Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “BEAM PRODUCTION”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Effect of nonuniform radial density distribution on the space charge dominated beam bunching

Beam dynamics of a space charge dominated beam during the bunch compression is studied self consistently for the case of fixed shape non-uniform bell shape and hollow shape density distributions in the transverse direction. We have used thick slices at different parts of the beam to account for variation in the beam radius in the study of the transverse dynamics. The longitudinal dynamics has been studied using the disc model. The axial variation of the radius of the slices and emittance growth arising from the phase dependence of the transverse rf forces are also included in the simulation. We have modified the beam envelope equation to take into account the longitudinal space charge effect on the transverse motion which arises due to the finite bunch size. To demonstrate the application of the theoretical formulations developed, we have studied a sinusoidal beam bunching system and presented detailed numerical results.

43 PARTICLE ACCELERATORS↗
DOE OSTI2011

Electrostatic Matching of a High Current Proton Beam to a RFQ

In order to demonstrate the operation of a prototype DWA (dielectric wall accelerator), it was necessary to modify the LEBT of a commercially procured proton RFQ (Radio Frequency Quadrupole) injector linac. The relatively high output current (35 mA) of the duoplasmatron ion source at the low injection energy of 35 keV to the RFQ presented a matching problem in the beam transport due to the high space charge, the fixed transport length, and the small beam size required at the RFQ. In addition, only the use of electrostatic lenses was considered in order to minimize the size of the system. The standard AccSys design using one decel-accel einzel lens proved to be insufficient, so three new solutions were proposed, each using a pair of decelerating einzel lenses. The tool used to optimize these designs was a newly developed feature of the program IGUN. The RFQ acceptance ellipse is plotted on top of the phase space data of the transport calculation together with an ellipse with the same Twiss parameters which just encloses all the trajectories. The quality of matching is then given as the ratio of the areas of these two ellipses, making optimization easy. This paper will present the results of this optimization and the performance of the actual equipment built and tested.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Study of multilayer-reflected beam profiles and their coherence properties using beamlines ID19 (ESRF) and 32-ID (APS)

The use of multilayer mirrors is an interesting alternative for reflective X-ray monochromatization with respect to reflection from crystal optics. The increased photon flux density due to the multilayers' larger bandwidth is of crucial importance for, e.g, full-field X-ray imaging applications. Drawbacks are the introduced modifications of the reflected beam profile as well as a certain loss of coherence, summarized as wavefront degradation. Our recent work has shown that the modification of the beam profile can vary with, e.g., the material composition of the coating applied. In order to verify our findings, a beamline round-robin has been initiated, comparing the wavefront profiles after reflection by selected multilayers at beamlines 32-ID (Advanced Photon Source) and ID19 (European Synchrotron Radiation Facility) with our initial results acquired at BM05 (ESRF) [1].

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Indus synchrotron source: A national facility

Indus Synchrotron Radiation complex at Raja Ramanna Centre for Advanced Technology at Indore, India houses two synchrotron radiation sources: Indus-1 and Indus-2 respectively. Indus-1 is a 450 MeV source emitting in VUV and soft x-ray region and operating at 100 mA since 1990 and Indus-2, designed for 2.5 GeV, 300 mA and is currently operating at 2 GeV and 100 mA. Indus-1 has five operational beamlines while Indus-2 has six beamlines installed and operational. Several materials research related problems have been investigated using the reflectivity and photo-electron spectroscopy beamlines at Indus-1 and also the beamlines at Indus-2. Here we will report the current status of both these sources and discuss a few of our studies carried out using these beamlines.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Commissioning of a microprobe-XRF beamline (BL-16) on Indus-2 synchrotron source

We report commissioning of the microprobe-XRF beamline on Indus-2 synchrotron source. The beamline has been recently made operational and is now open for the user's experiments. The beamline comprises of Si(111) double crystal monochromator and Kirkpatrick-Baez focusing optics. The beamline covers wide photon energy range of 4 - 20 keV using both collimated and micro-focused beam modes. The design details and the first commissioning results obtained using this beamline are presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Analysis of order contamination from toroidal grating monochromator of Indus-1 reflectivity beamline

The synchrotron radiation spectra of toroidal grating monochromators (TGM) often contaminated by significant amounts of higher orders. Quantitative estimation of order contamination is essential in order to perform quantitative spectroscopy measurements. At Indus-1 reflectivity beamline higher order contaminations from TGM monochromator are experimentally determined using a reflection grating analyzer. It is found that the order contamination in wavelength range of 50-200 A is less than 15%. Use of edge filters reduces the order contamination level below 5% in this wavelength range.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Gamma ray optics

Via refractive or diffractive scattering one can shape {gamma} ray beams in terms of beam divergence, spot size and monochromaticity. These concepts might be particular important in combination with future highly brilliant gamma ray sources and might push the sensibility of planned experiments by several orders of magnitude. We will demonstrate the experimental feasibility of gamma ray monochromatization on a ppm level and the creation of a gamma ray beam with nanoradian divergence. The results are obtained using the inpile target position of the High Flux Reactor of the ILL Grenoble and the crystal spectrometer GAMS. Since the refractive index is believed to vanish to zero with 1/E{sup 2}, the concept of refractive optics has never been considered for gamma rays. The combination of refractive optics with monochromator crystals is proposed to be a promising design. Using the crystal spectrometer GAMS, we have measured for the first time the refractive index at energies in the energy range of 180 - 2000 keV. The results indicate a deviation from simple 1/E{sup 2} extrapolation of X-ray results towards higher energies. A first interpretation of these new results will be presented. We will discuss the consequences of these results on the construction of refractive optics such as lenses or refracting prisms for gamma rays and their combination with single crystal monochromators.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Nuclear photonics at ultra-high counting rates and higher multipole excitations

Next-generation {gamma} beams from laser Compton-backscattering facilities like ELI-NP (Bucharest)] or MEGa-Ray (Livermore) will drastically exceed the photon flux presently available at existing facilities, reaching or even exceeding 10{sup 13}{gamma}/sec. The beam structure as presently foreseen for MEGa-Ray and ELI-NP builds upon a structure of macro-pulses ({approx}120 Hz) for the electron beam, accelerated with X-band technology at 11.5 GHz, resulting in a micro structure of 87 ps distance between the electron pulses acting as mirrors for a counterpropagating intense laser. In total each 8.3 ms a {gamma} pulse series with a duration of about 100 ns will impinge on the target, resulting in an instantaneous photon flux of about 10{sup 18}{gamma}/s, thus introducing major challenges in view of pile-up. Novel {gamma} optics will be applied to monochromatize the {gamma} beam to ultimately {Delta}E/E{approx}10{sup -6}. Thus level-selective spectroscopy of higher multipole excitations will become accessible with good contrast for the first time. Fast responding {gamma} detectors, e.g. based on advanced scintillator technology (e.g. LaBr{sub 3}(Ce)) allow for measurements with count rates as high as 10{sup 6}-10{sup 7}{gamma}/s without significant drop of performance. Data handling adapted to the beam conditions could be performed by fast digitizing electronics, able to sample data traces during the micro-pulse duration, while the subsequent macro-pulse gap of ca. 8 ms leaves ample time for data readout. A ball of LaBr{sub 3} detectors with digital readout appears to best suited for this novel type of nuclear photonics at ultra-high counting rates.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Betatron radiation based measurement of the electron-beam size in a wakefield accelerator

We present a spatial and spectral characterization of a laser-plasma based betatron source which allows us to determine the betatron oscillation amplitude of the electrons which decreases with increasing electron energies. Due to the observed oscillation amplitude and the independently measured x-ray source size of (1.8{+-}0.3){mu}m we are able to estimate the electron bunch diameter to be (1.6{+-}0.3){mu}m.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Applications of laser produced ion beams to nuclear analysis of materials

Laser produced ion beams have unique characteristics which are ultra-short pulse, very low emittance, and variety of nuclear species. These characteristics could be used for analyzing various materials like low Z ion doped heavy metals or ceramics. Energies of laser produced ion beam extend from 0.1MeV to 100MeV. Therefore, various nuclear processes can be induced in the interactions of ion beams with samples. The ion beam driven nuclear analysis has been developed for many years by using various electrostatic accelerators. To explore the applicability of laser ion beam to the analysis of the Li ion battery, a proton beam with the diameter of {approx} 1.0 {mu}m at Takasaki Ion Acceleration for Advanced Radiation Application (TIARA), JAEA was used. For the analysis, the PIGE (Particle-Induced Gamma Ray Emission) is used. The proton beam scans over Li battery electrode samples to diagnose Li density in the LiNi{sub 0.85}Co{sub 0.15}O{sub 2} anode. As the results, PIGE images for Li area density distributions are obtained with the spatial resolution of better than 1.5{mu}m FWHM. By the Li PIGE images, the depth dependence of de-intercalation levels of Li in the anode is obtained. By the POP experiments at TIARA, it is clarified that laser produced ion beam is appropriate for the Li ion battery analysis. 41.85.Lc, 41.75.Jv, 42.62.cf.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Optima MDxt: A high throughput 335 keV mid-dose implanter

The continuing demand for both energy purity and implant angle control along with high wafer throughput drove the development of the Axcelis Optima MDxt mid-dose ion implanter. The system utilizes electrostatic scanning, an electrostatic parallelizing lens and an electrostatic energy filter to produce energetically pure beams with high angular integrity. Based on field proven components, the Optima MDxt beamline architecture offers the high beam currents possible with singly charged species including arsenic at energies up to 335 keV as well as large currents from multiply charged species at energies extending over 1 MeV. Conversely, the excellent energy filtering capability allows high currents at low beam energies, since it is safe to utilize large deceleration ratios. This beamline is coupled with the >500 WPH capable endstation technology used on the Axcelis Optima XEx high energy ion implanter. The endstation includes in-situ angle measurements of the beam in order to maintain excellent beam-to-wafer implant angle control in both the horizontal and vertical directions. The Optima platform control system provides new generation dose control system that assures excellent dosimetry and charge control. This paper will describe the features and technologies that allow the Optima MDxt to provide superior process performance at the highest wafer throughput, and will provide examples of the process performance achievable.

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 OSTI2012

Neutralization of space charge on high-current low-energy ion beam by low-energy electrons supplied from silicon based field emitter arrays

Neutralization of space charge on a high-current and low-energy ion beam was attempted to reduce the divergence with an aid of low-energy electrons supplied from silicon based field emitter arrays (Si-FEAs). An argon ion beam with the energy of 500 eV and the current of 0.25 mA was produced by a microwave ion source. The initial beam divergence and the emittance were measured at the entrance of the analysis chamber in order to estimate the intrinsic factors for beam divergence. The current density distribution of the beam after transport of 730 mm was measured by a movable Faraday cup, with and without electron supply from Si-FEAs. A similar experiment was performed with tungsten filaments as an electron source. The results indicated that the electron supply from FEA had almost the same effect as the thermionic filament, and it was confirmed that both electron sources can neutralize the ion beam.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Comparison between single- and dual-electrode ion source systems for low-energy ion transport

Extraction of ions with energies below 100 eV has been demonstrated using a hot-cathode multi-cusp ion source equipped with extraction electrodes made of thin wires. Two electrode geometries, a single-electrode system, and a dual-electrode system were built and tested. The single-electrode configuration showed high ion beam current densities at shorter distances from the electrode but exhibited rapid attenuation as the distance from the electrode increased. Beam angular spread measurements showed similar beam divergence for both electrode configurations at low plasma densities. At high plasma densities and low extraction potentials, the single-electrode system showed the angular spread twice as large as that of the dual-electrode system. Energy distribution analyses showed a broader energy spread for ion beams extracted from a single-electrode set-up.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Resonance, particle dynamics, and particle transmission in the micro-accelerator platform

We describe particle dynamics in the Micro-Accelerator Platform (MAP), a slab-symmetric dielectric laser accelerator (DLA), and model the expected performance of recently fabricated MAP structures. The quality of the structure resonances has been characterized optically, and results are compared with simulation. 3D trajectory analysis is used to model acceleration in those same structures 'as built.' Results are applied to ongoing beam transmission and acceleration tests at NLCTA/E-163, in which transmission of 60 MeV injected electrons through the beam channel of the MAP was clearly observed, despite the overfilling of the structure by the beam.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Transformer ratio improvement for beam based plasma accelerators

Increasing the transformer ratio of wakefield accelerating systems improves the viability of present novel accelerating schemes. The use of asymmetric bunches to improve the transformer ratio of beam based plasma systems has been proposed for some time[1, 2] but suffered from lack appropriate beam creation systems. Recently these impediments have been overcome [3, 4] and the ability now exists to create bunches with current profiles shaped to overcome the symmetric beam limit of R {<=} 2. We present here work towards experiments designed to measure the transformer ratio of such beams, including theoretical models and simulations using VORPAL (a 3D capable PIC code) [5]. Specifically we discuss projects to be carried out in the quasi-nonlinear regime [6] at the UCLA Neptune Laboratory and the Accelerator Test Facility at Brookhaven National Lab.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

A real-time beam-profile monitor for a PET cyclotron

Beam profiles in medical cyclotrons are traditionally measured using techniques that do not provide any information about short-term fluctuations of the beam shape or beam intensity. To overcome this, we have developed a real-time harp beam profile monitor which can withstand beam power in excess of 300 W. The monitor and electronics were constructed and applied toward a 13 MeV proton beam with current of up to 25 {mu}A. Herein are reported preliminary beam-profile measurement results.

43 PARTICLE ACCELERATORS↗
DOE OSTI2013

Preliminary study on development of 300 Kv compact focused gaseous ion beam system

A new 300 kV compact focused gaseous ion beam (gas-FIB) system with three-stage acceleration lens was constructed at JAEA. The preliminary experiments of formation of the focused gaseous ion beams were carried out to show the availability of the gas-FIB system as a writing tool for 3D proton lithography. As a result of the experiments, it was proved that the focal point was kept at the same position under changing the kinetic energy but with keeping the kinetic energy ratio constant, which was defined as the ratio of kinetic energy in object side to that in image side for the third acceleration lens. This characteristic of the gas-FIB is a good point to advance the 3D proton lithography changing penetration depth in a sample by varying the beam energy.

43 PARTICLE ACCELERATORS↗