents Department

A practical high-energy high-luminosity {mu}{sup +} {minus} {mu}{sup {minus}} collider

Description: We present a candidate design for a high-energy high-luminosity {mu}{sup +}{minus}{mu} collider, with E{sub cm} = 4 TeV, L = 3 {times} 10{sup 4}cm{sup {minus}2}s{sup {minus}1}, using only existing technology. The design uses a rapid-cycling medium-energy proton synchrotron, which produces proton beam pulses which are focused onto two {pi}-producing targets, with two {pi}-decay transport lines producing {mu}{sup +{prime}}s. The {mu}`s are collected, rf-rotated, cooled and compressed into a recirculating linac for acceleration, and then transferred into a storage ring collider. The keys to high luminosity are maximal {mu} collection and cooling; innovations with these goals are presented, and future plans for collider development are discussed. This example demonstrates a novel high-energy collider type, which will permit exploration of elementary particle physics at energy frontiers beyond the reach of currently existing and proposed electron and hadron colliders.
Date: June 1994
Creator: Palmer, R. B.; Gallardo, J.; Neuffer, D. V. & Gallardo, J.
Partner: UNT Libraries Government Documents Department

Optimization of the Brookhaven ATF inline-injection system utilizing PARMELA

Description: An S-band, RF gun-linac, inline-injection system is being installed at the Brookhaven Accelerator Test Facility. An optimization of the system parameters has been done utilizing the electron beam code PARMELA. We describe the results of this procedure and estimate the brightness of the resulting electron beam. We also incorporate the effects of wake fields into the simulation and evaluate their effects on the beam brightness.
Date: June 1, 1994
Creator: Gallardo, J.C. & Kirk, H.G.
Partner: UNT Libraries Government Documents Department

Design of the muon collider lattice: Present status

Description: The last component of a muon collider facility, as presently envisioned, is a colliding-beam storage ring. Design studies on various problems for this ring have been in progress over the past year. In this paper we discuss the current status of the design. The projected muon currents require very low beta values at the IP, {beta}* = 3 mm, in order to achieve the design luminosity of L = 10{sup 35} cm{sup -2} s{sup -1}. The beta values in the final-focus quadrupoles are roughly 400 km. To cancel the corresponding chromaticities, sextupole schemes for local correction have been included in the optics of the experimental insertion. The hour-glass effect constraints the bunch length to be comparable too. To obtain such short bunches with reasonable rf voltage requires a very small value of the momentum compaction a, which can be obtained by using flexible momentum compaction (FMC) modules in the arcs. A preliminary design of a complete collider ring has now been made; it uses an experimental insertion and arc modules as well as a utility insertion. The layout of this ring is shown schematically, and its parameters are summarized. Though some engineering features are unrealistic, and the beam performance needs some improvement, we believe that this study can serve as the basis for a workable collider design. The remaining sections of the paper will describe the lattice, show beam behaviour, and discuss future design studies.
Date: May 1996
Creator: Garren, A.; Courant, E. & Gallardo, J.
Partner: UNT Libraries Government Documents Department

Coherent synchrotron radiation in the isochronous muon collider ring

Description: To achieve the luminosity of L = 10{sup 35} cm{sup {minus}2}s{sup {minus}1} in a {mu}{sup +}{mu}{sup {minus}} collider, two bunches per sign of N = 2 {times} 10{sup 12} particles each and a betatron function of {beta}* = 3 mm at the interaction point (IP) are required. This small {beta}* at the IP constrains the size of the bunch to be {sigma}{sub z} {approximately} {beta}*. To maintain this rather short bunch without excessive rf power consumption, an isochronous lattice has been chosen for the final collider ring. One of the important advantages of muons as opposed to electrons is that at up to at least TeV energy it is possible to accelerate muons in circular machines as their synchrotron radiation is reduced by a factor of (m{sub e}/m{sub {mu}}){sup 2} {approximately} 23 {times} 10{sup {minus}6} with respect to electrons. Nevertheless, the large number of muons in a short bunch suggests the possibility of strong shielded coherent synchrotron radiation. First, the author uses the well known formulae to evaluate the power of shielded coherent synchrotron radiation in the isochronous muon collider ring. Finally, following the results obtained by Kheifets and Zotter for a bunch with a Gaussian longitudinal charge distribution the author shows that the coherent synchrotron radiation in the isochronous {mu}{sup +}{mu}{sup {minus}} collider ring is negligible if the rms bunch length is larger than {approx} 0.3 mm.
Date: October 1, 1996
Creator: Gallardo, J.C.
Partner: UNT Libraries Government Documents Department

Final focus system for a muon collider: a test model

Description: The present scenario for a high luminosity 4 TeV on center of mass muon collider required a beta function {beta}* {approx} 3mm at the interaction point. We discuss a test model of a basic layout which satisfies the requirements although it is not fully realistic.
Date: January 1, 1996
Creator: Gallardo, J.C. & Palmer, R.B.
Partner: UNT Libraries Government Documents Department

A Compact and High Performance Muon Capture Channel for Muon Accelerators

Description: It is widely believed that a neutrino factory would deliver unparallel performance in studying neutrino mixing and would provide tremendous sensitivity to new physics in the neutrino sector. Here we will describe and simulate the front-end of the neutrino factory system, which plays critical role in determining the number of muons that can be accepted by the downstream accelerators. In this system, a proton bunch on a target creates secondaries that drift into a capture transport channel. A sequence of rf cavities forms the resulting muon beams into strings of bunches of differing energies, aligns the bunches to nearly equal central energies, and initiates ionization cooling. For this, the muon beams are transported through sections containing high-gradient cavities and strong focusing solenoids. In this paper we present results of optimization and variation studies toward obtaining the maximum number of muons for a neutrino factory by using a compact transport channel. It has been suggested computationally and experimentally that the maximum achievable gradient is enhanced by introducing an external magnetic field at right angles to the rf electric field since it suppresses field-emission processes. Here, we have discussed a possible scheme for extending the concept of magnetic insulation to capture, transport, and cool muons in a neutrino factory. We incorporated this idea into a new lattice design where the rf cavities are shaped so that their walls were tangential to the magnetic-field lines. We showed that, with magnetic insulation, the field-emitted electrons impact the cavity surface with energies four orders-of-magnitude less than in conventional pillbox cavities; consequently, damage from field-emission is suppressed significantly. While demanding in terms of power requirements, this neutrino factory lattice showed satisfactory performance in both cooling and collecting the accepted muons within the requirements for the IDSNF. Optimizations were also made to reduce heating on the absorber ...
Date: March 28, 2011
Creator: Stratakis, D.; Gallardo, J. & Palmer, R.B.
Partner: UNT Libraries Government Documents Department

Enhancement of RF Breakdown Threshold of Microwave Cavities by Magnetic Insulation

Description: Limitations on the maximum achievable accelerating gradient of microwave cavities can influence the performance, length, and cost of particle accelerators. Gradient limitations are believed to be initiated by electron emission from the cavity surfaces. Here, we show that field emission is effectively suppressed by applying a tangential magnetic field to the cavity walls, so higher gradients can be achieved. Numerical simulations indicate that the magnetic field prevents electrons leaving these surfaces and subsequently picking up energy from the electric field. Our results agree with current experimental data. Two specific examples illustrate the implementation of magnetic insulation into prospective particle accelerator applications. The ultimate goal of several research efforts is to integrate high-gradient radio-frequency (rf) structures into next generation particle accelerators. For instance, the Muon Accelerator Program is looking at developing low-frequency cavities for muon cooling, and the International Linear Collider is optimizing the performance of 1.3 GHz rf structures aimed at designing a 1 TeV electron-positron collider. Furthermore, the High Gradient RF Collaboration is examining high frequency (f > 10 GHz) structures intended for an electron-positron collider operating at energies in the TeV range. In all this research, the accelerating gradient will be one of the crucial parameters affecting their design, construction, and cost. Limitations from rf breakdown strongly influence the development of accelerators since it limits the machine's maximum gradient. The emission of electrons from the cavity surfaces seemingly is a necessary stage in the breakdown process, acting either as a direct cause of breakdown or as precursor for other secondary effects. Typically, electron currents arise from sharp edges or cracks on the cavities surfaces, where the strength of the electric field is strongly enhanced compared to that of the nominal field when the surfaces of the cavity are perfect planes. Subsequently, a stream of emitted electrons can be ...
Date: March 28, 2011
Creator: Stratakis, D.; Gallardo, J. & Palmer, R.B.
Partner: UNT Libraries Government Documents Department

FEASIBILITY STUDY II OF A MUON BASED NEUTRINO SOURCE.

Description: The concept of using a muon storage ring to provide a well characterized beam of muon and electron neutrinos (a Neutrino Factory) has been under study for a number of years now at various laboratories throughout the world. The physics program of a Neutrino Factoryis focused on the relatively unexplored neutrino sector. In conjunction with a detector located a suitable distance from the neutrino source, the facility would make valuable contributions to the study of neutrino masses and lepton mixing. A Neutrino Factory is expected to improve the measurement accuracy of sin{sup 2}(2{theta}{sub 23}) and {Delta}m{sup 2}{sub 32} and provide measurements of sin{sup 2}(2{theta}{sub 13}) and the sign of {Delta}m{sup 2}{sub 32}. It may also be able to measure CP violation in the lepton sector.
Date: June 30, 2001
Creator: GALLARDO,J.C.; OZAKI,S.; PALMER,R.B. & ZISMAN,M.
Partner: UNT Libraries Government Documents Department

A comparison of L-band and C-band RF guns as sources for inline-injection systems

Description: We consider the beam dynamics associated with installing a BNL type 1{1/2} cell L-band or C-band rf gun before two TESLA L-band cryomodules. This system will deliver a 25 MeV electron beam with peak currents on the order of 100 A suitable for further magnetic compression. We evaluate the injection systems utilizing the electron beam dynamic code PARMELA from the point of view of minimizing the transverse invariant emittance.
Date: June 1, 1995
Creator: Gallardo, J.C.; Kirk, H.G. & Meyerer, T.
Partner: UNT Libraries Government Documents Department

Magnetic performance of a fast excitation wiggler for inverse free-electron lasers

Description: With the objective of performing an inverse free-electron laser accelerator experiment, an iron dominated (Vanadium Permendur), fast excitation, high K planar wiggler has been guilt and measured. We present in this report an analysis of a constant period wiggler and several tapering configurations (gap=4 mm; 3.0 cm < {lambda}{sub {omega}} < 5.0 cm) when we drive it to a peak field of B{sub max} {approx} 1.4T.
Date: December 31, 1993
Creator: Gallardo, J.C.; Romano, T. & van Steenbergen, A.
Partner: UNT Libraries Government Documents Department

High luminosity muon collider design

Description: Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should be regarded as complementary. Parameters are given of 4 TeV high luminosity {mu}{sup +}{mu}{sup {minus}} collider, and of a 0.5 TeV lower luminosity demonstration machine. We discuss the various systems in such muon colliders.
Date: October 1996
Creator: Palmer, R. & Gallardo, J.
Partner: UNT Libraries Government Documents Department

Muon-muon and other high energy colliders

Description: The first section looks at the high energy physics advantages, disadvantages and luminosity requirements of hadron, of lepton and photon-photon colliders for comparison. The second section discusses the physics considerations for the muon collider. The third section covers muon collider components. The fourth section is about the intersection region and detectors. In the fifth section, the authors discuss modifications to enhance the muon polarization`s operating parameters with very small momentum spreads, operations at energies other than the maximum for which the machine is designed, and designs of machines for different maximum energies. The final section discusses a Research and Development plan aimed at the operation of a 0.5 TeV demonstration machine by the year 2010, and of the 4 TeV machine by the year 2020.
Date: February 1997
Creator: Palmer, R. B. & Gallardo, J. C.
Partner: UNT Libraries Government Documents Department

High energy colliders

Description: The authors consider the high energy physics advantages, disadvantages and luminosity requirements of hadron (pp, p{anti p}), lepton (e{sup +}e{sup {minus}}, {mu}{sup +}{mu}{sup {minus}}) and photon-photon colliders. Technical problems in obtaining increased energy in each type of machine are presented. The machines relative size are also discussed.
Date: February 1, 1997
Creator: Palmer, R.B. & Gallardo, J.C.
Partner: UNT Libraries Government Documents Department

Overview of a high luminosity {mu}{sup +}{mu}{sup {minus}} collider

Description: Muon Colliders have unique technical and physics advantages and disadvantages when compared with both hadron and electron machines. They should be regarded as complementary. Parameters are given of a 4 TeV high luminosity {mu}{sup +}{mu}{sup {minus}} collider, and of a 0.5 TeV lower luminosity demonstration machine. The authors discuss the various systems in such muon colliders.
Date: March 1, 1997
Creator: Palmer, R.B. & Gallardo, J.C.
Partner: UNT Libraries Government Documents Department

A comparison of L-band and C-band rf guns as sources for inline-injection systems

Description: We consider the beam dynamics associated with installing a BNL type 1 1/2 cell L-band or C-band rf gun before two TESLA L-band cryomodules. This system will deliver a 25 MeV electron beam with peak currents on the order of 100 A suitable for further magnetic compression. evaluate the injection systems utilizing the electron beam dynamic code PARMELA from the point of view of minimizing the transverse invariant emittance.
Date: December 1, 1994
Creator: Gallardo, J.C.; Kirk, H.G. & Meyerer, T.
Partner: UNT Libraries Government Documents Department

High luminosity particle colliders

Description: The authors consider the high energy physics advantages, disadvantages and luminosity requirements of hadron (pp, p{anti p}), lepton (e{sup +}e{sup {minus}}, {mu}{sup +}{mu}{sup {minus}}) and photon-photon colliders. Technical problems in obtaining increased energy in each type of machine are presented. The machines relative size are also discussed.
Date: March 1, 1997
Creator: Palmer, R.B. & Gallardo, J.C.
Partner: UNT Libraries Government Documents Department

Muon dynamics in a toroidal sector magnet

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

Future colliders

Description: The high energy physics advantages, disadvantages and luminosity requirements of hadron (pp, pp), of lepton (e{sup +}e{sup {minus}}, {mu}{sup +} {mu}{sup {minus}}) 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.
Date: October 1, 1996
Creator: Palmer, R.B. & Gallardo, J.C.
Partner: UNT Libraries Government Documents Department

Status of the BNL IFEL accelerator

Description: A 40 MeV electron beam, using the inverse free-electron laser interaction, has been accelerated by {Delta}E/E = 2.5% over a distance of 0.47 m. The electrons interact with a 1--2 GW CO{sub 2} laser beam bounded by a 2.8 mm ID sapphire circular waveguide in the presence of a tapered wiggler with Bmax {approx} 1 T and a period 2.89 cm {le} {lambda}{sub w} {le} 3.14 cm. The experimental results of {Delta}E/E as a function of electron energy E, peak magnetic field Bw and laser power W{sub 1} compare well with analytical and 1-D numerical simulations and permit scaling to higher laser power and electron energy. The present status of the IFEL accelerator and planned near term development are indicated.
Date: October 1, 1996
Creator: Steenbergen, A. van; Gallardo, J. & Sandweiss, J.
Partner: UNT Libraries Government Documents Department

SHORT RANGE WAKEFIELD IN A FLAT PILLBOX CAVITY GENERATED BY A SUB-RELATIVISTIC BEAM BUNCH.

Description: The short-range wakefield between two parallel conducting plates generated by a sub-relativistic beam bunch has been solved analytically by image charge method in time domain. Comparing with traditional modal analysis in frequency domain this algorithm simplifies mathematics and reveals great details of physics in electromagnetic field generation, propagation, reflection and causality. The calculated results have an excellent agreement with MAFIA and ABCI simulations in all range of beam velocities.
Date: June 18, 2001
Creator: WANG,H.; PALMER,R.B. & GALLARDO,J.
Partner: UNT Libraries Government Documents Department

MUON POLARIZATION IN A FRONT-END CHANNEL OF A NEUTRINO FACTORY.

Description: As one of the figures of merit, muon polarization and its correlation to the particle arrival time was studied for the high intensity muon beam source of a Neutrino Factory. Muon polarization, 100% polarized in the parent pion rest system, was tracked down the pion capture, phase rotation, and ionization cooling channels, using the BMT equation. A study was done of the dependence of the muon polarization and its correlation on the configuration of induction linac channels in the phase rotation channel. Depolarization effects of the muon polarization through absorbers in the ionization cooling channel was simulated.
Date: June 18, 2001
Creator: Fukui, Y.; Fernow, R. C. & Gallardo, J. C.
Partner: UNT Libraries Government Documents Department