SEARCH · Engineering Papers
Results for “ION BEAMS”
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.
Analysis of beam ion driven Alfvén eigenmode stability induced by Tungsten contamination in EAST
Alfvén eigenmodes (AE) activity is observed in the EAST high β N and low B T discharge 93910, operation scenario dedicated to explore the ITER baseline scenario. AEs are triggered after the plasma is contaminated by Tungsten that causes an abrupt variation of the thermal plasma and energetic particles (EPs) profiles. The aim of the present study is to analyze the AE stability in the 93910 discharge using the gyro-fluid code FAR3d, identifying the AE stability trends by comparing the plasma before and after the Tungsten contamination. Tungsten contamination causes the destabilization of Toroidal AEs (TAE) and Energetic particle modes (EPMs) in the same frequency range and radial location with respect to the experimental observation and M3D-K/GTAW code results. Next, a set of parametric studies are performed to analyze the effect of the thermal plasma and EP parameters on the AE stability. The analysis indicates a lower EP β threshold for the AEs destabilization if the EP energy increases, an improved AE stability of on-axis NBI configurations due to the stronger continuum damping in the inner plasma region as well as a large enhancement of the EP drive as the thermal ion density increases due to a higher ratio of the EP and Alfven velocities. Consequently, the simulations indicate the increment of the thermal ion density after the Tungsten contamination could be the main cause of the AE/EPM destabilization.
Optical Interference for the Guidance of Cryogenic Focused Ion Beam Milling Beyond the Axial Diffraction Limit
Using a tri-coincident cryogenic FIB-SEM-LM system, we identify an interferometric optical response that can be used for targeting lamella production to fluorescently labelled structures with accuracy beyond the diffraction limit. We demonstrate the approach using synthetic samples of fluorescent beads embedded in micron-scale droplets of water. Here, we then apply the approach to capture virions inside host cells. Successful targeting is confirmed by cryogenic electron tomography revealing clusters of virions in intracellular vesicles.
Efficient continuous wave accelerating structure for ion beams
Not Available
Nonintrusive measurement of time-resolved emittances of 1-GeV operational hydrogen ion beam using a laser comb
Not Available
Rapid charge redistribution leading to core hollowing in a high-intensity ion beam
Not Available
4D transverse phase space tomography of an operational hydrogen ion beam via noninvasive 2D measurements using laser wires
Not Available
rf chopper for prebunched radioactive ion beams
An rf chopper system is being designed for the ReAccelerator (ReA) linac at the Facility for Rare Isotope Beams at Michigan State University. The 80.5 MHz ReA radio-frequency quadrupole accelerates prebunched 16.1 MHz beams, producing four satellite bunches for every main bunch. The chopper system includes an rf deflector that kicks every bunch vertically to spatially separate main and satellite bunches. A constant magnetic field superimposed with the chopper electric field biases the beam trajectory to ensure the high-intensity bunches do not experience a net deflection and are injected straight to the ReA6 cryomodule or sent for experiments. The kicked bunches are low in intensity and will be sent to a beam dump, resulting in a clean 16.1 MHz beam structure, which allows for a reliable time-of-flight separation of the isotopes. Published by the American Physical Society 2024
Energy-chirp compensation of laser-driven ion beams enabled by structured targets
Not Available
Fragmentation Analysis of High-Energy Heavy Ion Beams for Single-Event Effects Testing at NSRL
Explore the source record for details and available documents.
Key aspects of sub-nanometer deterministic ion beam figuring for synchrotron hard x-ray mirror fabrication
Explore the source record for details and available documents.
Post-production correction of lamellar x-ray gratings by ion beam figuring
Explore the source record for details and available documents.
Comparison of Feschenko BSM and Fast Faraday Cup with Low Energy Ion Beams
A comparison between Fast Faraday Cup and Feschenko longitudinal bunch shape detectors was recently performed at HELIAC Advanced Demonstrator beamline at GSI. Feschenko bunch shape monitor (BSM) uses the time to space conversion by means of secondary electrons emitted from a wire correlated to a rf deflector, while the fast Faraday cup (FFC) measures the deposited charge in a cup geometry matched to 50 Ohm. The FFC design aims to minimize the bunch shape dilution due to field polarization and secondary electrons produced on irradiation. An He¹⁺ with 100 µA average current and 1.4 MeV/u kinetic energy is utilized for this comparison. A buncher upstream of the detectors was operated to focus the beam longitudinally. The results are discussed in this contribution.
LANL Projects to Address the 2017 EM Assessment of Ion Beam Facility
Project to remove and cap at roof remaining fume hoods, glove boxes and vent stack openings and to seal openings after removal.
Focused Ion Beam Failure Analysis and Circuit Edit Applications.
Abstract not provided.
Deterministic Positioning of Defect Based Qubits using Ion Beam Implantation for Nanofabrication and Modification.
Abstract not provided.
Deterministic Positioning of Defect Based Qubits using Ion Beam Implantation for Nanofabrication and Modification.
Abstract not provided.
Ion Beam Implantation for Nanofabrication and Modification.
Abstract not provided.