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Optimization of superconducting bending magnets for a 1.0 to 1.5 GeV compact light source

Description: Compact light sources are being proposed for protein crystallography, medical imaging, nano-machining and other areas of study that require intense sources of x rays at energies up to 35 keV. In order for a synchrotron light source to be attractive, its capital cost must, be kept low. The proposed compact light source has superconducting bending elements to bend the stored beam and produce the x rays. Additional focusing for the machine is provided by conventional quadrupoles. An important part of the cost optimization of a compact light source is the cost of the bending magnets. In the case of a machine with superconducting bending elements, the bending magnet system can represent close to half of the storage ring cost. The compact light source storage rings studied here have a range of stored electron energies from 1.0 to 1.5 GeV. For a number of reasons, it is desirable to keep the storage ring circumference below 30 meters. Cost optimization parameters include: (1) the number of superconducting bending elements in the ring, and (2) the central induction of the dipole. A machine design that features two superconducting dipoles in a single cryostat vacuum vessel is also discussed.
Date: June 1, 1995
Creator: Green, M.A. & Garren, A.A.
Partner: UNT Libraries Government Documents Department

Feasibility Study of Compact Gas-Filled Storage Ring for 6D Cooling of Muon Beams

Description: The future of elementary particle physics in the USA depends in part on the development of new machines such as the International Linear Collider, Muon Collider and Neutrino Factories which can produce particle beams of higher energy, intensity, or particle type than now exists. These beams will enable the continued exploration of the world of elementary particles and interactions. In addition, the associated development of new technologies and machines such as a Muon Ring Cooler is essential. This project was to undertake a feasibility study of a compact gas-filled storage ring for 6D cooling of muon beams. The ultimate goal, in Phase III, was to build, test, and operate a demonstration storage ring. The preferred lattice for the storage ring was determined and dynamic simulations of particles through the lattice were performed. A conceptual design and drawing of the magnets were made and a study of the RF cavity and possible injection/ejection scheme made. Commercial applications for the device were investigated and the writing of the Phase II proposal completed. The research findings conclude that a compact gas-filled storage ring for 6D cooling of muon beams is possible with further research and development.
Date: October 31, 2005
Creator: Garren, A. & Kolonlo, J.
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

Lattice design for a 50 on 50-GeV muon collider

Description: Two modes are being considered for a 50 on 50-GeV muon collider: one being a high-luminosity ring with broad momentum acceptance (dp/p of {approximately} 0.12%, rms) and the other lower luminosity with narrow momentum acceptance (dp/p of {approximately} 0.003%, rms). To reach the design luminosities, the value of beta at collision in the two rings must be 4 cm and 14 cm, respectively. In addition, the bunch length must be held comparable to the value of the collision beta to avoid luminosity dilution due to the hour-glass effect. To assist the rf system in preventing the bunch from spreading in time, the constraint of isochronicity is also imposed on the lattice. Finally, the circumference must be kept as small as possible to minimize luminosity degradation due to muon decay. Two lattice designs will be presented which meet all of these conditions. Furthermore, the lattice designs have been successfully merged into one physical ring with mutual components; the only difference being a short chicane required to match dispersion and floor coordinates from one lattice into the other.
Date: January 6, 2000
Creator: Johnstone, C.; Wan, W. & Garren, A.
Partner: UNT Libraries Government Documents Department

Fixed field circular accelerator designs

Description: The rapid rate and cycle time required to efficiently accelerate muons precludes conventional circular accelerators. Recirculating linacs provide one option, but the separate return arcs per acceleration pass may prove costly. Recent work on muon acceleration schemes has concentrated on designing fixed-field circular accelerators whose strong superconducting fields can sustain a factor of 4 increase in energy from injection to extraction. A 4 to 16 GeV fixed-field circular accelerator has been designed which allows large orbit excursions and the tune to vary as a function of momentum. Acceleration is .6 GeV per turn so the entire cycle consists of only 20 turns. In addition, a 16 to 64 GeV fixed-field circular accelerator has been designed which is more in keeping with the traditional Fixed Field Alternating Gradient machines. In this work the two machine designs are described.
Date: January 6, 2000
Creator: Johnstone, C.; Wan, W. & Garren, A.
Partner: UNT Libraries Government Documents Department

A Lattice for a Hybrid Fast-Ramping Muon Accelerator to 750 GeV

Description: We describe a lattice for accelerating muons from 375 GeV to 750 GeV. The lattice is a fast-ramping synchrotron with a mixture of fixed-field superconducting dipoles and warm dipoles, so as to have a high average bending field while still being able to rapidly change the average bending field as the beam momentum increases. For a 1.5 TeV center of mass muon collider, muons must be rapidly accelerated to 750 GeV. To accomplish this efficiently, we wish to make as many passes through the RF cavities as possible, while keeping the average RF gradients sufficiently high to avoid excess muon decays. A synchrotron where the magnets are very rapidly ramped has been envisioned as one option to accomplish this. The entire acceleration cycle takes place in less than 1 ms, presenting a technological challenge for the magnets. Clearly superconducting magnets cannot be ramped on this time scale, so instead room-temperature magnets will be ramped. To keep losses low, dipoles can use grain-oriented silicon steel, but quadrupoles will probably need to use more conventional steel, giving a lower maximum field for these high ramping rates. If we want to have a large average RF gradient and simultaneously make a large number of passes through the RF cavities, the average bending field must be high. To achieve such a large bending field while rapidly ramping magnets, it has been proposed to use a hybrid lattice consisting of interleaved superconducting dipoles and bipolar ramped dipoles. Due to the large single-bunch current and the relatively small apertures we desire (both because we would like to use high-frequency RF, and because power requirements and heating will be more reasonable for smaller aperture ramped magnets), collective effects are expected to be very significant. To reduce their effects, we propose to have strong synchrotron oscillations (a synchrotron ...
Date: September 6, 2011
Creator: Garren, A.A. & Berg, J.
Partner: UNT Libraries Government Documents Department

A Four Cell Lattice for the UCLA Compact Light Source Synchrotron

Description: The 1.5 GeV compact light source UCS proposed for UCLA must fit into a shielded vault that is 9.144 meters (30 feet) wide. In order for the machine to fit into the allowable space, the ring circumference must be reduced 36 meters, the circumference of the six cell lattice, to something like 26 or 27 meters. The four cell lattice described in this report has a ring circumference of 27.0 meters.
Date: March 12, 1999
Creator: Garren, A.A. & Green, M.A.
Partner: UNT Libraries Government Documents Department

Apiary B Factory Lattice Design

Description: The Apiary B Factory is a proposed high-intensity electron-positron collider. This paper presents the lattice design for this facility, which envisions two rings with unequal energies in the PEP tunnel. The design has many interesting optical and geometrical features due to the needs to conform to the existing tunnel, and to achieve the necessary emittances, damping times and vacuum. Existing hardware is used to a maximum extent.
Date: May 3, 1991
Creator: Donald, M.H.R. & Garren, A.A.
Partner: UNT Libraries Government Documents Department

APIARY B-Factory Separation Scheme

Description: A magnetic beam-separation scheme for an asymmetric-energy B Factory based on the SLAC electron-positron collider PEP is described that has the following properties: the beams collide head-on and are separated magnetically with sufficient clearance at the parasitic crossing points and at the septum, the magnets have large beam-stay-clear apertures, synchrotron radiation produces low detector backgrounds and acceptable heat loads, and the peak {beta}-function values and contributions to the chromaticities in the IR quadrupoles are moderate.
Date: May 3, 1991
Creator: Garren, A. & Sullivan, M.
Partner: UNT Libraries Government Documents Department

Hybrid Fast-Ramping Accelerator to 750 GeV/c: Refinement and Parameters over Full Energy Range

Description: Starting with the lattice design specified in [Garren and Berg, MAP-doc-4307, 2011], we refine parameters to get precise dispersion suppression in the straight sections and eliminate beta beating in the arcs. We then compute ramped magnet fields over the entire momentum range of 375 GeV/c to 750 GeV/c, and fit them to a polynomial in the momentum. We compute the time of flight and frequency slip factor over the entire momentum range, and discuss the consequences for longitudinal dynamics.
Date: March 2, 2012
Creator: S., Berg J. & Garren, A. A.
Partner: UNT Libraries Government Documents Department

Beam transport design for a recirculating-linac FEL driver

Description: The beam transport system for the CEBAF Industrial FEL includes a two-pass transport of the beam with acceleration from injector to wiggler, followed by energy recovery transport from wiggler to dump. From that context, the authors discuss the general problem of multi-pass energy-recovery beam transport for FELs. Tunable, nearly-isochronous, large-momentum-acceptance transport systems are required. The entire transport must preserve beam quality, particularly in the acceleration transport to the wiggler, and have low losses throughout the entire system. Various possible designs are presented, and results of dynamic analyses are discussed.
Date: July 1, 1996
Creator: Neuffer, D.; Douglas, D.; Li, Z.; Cornacchia, M. & Garren, A.
Partner: UNT Libraries Government Documents Department


Description: This paper compares various types of recirculating accelerators, outlining the advantages and disadvantages of various approaches. The accelerators are characterized according to the types of arcs they use: whether there is a single arc for the entire recirculator or there are multiple arcs, and whether the arc(s) are isochronous or non-isochronous.
Date: April 7, 2000
Partner: UNT Libraries Government Documents Department


Description: We describe progress toward the design and analysis of a storage ring for cooling a muon beam by the process of ionization cooling. Our primary strategy entails the design and optimization of the lattice using the code SYNCH, followed by the transfer of parameters to the code ICOOL which allows for the tracking of particles through rf cavities and absorbers of various dimensions. Our ultimate goal is to obtain longitudinal cooling and either transverse cooling or minimal transverse emittance heating.
Date: July 1, 2001
Partner: UNT Libraries Government Documents Department


Description: This report presents an attempt of the lattice design with a fixed field alternating gradient (FFAG) magnets without the usual opposite bends. It should allow particle acceleration through a small aperture. An example was made for the muon beam acceleration in an energy range 10-20 GeV with distributed RF cavities. The dispersion function for the central energy of 15 GeV has maximum value of the order of 7 cm. The lattice is composed of a combined function elements and sextupoles. We present the magnet configuration, orbit, chromaticities, tunes, and betatron function dependence on momentum (energies) during acceleration. For the lattice design we used SYNCH an MAD programs. For these large momentum offsets {delta}p/p = +-33% we found discrepancies between analytical and codes' results. This will be corrected in the new versions of codes (MAD-X). Because of uncertainties of the programs MAD and SYNCH some details of the presented results might not be correct.
Date: June 2, 2002
Partner: UNT Libraries Government Documents Department

Scraping beam halo in {mu} {sup +} {mu} {sup minus} colliders

Description: Beam halo scraping schemes have been explored in the 50 x 50 GeV and 2 x 2 TeV {mu}{sup +}{mu}{sup -} colliders using both absorbers and electrostatic deflectors. Utility sections have been specially designed into the rings for scraping. Results of realistic STRUCT- MARS Monte-Carlo simulations show that for the low-energy machine a scheme with a 5 m long steel absorber suppresses losses in the interaction region by three orders of magnitude. The same scraping efficiency at 2 TeV is achieved only by complete extraction of beam halo from the machine. The effect of beam-induced power dissipation in the collider superconducting magnets and detector backgrounds is shown both for the first few turns after injection and for the rest of the cycle.
Date: January 1, 1998
Creator: Drozhdin, A.; Mokhov, N.; Johnstone, C.; Wan, W. & Garren, A.
Partner: UNT Libraries Government Documents Department

Status of Studies of Achromat-based 6D Ionization Cooling Rings for Muons

Description: Six dimensional ionization cooling of muons is needed to achieve the necessary luminosity for a muon collider. If that cooling could occur over multiple turns in a closed ring, there would be significant cost savings over a single-pass cooling channel. We report on the status of a cooling ring with achromatic arcs. The achromatic design permits the design to easily switch between a closed ring and a snaking geometry on injection or extraction from the ring. The ring is designed with sufficient space in each superperiod for injection and extraction magnets. We describe the ring's lattice design, performance, and injection/extraction requirements.
Date: September 4, 2011
Creator: Ding, X.; Kirk, H.; Cline, D.; Garren, A. A. & Berg, J. S.
Partner: UNT Libraries Government Documents Department

Principles of interaction region design in Hadron Colliders and their application to the SSC

Description: The high luminosity Interaction Regions (IRs) are an important part of the lattice in colliding beam machines. The performance of the collider may depend significantly on the particular design of the IRs. In this paper we discuss the general principles of IR design and apply these principles to the design of the Superconducting Super Collider Interaction Regions.
Date: January 1, 1994
Creator: Nosochkov, Y.; Sen, T.; Courant, E.; Garren, A.; Ritson, D.M.; Stirninh, T. et al.
Partner: UNT Libraries Government Documents Department