BNL, Upton, Long Island, New York, USA
Fermilab, Batavia, Illinois, USA
FRIB, East Lansing, Michigan, USA
The Electron-Ion Collider (EIC) is being envisioned as the next facility to be constructed by the DOE Nuclear Physics program. Brookhaven National Laboratory is proposing eRHIC, a facility based on the existing RHIC complex as a cost effective realization of the EIC project with a peak luminosity of 1034 cm-2 sec-1. An electron storage ring with an energy range from 5 to 18 GeV will be added in the existing RHIC tunnel. A spin-transparent rapid-cycling synchrotron (RCS) will serve as a full-energy polarized electron injector. Recent design improvements include reduction of the IR magnet strengths to avoid the necessity for Nb3Sn magnets, and a novel hadron injection scheme to maximize the integrated luminosity. We will provide an overview of this proposed project and present the current design status.
BNL, Upton, Long Island, New York, USA
RadiaSoft LLC, Boulder, Colorado, USA
Best Medical International, Springfield, USA
Everson Tesla Inc., Nazareth, Pennsylvania, USA
The ion Rapid Cycle Medical Synchrotron (iRCMS) * will provide proton and C ion bunches with maximum energy 270 MeV and 450 MeV/u respectively at a frequency of 15 Hz for treating cancerous tumors. One of the six cells of the iRCMS has been designed, built and magnetic field measurements have been performed. We will present results from the static and AC electromagnetic study of the iRCMS cell and compare the measured magnetic fields with those calculated using the OPERA computer code **. In addition the beam optics of the cell will be calculated based on the experimental fields using the zgoubi computer code *** and compared with the designed beam optics.
* D. Trbojevic, iRCMS Magnet Review, BNL, Sept. 6, 2012 (unpublished)
** OPERA computer code https://operafea.com/
*** The zgoubi computer code https://www.bnl.gov/isd/documents/79375.pdf
BNL, Upton, Long Island, New York, USA
In the coming RHIC low energy scan, the electron cooling technique is to be used to cool the ions 197Au79+ with its energy range between 3.85~GeV/nucleon to 5.75~GeV/nucleon. To overlap the electron beam and the 197Au79+ beam at the cooling section, a recombination monitor is to be used to detect the maximum flux of 197Au78+ ions generated in the cooling section. In the previous studies, we tracked 197Au78+ ions through the RHIC lattice defined with 197Au79+ with an equivalent momentum deviation. In the article, we explode different symplectic ways to track 197Au78+ ions exactly. We calculate and compare the trajectories and loss map of 197Au78+ ions through the RHIC ring.
BNL, Upton, Long Island, New York, USA
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
Douglas Consulting, York, Virginia, USA
SLAC, Menlo Park, California, USA
We are successfully commissioning a unique Cornell University and Brookhaven National Laboratory Electron Recovery Linac (ERL) Test Accelerator ’CBETA’ [1]. The ERL has four accelerating passes through the supercon-ducting linac with a single Fixed Field Alternating Linear Gradient (FFA-LG) return beam line built of the Halbach type permanent magnets. CBETA ERL accelerates elec-trons from 42 MeV to 150 MeV, with the 6 MeV injec-tor. The novelties are that four electron beams, with ener-gies of 42, 78, 114, and 150 MeV, are merged by spreader beam lines into a single arc FFA-LG beam line. The elec-tron beams from the Main Linac Cryomodule (MLC) pass through the FFA-LG arc and are adiabatically merged into a single straight line. From the straight section the beams are brought back to the MLC the same way. This is the first 4 pass superconducting ERL and the first single permanent magnet return line.
BNL, Upton, Long Island, New York, USA
Spin flipper experiments during RHIC Run 17 have demonstrated the 97% effectiveness of polarization sign reversal during stores. Zgoubi numerical simulations were setup to reproduce the experimental conditions. A very good agreement between the experimental measurements and simulation results was achieved at 23.8GeV, thus the simulations are being used to help optimize the various Spin Flipper parameters. The ultimate goal for these simulations is to serve as guidance towards a perfect flip at high energies to allow a routine Spin Flipper use during physics runs.
BNL, Upton, Long Island, New York, USA
An ac dipole will be used for the efficient transport of polarized 3He in the AGS Booster as it is accelerated to |Gγ|=10.5. The ac dipole introduces a coherent vertical beam oscillation which allows preservation of polarization through the two intrinsic resonances Gγ=12-νy and Gγ=6+νy resonances, by full spin flipping. The AGS Booster ac dipole will be tested with protons crossing the Gγ=0+νy intrinsic resonance, which has ac dipole requirements similar to polarized 3He crossing the Gγ=12-νy resonance, providing a convenient proof of principle. This paper gives a status of the project.
BNL, Upton, Long Island, New York, USA
An ac dipole system is installed in the AGS Booster in view of acceleration of polarized helion for RHIC and the eRHIC EIC. The amplitude of the vertical coherent oscillations induced by the ac dipole depends greatly on the resonance proximity parameter, δm, which is the distance between resonance tune and driving tune. Due to the non-zero momentum spread, particles with different momenta will have different value of δm. The rapid acceleration rate of the booster would cause δm to sweep, the amount of which would depend on the energy and the duration of the ac dipole cycle. These effects are simulated using zgoubi, which set a range of δm values suitable for both high spin flip efficiency and minimizing emittance growth, and the results of the simulations are discussed.
BNL, Upton, Long Island, New York, USA
The future eRHIC collider * will collide 5, 10, and 18 GeV polarized electrons with 250 GeV polarized protons, 210 GeV/u polarized 3He ions and other heavy ion species which are already produced by the RHIC accelerator. To increase the luminosity during collisions the number of circulating hadron bunches will increase to 330 and this requires a modification of the injection hadrons into the RHIC accelerator. This paper describes this injection scheme which is compatible with a design option which uses two hadron rings, one ring for accelerating the hadron beam and the other ring for storing the circulating beam to increase even further the integrated luminosity of the electron-hadron collisions. This two-hadron-rings option will be presented in the conference.
tsoupas@bnl.gov
* ICFA BD Newsletter No. 74 http://icfa-bd.kek.jp/
JLab, Newport News, Virginia, USA
BNL, Upton, Long Island, New York, USA
MIPT, Dolgoprudniy, Moscow Region, Russia
ODU, Norfolk, Virginia, USA
Science and Technique Laboratory Zaryad, Novosibirsk, Russia
High electron and ion polarizations are some of the key design requirements of a future Electron Ion Collider (EIC). The transparent spin mode, a concept inspired by the figure 8 ring design of JLEIC, is a novel technique for preservation and control of electron and ion spin polarizations in a collider or storage ring. 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 the beam’s orbital characteristics. It offers unique opportunities for polarization maintenance and control in Jefferson Lab’s JLEIC and in BNL’s eRHIC. The transparent spin mode has been demonstrated in simulations and we now plan to test it experimentally. We present a design of an experiment using a polarized proton beam stored in one of the RHIC rings. In the experiment, one of the RHIC rings is configured in the transparent spin mode by aligning the axes of its two Siberian snakes. The experiment goals, procedures, hardware requirements and expected results are presented.
JLab, Newport News, Virginia, USA
BNL, Upton, Long Island, New York, USA
MIPT, Dolgoprudniy, Moscow Region, Russia
ODU, Norfolk, Virginia, USA
Science and Technique Laboratory Zaryad, Novosibirsk, Russia
In the Spin Transparency (ST) mode of RHIC, the axes of its Siberian snakes are parallel. The spin tune in the ST mode is zero and the spin motion becomes degenerate: any spin direction repeats every particle turn. In contrast, the lattice of a conventional collider determines a unique stable periodic spin direction, so that the collider operates in the Preferred Spin (PS) mode. Contributions of perturbing magnetic fields to the spin resonance strengths in the PS mode are usually calculated using the spin response function. However, in that form, it is not applicable in the ST mode. This paper presents a response function formalism expanded for the ST mode of operation of conventional colliders with two identical Siberian snakes in the highly-relativistic limit. We present calculations of the spin response function for RHIC in the ST mode.
RadiaSoft LLC, Boulder, Colorado, USA
ParaTools, Inc., Eugene, Oregon, USA
BNL, Upton, Long Island, New York, USA
Sourcery Institute, Oakland, California, USA
The particle tracking code Zgoubi * has been used for a broad array of accelerator design studies, including FFAGs and EICs. Zgoubi is currently being used to evaluate the spin polarization performance of proposed designs for both JLEIC ** and eRHIC ***, and to prepare for commissioning the CBETA BNL-Cornell FFAG return loop ERL ****. We describe our on-going work on several fronts, including efforts to parallelize Zgoubi using new features of Fortran 2018 *****, and a new implementation of Zgoubi’s particle update algorithm. We also describe a new, web-based graphical interface for Zgoubi.
* F. Méot, FERMILAB-TM-2010, 1997
** J. Martinez-Marin et al., IPAC18, MOPMF004
*** V.H. Ranjbar et al., IPAC18, MOPMF016
**** F. Méot et al., NIM-A 896:60, 2018
***** wg5-fortran.org/f2018.html
BNL, Upton, Long Island, New York, USA
Best Medical International, Springfield, USA
The Brookhaven National Laboratory continues to provide technical support and guidance to Best Medical International to build and test a 60 degree magnetic arc of a rapid-cycling ion synchrotron for cancer treatment. The 60 degree magnetic sector on its guirder has undergone field measurements, including the production of partial 3D field maps. Concurrently, OPERA field map computations as well as lattice and beam dynamics simulations have been performed, aimed at both preparing and analyzing the field measurements. Contingency responses aimed at adapting to non-ideal orbit and optics have been devised. These works and their outcomes are summarized here.