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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.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

First demonstration of a cryocooler conduction cooled superconducting radiofrequency cavity operating at practical cw accelerating gradients

Abstract We demonstrate practical accelerating gradients on a superconducting radiofrequency (SRF) accelerator cavity with cryocooler conduction cooling, a cooling technique that does not involve the complexities of the conventional liquid helium bath. A design is first presented that enables conduction cooling an elliptical-cell SRF cavity. Implementing this design, a single cell 650 MHz Nb 3 Sn cavity coupled using high purity aluminum thermal links to a 4 K pulse tube cryocooler generated accelerating gradients up to 6.6 MV m −1 at 100% duty cycle. The experiments were carried out with the cavity-cryocooler assembly in a simple vacuum vessel, completely free of circulating liquid cryogens. We anticipate that this cryocooling technique will make the SRF technology accessible to interested accelerator researchers who lack access to full-stack helium cryogenic systems. Furthermore, the technique can lead to SRF based compact sources of high average power electron beams for environmental protection and industrial applications. A concept of such an SRF compact accelerator is presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Development of a cryocooler conduction-cooled 650 MHz SRF cavity operating at ~10 MV/m cw accelerating gradient

SRF cavities for particle acceleration are conventionally operated immersed in a bath of liquid helium at 4.2 K and below. Although this cooling configuration is practically and economically viable for large scientific accelerator installations, it may not be so for smaller accelerators intended for industrial applications such as the treatment of wastewater, sludge, flue gases, etc. In this paper, we describe a procedure to operate SRF cavities without liquid helium that can be used to construct electron-beam sources for industrial applications of electron irradiation (1-10 MeV electron energy). In this procedure, an elliptical single-cell 650 MHz niobium-tin coated niobium cavity is coupled to a closed-cycle 4.2 K cryocooler using high purity aluminum thermal links. The cryocooler conductively extracts heat (RF dissipation) from the cavity without requiring liquid helium around the cavity. We present construction details of this cryocooler conduction-cooling technique and systematic experiments that have demonstrated ~10 MV/m cw gradient on the cavity. By straightforward scaling up the cavity length and number of cryocoolers, the technique will provide the complete range of 1-10 MeV electron energy for industrial applications.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Modeling the cooldown of cryocooler conduction-cooled devices

Cryocooler conduction cooled devices can experience significant cooldown time due to lower available cooling capacity compares to convection cooled devices. Therefore, the cooldown time is an important design parameter for conduction cooled devices. This article introduces a framework developed in Python for calculating the cooldown profiles and cooldown time of cryocooler conduction-cooled devices such as superconducting magnets and accelerator cavities. The cooldown time estimation problem is essentially a system of ordinary first-order differential equations comprising the material properties (temperature dependent thermal conductivity and specific heat capacity) of the components intertwined with the prevailing heat transfer channels (conduction, radiation, and heat flow across pressed contacts) and the cryocooler capacity. The formulation of this ODE system is first presented. This ODE system is then solved using the in-built Python library odeint. A case study is presented comprising a small cryocooler conduction-cooled copper stabilized niobium-titanium magnet. The case study is supplemented with the Python script enabling the reader to simply tweak the device design parameters and optimize the design from the point of view of slow/fast cooldown.

43 PARTICLE ACCELERATORS↗
DOE OSTI2025

Cooling Design and Thermal Analysis for Thermal Shields of a Cryocooler-Cooled Superconducting ECR Ion Source MARS-D Magnet

Here, a demonstrative NbTi based Mixed Axial and Radial field System (MARS-D) is being developed for a next-Generation Electron Cyclotron Resonance Ion Source (ECRIS) at Lawrence Berkeley National Laboratory (LBL), which employs a novel closed-loop coil design scheme that more efficiently utilizes conductor fields and extend the application of NbTi for high frequency (up to 45 GHz) ECR operation. The NbTi MARS-D magnet consists of a single hexagonally shaped closed-loop coil and a set of auxiliary solenoids. A cryostat for cooling the MARS-D magnet is under design at LBL. The MARS-D magnet working around 4.2 K will be bath-cooled in liquid helium using multiple two-stage cryocoolers. An intermediate temperature thermal radiation shield is adopted to reduce the heat leakage imposed on 4.2 K coil cold mass from room temperature. The thermal shield is conduction-cooled by the first-stage cold heads of four two-stage cryocoolers and the cold head of a single-stage cryocooler shared with nine binary leads. The temperature in the area of the shield that warm ends of HTS leads are mounted on is expected no higher than 60 K, which is limited by maximum allowable working temperature of HTS leads. The paper presents thermal analysis on the thermal radiation shield including heat loads and effects of eddy current induced during quench on its material selection.

ECRIS↗
DOE OSTI2020

Cryocooler conduction-cooled SRF cavities for compact particle accelerators

Cryocooler conduction cooling offers simple, reliable cryogenics for developing industrial SRF e-beam accelerators. Conduction-cooled SRF R&D at Fermilab: first demonstration >6.5 MV/m cw on a 650 MHz Nb 3 Sn coated cavity; prototype development and high power accelerators designs in progress. Cryocooler conduction cooling can greatly expand access to SRF: university groups, industries can embark on in house SRF R&D without needing full stack helium cryogenic systems

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Multicaloric Cryocooling Using Heavy Rare-Earth Free La(Fe,Si) 13 -Based Compounds

The transition toward a carbon-neutral society based on renewable energies goes hand in hand with the availability of energy-efficient technologies. Here, magnetocaloric cooling is a very promising refrigeration technology to fulfill this role regarding cryogenic gas liquefaction. However, the current reliance on highly resource critical, heavy rare-earth-based compounds as magnetocaloric material makes global usage unsustainable. Here, we aim to mitigate this limitation through the utilization of a multicaloric cooling concept, which uses the external stimuli of isotropic pressure and magnetic field to tailor and induce magnetostructural phase transitions associated with large caloric effects. In this study, La 0.7 Ce 0.3 Fe 11.6 Si 1.4 is used as a nontoxic, low-cost, low-criticality multiferroic material to explore the potential, challenges, and peculiarities of multicaloric cryocooling, achieving maximum isothermal entropy changes up to −28 J (kg K) −1 in the temperature range from 190 K down to 30 K. Thus, the multicaloric cooling approach offers an additional degree of freedom to tailor the phase transition properties and may lead to energy-efficient and environmentally friendly gas liquefaction based on designed-for-purpose, noncritical multiferroic materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Cryocooler conduction-cooled SRF accelerator design for industrial applications

Principal Investigator Dr. Ram Dhuley has led R&D efforts at the U.S. Department of Energy's Fermi National Accelerator Laboratory to design a cryocooler conduction-cooled SRF accelerator for e-beam irradiation treatment of wastewater. This is a spotlight on the accelerator design and its enabling core technologies.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Deployable Cryocooler Based Cryomodule

Superconducting Radio Frequency (SRF) linear accelerators (linacs) have shown tremendous promise in extending the intensity frontier of particle accelerator technology. However, they are large and complex systems, requiring a central refrigeration system and complex piping to distribute liquid helium and nitrogen to the accelerating cavities. In response to these problems, RadiaBeam Technologies, LLC. proposes to develop a small mobile cryomodule that can be safely deployed to its planned field location. The scope of this work is to provide RadiaBeam with the specifications for a complete 650 MHz RF cavity model that can be incorporated into a compact SRF accelerator. Fermilab’s contribution will involve sharing contact resistance measurements, design parameters, and solid models. Design parameters will include the cavity frequency and gradient, length of the linac, number of cryocoolers, etc. This will ensure that the design is useful for practical linacs. A complete cryomodule design is envisioned. Radiabeam will design the cryomodule based on input from Fermilab’s experience on conduction cooling and the needs for a compact SRF accelerator.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Cryocooled cold trap system for the SuperCDMS dilution refrigerator

Operating 6,800 feet underground at the SNOLAB facility in Sudbury, Ontario, Canada, the dilution refrigerator-cooled SuperCDMS SNOLAB (Super Cryogenic Dark Matter Search at the Sudbury Neutrino Observatory Laboratory) experiment has been designed for maximum cryogenic up-time and remote operations. A key element in achieving these goals is a pair cold traps in the helium circulation stream of the dilution refrigerator; the first operating near liquid nitrogen temperatures and the second operating near liquid helium temperatures. Previous experience with the CDMS experiment, located underground at the Soudan Under-ground Laboratory, has given significant operational experience with dilution refrigerator cold traps and has solidified the demand of a system of dual cold traps. Unlike the CDMS-era system, the new SuperCDMS system will feature a cryocooler powered liquid nitrogen re-liquefying system (as opposed to regular under-ground re-filling of cold trap dewars using portable nitrogen dewars) and a cryogen-free 4 K cold trap, which eliminates the need for a bath of liquid helium.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Rapid Cryogenic Electrical Characterization of Materials and Devices Using Gifford-McMahon Cryocoolers

Thin-film heterostructures are necessary building blocks for superconducting and phononic quantum computing devices. Many new generations of quantum hardware demand extensive materials research to optimize performances at cryogenic temperatures (below 10 K). Here, we demonstrate compact cryogenic measurement systems capable of reaching sub-10K temperatures in less than three hours with the ability to measure AC/DC resistance and dielectric properties of thin-film materials. Our platform utilizes Gifford-McMahon (GM) cryocoolers as effective tools for providing high throughput cooling-warming cycles. We successfully used the GM-based measurement systems to measure 1) the superconducting transition temperature for Nb thin films (T c ~7.8 K), and 2) the temperature dependence of the dielectric constant in SiO 2 thin films down to 10 K. The fast electrical characterization feedback will be critical in developing robust materials and components for cryogenic computing devices.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Thermal Analysis of a Superconducting Undulator Cryostat for the APS Upgrade

The Advanced Photon Source Upgrade includes four 4.8-m-long superconducting undulator (SCU) cryostats, each containing two planar undulator NbTi magnets up to 1.9 m long. The cooling is provided by six cryocoolers arranged in three thermal circuits. The magnets are indirectly cooled with LHe penetrating through channels in the magnet cores. This 4 K circuit, which also includes a LHe tank, is cooled by five 4 K cryocooler 2nd stages. A beam vacuum, which is thermally isolated from the magnets, is cooled by one 10 K cryocooler 2nd stage. A thermal shield and warm parts of current leads are cooled by the 1st stages of all six cryocoolers. This paper presents an ANSYS-based thermal analysis of the new SCU cryostat including all thermal circuits. The benchmarked thermal conductance between the cryocooler cold heads and the LHe tank are used in the calculations as well as the measured cryocooler load lines. The model predicts temperatures in the system, total 4 K heat loads, and excess cooling power for various operational modes of the undulator.

Shiroyanagi, Y.↗
DOE OSTI2024

Cryogenic aspects of a 20 MW class low-temperature superconducting generator for the renewables industry

In this paper we give a progress update on the cryogenic design for cooling a 20 MW class, partially superconducting generator with stationary field coils for offshore wind renewables industry [1-2]. This is a continuation of an earlier program on a 10 MW system dating back ten years. Whereas this new power rating increase leads to a radial diameter expansion of the superconducting field coils from 4 to > 9.5 m, it maintains the axial length. We show the design based on this scaled up with enlarged diameter. The field coil size increase asks for higher cooling power that leads to a bigger cold box size to accommodate the cryocoolers. In the design, as many as 8 cryocoolers can be accessed and serviced from the nacelle that houses the main cryogenic components. A typical thermal load balance sheet with all components is given and compared against the available cryocooler cooling power at different operating conditions. Due to the cryocoolers’ local point of contact cooling within the nacelle, the temperature gradient of the thermal shield that fully encloses the cold mass with its embedded field coils needs to be balanced out to minimize the heat burden on the field coils. This requires additional analytical efforts and implementation of further design features. The extended nacelle houses the cold box with its cryogenic infrastructure. The interface for the envisaged cryogenic pushbutton closed-loop circulating system remains invisible, requires no handling of cryogenic liquids and is hermetically closed. The field coil diameter increase also leads to a greater initial helium gas storage volume. In addition, it requires higher initial room temperature fill pressure within the toroidal helium vapor storage tanks and in cooling tubes connecting to the cryocoolers. The toroidal helium gas tanks are thermally coupled with the thermal shield so that helium convection inside the storage tank can improve heat transfer and reduce the temperature gradient of the thermal shield. Besides those heat transfer challenges, additional mechanical strain within this large structure is exerted on the torque tubes during initial cooldown and when energizing field coils. Some of those design challenges are quite unexpected, leading to novel workarounds in order to maintain the chosen cooling strategy. Finally, we assess those design limitations in view of further cryogenic scalability with emphasis on manufacturability and assembly.

cryogenics↗