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At least 19 records

Micro-aligned 1 Tesla Solenoid for High-energy Bunched-beam Electron Cooling

Electron cooling of ion beams requires precise alignment of the electron beam with the equilibrium trajectory of the ion bunch. In magnetized cooling the cooling rate is enhanced by transverse confinement of each electron on a magnetic line of force. The magnetic lines of force must therefore be aligned with the ion bunch trajectory everywhere along the extent of the solenoid. For the parameters required for JLEIC, a solenoid with bore field ~1 T, length ~30 m, and rms alignment of ~micro-radian is required. Such alignment has never been accomplished. The design of a micro-aligned solenoid is presented. A gap-separated stack of thin steel washers is located along the bore of the solenoid. The flux plate stack shields transverse magnetic fields from the interior, so that axial alignment is enhanced by a factor of ~10.

43 PARTICLE ACCELERATORS↗

Studies of Conventional and ERL-Based Re-Circulator Electron Cooling for an Electron Ion Collider (Final Report)

The envisioned Electron Ion Collider will be comprised of a chain of accelerators, each employing electron cooling. Depending on the purpose, each accelerator will employ some form of electron cooling: conventional DC type, Energy Recovering Linac-based recirculator, or coherent electron cooling. Each electron cooling type has its own peculiarities that need to be studied, understood, and their performance optimized to maximize luminosity; these are the subjects of this project. In particular, we developed the first microscopic electron cooling modeling and simulation framework that was also benchmarked against experiment. We proved for the first time the feasibility of first principle, accurate and efficient electron cooling simulations with a minimal number of assumptions and approximations that match empirical studies.

43 PARTICLE ACCELERATORS↗

Generation of High-Charge Magnetized Electron Beams Consistent With JLEIC Electron Cooling Requirements

The proposed Jefferson Lab Electron-Ion Collider (JLEIC), currently under design, relies on electron cooling in order to achieve the desired luminosity. This includes an electron beam with >55 Mev, 3.2 nC bunches that cools hadron beams with energies up to 100 GeV. To enhance the cooling, the electron beam must be magnetized with a specific eigen-emittance partition. This paper explores the use of the Fermilab Accelerator Science and Technology (FAST) facility to demonstrate the generation of an electron beam with parameters consistent with those required in the JLEIC high-energy cooler. We demonstrate via simulations the generation of the required electron-beam parameters and perform a preliminary experiment to validate FAST capabilities to produce such beams.

43 PARTICLE ACCELERATORS↗

Three-dimensional analysis of microbunched electron cooling

Microbunched electron cooling (MBEC, Ratner, ), a special category of coherent electron cooling, has been under consideration as a candidate method for the strong hadron cooling component of the Electron Ion Collider (EIC) at BNL. Most of the theoretical treatments of this scheme so far have been based on simplified models for the key space charge effect in which electrons and/or hadrons are approximated by charged disks. Although such disk-based models provide a flexible tool that captures a good part of the underlying physics, they lack the fidelity and robustness of a rigorous analysis that explicitly treats the hadron and cooler electron beams as collections of point charges. In this paper, we present such a rigorous, three-dimensional (3D) model, both from a theory-based and a simulation perspective. Specifically, we calculate the generalized wakefield (or Green’s function) of the cooling system—a crucial quantity that determines the overall performance—paying special attention to the dependence of the wake on the hadron transverse positions. Additionally, our treatment takes into account previously neglected 3D effects that can cause damping of the plasma oscillations in the amplification section of the cooler, such as focusing and the angular spread of the electron beam. Published by the American Physical Society 2025

43 PARTICLE ACCELERATORS↗

Photoinjector generation of high-charge magnetized beams for electron-cooling applications

Electron cooling offers a relatively simple scheme to enable high-luminosity collisions in future electron–ion and hadron colliders. Contemplated TeV-energy hadron colliders require relativistic (sub 100 MeV) high-charge [] electron beams with a specific transverse eigenemittance partition. This paper discusses the generation of high-charge ( nC) 40 MeV electron bunches with eigenemittance partition consistent with requirements associated with electron-cooling option for future electron–ion colliders. The supporting experiment was performed at the FAST facility at Fermilab. The data are compared with numerical simulations and the results discussed in the context of beam requirement for future electron–ion colliders.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Electron diffusion in microbunched electron cooling

Coherent electron cooling is a novel method to cool dense hadron beams on timescales of a few hours. This method uses a copropagating beam of electrons to pick up the density fluctuations within the hadron beam in one straight section and then provides corrective energy kicks to the hadrons in a downstream straight, cooling the beam. Microbunched electron cooling is an extension of this idea, which induces a microbunching instability in the electron beam as it travels between the two straights, amplifying the signal. However, initial noise in the electron bunch will also be amplified, providing random kicks to the hadrons downstream which tend to increase their emittance. In this paper, we develop an analytic estimate of the effect of the electron noise and benchmark it against simulations. We also discuss how this effect has impacted the cooler design. Published by the American Physical Society 2024

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Numerical and Experimental Study of a Novel Additively Manufactured Metal-Polymer Composite Heat-Exchanger for Liquid Cooling Electronics

In order to meet increasing power-dissipation requirements of the electronics industry, compact, low-cost, and lightweight heat exchangers (HXs) are desired. With proper design, materials, and manufacture, polymer composite heat exchangers could meet these requirements. This paper presents a novel crossflow air-to-water, low-cost, and lightweight metal-polymer composite HX. This HX, which is entirely additively manufactured, utilizes a novel cross-media approach that provides direct heat exchange between air and liquid sides by using connecting fins. A robust numerical model was developed, which includes the dimensional effects of additive manufacturing. The study consists of a simplified 3D CFD model based on ellipsoidal-shaped staggered tube banks for the laminar range. It then uses an analytical approach to compute entire HX performance. The model is validated experimentally within 8% for thermal performance, 12% for air-side impedance, and 18% for water-side impedance. Finally, HX is compared with a conventional CPU radiator and performs within 10% of the conventional unit for reasonable flow rates and pressure-drop ranges. Moreover, HX also provides added design and cost advantages over the conventional unit, which makes the HX a potential candidate for electronic cooling applications.

30 DIRECT ENERGY CONVERSION↗

Photoinjector Generation of High-Charge Magnetized Beams for Electron-Cooling Applications

Electron-cooling offers a relatively simple scheme to enable high-luminosity collisions in future electron-ion and hadron colliders. Contemplated TeV-energy hadron colliders require relativistic (sub 100 MeV) high-charge [${\cal O}(\mbox{nC})$] electron beams with a specific transverse eigenemittance partition. This paper discusses the generation of high-charge ($Q\le 3.2$~nC) 40 MeV electron bunches with eigenemittance partition consistent with requirements associated with electron-cooling option for future electron-ion colliders. The supporting experiment was performed at the FAST facility at FermiLab. The data are compared with numerical simulations and the results discussed in the context of beam requirement for future electron-ion colliders.

43 PARTICLE ACCELERATORS↗

Development of an ERL for Coherent Electron Cooling at the Electron-Ion Collider

The Electron-Ion Collider (EIC) is currently under development of to be built at Brookhaven National Lab and requires cooling during collisions in order to preserve the quality of the hadron beam despite degradation due to intra-beam scattering and beam-beam effect. An Energy Recovery Linac (ERL) is being designed to deliver the necessary electron beam for the Coherent electron Cooling (CeC) of the hadron beam, with an electron bunch charge of 1 nC and an average current of 100 mA; two modes of operation are being developed for 150 and 55 MeV electrons, corresponding to 275 and 100 GeV protons. The injector of this SHC-ERL is shared with the Precooler ERL, which cools lower energy proton beams via bunched-beam cooling, as used in Low Energy RHIC electron Cooling (LEReC). This paper reviews the current state of the design.

Accelerator Physics↗

Development of an ERL for Coherent Electron Cooling at the Electron-Ion Collider

The Electron-Ion Collider (EIC) is currently under development to be built at Brookhaven National Lab and requires cooling during collisions in order to mitigate the hadron beam emittance degradation due to intra-beam scattering and beam-beam effects. An Energy Recovery Linac (ERL) is being designed to deliver the necessary electron beam for Coherent electron Cooling (CeC) of the hadron beam, with an electron bunch charge of 1 nC and an average current of 100 mA; two modes of operation are being developed for 150 and 55 MeV electrons, corresponding to 275 and 100 GeV protons. The injector of this Strong Hadron Cooler ERL (SHC-ERL) is shared with the Pre-cooler ERL, which cools lower energy proton beams via bunched beam cooling, as used in the Low Energy RHIC electron Cooling (LEReC). This paper reviews the current state of the design.

Deitrick, K.↗

High Energy ERLs for Electron Cooling

Future electron-ion colliders such as the recently approved eRHIC collide high-intensity ion beams with high current electron beams. The electron beams take advantage of synchrotron radiation to damp emittances but the ion beams must be cooled via some beam-cooling mechanism, including electron cooling. The ion energies are typically a few hundreds of GeV per nucleon. At this energy, a DC cooler powered by an electrostatic accelerator, the preferred cooling approach on existing machines, is not feasible. An ERL, in principle, can provide the high current and brightness to cool these high-brightness ion beams. The beam quality requirements are much different from previous ERLs designs used for FELs. The cooling bunch must be very long to match the ion beam and the relative energy spread must be very small. Incoherent cooling can be enhanced with magnetized beams, but the magnetization must be maintained throughout the ERL. An alternate cooling mechanism, the so-called Coherent Electron Cooling, is, in principle, stronger and can be done with non-magnetized beams. We will present two applications of an ERL to high energy electron cooling and describe some of the technical challenges that must be overcome to operate such an ERL

Benson, Stephen↗

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↗

Modular jet impingement assemblies with passive and active flow control for electronics cooling

Power electronics modules having modular jet impingement assembly utilized to cool heat generating devices are disclosed. The modular jet impingement assemblies include a modular manifold having a distribution recess, one or more angled inlet connection tubes positioned at an inlet end of the modular manifold that fluidly couple the inlet tube to the distribution recess and one or more outlet connection tubes positioned at an outlet end of the modular manifold that fluidly coupling the outlet tube to the distribution recess. The modular jet impingement assemblies include a manifold insert removably positioned within the distribution recess and include one or more inlet branch channels each including an impinging slot and one or more outlet branch channels each including a collecting slot. Further a heat transfer plate coupled to the modular manifold, the heat transfer plate comprising an impingement surface including an array of fins that extend toward the manifold insert.

42 ENGINEERING↗

Cooling and diffusion rates in coherent electron cooling concepts

We present analytic cooling and diffusion rates for a simplified model of coherent electron cooling (CEC), based on a proton energy kick at each turn. This model also allows to estimate analytically the rms value of electron beam density fluctuations in the "kicker" section. Having such analytic expressions should allow for better understanding of the CEC mechanism, and for a quicker analysis and optimization of main system parameters. Our analysis is applicable to any CEC amplification mechanism, as long as the wake (kick) function is available.

43 PARTICLE ACCELERATORS↗

Development of the electron cooling simulation program for JLEIC

In the JLab Electron Ion Collider (JLEIC) project the traditional electron cooling technique is used to reduce the ion beam emittance at the booster ring, and to compensate the intrabeam scattering effect and maintain the ion beam emittance during collision at the collider ring. A new electron cooling process simulation program has been developed to fulfill the requirements of the JLEIC electron cooler design. The new program allows the users to calculate the electron cooling rate and simulate the cooling process with either DC or bunched electron beam to cool either coasting or bunched ion beam. It has been benchmarked with BETACOOL in aspect of accuracy and efficiency. In typical electron cooling process of JLEIC, the two programs agree very well and we have seen a significant improvement of computational speed using the new one. Being adaptive to the modern multicore hardware makes it possible to further enhance the efficiency for computationally intensive problems. The new program is being actively used in the electron cooling study and cooler design for JLEIC. We will present our models and some simulation results in this paper.

Zhang, He↗