TUOCB2
JLab, Newport News, Virginia, USA
The design strategy of an electron-ion collider for reaching high luminosities is presently based on application of strong cooling of the ion beams during collisions. In this paper, we present the main design parameters for JLEIC, a Jefferson Lab proposal of an electron-ion collider, to reach ultimate high luminosity up to 2x1034 /cm2/s.
ANL, Argonne, USA
JLab, Newport News, Virginia, USA
A key component of the recently proposed alternative design approach for the JLab-EIC (JLEIC) ion complex is to consolidate the electron storage ring (e-ring) as a large booster for the ions*. A preliminary parameter study showed that it is possible to do so for different design options of the e-ring. In this paper we will report on the adaptation of the e-ring lattice to accelerate ions. After studying the beam dynamics at the injection and extraction energies, we will determine the RF requirements for ion acceleration, in particular the number of required accelerating sections and their locations. The effect of this potential lattice change on the electron beam will be investigated. In a second stage, we will focus on the spin manipulation and determine if the spin rotators and flippers available for the electron could be used for the ions.
* An Alternative Approach for the JLEIC Ion Accelerator Complex, B. Mustapha et al, Proceedings of NAPAC-2016, October 9-14, Chicago, IL.
JLab, Newport News, Virginia, USA
MIPT, Dolgoprudniy, Moscow Region, Russia
Science and Technique Laboratory Zaryad, Novosibirsk, Russia
The figure-8-shaped ion collider ring of Jefferson Lab Electron-Ion Collider (JLEIC) is transparent to the spin. It allows one to preserve proton and deuteron polarizations using weak stabilizing solenoids when accelerating the beam up to 100 GeV/c. When the stabilizing solenoids are introduced into the collider's lattice, the particle spins precess about a spin field, which consists of the field induced by the stabilizing solenoids and the zero-integer spin resonance strength. During acceleration of the beam, the induced spin field is maintained constant while the resonance strength experiences significant changes in the regions of interference peaks. The beam polarization depends on the field ramp rate of the arc magnets. Its component along the spin field is preserved if acceleration is adiabatic. We present the results of our theoretical analysis and numerical modeling of the spin dynamics during acceleration of protons and deuterons in the JLEIC ion collider ring. We demonstrate high stabil-ity of the deuteron polarization in figure-8 accelerators. We analyze a change in the beam polarization when crossing the transition energy.
SLAC, Menlo Park, California, USA
JLab, Newport News, Virginia, USA
Self Employment, Private address, USA
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.
JLab, Newport News, Virginia, USA
DESY, Hamburg, Germany
The design of an electron polarization scheme in the Jefferson Lab Electron-Ion Collider (JLEIC) aims to attain a high longitudinal electron polarization (over 70%) at collision points as required by the nuclear physics program. Comprehensive strategies for achieving this goal have been considered and developed including injection of highly polarized electrons from CEBAF, mechanisms for manipulation and preservation of the polarization in the JLEIC collider ring and measurement of the electron polarization. In particular, maintaining a sufficiently long polarization lifetime is crucial for accumulation of adequate experimental statistics. The chosen electron polarization configuration, based on the unique figure-8 geometry of the ring, removes the electron spin-tune energy dependence. This significantly simplifies the control of the electron polarization and suppresses the synchrotron sideband resonances. This paper reports recent studies and simulations of the electron polarization dynamics in the JLEIC electron collider ring.
JLab, Newport News, Virginia, USA
SLAC, Menlo Park, California, USA
Self Employment, Private address, USA
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-2ses−1, small beta-star are necessary at the IP, which also means large beta 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.
ODU, Norfolk, Virginia, USA
ODU CS, Norfolk, Virginia, USA
JLab, Newport News, Virginia, USA
Future machines such as the electron-ion colliders (JLEIC), linac-ring machines (eRHIC) or LHeC are particularly sensitive to beam-beam effects. This is the limiting factor for long-term stability and high luminosity reach. The complexity of the non-linear dynamics makes it challenging to perform such simulations which require millions of turns. Until recently, most of the methods used linear approximations and/or tracking for a limited number of turns. We have developed a framework which exploits a massively parallel Graphical Processing Units (GPU) architecture to allow for tracking millions of turns in a sympletic way up to an arbitrary order and colliding them at each turn. The code is called GHOST for GPU-accelerated High-Order Symplectic Tracking. As of now, there is no other code in existence that can accurately model the single-particle non-linear dynamics and the beam-beam effect at the same time for a large enough number of turns required to verify the long-term stability of a collider. Our approach relies on a matrix-based arbitrary-order symplectic particle tracking for beam transport and the Bassetti-Erskine approximation for the beam-beam interaction.