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Summary of the working group on high current transport and final focus lenses

Description: The group reviewed recent work, and then addressed itself to relating the current understanding of relevant beam transport effects to the four reference concepts. In addition there was discussion on plans for future experimental and theoretical work. Discussions covered the following topics: (1) Transverse instabilities on intense beams through periodic focusing systems, (2) evaluation and correction of chromatic aberrations in the final beam transport lines, (3) evaluation and correction of geometric aberrations due to quadrupole fringe fields, and (4) ion focusing by electrons.
Date: September 1, 1978
Creator: Garren, A.A.
Partner: UNT Libraries Government Documents Department

20 TeV collider lattices with low-. beta. insertions

Description: A lattice containing insertions designed for collisions of 20 TeV proton beams at crossing points having beta values of two meters or less is presented. The machine would use high-field double bore superconducting magnets, with opposite focusing action on the two beams passing through each quadrupole. Hence the focusing pattern in the insertions is antisymmetric about the crossings. The beams, separated by 16 cms in the arcs are made colinear by dipoles common to both beams and then focused to the low-..beta.. collision points by quadrupole triplets. A similar machine design for pp collisions is also included.
Date: August 1, 1983
Creator: Garren, A.A.
Partner: UNT Libraries Government Documents Department

6. 5 Tesla SSC lattice example

Description: This note presents an example SSC collider lattice for 20 TeV proton beams using 6.5 Tesla double bore magnets, six collision points, and anti-symmetric insertions.
Date: January 1, 1984
Creator: Garren, A.A.
Partner: UNT Libraries Government Documents Department

Lattice and bypass design for a coherent xuv facility

Description: The design of a magnet lattice and bypass for a coherent radiation facility is discussed. The lattice is the missing magnet FODO structure first proposed by Vignola for a 6 GeV light source. This has been adapted for a 750-1300 MeV electron storage ring for use with both conventional insertion devices and a high gain FEL optimized for output at 400 A. The latter device requires that the electron bunch be deflected into a small aperture bypass, then reinjected into the ring where the perturbing effects of the FEL are damped out. 8 refs., 7 figs.
Date: May 1, 1985
Creator: Jackson, A.; Garren, A.A. & Vignola, G.
Partner: UNT Libraries Government Documents Department

Beam separation for p-anti p collisions in a single ring in the multibunch mode

Description: A discussion is given of proton-antiproton colliding beam operation in storage rings. Some means of separating the beams at points where no experiment is being performed seems to be an important feature for a p-anti p colliding beam ring. By exciting a betatron oscillation in some appropriate, localized region, one could create a specific collision point while at the same time cause the p and anti p beams to oscillate in opposition so that their orbits meet at only a small number of points, roughly given by twice the tune, 2..nu...
Date: January 1, 1978
Creator: Berley, D.; Garren, A.A. & Month, M.
Partner: UNT Libraries Government Documents Department

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

Controlling the crossing angle in the SSC (Superconducting Super Collider)

Description: The colliding beams in the SSC must cross at a small angle, so that when the bunches pass each other away from the interaction point (IP), they are sufficiently separated to avoid disruptive beam-beam forces. However, the crossing angle is so small that the adjacent quadrupoles must be common to both beams. Only after passing through four common quadrupoles on each side of the IP, are the beams split by vertical dipoles into separate beamlines. In order to make the closed orbits of the two beams cross at a definite angle at the IP (within a range up to 150 {mu}rad), a series of correction dipoles are placed in the insertions. If these dipoles are excited in such a way as to control the closed orbits alone, the dispersion will be mismatched, reaching values of up to 50 cm in the arcs. This mismatch is due to the closed orbit displacements in the interaction region (IR) quadrupoles, causing them to act as bending magnets. Therefore, both the closed orbit and dispersion must be matched simultaneously. Solutions to this problem are presented. 6 figs.
Date: April 1, 1989
Creator: Garren, A. A. & Johnson, D. E.
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

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


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

SSC test lattices

Description: A set of eight test lattices for the SSC have been devised for such purposes as the investigation of the dependences of chromatic properties and dynamic aperture on the type, field, physical aperture and errors of the magnets, on the sextupole correction scheme, on the tunes and on the cell phase advances. They are distinguished from realistic lattices in that certain features of the latter are missing - most notably the crossing magnets that bring the two counter-rotating proton beams into collision at the interaction points, and the utility insertions, which are the sites for the injection, beam abort, and radiofrequency systems. Furthermore the placement of magnets in the cells is simplified. 7 refs., 9 figs., 2 tabs.
Date: April 20, 1985
Creator: Courant, E.D.; Douglas, D.R.; Garren, A.A. & Johnson, D.E.
Partner: UNT Libraries Government Documents Department

Issues in storage-ring for operation of high-gain FELs

Description: A high-gain free electron laser (FEL), placed in a special by-pass of a storage ring, can provide tens of magewatts of coherent power at wavelengths shorter than 1000 A. The requirements on beam quality, (few hundred amperes of peak current, emittance of the order of 10/sup -8/ m-rad, and relative energy spread less than 0.002) are demanding but lie within the limits of modern storage ring technology. In this paper, we study various issues in storage ring design and FEL physics for operation of a high-gain FEL. Topics included are the requirements on beam parameters for FEL operation, coherent instabilities and intrabeam scattering effects in the storage ring, lattice design, and FEL performance computered by 2-D simulations.
Date: December 1, 1984
Creator: Kim, K.J.; Bisognano, J.J.; Garren, A.A.; Halbach, K. & Peterson, J.M.
Partner: UNT Libraries Government Documents Department

Superconducting proton storage ring for PEP

Description: In order to provide for electron-proton collisions in the PEP system, plans for a high-energy superconducting proton storage ring are being explored. The energy is constrained to 300 GeV by the radius of the PEP tunnel (350 meters) and the field strength (7 tesla) expected to be available in practical superconducting magnets. A new configuration has been developed in which the proton ring vertically crosses the horizontal electron ring in 4 of the 6 straight-sections. Synchronization of the two beams is provided by means of bypasses in the two non-crossing straight sections in the electron ring. The proton injector is a 5 GeV/c synchrotron 1/18 as large as the main ring.
Date: March 1, 1979
Creator: Garren, A.A.; Molishever, E.L.; Peterson, J.M. & Sah, R.C.
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

An Isochronous Lattice for PEP

Description: With e{sup +}e{sup -} storage rings operating in a quasi-isochronous mode, it might be possible to produce short bunches with length {sigma}{sub z} < 1 cm. The unique characteristics of the short bunches could then be utilized for synchrotron radiation applications or colliders with mm-scale {beta}*. In principle, the design of a quasi-isochronous storage ring is relatively straight-forward, but experimental studies with electron storage rings in this configuration have not been carried out. The purpose of this paper is to demonstrate that an isochronous lattice design is compatible with PEP given a minimum of hardware modifications.
Date: April 1, 1991
Creator: Corbett, W.J.; Donald, M.H.R. & Garren, A.A.
Partner: UNT Libraries Government Documents Department

SYNCH: A program for design and analysis of synchrotrons and beamlines -- user`s guide

Description: SYNCH is a computer program for use in the design and analysis of synchrotrons, storage rings, and beamlines. It has a large repertoire of commands that can be accessed in a flexible way. The input statements and the results of the calculations they invoke are saved in an internal database so that this information may be shared by other statements. SYNCH is the first accelerator program to organize its input in the form of a language. The statements, which resemble sentences, provide a natural way of describing lattices and invoking relevant calculations. The organization of the program is modular, so that it has been possible to expand its capabilities progressively.
Date: December 31, 1993
Creator: Garren, A.A.; Kenney, A.S.; Courant, E.D.; Russell, A.D. & Syphers, M.J.
Partner: UNT Libraries Government Documents Department

Storage-ring FEL for the vuv

Description: A free-electron laser for the vuv operating in a storage ring requires an electron beam of high density and low energy spread and a short wavelength, narrow-gap undulator. These conditions tend to produce longitudinal and transverse beam instabilities, excessive beam growth through multiple intrabeam scattering, and a short gas-scattering lifetime. Passing the beam only occasionally through the undulator in a by-pass straight section, as proposed by Murphy and Pellegrini, allows operation in a high-gain, single-pass mode and a long gas-scattering lifetime. Several storage ring designs have been considered to see how best to satisfy the several requirements. Each features a by-pass, a low-emittance lattice, and built-in wigglers for enhanced damping to counteract the intra-beam scattering. 15 references, 3 figures, 2 tables.
Date: September 1, 1984
Creator: Peterson, J.M.; Bisognano, J.J.; Garren, A.A.; Halbach, K.; Kim, K.J. & Sah, R.C.
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 will present 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. 8 figs. 1 tab.
Date: April 1, 1991
Creator: Donald, M.H.R. (Stanford Linear Accelerator Center, Menlo Park, CA (USA)) & Garren, A.A. (Lawrence Berkeley Lab., CA (USA))
Partner: UNT Libraries Government Documents Department

A superconducting bending magnet system for a compact synchrotron light source

Description: High intensity, high energy X-rays for use in protein crystallography, nano-machining and medical applications, such as non invasive coronary angiography, can be produced by a 1.2 to 1.5 GeV electron storage ring compact light source with 6 to 8 tesla superconducting bending magnets. Because the bending magnets are to be superconducting, the storage ring energy can be over factor of two lower than a conventional storage ring that delivers same photon energy. The ring, which has superconducting bending magnets, is smaller in circumference and has the advantage of having fewer particles in the ring for a given x ray source intensity. The proposed storage ring is a separated function accelerator ring with six superconducting bending magnet units. Conventional quadruples and correction elements would be located between the bending magnets. Because the synchrotron radiation is generated in the bend, the superconducting bending magnets must have a warm vacuum chamber for the electron beam. Variations of a superferric magnet design have been studied for this application. This report presents a superferric H magnet design that can produce good quality magnetic field in a region that is 50 mm high by 100 mm wide. This modified superferric H magnet design has saturated iron poles but the magnetic flux is returned from one pole to the other through an unsaturated iron return path. The dipole magnet required for a compact storage ring must be physically short (380 mm long), and the field must fall off rapidly at the ends of the magnet. This report describes a preliminary design for a pair of 6.894 tesia, thirty degree bending magnets in a common vacuum vessel for use in a 1.5 GeV compact storage ring light source.
Date: July 1, 1995
Creator: Green, M.A.; Garren, A.A.; Leung, E.M.; Madura, D.D.; Cline, D.B.; Kolonko, J.J. et al.
Partner: UNT Libraries Government Documents Department


Description: Ionization cooling is an essential component of a neutrino factory or a muon collider. Ionization cooling in the transverse dimensions is reasonably straightforward, and has been incorporated in published neutrino factory studies. Achieving cooling in the longitudinal dimensions is more difficult, but has the potential to greatly improve the performance of neutrino factories, and is essential to muon colliders. Much progress has recently been made in describing ring cooling lattices which achieve cooling in all three phase space planes, and in the design of the required, but difficult, injection systems. Ring cooling lattices also have the potential of significantly reduced cost compared to single-pass cooling systems with comparable performance. We will present some recent lattice designs, describing their theory, features, and performance, including injection and extraction systems.
Date: June 3, 2002
Creator: KIM,K.J.; WANG,C.X.; BERG,J.S.; FERNOW,R.; KIRK,H.; PALMER,R. et al.
Partner: UNT Libraries Government Documents Department