Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “JLEIC”

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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Coupled Bunch Instability from JLEIC Crab Cavity Higher Order Modes

Particle bunches traveling in a ring can excite wakefields inside any radio-frequency (rf) element present. These electromagnetic modes can resonate long enough and interact with subsequent passing bunches. A coherent oscillation between bunches can quickly become an instability and needs to be addressed. The Jefferson Lab Electron-Ion Collider (JLEIC) has a large 50 mrad crossing angle and thus relies on bunch crabbing to achieve high luminosity. Bunch crabbing is done with compact superconducting rf dipole cavities. We study coupled bunch oscillations driven by the higher order modes (HOM) of multi-cell rf dipole (rfd) crab cavities under study for JLEIC, we calculate the instability growth time assuming a symmetric beam frequency spectrum, identify the HOM driving the instability and discuss mitigation measures.

Sosa Guitron, Salvador I.↗
DOE OSTI2018

LONGITUDINAL COUPLED BUNCH INSTABILITY IN JLEIC

The luminosity performance of the JLEIC design is achieved by using a high bunch repetition rate (476MHz) with moderate bunch charges, similar to the strategy employed in modern lepton colliders. Such a bunch configuration will make single bunch instabilities less problematic, yet makes the machine more prone to the onset of longitudinal and transverse coupled bunch instabilities. Consequently, this will set higher demands on the bunch-by-bunch feedback systems to mitigate the multi-bunch instabilities. In this paper we present our detailed analysis of the growth rate of the coupled bunch instabilities for beams in both the electron and ion rings due to the accelerating RF cavities in JLEIC at the collision scenario. The implication of the growth rate on the feedback system will be discussed.

Li, Rui↗
DOE OSTI2018

Toroidal merger simulations for the JLEIC bunched beam electron cooler ring

The bunched beam electron cooler ring for the Jefferson Lab Electron-Ion Collider (JLEIC) requires a merger system to transport magnetized electron beams of two different energies to the same energy recovery linac (ERL) beamline. The system is especially challenging compared to existing mergers for ERL or hadron cooling applications (as at COSY) due to the small separation in energy between the two beams; for the JLEIC bunched beam cooler, the two beam energies may only differ by a factor of 4. An additional complication is the use of a magnetized beam. A toroidal merger system is studied using G4Beamline/GEANT4. Preservation of the quality of the low energy beam from the injector is especially vital for efficient cooling performance and compatibility with the ERL. Effects of the toroidal system on transverse and longitudinal emittances of the magnetized beams, as well as space charge effects, are presented and discussed.

Sy, Amy V.↗
DOE OSTI2018

Dispersive Electron Cooling for JLEIC

JLEIC is the electron ion collider under design at Jefferson Lab, which will provide a luminosity up to 1034 cm-2s-1. To reach the high luminosity, short ion and electron bunches with high charge density colliding in high frequency are proposed in JLEIC design. The high charge density of the ion beam leads to strong intrabeam scattering effect, which enlarges the ion beam emittance and ruins the luminosity if not mitigated. Magnetized electron cooling is implemented to overcome the intrabeam scattering effect and to reduce or maintain the ion beam emittance. In this paper, we discuss the redistribution of the cooling effects in the longitudinal and the transverse directions by introducing the dispersion of the ion beam in the cooling section. When the charge density of the cooling electron beam varies, the dispersion of the ion beam leads to an increase of the transverse cooling rate and a reduction of the longitudinal cooling rate, while the total decrement of the Courant-Snyder invariant of the ion beam increases. Both theoretical analysis and numerical calculation are presented.

Zhang, He↗
DOE OSTI2019

Status Update of a Harmonic Kicker Development for JLEIC

The Jefferson Lab Electron-Ion Collider (JLEIC) is an asymmetric high luminosity ring-ring collider proposed as the next major R&D facility for the nuclear physics community. Both of JLEIC?s electron and ion collider rings have high beam current with gaps serving the pur-poses of beam abort, ion clearing, etc. Those gaps will cause time-varying beam loading in the storage RF cavi-ties, and may result in modulation of cavity RF phase/voltage and cyclic shift of collision point, which could lead to significant luminosity loss. We studied a few approaches to mitigate the RF phase modulation and IP shift, such as correcting the RF phase/voltage modula-tion with traditional LLRF feedback, one-turn feedback (OTFB), or RF feedforward (FF); optimizing the bunch fill pattern to limit the RF phase/voltage modulation to a small fraction of the bunch trains in the collider ring; or matching the RF phase modulation in the two rings. The preliminary results are discussed in this paper.

Guo, Jiquan↗
DOE OSTI2019

HIGH CURRENT HIGH CHARGE MAGNETIZED AND BUNCHED ELEC-TRON BEAM FROM A DC PHOTOGUN FOR JLEIC COOLER

A high current, high charge magnetized electron beam-line was developed for fast and efficient cooling of ion beams for the proposed Jefferson Lab Electron Ion Col-lider (JLEIC). In this paper, we describe recent achieve-ments that include the generation of picosecond-bunch magnetized beams at average currents up to 28 mA with exceptionally long photocathode lifetime, and independent demonstrations of magnetized beam with high bunch charge up to 700 pC at 10s of kHz repetition rates. In addition, a detailed description of an extremely stable and reliable fiber-based drive laser system that employs a gain-switched master oscillator is presented. These ac-complishments mark important steps toward demonstrat-ing the feasibility of a technically challenging JLEIC cooler design using magnetized beams

Adderley, P.↗
DOE OSTI2019

Luminosity Studies of Asymmetric Crab crossing in JLEIC

The proposed Jefferson Lab Electron Ion Collider (JLEIC) currently plans to use a crab crossing scheme to maximize the available luminosity. It had been suggested by that space and cost savings, as well as hadron beam quality improvements could be realized by leaving the ion beam un-crabbed and increasing the crabbing angle of the electron beam. We also examine the two bunches crabbed at different angles, as well as at different crabbing frequencies to determine the maximum achievable luminosity for both JLEIC and LHC parameters.

Nissen, Edith↗
DOE OSTI2016

Study of beam synchronization at JLEIC

The ion collider ring of Jefferson Labs Electron-Ion Collider (JLEIC) accommodates a wide range of ion energies, from 20 to 100 GeV for protons or from 8 to 40 GeV per nucleon for lead ions. In this medium energy range, ions are not fully relativistic, which means values of their relativistic beta are slightly below 1, leading to an energy dependence of revolution time of the collider ring. On the other hand, electrons with energy 3 GeV and above are already ultra-relativistic such that their speeds are effectively equal to the speed of light. The difference in speeds of colliding electrons and ions in JLEIC, when translated into a path-length difference necessary to maintain the same timing between electron and ion bunches, is quite large. In this paper, we explore schemes for synchronizing the electron and ion bunches at a collision point as the ion energy is varied.

Morozov, Vasiliy↗
DOE OSTI2020

Design of the Multi-Ion Injector Linac for the JLAB EIC (JLEIC)

An Electron Ion Collider (EIC) is the highest priority for future U.S. accelerator-based nuclear physics facility following the completion of the Facility for Rare Isotope Beams (FRIB). Two laboratories are competing to host the future EIC: Brookhaven National Lab. (BNL) and Jefferson Lab. (JLab). The baseline design of JLab's Electron Ion Collider (JLEIC) ion complex comprises a pulsed superconducting (SC) linac injector capable of accelerating all ions from protons to lead, where proton and light ion beams can be polarized. After reviewing the design requirements for the injector linac, important design choices such as the room-temperature (RT) section design, the transition energy between the RT and SC sections and the stripping energy for heavy ions will be discussed. The design of the different linac sections will be presented as well as the results of end-to-end beam dynamics simulations for polarized deuterons and unpolarized lead ions.

Mustapha, B.↗
DOE OSTI2017

Impact of the Tilted Detector Solenoid on the Ion Polarization at JLEIC

Jefferson Lab Electron Ion Collider (JLEIC) is a figure-8 collider "transparent" to the spin. This allows one to control the ion polarization using a universal 3D spin rotator based on weak solenoids. Besides the 3D spin rotator, a coherent effect on the spin is produced by a detector solenoid together with the dipole correctors and anti-solenoids compensating betatron oscillation coupling. The 4 m long detector solenoid is positioned along a straight section of the electron ring and makes a 50 mrad horizontal angle with a straight section of the ion ring. Such a large crossing angle is needed for a quick separation of the two colliding beams near the interaction point to make sufficient space for placement of interaction region magnets and to avoid parasitic collisions of shortly-spaced 476 MHz electron and ion bunches. We present a numerical analysis of the detector solenoid effect on the proton and deuteron polarizations. We demonstrate that the effect of the detector solenoid on the proton and deuteron polarizations can be compensated globally using an additional 3D rotator located anywhere in the ring.

47 OTHER INSTRUMENTATION↗
DOE OSTI2016

BEAM DYNAMICS ANALYSIS FOR THE ULTRA-FAST KICKER IN CIRCULAR COOLER RING OF JLEIC

An ultra-fast kicker system consisting of four quarter wavelength resonator based deflecting cavities was developed that simultaneously resonates at 10 subharmonic modes of the 476.3MHz bunch repetition frequency. Thus every 10th bunch in the bunch train will experience a transverse kick while all the other bunches are undisturbed. This fast kicker is being developed for the Energy Recovery Linac (ERL) based electron Circular Cooler Ring (CCR) in the proposed Jefferson Lab Electron Ion Collider (JLEIC, previously MEIC). The electron bunches can be reused 10-30 turns thus the beam current in the ERL can be reduced to 1/10 - 1/30 (150mA - 50mA) of the cooling bunch current (1.5A). In this paper, several methods to synthesize such a kicker waveform and the comparison made by the beam dynamics tracking in Elegant will be discussed.

Huang, Yulu↗
DOE OSTI2016

INJECTION OPTICS FOR THE JLEIC ION COLLIDER RING

The Jefferson Lab Electron-Ion Collider (JLEIC) will accelerate protons and ions from 8 GeV to 100 GeV. A very low beta function at the Interaction Point (IP) is needed to achieve the required luminosity. One consequence of the low beta optics is that the beta function in the final focusing (FF) quadrupoles is extremely high. This leads to a large beam size in these magnets as well as strong sensitivity to errors which limits the dynamic aperture. These effects are stronger at injection energy where the beam size is maximum, and therefore very large aperture FF magnets are required to allow a large dynamic aperture. A standard solution is a relaxed injection optics with IP beta function large enough to provide a reasonable FF aperture. This also reduces the effects of FF errors resulting in a larger dynamic aperture at injection. We describe the ion ring injection optics design as well as a beta-squeeze transition from the injection to collision optics.

Morozov, Vasiliy↗
DOE OSTI2016

Towards a Small Emittance Design of the JLEIC Electron Collider Ring

The electron collider ring of the Jefferson Lab Electron-Ion Collider (JLEIC) is designed to provide an electron beam with a small beam size at the IP for collisions with an ion beam in order to reach a desired high luminosity. For a chosen beta-star at the IP, electron beam size is determined by the equilibrium emittance that can be obtained through a linear optics design. This paper briefly describes the baseline design of the electron collider ring reusing PEP-II components and considering their parameters (such as dipole sagitta, magnet field strengths and acceptable synchrotron radiation power) and reports a few approaches to reducing the equilibrium emittance in the electron collider ring.

Lin, Fanglei↗
DOE OSTI2017

Integration of the full-acceptance detector into the JLEIC

For physics requirements, the JLEIC (Jefferson Lab Electron Ion Collider) has a full-acceptance detector, which brings many new challenges to the beam dynamics integration. For example, asymmetric lattice and beam envelopes at interaction region (IR), forward detection, and large crossing angle with crab dynamics. Also some common problems complicate the picture, like coupling and coherent orbit from detector solenoid, high chromaticity and high multipole sensitivity from low beta-star at interaction point (IP), collision mode with different energy and ion species. Meanwhile, to get a luminosity level of a few 1033 cm-2sec-1, small ?* are necessary at the IP, which also means large ? in the final focus area, chromaticity correction sections, etc. This sets a constraint on the field quality of magnets in large beta areas, in order to ensure a large enough dynamic aperture (DA). In this context, limiting multipole components of magnets are surveyed to get a standard line. And continuously, multipole magnets as dedicated correctors are studied to provide semi-local corrections of specific multipole components beyond the standard line. This report will mention those contents.

Wei, G.H.↗
DOE OSTI2017

Update on the JLEIC Electron Collider Ring Design

We present an update on the lattice design of the electron ring of the Jefferson Lab Electron-Ion Collider (JLEIC). The electron and ion collider rings feature a unique figure-8 layout providing optimal conditions for preservation of beam polarization. The rings include two arcs and two intersecting long straight sections containing a low-beta interaction region (IR) with special optics for detector polarimetry, electron beam spin rotator sections, ion beam cooling sections, and RF-cavity sections. Recent development of the electron ring lattice has been focused on minimizing the beam emittance while providing an efficient non-linear chromaticity correction and large dynamic aperture. We describe and compare three lattice designs, from which we determine the best option.

Nosochkov, Y.↗
DOE OSTI2017

Design of imaginary transition gamma booster synchrotron for the Jefferson Lab EIC (JLEIC)

Baseline design of the JLEIC booster synchrotron is presented. Its aim is to inject and accumulate heavy ions and protons at 285 MeV, to accelerate them to about 7 GeV, and finally to extract the beam into the ion collider ring. The Figure-8 ring features two 2600 achromatic arcs configured with negative momentum compaction optics, designed to avoid transition crossing for all ion species during the course of acceleration. The lattice also features a specialized high dispersion injection insert optimized to facilitate the transverse phase-space painting in both planes for multi-turn ion injection. Furthermore, the lattice has been optimized to ease chromaticity correction with two families of sextupoles in each plane. The booster ring is configured with super-ferric, 3 Tesla bends. We are presently launching optimization of the booster synchrotron design to operate in the extreme space-charge dominated regime.

Bogacz, Alex↗
DOE OSTI2018

Beam formation in the alternative JLEIC ion complex

The proposed alternative design approach for the JLab-EIC (JLEIC) ion complex uses a more compact linac and pre-booster, and consolidates the electron storage ring (ering) as a large booster for the ions. Following a parameter study showing the feasibility of this design approach, we have adapted the e-ring lattice by adding RF sections to accelerate ion beams. In this study, we focus on the transverse beam formation for protons and lead ions from the ion source to collision point including the linac, pre-booster, e-ring and collider ring. Effects such as stripping injection, space charge, intra-beam scattering and beam cooling determine the total charge accumulated in each ring and the final luminosity of the collider.

Mustapha, Brahim↗
DOE OSTI2018

Calculations of Beam-Beam Effect and Luminosity for Crab Dynamics Simulations in JLEIC

Crab crossing is an integral part of the Jefferson Lab Electron-Ion Collider (JLEIC) design to achieve high luminosity while meeting the detection and physics pro-gram requirements. The crab crossing scheme provides a head-on beam-beam collision for beams with a nonzero crossing angle. Simulations of crabbing dynamics currently do not include beam-beam effects. We describe a framework for accurate simulation of beam-beam effects on crabbing dynamics by applying a numerical calculation of the Bassetti-Erskine analytic solution to symplectic particle tracking codes. The numerical calculation is benchmarked against the analytic solution by calculating the luminosity reduction for several colliding beam scenarios. Benchmarking results show good agreement be-tween the numerical calculation and analytic solution, paving the way for implementation of the beam-beam kick to Elegant tracking simulations.

Huang, He↗