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Design of a grating for studying Smith-Purcell radiation and electron acceleration

Description: We describe work on the design of a diffraction grating which we intend to use for studying the production of Smith-Purcell radiation and the acceleration of electrons. We have developed computer codes based on the solution of the appropriate Maxwell's equations. A specific grating profile is given which is feasible to construct and which supports enhanced surface accelerating modes. We examine the possibility of using the Smith-Purcell effect to make a beam position monitor. 13 refs., 10 figs., 2 tabs.
Date: January 1, 1989
Creator: Fernow, R.C.
Partner: UNT Libraries Government Documents Department

Fundamental principles of particle detectors

Description: This paper goes through the fundamental physics of particles-matter interactions which is necessary for the detection of these particles with detectors. A listing of 41 concepts and detector principles are given. 14 refs., 11 figs.
Date: January 1, 1988
Creator: Fernow, R.C.
Partner: UNT Libraries Government Documents Department

Superconducting combined function magnets

Description: Superconducting accelerators and storage rings, presently under construction or in the design phase, are based on separate dipole and quadrupole magnets. It is here suggested that a hybrid lattice configuration consisting of dipoles and combined function gradient magnets would: (1) reduce the number of magnet units and their total cost; and (2) increase the filling factor and thus the energy at a given field. Coil cross sections are presented for the example of the Brookhaven Colliding Beam Accelerator. An asymmetric two-layer cable gradient magnet would have transfer functions of 10.42 G/A and 0.628 G cm/sup -1//A versus 15.77 G/A and 2.03 G cm/sup -1//A of the present separate dipoles and quadrupoles.
Date: January 1, 1983
Creator: Hahn, H. & Fernow, R.C.
Partner: UNT Libraries Government Documents Department

Far field acceleration

Description: Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail.
Date: July 1995
Creator: Fernow, R. C.
Partner: UNT Libraries Government Documents Department

Proceedings of the switched power workshop

Description: These proceedings contain most of the presentations given at a workshop on the current state of research in techniques for switched power acceleration. The proceedings are divided, as was the workshop itself, into two parts. Part 1, contains the latest results from a number of groups active in switched power research. The major topic here is a method for switching externally supplied power onto a transmission line. Advocates for vacuum photodiode switching, solid state switching, gas switching, and synthetic pulse generation are all presented. Other important areas of research described in this section concern: external electrical and laser pulsing systems; the properties of the created electromagnetic pulse; structures used for transporting the electromagnetic pulse to the region where the electron beam is located; and possible applications. Part 2 of the proceedings considers the problem of designing a high brightness electron gun using switched power as the power source. This is an important first step in demonstrating the usefulness of switched power techniques for accelerator physics. In addition such a gun could have immediate practical importance for advanced acceleration studies since the brightness could exceed that of present sources by several orders of magnitude. I would like to take this opportunity to thank Kathleen Tuohy and Patricia Tuttle for their assistance in organizing and running the workshop. Their tireless efforts contribute greatly to a very productive meeting.
Date: January 1, 1988
Creator: Fernow, R.C. (ed.)
Partner: UNT Libraries Government Documents Department

The grating as an accelerating structure

Description: This report considers the use of a diffraction grating as an accelerating structure for charged particle beams. We examine the functional dependence of the electromagnetic fields above the surface of a grating. Calculations are made of the strength of the accelerating modes for structures with {pi} and 2{pi} phase advance per period and for incident waves polarized with either the E or H vector along the grooves of the grating. We consider examples of using gratings in a laser linac and in a grating lens. We also briefly examine previous results published about this subject. 36 refs.
Date: February 1, 1991
Creator: Fernow, R.C.
Partner: UNT Libraries Government Documents Department

Acceleration using total internal reflection

Description: This report considers the use of a dielectric slab undergoing total internal reflection as an accelerating structure for charged particle beams. We examine the functional dependence of the electromagnetic fields above the surface of the dielectric for polarized incident waves. We present an experimental arrangement for testing the performance of the method, using apparatus under construction for the Grating Acceleration experiment at Brookhaven National Laboratory. 13 refs., 4 figs., 2 tabs.
Date: June 7, 1991
Creator: Fernow, R.C.
Partner: UNT Libraries Government Documents Department

Magnetic design for the ATF beamline. number sign. 1

Description: This report gives a self-consistent conceptual design for the final focusing'' beam optics and analysis spectrometer optics for the Grating Acceleration Experiment, the Inverse Cerenkov Acceleration Experiment, and the Nonlinear Compton Scattering Experiment. The introductory section describes the basic principles and constraints involved in the overall design. The next two sections give second order TRANSPORT calculations for the final focus system and the spectrometer system for the three experiments. The fourth section presents Monte Carlo simulations of the expected x-y distributions for the spectrometer detector for the three experiments. Appendices A and B contains further details about the assumptions used in the Monte Carlo simulations. Appendix C contains the working drawings used for determining distances on the experimental floor.
Date: February 5, 1992
Creator: Fernow, R.C.
Partner: UNT Libraries Government Documents Department

Application of switched-power techniques to quadrupoles

Description: Electric fields on the order of 1 GV/m may be achievable with very short (few ps) pulses. A field of 0.3 GV/m is equivalent in deflecting strength to a magnetic field of 1 Tesla. We consider here the possibility of replacing magnets (specifically final focus quadrupoles) with laser-switched devices. 7 refs., 3 figs.
Date: January 1, 1988
Creator: Aronson, S.H. & Fernow, R.C.
Partner: UNT Libraries Government Documents Department

ICOOL: A TOOL FOR MUON COLLIDER SIMULATIONS.

Description: Current ideas for designing neutrino factories [ 1,2] and muon colliders [3] require unique configurations of fields and materials to prepare the muon beam for acceleration. This so-called front end system must accomplish the goals of phase rotation, bunching and cooling. We have continued the development of a 3-D tracking code, ICOOL [4], for examining possible muon collider front end configurations. A system is described in terms of a series of longitudinal regions with associated material and field properties. The tracking takes place in a coordinate system that follows a reference orbit through the system. The code takes into account decays and interactions of {approx}50-500 MeV/c muons in matter. Material geometry regions include cylinders and wedges. A number of analytic models are provided for describing the field configurations. Simple diagnostics are built into the code, including calculation of emittances and correlations, longitudinal traces, histograms and scatter plots. A number of auxiliary codes can be used for pre-processing, post-processing and optimization.
Date: September 28, 2001
Creator: FERNOW,R.C.
Partner: UNT Libraries Government Documents Department

Muon Collider Final Cooling in 30-50 T Solenoids

Description: Muon ionization cooling to the required normalized rms emittance of 25 microns transverse, and 72 mm longitudinal, can be achieved with liquid hydrogen in high field solenoids, provided that the momenta are low enough. At low momenta, the longitudinal emittance rises from the negative slope of energy loss versus energy. Assuming initial emittances that have been achieved in six dimensional cooling simulations, optimized designs are given using solenoid fields limited to 30, 40, and 50 T. The required final emittances are achieved for the two higher field cases. Preliminary simulations of transverse cooling in hydrogen, at low energies, suggests that muon collider emittance requirements can be met using solenoid fields of 40 T or more. It might also be acceptable with 30 T. But these simulations did not include hydrogen windows,matching or reacceleration, whose performance, with one exception, was based on numerical estimates. Full simulations of more stages are planned. The design and simulation of hydrogen windows must be included, and space charge effects, and absorber heating, calculated.
Date: March 28, 2011
Creator: Palmer, R.B.; Fernow, R.C. & Lederman, J.
Partner: UNT Libraries Government Documents Department

Six Dimensional Bunch Merging for Muon Collider Cooling

Description: A muon collider requires single, intense, muon bunches with small emittances in all six dimensions. It is most efficient to initally phase-rotate the muons into many separate bunches, cool these bunches in six dimensions (6D), and, when cool enough, merge them into single bunches (one of each sign). Previous studies only merged in longitudinal phase space (2D). In this paper we describe merging in all six dimensions (6D). The scheme uses rf for longitudinal merging, and kickers and transports with differing lengths (trombones) for transverse merging. Preliminary simulations, including incorporation in 6D cooling, is described. Muons are efficiently generated by pion decay, but they then have very large emittances. A muon collider requires low emittances, which can be achieved using transverse ionization cooling, combined with emittance exchange using dispersion and shaped absorbers. For efficient capture, muons are first phase-rotated by rf into a train of many bunches. But for high luminosity, we need just one bunch of each sign, so after some initial cooling, these bunches should be merged.
Date: March 28, 2011
Creator: Palmer, R.B. & Fernow, R.C.
Partner: UNT Libraries Government Documents Department

Tapered Six-Dimensional Cooling Channel for a Muon Collider

Description: A high-luminosity muon collider requires a reduction of the six-dimensional emittance of the captured muon beam by a factor of {approx} 10{sup 6}. Most of this cooling takes place in a dispersive channel that simultaneously reduces all six phase space dimensions. We describe a tapered 6D cooling channel that should meet the requirements of a muon collider. The parameters of the channel are given and preliminary simulations are shown of the expected performance. A complete scheme for cooling a muon beam sufficiently for use in a muon collider has been previously described. This scheme uses separate 6D ionization cooling channels for the two signs of the particle charge. In each, a channel first reduces the emittance of a train of muon bunches until they can be injected into a bunch-merging system. The single muon bunches, one of each sign, are then sent through a second tapered 6D cooling channel where the transverse emittance is reduced as much as possible and the longitudinal emittance is cooled to a value below that needed for the collider. The beam can then be recombined and sent through a final cooling channel using high-field solenoids that cools the transverse emittance to the required values for the collider while allowing the longitudinal emittance to grow. This paper mainly describes the design of the 6D cooling channel before bunch merging. Cooling efficiency is conveniently measured using a parameter Q, which is defined as the rate of change of 6D emittance divided by the rate of change of the number of muons in the beam. In a given lattice Q starts off small due to losses from initial matching, then rises to a large value (Q {approx} 15 is typical for the channels discussed here), and finally falls as the emittance of the beam approaches its equilibrium value. ...
Date: March 28, 2011
Creator: Palmer, R.B. & Fernow, R.C.
Partner: UNT Libraries Government Documents Department

Report of the working group on data taking with bunched beams

Description: The purpose of this working group was to consider the problems created for experimenters under the bunched beam running conditions of ISABELLE Phase I. Some indication is given of the nature of the problem, the kinds of experiments that will have difficulties are identified, and some of the possibilities for dealing with them are considered.
Date: January 1, 1981
Creator: Blumenfeld, B.; Fernow, R. C.; Herrera, J. C.; Kabe, S.; Marx, M.; Nappi, A. et al.
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

MUON POLARIZATION EFFECTS IN THE FRONT END OF THE NEUTRINO FACTORY

Description: The authors summarize the methods used for simulation of polarization effects in the front end of a possible neutrino factory. They first discuss the helicity of muons in the pion decay process. They find that, neglecting acceptance considerations, the average helicity asymptotically approaches a magnitude of 0.185 at large pion momenta. Next they describe the methods used for tracking the spin through the complicated electromagnetic field configurations in the front end of the neutrino factory, including rf phase rotation and ionization cooling channels. Various depolarizing effects in matter are then considered, including multiple Coulomb scattering and elastic scattering from atomic electrons. Finally, they include all these effects in a simulation of a 480 m long, double phase rotation front end scenario.
Date: June 12, 2000
Creator: FERNOW,R.C.; GALLARDO,J.C. & FUKUI,Y.
Partner: UNT Libraries Government Documents Department

Possible demonstration of ionization cooling using absorbers in a solenoidal field

Description: Ionization cooling may play an important role in reducing the phase space volume of muons for a future muon-muon collider. We describe a possible experiment to demonstrate transverse emittance cooling using a muon beam at the AGS at Brookhaven National Laboratory. The experiment uses device dimensions and parameters and beam conditions similar to what is expected in an actual muon-muon collider.
Date: December 1, 1995
Creator: Fernow, R.C.; Gallardo, J.C. & Kirk, H.G.
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 hydrogen absorbers immersed in a solenoid with alternating focusing field and rf linacs at the zero field points. Solenoids and toroidal sectors have a natural place in muon collider design given the large emittance of the beam and consequently, the large transverse momentum of the initial pion beam or the decay muon beam. Bent solenoids as shown were studied for use at the front end of the machine, as part of the capture channel and more recently as part of a diagnostic setup to measure the position and momentum of muons. The authors present a Hamiltonian formulation of muon dynamics in toroidal sector solenoids (bent solenoid).
Date: January 1998
Creator: Gallardo, J. C.; Fernow, R. C. & Palmer, R. B.
Partner: UNT Libraries Government Documents Department

ATF beamline 1 analysis spectrometer

Description: We describe the design parameters and expected performance of the analysis spectrometer for beamline 1 at the BNL Accelerator Test Facility. The spectrometer should be well suited for measuring the change in energy caused by the first generation laser acceleration experiments.
Date: January 1, 1993
Creator: Fernow, R.C.; Kirk, H.G. & Ulc, S.
Partner: UNT Libraries Government Documents Department

Solenoid fringe field compensation for the Cluster Klystron

Description: Optimization of the solenoid pancake currents so as to have a uniform axial magnetic field over an extended volume, is very important for the successful operation of the Cluster Klystron. By boosting the first and the last pancake currents by 35%, a uniform field Br/Bz {le} 0.1% at radius R {le} 2 cm can be extended from {+-} 7 cm to {+-} 16 cm. The result confirms simulations and the requirements for a 3-beam Cluster Klystron Experiment are achieved.
Date: April 1, 1996
Creator: Wang, H.; Fernow, R.C.; Kirk, H.G.; Palmer, R.B. & Zhao, Y.
Partner: UNT Libraries Government Documents Department

Ionization cooling in the muon collider

Description: The muon beams in a high luminosity muon collider are produced with a very large emittance. The process of ionization cooling offers a method for reducing the 6-dimensional normalized emittance of the beam by a factor of {approx} 10{sup 6}. A simple analytic theory has been developed that demonstrates the dependence of the net cooling on various experimental parameters. The simple theory has been checked and realistic arrangements have been examined using Monte Carlo simulations. Transverse cooling of the initial beam can be achieved using passive Li absorbers in a FOFO lattice. The last factor of 10 in transverse cooling probably requires the use of current-carrying Li lenses. Efficient longitudinal cooling requires the use of wedge shaped absorbers in a dispersive section of the beam line. An example, multi-stage cooling scenario has been developed that meets the requirements of the muon collider. Preliminary designs have been made of solenoids for use in the FOFO lattice and of solenoids and dipoles for use in the emittance exchange sections. Detailed simulation work, farther optimization, and preparations for experimental demonstrations of critical components are currently in progress.
Date: October 1996
Creator: Fernow, R. C.; Gallardo, J. C.; Kirk, H. G. & Palmer, R. B.
Partner: UNT Libraries Government Documents Department

Monte Carlo simulations of muon production

Description: Muon production requirements for a muon collider are presented. Production of muons from pion decay is studied. Lithium lenses and solenoids are considered for focusing pions from a target, and for matching the pions into a decay channel. Pion decay channels of alternating quadrupoles and long solenoids are compared. Monte Carlo simulations are presented for production of {pi} {yields} {mu} by protons over a wide energy range, and criteria for choosing the best proton energy are discussed.
Date: March 1, 1995
Creator: Palmer, R.B.; Gallardo, J.C.; Fernow, R.C.; Torun, Y.; Neuffer, D. & Winn, D.
Partner: UNT Libraries Government Documents Department

Obwervation of 10 {mu}m Smith-Purcell radiation from 45 MeV electrons

Description: Using the high-brightness, high-energy electron beam at the Brookhaven Accelerator Test Facility we observe forward directed Smith-Purcell radiation in the mid-infrared spectral regime. This radiation can prove useful as a source of infrared radiation for other scientific studies as well as a providing a precursor investigation of the inverse process, namely the acceleration of electrons by means of the coupling of laser light with electrons via micro-structures.
Date: February 1, 1997
Creator: Fernow, R.C.; Robertson, S.H.; Brownell, J.H. & Walsh, J.E.
Partner: UNT Libraries Government Documents Department