Collimation system baseline design for the electron storage ring at the Electron-Ion Collider
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73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Engineering topics
Hetzel, Charles
Publications and source records attributed to Hetzel, Charles.
Simulation and measurement of beam-induced heating of ceramic vacuum chambers
In this article, we summarize recent theoretical and experimental studies of the impedance and beam-induced heating of titanium-coated ceramic vacuum chambers used in the NSLS-II injection kickers. The impedance was calculated using the field matching theory assuming planar approximation and compared with the mpedanceake2 code. For the coating thickness of a few microns, we demonstrated that the beam-induced power is dissipated in the titanium coating and that the longitudinally averaged two-dimensional power density is approximated by an analytical expression, thus allowing the use of a simplified model of the power density as input for the code to simulate the temperature distribution with realistic nonuniform thickness of the Ti coating. For a few values of the NSLS-II beam current, we measured the beam-induced heating of two ceramic chambers using thermal sensors installed along the chamber and compared the measurement results with the simulations. Published by the American Physical Society 2024
36 MATERIALS SCIENCE↗
The EIC accelerator: design highlights and project status
The design of the electron-ion collider (EIC) at Brookhaven National Laboratory is well underway, aiming at a peak electron-proton luminosity of 10e+34 cm^-1·sec^-1. This high luminosity, the wide center-of-mass energy range from 29 to 141 GeV (e-p) and the high level of polarization require innovative solutions to maximize the performance of the machine, which makes the EIC one of the most challenging accelerator projects to date. The complexity of the EIC will be discussed, and the project status and plans will be presented.
43 PARTICLE ACCELERATORS↗
Progress on the design of the interaction region of the Electron-Ion Collider EIC
We present an update on the design of the Interaction Region (IR) for the the Electron Ion Collider (EIC) being built at Brookhaven National Laboratory (BNL). The EIC will collide high energy and highly polarized hadron and electron beams with a center of mass energy up to 140 GeV with luminosities of up to 10^34 /cm^2/s. The IR, located at RHIC's IR6, is designed to meet the requirements of the nuclear physics community as outlined in [1]. A second IR is technically feasible but not part of the project.The magnet apertures are sufficiently large to allow desired collision products to reach the far-forward detectors; the electron magnet apertures in the rear direction are chosen to be large enough to pass the synchrotron radiation fan. In the forward direction the electron apertures are large enough for non-Gaussian tails.The paper discusses a number of recent recent changes to the design. The machine free region was recently increased from 9 to 9.5 m to allow for more space in the forward direction for the detector. The superconducting magnets on the forward side now operate at 1.9 K, which helps crosstalk and space issues.
43 PARTICLE ACCELERATORS↗
Design Status of the Electron-Ion Collider
The Electron-Ion Collider is gearing up for "Critical Decision 2", theproject baseline with defined scope, cost and schedule.Lattice designs are beingfinalized, and preliminary component design is being carried out. Beam dynamicsstudies such as dynamic aperture optimization, instability and polarizationstudies, and beam-beam simulations are continuing in parallel. We report onthe latest developments and the overall status of the project, and presentthe plans for future activities.
43 PARTICLE ACCELERATORS↗
eRHIC Electron Ring Design Status
For the proposed electron-ion collider eRHIC, an electron storage ring will be installed in the existing RHIC tunnel. To reach the high luminosity of up to 10³⁴ cm⁻² sec⁻¹, beam currents up to 2.5A have to be stored. Besides high luminosity the physics program requires spin polarization levels of 70 percent, with both spin "up" and spin "down" orientations present in the fill. This is only feasible by using a full-energy spin polarized injector that replaces bunches faster than the depolarization rate. To limit the repetition rate of that injector to about one hertz, the polarization lifetime in the storage ring has to be maximized by proper spin matching and countermeasures for the machine misalignments. We will give an overview of the electron storage ring design.
43 PARTICLE ACCELERATORS↗
Vacuum sealing flange
Flange technologies are described for a flange comprising a first and second side. Each side may include a knife edge surface disposed circumferentially around a base surface and a periphery section disposed around the knife edge surface. The knife edge surface and the periphery section are effective to define grooves therebetween. The flange may include an alloy with a relatively high thermal conductivity and yield strength. The flange may include water channels to remove heat.
Sharma, Sushil Kumar↗
Beam-induced power in HEX SCW
A superconducting wiggler (SCW) is planned to be installed in NSLS-II for HEX beamline. Interaction of the electron beam with the resistive-wall impedance of the low-gap SCW liner and with the geometric impedance of the transition sections results in excitation of electromagnetic fields, dissipation of which contributes heat load in the cold volume. The beam-induced power caused by the beam-impedance interaction is estimated using analytical formulae and computer simulations.
36 MATERIALS SCIENCE↗
Re-Evaluation of Active Interlock Envelopes Considering Insertion Device Correction Coils
The Active Interlock (AI) is a system that ensures that the beam position and angle through the NSLS-II storage ring is located so that the machine apertures that may be struck by synchrotron radiation are not exposed to high power beam which may compromise them. Of particular importance in the NSLS-II is to maintain the beam position and angle within the insertion device (ID) straights where insertions devices make high power x-ray beams for users which may compromise the storage ring vacuum chamber. The beam position and angle in the center of the insertion device is calculated using a pair of beam position monitors (BPMs) on either side of the device. The safe area of positions and angles within the insertion device is called the AI envelope. If there is a magnetic element between the BPMs, it needs to be accounted for in the calculation of the beam position and angle. In addition to the permanent magnet arrays that comprise the insertion device itself, there are correction coils that are used to correct any orbit distortions that are generated by imperfections in the device. It has recently come to our attention that these coils are not considered in the AI calculations, nor are the currents in these coils read by the AI. As it may be possible in theory for these coils to produce angles large enough that the synchrotron radiation beam may damage components, we analyzed the possibility for all ID types and configurations. In this report we show what changes are necessary for the AI envelope, and limits placed upon the correction coils to maintain operation of the storage ring without compromising protection.
36 MATERIALS SCIENCE↗