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Results for “BEAM FOCUSING MAGNETS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

SU-F-T-211: Evaluation of a Dual Focusing Magnet System for the Treatment of Small Proton Targets

Purpose: To investigate magnetic focusing for small volume proton targets using a doublet combination of quadrupole rare earth permanent magnet Halbach cylinder assemblies Methods: Monte Carlo computer simulations were performed using the Geant4 toolkit to compare dose depositions of proton beams transported through two focusing magnets or in their absence. Proton beams with energies of 127 MeV and initial diameters of 5, 8 and 10 mm were delivered through two identical focusing magnets similar to those currently in experimental use at Loma Linda University Medical Center. Analogous experiments used optimized configurations based on the simulation results. Dose was measured by a diode detector and Gafchromic EBT3 film and compared to simulation data. Based on results from the experimental data, an additional set of simulations was performed with an initial beam diameter of 18 mm and a two differing length magnets (40mm & 68mm). Results: Experimental data matched well with Monte Carlo simulations. However, under conditions necessary to produce circular beam spots at target depth, magnetically focused beams using two identical 40 mm length magnets did not meet all of our performance criteria of circular beam spots, improved peak to entrance (P/E) dose ratios and dose delivery efficiencies. The simulations using the longer 68 mm 2nd magnet yielded better results with 34% better P/E dose ratio and 20–50% better dose delivery efficiencies when compared to unfocused 10 mm beams. Conclusion: While magnetic focusing using two magnets with identical focusing power did not yield desired results, ongoing Monte Carlo simulations suggest that increasing the length of the 2nd magnet to 68 mm could improve P/E dose ratios and dose efficiencies. Future work includes additional experimental validation of the longer 2nd magnet setup as well as experiments with triplet magnet systems. This project was sponsored with funding from the Department of Defense (DOD# W81XWH-BAA-10-1).

60 APPLIED LIFE SCIENCES↗
DOE OSTI2015

Moly99 Production Facility: Report on Beamline Components, Requirements, Costs

In FY14 we completed the design of the beam line for the linear accelerator production design concept. This design included a set of three bending magnets, quadrupole focusing magnets, and octopoles to flatten the beam on target. This design was generic and applicable to multiple different accelerators if necessary. In FY15 we built on that work to create specifications for the individual beam optic elements, including power supply requirements. This report captures the specification of beam line components with initial cost estimates for the NorthStar production facility.This report is organized as follows: The motivation of the beamline design is introduced briefly, along with renderings of the design. After that, a specific list is provided, which accounts for each beamline component, including part numbers and costs, to construct the beamline. After that, this report details the important sections of the beamline and individual components. A final summary and list of follow-on activities completes this report.

07 ISOTOPE AND RADIATION SOURCES↗
NASA NTRS1999

Three-Dimensional Simulations of Electron Beams Focused by Periodic Permanent Magnets

A fully three-dimensional (3D) model of an electron beam focused by a periodic permanent magnet (PPM) stack has been developed. First, the simulation code MAFIA was used to model a PPM stack using the magnetostatic solver. The exact geometry of the magnetic focusing structure was modeled; thus, no approximations were made regarding the off-axis fields. The fields from the static solver were loaded into the 3D particle-in-cell (PIC) solver of MAFIA where fully 3D behavior of the beam was simulated in the magnetic focusing field. The PIC solver computes the time-integration of electromagnetic fields simultaneously with the time integration of the equations of motion of charged particles that move under the influence of those fields. Fields caused by those moving charges are also taken into account; thus, effects like space charge and magnetic forces between particles are fully simulated. The electron beam is simulated by a number of macro-particles. These macro-particles represent a given charge Q amounting to that of several million electrons in order to conserve computational time and memory. Particle motion is unrestricted, so particle trajectories can cross paths and move in three dimensions under the influence of 3D electric and magnetic fields. Correspondingly, there is no limit on the initial current density distribution of the electron beam, nor its density distribution at any time during the simulation. Simulation results including beam current density, percent ripple and percent transmission will be presented, and the effects current, magnetic focusing strength and thermal velocities have on beam behavior will be demonstrated using 3D movies showing the evolution of beam characteristics in time and space. Unlike typical beam optics models, this 3D model allows simulation of asymmetric designs such as non- circularly symmetric electrostatic or magnetic focusing as well as the inclusion of input/output couplers.

Kory, Carol L.↗
DOE OSTI2015

Muon Tracking Studies in a Skew Parametric Resonance Ionization Cooling Channel

Skew Parametric-resonance Ionization Cooling (SPIC) is an extension of the Parametric-resonance Ionization Cooling (PIC) framework that has previously been explored as the final 6D cooling stage of a high-luminosity muon collider. The addition of skew quadrupoles to the PIC magnetic focusing channel induces coupled dynamic behavior of the beam that is radially periodic. The periodicity of the radial motion allows for the avoidance of unwanted resonances in the horizontal and vertical transverse planes, while still providing periodic locations at which ionization cooling components can be implemented. A first practical implementation of the magnetic field components required in the SPIC channel is modeled in MADX. Dynamic features of the coupled correlated optics with and without induced parametric resonance are presented and discussed.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Fabrication of compound refractive lens using soft and deep X-ray lithography beamline on Indus-2

X-ray compound refractive lenses (CRL) have been fabricated using Soft and Deep X-ray lithography (SDXRL) beamline on Indus-2. Upto 50 parabolic lenses are fabricated in PMMA using 1X X-ray mask. The mask contains of 20 micron thick gold absorbing pattern on polyimide membrane. The lens fabrication is done by exposing 500 {mu}m thick PMMA sheets to 5-12keV X-rays from Indus-2. The fabricated CRL will be suitable for generating focused X-ray beam of Indus-2 bending magnet source.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Laser induced focusing for over-dense plasma beams

The capability of ion acceleration with high power, pulsed lasers has become an active field of research in the past years. In this context, the radiation pressure acceleration (RPA) mechanism has been the topic of numerous theoretical and experimental publications. Within that mechanism, a high power, pulsed laser beam hits a thin film target. In contrast to the target normal sheath acceleration, the entire film target is accelerated as a bulk by the radiation pressure of the laser. Simulations predict heavy ion beams with kinetic energy up to GeV, as well as solid body densities. However, there are several effects which limit the efficiency of the RPA: On the one hand, the Rayleigh-Taylor-instability limits the predicted density. On the other hand, conventional accelerator elements, such as magnetic focusing devices are too bulky to be installed right after the target. Therefore, we present a new beam transport method, suitable for RPA-like/over-dense plasma beams: laser induced focusing.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

SuperKEKB beam final focus superconducting magnet system

The SuperKEKB was designed and constructed as the upgraded accelerator of KEKB. In this accelerator design, the nano-beam scheme of collision was applied and a luminosity of 8 x10 35 cm -2 s -1 was targeted. In the design, the beam final focus system was the key component in the accelerator hardware elements. This final focus system consists of 55 superconducting magnets. In this paper, the designs of the magnets, the cryostats and the cryogenic system are shown, and the field measurement results are reported. The SuperKEKB beam operation with the final focus system started on 2018 March 19, and the magnet quench events up to 2020 December 16 are described.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Beam energy tracking system on Optima XEx high energy ion implanter

The Axcelis Optima XEx high energy implanter is an RF linac-based implanter with 12 RF resonators for beam acceleration. Even though each acceleration field is an alternating, sinusoidal RF field, the well known phase-focusing principle produces a beam with a sharp quasi-monoenergetic energy spectrum. A magnetic energy filter after the linac further attenuates the low energy continuum in the energy spectrum often associated with RF acceleration. The final beam energy is a function of the phase and amplitude of the 12 resonators in the linac. When tuning a beam, the magnetic energy filter is set to the desired energy, and each linac parameter is tuned to maximize the transmission through the filter. Once a beam is set up, all the parameters are stored in a recipe, which can be easily tuned and has proven to be quite repeatable. The magnetic field setting of the energy filter selects the beam energy from the RF Linac accelerator, and in-situ verification of beam energy in addition to the magnetic energy filter setting has long been desired. An independent energy tracking system was developed for this purpose, using the existing electrostatic beam scanner as a deflector to construct an in-situ electrostatic energy analyzer. This paper will describe the system and performance of the beam energy tracking system.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Self-neutralized ion beam

A vacuum arc ion source provides high current beams of metal ions that have been used both for accelerator injection and for ion implantation, and in both of these applications the degree of space charge neutralization of the beam is important. In accelerator injection application, the beam from the ion source may be accelerated further (post-acceleration), redirected by a bending magnet(s), or focused with magnetic or electrostatic lenses, and knowledge of the beam space charge is needed for optimal design of the optical elements. In ion implantation application, any build-up of positive charge in the insulating targets must be compensated by a simultaneous flux of cold electrons so as to provide overall charge neutrality of the target. We show that in line-of-sight ion implantation using a vacuum arc ion source, the high current ion beam carries along its own background sea of cold electrons, and this copious source of electrons provides a ''self-neutralizing'' feature to the beam. Here we describe experiments carried out in order to demonstrate this effect, and we provide an analysis showing that the beam is space-charge-neutralized to a very high degree.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Emittance growth in the DARHT Axis-II Downstream Transport

Using a particle-in-cell (PIC) code, we investigated the possibilities for emittance growth through the quadrupole magnets of the system used to transport the high-current electron beam from an induction accelerator to the bremsstrahlung converter target used for flash radiography. We found that even highly mismatched beams exhibited little emittance growth (< 6%), which we attribute to softening of their initial hard edge current distributions. We also used this PIC code to evaluate the accuracy of emittance measurements using a solenoid focal scan following the quadrupole magnets. If the beam is round after the solenoids, the simulations indicate that the measurement is highly accurate, but it is substantially inaccurate for elliptical beams

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

The Status of the Superomega Muon Beamline

The Superomega muon beamline is currently under construction at Experimental hall No. 2 of the Materials and Life Science Facility at J-PARC in Tokai, Japan. The beamline has a large solid angle acceptance, and will produce the highest intensity pulsed muon beam in the world. The beamline is designed to capture both surface positive and cloud negative muons for simultaneous use in a variety of experiments. The expected rate of surface muons for this beamline is 4x10{sup 8}{mu}{sup +}/s, and that for cloud muons is 10{sup 7}{mu}{sup -}/s. The beamline consists of the normal-conducting capture solenoid, the superconducting curved transport solenoid and axial focusing solenoid. The construction of the capture solenoid has been completed and installed in March 2009, and the transport solenoid is now fabricated, and will be installed in the summer of 2011. The calculation of the beamline optics of the axial focusing solenoid is underway.

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

Beam handling and transport solutions

The main purpose of the present study is to investigate the possibility to characterize the particle beams produced by the laser-target interaction in terms of collection, focusing and energy selection in order to evaluate the feasibility of a laser-driven facility in the field of medical application and, in particular, for hadrontherapy.

43 PARTICLE ACCELERATORS↗
DOE OSTI2016

Beam line shielding calculations for an Electron Accelerator Mo-99 production facility

The purpose of this study is to evaluate the photon and neutron fields in and around the latest beam line design for the Mo-99 production facility. The radiation dose to the beam line components (quadrupoles, dipoles, beam stops and the linear accelerator) are calculated in the present report. The beam line design assumes placement of two cameras: infra red (IR) and optical transition radiation (OTR) for continuous monitoring of the beam spot on target during irradiation. The cameras will be placed off the beam axis offset in vertical direction. We explored typical shielding arrangements for the cameras and report the resulting neutron and photon dose fields.

43 PARTICLE ACCELERATORS↗
NASA NTRS1988

Development of a 75-watt 60-GHz traveling-wave tube for intersatellite communications

This program covers the initial design and development of a 75 watt, 60 GHz traveling-wave tube for intersatellite communications. The objective frequency band was 59 to 64 GHz, with a minimum tube gain of 35 dB. The objective overall efficiency at saturation was 40 percent. The tube, designated the 961H, used a coupled-cavity interaction circuit with periodic permanent magnet beam focusing to minimize the weight. For efficiency enhancement, it incorporated a four-stage depressed collector capable of radiation cooling in space. The electron gun had a low-temperature (type-M) cathode and an isolated anode. Two tubes were built and tested; one feasibility model with a single-stage collector and one experimental model that incorporated the multistage collector.

Rousseau, A. L.↗
DOE OSTI2015

CSR induced microbunching gain estimation including transient effects in transport and recirculation arcs

The coherent synchrotron radiation (CSR) of a high brightness electron beam traversing a series of dipoles, such as transport or recirculation arcs, may result in the microbunching instability (μBI). To accurately quantify the direct consequence of this effect, we further extend our previously developed semi-analytical Vlasov solver to include more relevant coherent radiation models than the steady-state free-space CSR impedance, such as the entrance and exit transient effects derived from upstream beam entering to and exiting from individual dipoles. The resultant microbunching gain functions and spectra for our example lattices are presented and compared with particle tracking simulation. Some underlying physics with inclusion of these effects are also discussed.

43 PARTICLE ACCELERATORS↗