Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “electronics cooling”

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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

EXPERIMENTS ON ELECTRON COOLING AND INTENSE SPACE-CHARGE AT IOTA

The Integrable Optics Test Accelerator at Fermilab will explore beam dynamics in a ring with intense space-charge using 2.5 MeV proton beams with an incoherent tune shift approaching -0.5. We will use this machine to explore the interplay between electron cooling, intense space-charge, and coherent instabilities. In this contribution, we describe the machine setup including the design of the electron cooler and the lattice, list specific experiments and discuss the results of numerical simulations which include the effects of electron cooling and transverse space-charge forces.

Banerjee, N.↗
DOE OSTI2023

Experiments On Electron Cooling and Intense Space-charge at IOTA

The Integrable Optics Test Accelerator at Fermilab will explore beam dynamics in a ring with intense space-charge using 2.5 MeV proton beams with an incoherent tune shift approaching -0.5. We will use this machine to explore the interplay between electron cooling, intense space-charge, and coherent instabilities. In this contribution, we describe the machine setup including the design of the electron cooler and the lattice, list specific experiments and discuss the results of numerical simulations which include the effects of electron cooling and transverse space-charge forces.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

Competing Channels for Hot-Electron Cooling in Graphene

We report here on temperature-dependent photocurrent measurements of high-quality dual-gated monolayer graphene p - n junction devices. A photothermoelectric effect governs the photocurrent response in our devices, allowing us to track the hot-electron temperature and probe hot-electron cooling channels over a wide temperature range (4 to 300 K). At high temperatures ( T > T * ), we found that both the peak photocurrent and the hot spot size decreased with temperature, while at low temperatures ( T < T * ), we found the opposite, namely that the peak photocurrent and the hot spot size increased with temperature. This nonmonotonic temperature dependence can be understood as resulting from the competition between two hot-electron cooling pathways: (a) (intrinsic) momentum-conserving normal collisions that dominates at low temperatures and (b) (extrinsic) disorder-assisted supercollisions that dominates at high temperatures. Gate control in our high-quality samples allows us to resolve the two processes in the same device for the first time. The peak temperature T * depends on carrier density and disorder concentration, thus allowing for an unprecedented way of controlling graphene’s photoresponse.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Simulations of coherent electron cooling with two types of amplifiers

The SPACE code is a parallel, relativistic, three-dimensional, electromagnetic, particle-in-cell code developed for the simulations of beam dynamics and interactions. The SPACE code can perform simulations with various beam distributions, different types of boundary conditions, and flexible beam line, as well as provide sufficient processing routines for data analyses and visualization. Finally, self-consistent, highly resolved and realistic simulations were performed using the SPACE code to study the coherent electron cooling (CeC) experiment with two types of amplifiers, the free electron laser (FEL) and plasma-cascade micro-bunching amplifiers.

43 PARTICLE ACCELERATORS↗
DOE OSTI2019

Dispersion and electron cooling

It is known [1] that dispersion can be used to redistribute the electron cooling force. This note presents a simple model explaining why. Some addition details relevant to implementing a more detailed analysis are included.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Observation of dynamics of impurity photoconductivity in n-GaAs caused by electron cooling

Experimental investigation of the time dependence of impurity photoconductivity in n-GaAs is carried out upon pulsed optical excitation. It is shown that a change in the photoconductivity is determined mainly by electron cooling in the first 20 ns after photoexcitation. A theoretical model for describing the dependences under observation is proposed.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Electron Cooling With Space-Charge Dominated Proton Beams at IOTA

We describe a new electron cooler being developed for 2.5 MeV protons at the Integrable Optics Test Accelerator (IOTA), which is a highly re-configurable storage ring at Fermilab. This system would enable the study of magnetized electron cooling in the presence of intense space-charge with transverse tune shifts approaching -0.5 as well as highly non-linear focusing optics in the IOTA ring. We present an overview of the design, simulations and hardware to be used for this project.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Automotive Power Electronics Cooling Technology Research at NREL

This presentation describes power electronics thermal management technologies used for on-road EVs. Examples are provided and heat exchangers are described. Advanced cooling technologies developed are NREL to enable increased power density and enable high WBG temperature operation are then presented. The performance (e.g., thermal resistance, pumping power) of the advanced power electronics cooling technologies are compared to the performance of current, on-road technology.

ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2023

Power Electronics Cooling Technology Research at NREL

This presentation describes power electronics thermal management technologies used for on-road EVs. Examples are provided and heat exchangers are described. Advanced cooling technologies developed are NREL to enable increased power density and enable high WBG temperature operation are then presented. The performance (e.g., thermal resistance, pumping power) of the advanced power electronics cooling technologies are compared to the performance of current, on-road technology.

DIRECT ENERGY CONVERSION↗
DOE OSTI2019

The Effect of Nanofluids on the Heat-Transfer Capacity of Miniature Thermosyphons for Electronics Cooling

Stable nanofluids based on DG-100 grade carbon black and carbon nanotubes have been prepared, and their influence on the maximum heat-transfer capacity and thermal resistance of closed-loop two-phase thermosyphons (TPTs) intended for electronics cooling have been studied. A more than twofold increase in the critical heat flux of these TPTs as compared to those filled with water has been obtained along with a sharp decrease in their thermal resistance. It is suggested that this effect is not only due to the high thermal conductivity of the proposed nanofluids, but is also related to the formation of a specific porous structure hindering the appearance of a vapor film and enhancing the boiling process.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2015

Electron cooling and finite potential drop in a magnetized plasma expansion

The steady, collisionless, slender flow of a magnetized plasma into a surrounding vacuum is considered. The ion component is modeled as mono-energetic, while electrons are assumed Maxwellian upstream. The magnetic field has a convergent-divergent geometry, and attention is restricted to its paraxial region, so that 2D and drift effects are ignored. By using the conservation of energy and magnetic moment of particles and the quasi-neutrality condition, the ambipolar electric field and the distribution functions of both species are calculated self-consistently, paying attention to the existence of effective potential barriers associated to magnetic mirroring. The solution is used to find the total potential drop for a set of upstream conditions, plus the axial evolution of various moments of interest (density, temperatures, and heat fluxes). The results illuminate the behavior of magnetic nozzles, plasma jets, and other configurations of interest, showing, in particular, in the divergent plasma the collisionless cooling of electrons, and the generation of collisionless electron heat fluxes.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗