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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

ORBIT CORRECTION STUDIES ON THE ELECTRON TRANSPORT LINE FROM RCS TO ESR

A dedicated electron transfer line from Rapid Cycling Synchrotron (RCS) to Electron Storage Ring (ESR), referred to as the RTE line has been designed for the Electron-Ion Collider (EIC). The beamline follows a straight-line geometry, with a length of 133 m, and is consists with two matching sections and a FODO section for beam diagnostics. Imperfections with magnet alignments introduce orbit distortions, making orbit correction scheme a critical component in the design. To facilitate orbit correction, each quadrupole magnet is equipped with a pair of beam position monitors (BPMs) and kickers. The Singular Value Decomposition (SVD) algorithm is used for orbit correction and tolerance studies. This paper presents the ongoing progress in the optics design and error correction scheme of the RTE line.

Neththikumara, I. [Thomas Jefferson National Accel↗
DOE OSTI2024

Rapid Tuning of Synchrotron Surrogate Model at the Recycler Ring

The 8 GeV proton-storage Recycler Ring (RR) is essential for reaching megawatt beam intensity goals for the DUNE neutrino beam at Fermilab. Custom shims on each RR permanent magnet were designed to cancel manufacturing defects and bring magnetic fields to the design values. Remaining imperfections cause the observed tune variation vs energy to deviate from what is calculated using the design fields. Using the POUNDERS (“Practical Optimization Using No Derivatives for sums of Squares”) optimization method with Synergia in the loop, we demonstrate rapid convergence to a set of additive, higher-order multipole moments of these magnetic shims which reproduce that observed variation, and show that the convergence advantage grows with the parameter-space dimensionality.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Direct observation of 𝛽 and 𝛾 decay from a high-spin long-lived isomer in 187 Ta

187 Ta (Z = 73, N = 114) is located in the neutron-rich A ≈ 190 region where a prolate-to-oblate shape transition via triaxial softness is predicted to take place. A preceding work on the K π = (25/2 - ) isomer and a rotational band to which the isomer decays carried out by the same collaboration revealed that axial symmetry is slightly violated in this nucleus. Here, this paper focuses on a higher-lying isomer, which was previously identified at 2933(14) keV by mass measurements with the Experimental Storage Ring at GSI. The isomer of interest has been populated by a multinucleon transfer reaction with a 136 Xe primary beam incident on a natural tungsten target, using the KEK Isotope Separation System at RIKEN. New experimental findings obtained in the present paper include the internal and external β-decay branches from the high-spin isomer and a revised half-life of 136(24) s. The evaluated hindrances for K-forbidden transitions put constraints on the spin-parity assignment, which can be interpreted as being ascribed to a prolate shape with a five-quasiparticle configuration by model calculations.

beta decay↗
DOE OSTI2021

Fabrication and Testing of 18-mm-Period, 0.5-m-Long Nb 3 Sn Superconducting Undulator

The Advanced Photon Source at Argonne National Laboratory, in collaboration with FNAL and LBNL, is developing a Nb 3 Sn superconducting undulator with the goal of installing this device on the APS storage ring and providing APS users with the novel radiation source. A series of short, similar to ~ 8-cm-long, 18-mm-period undulator prototype magnets have been designed, fabricated, and tested. The same design was scaled to fabricate a 0.5-m-long undulator prototype. Tests of this prototype showed that the designed peak magnetic field of 1.2 T at 850 A was successfully achieved. It represents at least a 20% improvement in comparison with a NbTi SCU having the same period and magnetic gap. Test results and lessons learned from the design process are reported here.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

LAMP-PSR Scoping Studies Report

This report summarizes work performed from July – September 2023, performing an initial evaluation for the LANSCE Proton Storage Ring upgrade option “B.” The studies identified potential pathsforward, performing initial beam dynamics studies, and surveying various technology options different aspects of the upgrade. Taken together, the studies provide an “early look” at the feasibility, challenges and alternative methods for pursuing Option “B,” and give guidance towards more detailed design concept development needed as work progresses. Generally speaking, no major obstacles were identified in pursuing the Option “B” PSR upgrade path in terms of the machine physics or overall system architecture. Several areas of concern have been identified; we note that these primarily center on technology choice and must be addressed regardless of the upgrade path selected, and none of the concerns are considered insurmountable.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Study of Fluctuations in Undulator Radiation in the IOTA Ring at Fermilab

We study turn-by-turn fluctuations in the number of emitted photons in an undulator, installed in the IOTA electron storage ring at Fermilab, with an InGaAs PIN photodiode and an integrating circuit. In this paper, we present a theoretical model for the experimental data from previous similar experiments and in our present experiment, we attempt to verify the model in an independent and a more systematic way. Moreover, in our experiment we consider the regime of very small fluctuation when the contribution from the photon shot noise is significant, whereas we believe it was negligible in the previous experiments. Accordingly, we present certain critical improvements in the experimental setup that let us measure such a small fluctuation.

43 PARTICLE ACCELERATORS↗
DOE OSTI2026

Thermal Compton Scattering of Electron Beams on Blackbody Photons: A Monte Carlo Event Generator for Multi-Turn Tracking at the Electron-Ion Collider

Compton scattering of ultra-relativistic electrons on thermal (blackbody) photons is typically a subdominant process in electron storage rings, but at sufficiently high electron energy and low residual gas pressure it can become competitive with beam-gas scattering and contribute to dis tributed losses and backgrounds. We present a self-contained Monte Carlo event generator for thermal Compton scattering designed for integration into multi-turn tracking workflows. The im plementation follows H. Burkhardt’s proposal method: trial scattering angles are sampled from the Thomson differential cross section and accepted/rejected using the Klein-Nishina to Thomson ratio, yielding the correct Compton spectrum while retaining simple absolute-rate normalization. Ther mal photon energies are sampled from the blackbody photon-number spectrum via an exact mixture representation.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

HIGH POWER COUPLER DEVELOPMENT FOR EIC

The synchrotron radiation loss in EIC Electron Storage Ring is as high as up to 10 MW. This energy loss will be compensated by 17 2K 591 MHz single-cell SRF cavities with a combined total of 34 high power fundamental power couplers. Each power coupler will operate 92% of revolution time CW and ~8% of revolution time with 400 kW forward power due to the beam abort gap. To satisfy the EIC needs, we developed two 500 kW standing-wave FPC designs at BNL based on either a BeO and an Al2O3 RF window. This paper will briefly summarize test results of the BeO window FPC, and describe the design development of the Al2O3 window based FPC.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

High power coupler development for EIC

The synchrotron radiation loss in EIC Electron Storage Ring is as high as up to 10 MW. This energy loss will be compensated by 17 2K 591 MHz single-cell SRF cavities with a combined total of 34 high power fundamental power couplers. Each power coupler will operate 92% of revolution time CW and ~8% of revolution time with 400 kW forward power due to the beam abort gap. To satisfy the EIC needs, we developed two 500 kW standing-wave FPC designs at BNL based on either a BeO and an Al 2 O 3 RF window. This paper will briefly summarize test results of the BeO window FPC , and describe the design development of the Al 2 O 3 window based FPC.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Single-Bunch Instabilities Driven by Space Charge During Low-Energy Cooling at Injection in the EIC Hadron Storage Ring

This paper presents a simulation-based study of single-bunch dynamics at the injection energy of 23.8 GeV for protons in the EIC hadron storage ring, focusing on the impact of space-charge–driven instabilities. The analysis demonstrates that at this energy, the proton bunch experiences significant transverse space-charge forces, which can reduce the stability margin in the presence of the geometric and resistive wall impedance. Various collective effects were considered, with particular attention to the nonlinear nature of the transverse space charge. To stabilize the beam, high chromaticity and octupoles were introduced and their effects analyzed using the ELEGANT code. The results provide a quantitative assessment of the stability thresholds and offer guidance for the machine design and operational strategy at injection.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Sextupole reduction via chaos suppression at NSLS-II

We revisit the nonlinear lattice design approach for the National Synchrotron Light Source II (NSLS-II) storage ring. By suppressing chaos, we identify alternative sextupole configurations to the original design, which relied on the conventional approach of simultaneously minimizing Resonance Driving Terms (RDTs) and Amplitude-Dependent Detuning (ADD). These alternatives achieve comparable performance while requiring fewer sextupoles. A detailed comparison of two representative solutions is presented and supported by experimental validation. Our results indicate that dynamic aperture correlates more strongly with global chaos than with individual RDTs, and that the importance of minimizing ADD may have been overstated in earlier design approach.

43 PARTICLE ACCELERATORS↗
DOE OSTI2021

A BEAM SCREEN TO PREPARE THE RHIC VACUUM CHAMBER FOR EIC HADRON BEAMS: CONCEPTUAL DESIGN AND REQUIREMENTS

The Electron Ion Collider (EIC) Hadron Storage Ring (HSR) will use the existing Relativistic Heavy Ion Collider storage rings, including the superconducting magnet arcs [1]. The vacuum chambers in the superconducting magnets and the cold mass interconnects were not designed for EIC beams and so must be updated to reduce resistive-wall heating and to suppress e-clouds. To do so without compromising the EIC luminosity goal, a stainless steel beam screen with colaminated copper and a thin layer of amorphous carbon will be installed. This paper describes the main requirements that our solution for the hadron ring vacuum chamber needs to satisfy, including impedance, aperture limitations, vacuum, thermal and structural stability, mechanical design, installation and operation. The conceptual design of the beam screen currently under development is introduced.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Beam optics ramping in underconstrained lattice design: Application to Electron-Ion Collider hadron storage ring cooling section

This paper presents the lattice design and optics ramping strategy for the cooling section of the hadron storage ring at the electron-ion collider. The main challenge is that available tuning knobs exceed beam-optics constraints. Independently optimized injection and top-energy optics often yield disconnected solutions, making interpolation impossible. To address this, we propose two new methods. The first is an intermediate-penalty scheme that ensures ramping path continuity by penalizing constraint violations at intermediate states. The second is a continuation-based approach that adapts high-energy optics to low energy, guided by an adaptive weighting scheme to balance injection and ramping constraints. The solutions meet all beam dynamics and hardware limits. The two methods offer a general strategy for ramping in systems where the solution space is under-constrained and the starting and target configurations are far apart.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Ring-based electron cooler for EIC

An Electron Ion Collider (EIC) at Brookhaven National Laboratory (BNL) is being proposed as a new discovery machine for the nuclear physics and quantum chromodynamics. The hadron beam cooling plays an important role in the EIC machine to achieve its physics goals. The most challenging is cooling of protons at the highest energy in the EIC. In this paper, we present a possible design of a ring-based electron cooler for the high energy hadron beam cooling. In proposed approach, the electrons will cool the hadrons while being cooled themselves by radiation damping in the storage ring. For design of the cooler using storage ring approach several aspects becomes very important, including electron ring optics design, chromaticity correction, calculate the dynamic aperture, radiation damping, quantum excitation, and intrabeam scattering (IBS). In addition, such effects as beam-beam scattering (BBS) due to interaction of electrons with hadrons become of special concern. In this paper, we discuss and take into design all the effects above, as well as introduce generalized treatment of the BBS and 3-D quantum lifetime. A special feature of our design is an effective use of dispersion in the cooling section, both for the ions and electrons, to redistribute the cooling rate between the longitudinal and horizontal planes. Finally, the cooling performance is simulated for proton beam at the top energy of the EIC. Our conclusion is that such ring-based cooler could be a feasible approach to provide required parameters of hadron beam at the top energy of 275 GeV for the EIC.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Beam and Spin Optics Simulation Tutorials, Using Zgoubi Exercises and Solutions 2 - RHIC Run 22 Spin Transparency Experiment

High electron and ion polarizations are paramount design requirements for the future Electron Ion Collider (EIC) at BNL. A “spin transparency” mode of operation, inherited from the “figure-8” ring design [1], allows preservation and control of electron and ion spin polarization in a collider or storage ring [2, 3]. It makes the ring lattice “invisible” to the spin and allows for polarization control by small quasi-static magnetic fields with practically no effect on beam orbital parameters. Beam polarization can then be fully controlled by small adjustments of snake axis orientation (a few degrees) and snake strengths (a few percent); polarization orientation at IPs can be controlled without spin rotators, spins can be adiabatically flipped without the need of ac magnets. The transparent spin mode has been demonstrated in simulations [2] for the purpose of being tested experimentally during RHIC Run 22. This experiment was aimed at providing data to validate the principles. Yellow RHIC ring (Fig. 1.1) was configured in the transparent spin mode by aligning the axes of its two helical snakes (located respectively in the 3 o’clock and 9 o’clock sextants) parallel to the longitudinal axis. Experiment goals and expected results, ad hoc procedures and hardware requirements, are addressed in Refs. [2, 3].

43 PARTICLE ACCELERATORS↗
NASA NTRS1992

Multispectral observations of the Jovian aurora

The upper atmospheres of the Earth and the outer planets form a screen on which precipitating charged particles, like the electron beam in a television, trace fleeting, but revealing patterns of visible, ultraviolet, infrared, and x ray emissions that offer valuable clues to processes occurring within the planetary magnetospheres. At Earth, years of in situ measurements, as well as ground based observations, have yielded a picture (still fuzzy) where the interaction of the solar wind with the magnetosphere of the Earth provides a complex path for the storage and release of energy during magnetic substorms; the ultimate manifestation of terrestrial auroral processes. More recent global imaging of substorm events from high above the Earth (greater than 3.5 R(sub e)) by Dynamics Explorer have made a unique contribution towards understanding the global and temporal evolution of such auroral events by providing a morphological perspective and by providing the crucial observational link that allows the separation of spatial and temporal variations inherent in the interpretation of in situ data. A similar role was played by the Hubble Space Telescope (HST) during the recent encounter of Ulysses with Jupiter in helping to define a new paradigm in Jovian auroral physics. The old paradigm portrayed Jupiter's magnetosphere as totally dominated by internal processes (i.e. Io related tori, heavy ions, etc.) where energetic heavy ion precipitation in the inner magnetosphere was solely responsible for the observed auroral phenomena. Ulysses and HST portray a more Earth-like paradigm where electron acceleration in the outer magnetosphere near the boundary with the solar wind plays a distinct role in the formation of auroral hot spots, yet energetic heavy ions also enter into the picture (similar to the role of the energetic ions from the terrestrial ring current during magnetic substorms). These heavy ions as a result of excitation during their transit through the atmosphere produce the x ray emissions observed in Roentgensatellit (ROSAT) x ray energy spectra.

Source record↗
DOE OSTI2023

Lattice Design of the EIC Electron Storage Ring for Energies Down to 5 GeV

The Electron-Ion Collider (EIC) at Brookhaven National Laboratory will feature an electron storage ring that will circulate polarized beams with energies up to 18 GeV. Recently a study has been undertaken to extend the minimum energy from 6 GeV to 5 GeV. As the solenoid-based spin rotators around the interaction point require specific bending angles that depend on the energy range, this change results in major changes to the geometry. Moreover, avoiding interference of the electron beamline with the other beamlines in the tunnel, as well as with the tunnel walls, is a formidable challenge, especially at the location of the large-diameter superconducting solenoids. In this contribution, the details of the modified spin rotators, geometrical layout, and optics of the revised lattice are presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Thermal simulation of the EIC HSR interconnect module - RF fingers

The Electron Ion Collider (EIC) Hadron Storage Ring (HSR) will reuse most of the existing superconducting magnets from the RHIC storage ring. However, the existing beam vacuum chamber and stripline BPMs will not be compatible with the planned EIC hadron bunches that will have a 3x higher intensity and be 10x shorter, and some operational scenarios with large radial offsets of the beam in the vacuum chamber. To address these challenges, a copper coated beam screen will be implemented, the existing RHIC stripline BPMs will be shielded and an interconnect module design, including new BPM will be installed adjacent to the existing BPMs. A thermal analysis of the new arc BPM interconnect housing has been conducted to assess the heating caused by beam induced resistive wall heating and electron cloud heating. An analysis of the BPM module has been made and reported separately. This report will focus on the other side of the interconnect module, containing the RF fingers.

43 PARTICLE ACCELERATORS↗