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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

DXRD : a user-friendly suite of two- and multiple-beam dynamical X-ray diffraction programs

The DXRD program suite consisting of a series of dynamical theory programs is introduced for computing dynamical X-ray diffraction from single crystals. Its interactive graphical user interfaces (GUIs) allow general users to make complicated calculations with minimal effort. It can calculate plane-wave Darwin curves of single crystals (or multiple crystals) for both the Bragg and Laue cases, including grazing-incidence diffraction and backward diffraction (with Bragg angles approaching 90°). It is also capable of simulating rocking curves for divergent incident X-ray beams with finite bandwidths. A unique feature of DXRD is that it provides a convenient GUI-based multiple-beam diffraction program that can accurately compute arbitrary N-beam diffraction of any geometry using a universal 4N × 4N matrix method. DXRD also provides a mapping program for plotting all the multiple-beam diffraction lines (monochromator glitches) in the azimuth–energy coordinate system. All these functions make DXRD a convenient and powerful software tool for designing crystal-based synchrotron/X-ray optics (monochromators, analyzers, polarizers, phase plates etc.) and for crystal characterization, X-ray spectroscopy and X-ray diffraction teaching.

Bragg reflection↗
DOE OSTI2018

Muon Beam Dynamics and Spin Dynamics in the g-2 Storage Ring

The goal of the new g-2 experiment at fermilab is a measurement of the anomalous magnetic moment of the muon, with uncertainty of less than 140 ppb. The experimental method is to store a beam of polarized muons in a storage ring with pure vertical dipole field and electrostatic focusing, and to measure the precession frequency. Control of the systematics depends on unprecedented knowledge of the details of the phase space of the muon distribution. That knowledge is derived from direct measurements with scintillating fiber detectors that are inserted into the muon beam for diagnostic measurements, traceback straw tube tracking chambers, as well as the calorimeters that measure energy, time and position of the decay positrons. The interpretation of the measurements depends on a detailed model of the storage ring guide field. This invited talk presents results of studies of the distribution from the commissioning run of the experiment.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

Beam dynamics for Scorpius with the CDR end-to-end tune: I. Transport

An end-to-end (E2E) simulation of Scorpius was performed for the Conceptual Design Report (CDR). This simulation used a tune significantly different than the tune used for assessing beam stability for the CDR. Since the E2E tune has some desirable features, the stability assessment has been repeated for the E2E tune. In this article I briefly discuss some of the groundwork for the simulations of stable beam transport, and the results. These simulation results show that there is no emittance growth for stable transport with a beam well matched to the magnetic tune. Future articles will cover beam stability that can be expected with E2E tune.

47 OTHER INSTRUMENTATION↗
DOE OSTI2018

Beam Dynamics for Scorpius with the CDR end-to-end tune: II. Short-pulse stability

An end-to-end simulation of Scorpius was performed for the Conceptual Design Report. This simulation used a tune significantly different than the tune used for assessing beam stability. Therefore, the stability assessment has been repeated with the end-to end tune in order to ensure that motion due to instabilities will not significantly blur the radiographic source spot.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Beam Dynamics Study of PIP-II Superconducting Linac in the Presece of Misalignment Errors

The Proton Improvement Plan (PIP)-II is a proposed high intensity proton facility being developed at the Fermilab. The PIP-II is primarily based on construction of a new superconducting radio frequency (SRF) linear accelerator (linac) that would deliver an average beam current of 2mA with output energy up to 800 MeV. The linac performance is mainly determined by beam sensitivity against various component errors. These errors trigger not only emittance dilution but also a beam loss in worst cases. This paper discusses effects of component misalignments on the beam and presents alignment budget for the PIP-II SRF linac.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

Beam Dynamics Study of PIP-II Superconducting Linac in the Presence of Misalignment Errors

The Proton Improvement Plan (PIP)-II is a proposed high intensity proton facility being developed at the Fermilab. The PIP-II is primarily based on construction of a new superconducting radio frequency (SRF) linear accelerator (linac) that would deliver an average beam current of 2mA with output energy up to 800 MeV. The linac performance is mainly determined by beam sensitivity against various component errors. These errors trigger not only emittance dilution but also a beam loss in worst cases. This paper discusses effects of component misalignments on the beam and presents alignment budget for the PIP-II SRF linac.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Summary of Jefferson Lab LDRD on FFA@CEBAF Beam Dynamics Simulations

As Thomas Jefferson National Accelerator Facility (Jefferson Lab) looks toward the future, we are considering expanding our energy reach by using Fixed-Field Alternating Gradient (FFA) technology. Significant efforts have been made to design a hybrid accelerator which combines conventional recirculating electron LINAC design with permanent magnet-based FFA technology to increase the number of beam recirculations, and thus the energy. In an effort to further this progress, Jefferson Lab awarded a Laboratory Directed Research and Development (LDRD) grant to focus not on the design, but on detailed simulations of the designs created by the larger collaboration. This document will summarize the work performed during this LDRD, and direct the reader to other proceedings which describe elements of the work in greater detail.

Deitrick, K.↗
DOE OSTI2021

SHarD: A beam dynamics simulation code for dielectric laser accelerators based on spatial harmonic field expansion

In order to demonstrate acceleration of electrons to relativistic scales by an on chip dielectric laser accelerator (DLA), a ponderomotive focusing scheme capable of capturing and transporting electrons through nanometer-scale apertures over extended interaction lengths has been proposed. Here we present a Matlab-based numerical code (SHarD) utilizing a spatial harmonic expansion of the fields within the dielectric structure to simulate the evolution of the beam phase space distribution in this scheme. The code can be used to optimize key-parameters for the accelerator performance such as the final energy, transverse spot size evolution and total number of electrons accelerated through currently fabricated structures. Eventually, the simulation model will be applied to inform the phase mask profile to be added to a pulse front tilt drive laser pulse using a liquid crystal mask in the experimental setup being assembled at UCLA Pegasus Laboratory.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

PART 2: Initial Beam Dynamics Results of an Integrated and Compact 1.3 GHZ Superconducting Radio Frequency (SRF) Electron Source

This paper is the continuation of a technical paper which is called “Detailed Electromagnetic Design of an Integrated and Compact 1.3 GHz Superconducting Radio Frequency (SRF) Electron Source” [1]. In the previous paper, we examined if a promising RF electromagnetic design of the gun and cathode region could be achieved. Further, we examined if this gun region could be fully integrated, in terms of the electromagnetic RF design, with the rest of the accelerator, keeping in mind the overall goal of compactness and reduction of duplicative infrastructure commonly associated with separated function electron guns and structures. While we convinced ourselves thus far that the RF electromagnetic design of our concept is feasible, we also needed to perform particle tracking to assess the beam properties through the entire system, understand and remediate any beam loss. For this step, we examined the cathode region and analyzed the gating process of the thermionic cathode, as losses would most likely be attributed to releasing electrons into the accelerating structure during an unfavorable phase window.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Effect of interparticle fields and radiation reaction on beam dynamics

The dynamics of relativistic particles in an intense electromagnetic field can be described by the Landau-Lifshitz (LL) equation, where the radiation reaction (RR) is accounted for via a self-force, and interparticle fields are often neglected as an approximation. However, the inclusion of interparticle fields is necessary to ensure energy-momentum conservation, particularly during coherent emission. Here we present (i) an analytical proof showing that the energy-momentum conservation law of the Hamilton-Rohrlich-Dirac action, which is divergence free and describes a generic system of interacting charges, respects causality and provides physically sensible results; (ii) a simple generalization of the LL equation for many particles evaluated as a function of the total field, i.e., the sum of the external and interparticle fields. By performing first-principles numerical simulations of a neutral, relativistic bunch of electrons and positrons (e − /e + ) colliding with a laser pulse, this theory is shown to satisfy energy-momentum conservation when interparticle fields and RR are simultaneously taken into account; and (iii) the combined effect of interparticle fields and RR primarily affects the tail of the particle energy distribution. Additionally, our first-principles simulations show that the effect of interparticle fields on beam energy loss becomes smaller when most of the radiated energy is incoherent.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2019

Improvement of machine learning enhanced genetic algorithm for nonlinear beam dynamics optimization

On top of the genetic algorithm enhanced by machine learning for nonlinear lattice optimization, as proposed in Li et al. (2018), an improved repopulation technique has been developed. Different weight coefficients for defining the “elite cluster” were compared to discern the fastest convergence in two classic optimization test problems. Additonally, the volume of the parameter space for generating potentially competitive candidates was further confined by repopulation in the vicinity of randomly selected “elite seeds”. The new repopulation technique significantly improves the quality of newly populated candidates by excluding the less competitive seeds introduced by the old repopulation algorithm. Finally, this technique has been validated, having a faster convergence for test problems first, and then applied to the nonlinear lattice optimization for the High Energy Photon Source storage ring.

36 MATERIALS SCIENCE↗