Cryogenic Module Research Articles

Cryogenic Modules for Synergistic O2 Generation and CO2 Retention in Closed-Circuit Escape Respirators

Since 2018, NASA and the National Institute for Occupational Safety and Health (NIOSH) have been developing a liquid oxygen storage module (LOXSM) based on the NASA patent-pending Cryogenic Flux Capacitor (CFC) technology. LOXSM’s could potentially replace the gaseous or chemical-based oxygen supply in current closed-circuit escape respirators (CCER), with reducing CCER size being a primary goal. By virtue of the CFC functionality, cryogenic oxygen stored within the LOXSM is released in response to heat input, ideally from the breathing loop. Prior efforts focused on the oxygen storage potential of silica aerogel materials that the CFC utilizes, and were previously reported. Current work explored the LOXSM’s potential to remove and retain CO2 produced by the CCER user, in conjunction with oxygen generation, creating a synergy that may be exploited to reduce or eliminate the chemical CO2 absorber used in current CCERs. A test program for determining CO2 retention is presented, as well as the evolution of LOXSM prototypes. Testing showed that it is possible to completely remove CO2 out of an effluent stream at the flowrate required for the capacity of the CCER for an appreciable time, and that the LOXSM prototype design progression had a positive effect on that duration.

Design of the cryogenic loop for the superconducting toroidal-field magnets of the Divertor Tokamak Test

The design of the cryogenic circuit for the toroidal field magnets has a relevant role in the overall costs of the DTT cryogenic plant (or cryoplant), hence numerical tools can be useful to investigate and to compare different configurations for the TF cooling circuit in support of the selection of the most suitable one. The system-level cryogenic circuit module of the validated thermal–hydraulic 4C code is adopted in this work to model the DTT TF cooling system. At first, the model of the reference circuit layout is implemented and simulated during the plasma pulsed operation of the DTT machine, highlighting the necessity to reduce the heat load transferred to the refrigerator due to the large power consumption of the cold compressor. In view of the above, different TF circuit layouts and optimization strategies are presented, including mitigation strategies for the smoothing of the peak heat load to the refrigerator, leading to a reduction of the cold compressor power up to the 66% with respect to that computed for the reference TF cryogenic circuit layout.

Instability and halo for double-periodic focusing structure

This paper presents a comprehensive investigation into the beam transport issue in the double-period focusing structure of low energy proton/ion cryogenic superconducting linear accelerators (CSLA). The structure, consisting of a large period corresponding to a cryogenic refrigeration module and a small period of focusing solenoid, is modeled with solenoids and drifts to study the impact of higher-order resonances on beam halo in transverse phase spaces without considering the acceleration. Numerical simulation reveals that the double-period structure can cause beam envelope instability even when the small periodic zero-current phase advance (σ0f) is less than 90°, making it more susceptible than the fully periodic structure. The study identifies that 2:1 resonance remains a major factor contributing to the formation of beam halo, particularly in the double-period structure. Furthermore, through exploration of different matching modes, the paper elucidates that not only 2:1 resonance but also higher-order resonances can lead to beam halo formation for space charge dominated beam. The oscillation frequency spectrum of the matched envelope is obtained using fast Fourier transform. It is recommended that particle oscillation frequencies avoid matching the identical fundamental frequency and its multiples of the matched envelope. Overall, the findings of this study can serve as valuable references for the design and optimization of CSLA.

Investigation of cryogenic friction and wear properties of Invar 36 alloy against Si3N4 ceramic balls

The existing materials for liquefied natural gas (LNG) cryogenic submersible pump bearings are very susceptible to wear and failure in LNG environments where oil lubricants and greases are ineffective, posing a major hazard to the safety of LNG storage and transportation. Therefore, searching for a type of material with excellent cryogenic tribological properties for improving the life of LNG bearings has become a huge challenge for researchers. Invar 36 alloy, as a low expansion nickel-titanium alloy, is used in control instruments, moulds, laser control equipment, and materials of LNG transport hull at temperatures below −162 °C. However, there is a lack of research data in the field of bearings. Currently, the Si3N4 ceramic balls are widely used in ceramic hybrid ball bearings and exhibit excellent tribological properties. In this work, the tribological performance of Invar 36 alloy is mainly investigated against Si3N4 ceramic ball under extremely cryogenic and dry conditions using the modified ball-on-disk tribometer with a cryogenic module, with temperatures as low as −196 °C. All experiments are performed at loads of 0.5 N, 1 N, 1.5 N, and 2 N, and at temperatures of 20 °C, 0 °C, −78 °C, and −196 °C, respectively. The experimental results show that the coefficient of friction (COF) and wear rate decrease with temperature and load, with a minimum value of −196 °C. The Invar 36 alloy exhibits excellent tribological properties, whose COF decreases gradually from 20 °C to −78 °C. However, as the temperature drops to −196 °C, the COF decreases abruptly, reaching a minimum value at −196 °C. On the contrary, the COF gradually increases with load. In addition, a commercial bearing grade material (G95Cr18 steel) is tested and compared under the same conditions, proving that Invar 36 alloy exhibits better tribological properties than G95Cr18 steel, with a wear rate 55.43% lower than G95Cr18 steel at −196 °C. Further simulation comparisons demonstrate that, due to its extremely low coefficient of thermal expansion, Invar 36 alloy exhibits higher toughness and strength than G95Cr18 steel under cryogenic conditions. This study complements the tribological data of Invar 36 alloy and G95Cr18 steel against Si3N4 ceramic balls under different temperatures and loads and provides important theoretical guidance and technical support for the bearings’ future development of LNG cryogenic submersible pump.

Deep Reinforcement Learning on FPGA for Self-Healing Cryogenic Power Amplifier Control

Wireless sensing and communication for space exploration in areas inaccessible to human often suffer from severe performance degradation due to the cryogenic effects on the transmitters’ circuits. To survive extreme temperatures, programmable radio frequency (RF) power amplifiers (PA) can be built into the transmitter, and intelligent PA controllers need to be integrated into the system to interact with the environment and restore the PA’s functionalities. This problem can be modeled as the controller acts (control the PA) in an environment to maximize the reward (signal quality), and it is most suitable to use reinforcement learning as a solution. This paper presents a cryogenic and energy-efficient reinforcement learning (RL) module on Field Programmable Gate Arrays (FPGA) that can directly program the PA. By characterizing a self-healing PA in a liquid nitrogen environment, we generated an RF signal data set and built an interactive RL environment to model the PA’s behaviors across its configurations and cryogenic temperatures down to −197°C. We developed a deep RL model with a high generalization capability introduced by the neural networks to control the PA and restore its performance. The RL model with fixed-point training and inference is implemented on FPGA to survive the cryogenic conditions and carry out fast and low-power training and inference for PA control. All functionalities of the programmed FPGA operate correctly in the cryogenic testing environment.

Realizing high conversion efficiency in shallow cryogenic thermoelectric module based on n-type BiSb and p-type MgAgSb materials

The thermoelectric (TE) modules have been extensively studied, which have the features of recovery of waste heat energy into electricity. At present, many TE researches focus on the materials and modules of medium and high-temperature regions and hardly report on shallow cryogenic TE modules (173–300 K) aiming for the utilization of cold energy of liquefied natural gas (LNG). In this work, the TE arms of shallow cryogenic modules are composed of p-type MgAgSb-based materials synthesized by ordinary ball milling and n-type Bi85Sb15 synthesized by melting. By optimizing the raw material ratio of MgAgSb materials and the SPS pressure, the average ZT of MgAgSb-based material was increased from 0.196 to 0.482 at the temperature range of 173–300 K. Therefore, the maximum simulation conversion efficiency of the module by the optimization of the module structure and materials can achieve 1.95% at the temperature range of 200–300 K, which is 144% higher than that of the non-optimized module. Meanwhile, the maximum measured conversion efficiency of the corresponding manufacturing module reaches 1.76%, which is 2.63 times higher than that of the non-optimized manufacturing module. This work provides a reference for improving module conversion efficiency by optimizing materials and module structure in cryogenic environment.

Development of cryogenic insulation supporter module for a 220 kV 2G-tape-based resistive fault current limiter

Resistive type superconducting fault current limiter (R-SFCL) is one of the most promising candidates to suppress fault currents in power grids. However, the violently boiled cryogen liquids, commonly liquid nitrogen, occurred due to fault currents, poses a crucial cryogenic insulation challenge for R-SFCL. Here we report the design and development of a Cryogenic Insulation Supporter Module (CISM) for a 220 kV R-SFCL. First, we present the design and test of the prototype Cryogenic Insulations Supporter (CIS). The developed CIS passed the high voltage tests under operating conditions. Following on this, we then present the design of CISM, which consists of 14 CISs, with the length and outer diameter of 12 m and 2.5 m, respectively.

Cryogenic design of the crab cavity modules for the High Luminosity LHC at CERN

The High Luminosity Large Hadron Collider (HL-LHC) upgrade is planned to take place during next long shut down of the LHC, starting in 2025. During this period the matching sections of both ATLAS and CMS experiments will be upgraded to allow for increasing collisions rate and more efficient luminosity production. One of the new element which will be introduced to the layout is the beam deflecting RF system so-called as crab cavities. Eight crab cavities modules, operating in superfluid helium, will be installed in this new machine layout. This paper will focus on the cryogenic design solutions adopted and integrated in the crab cavities cryogenic modules. The concept of the cryogenic modules was created in 2012 and evolved over the years with introduced optimizations of the cryogenic local cooling loops and related safety system. Design aspects of the chosen solutions for the first prototype and LHC compatible solution will be discussed. The thermal behavior results from operation on SPS proton beam from the first prototype module will be developed.

Feasibility Study of a W-Band Multibeam Heterodyne Receiver for the Gregorian Focus of the Sardinia Radio Telescope

We report on the feasibility study of a W-band multibeam heterodyne receiver for the Sardinia Radio Telescope (SRT), a general purpose fully steerable 64-m diameter antenna located on the Sardinia island, Italy, managed by INAF (“Istituto Nazionale di Astrofisica,” Italy). The W-band front-end is designed for the telescope Gregorian focal plane and will detect both continuum and molecular spectral lines from astronomical sources and radio emission from the Sun in the 3 mm atmospheric window. The goal specification of the receiver is a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 4$ </tex-math></inline-formula> focal plane array operating in dual-linear polarization with a front-end consisting of feed-horns placed in cascade with waveguide Orthomode Transducers (OMTs) and LNAs (Low Noise Amplifiers) cryogenically cooled at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\approx $ </tex-math></inline-formula> 20 K. The instantaneous FoV (Field of View) of the telescope is limited by the shaping of the 64-m primary and 7.9-m secondary mirrors. The cryogenic modules are designed to fit in the usable area of the focal plane and provide high-quality beam patterns with high antenna efficiency across the 70 – 116 GHz Radio Frequency (RF) band. The FoV covered by the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4\times 4$ </tex-math></inline-formula> array is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.15\times 2.15$ </tex-math></inline-formula> arcmin <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , unfilled, with separation between contiguous elements of 43 arcsec. Dual-sideband separation (2SB) down-conversion mixers are designed to be placed at the cryostat output and arranged in four four-pixel down-conversion modules with 4 – 12 GHz Intermediate Frequency (IF) bands (both Upper Side Band and Lower Side Band selectable for any pixel and polarization). The receiver utilizes a mechanical derotator to track the parallactic angle.

Dynamic simulation on flow characteristics of KSTAR PF magnet cryogenic network

During its nominal operation, strong current variation, more than 10 kA per second, can be imposed on the KSTAR PF (Poloidal Field) magnet system. Due to AC loss, transient massive backward flow can occur, especially at the cryogen inlets of each magnet. To protect cryogen circulator, several valves are activated to adjust or lower pressure below the circulator's operation limit. In this work, we discuss whether currently available thermo-hydraulic code, such as SUPERMAGNET, can describe this overall dynamic flow characteristics of KSTAR PF magnet cryogenic network. First, three major functions of the KSTAR PF magnet cryogenic system during plasma operation are classified and discussed. Cryogenic components mostly related with other functions, such as cool-down process, are removed from the simulation circuit to minimize computation time. SUPERMAGNET code was used with a slight modification in its cryogenic network simulation module, FLOWER. The codes for cryogenic valves are modified so that not only steady state but also general compressible flows can be described. A case study for an actual KSTAR plasma operation has been intensively carried out. It was shown that most relevant data, pressure, temperature and mass-flow, at the inlets and outlets of the magnet, are in agreement with simulation results.

Development of cryogenic cooler based on n-type Bi-Sb thermoelectric and HTSC

Single crystals of n-Bi-Sb solid solutions with Sb content of 7–15 at.% are the most efficient thermoelectric (TE) materials over the temperature range of T ≤ 200 K. However, the use of these materials for construction of real thermoelectric devices are limited due to low mechanical strength. In this paper, for strengthening Bi-Sb single crystals, the method of the extrusion in a liquid medium under high hydrostatic pressure has been developed. The thermoelectric properties of Bi0.91Sb0.09 extruded crystals and single crystals were studied over the entire temperature range of 77–200 K. The high dimensionless thermoelectric figure of merit ~0.95 was obtained for the Bi0.91Sb0.09 single crystal measured in the transverse magnetic field. Unique thermoelectric coolers for operating temperatures below 100 K based on the n-type Bi0.91Sb0.09 leg and a passive leg based on a high-temperature YBa2Cu3O7-x superconductor (HTSC) films have been constructed. The achieved maximum value of temperature difference ΔT = 14 K and the maximum cooling capacity Qc = 0.4 W (the temperature of the hot side of cryogenic module Th = 80 K, an electric current I = 6.4 A and a voltage V = 0.10 V) makes evident that using of the Bi-Sb extruded crystals in place of single crystals for the cryogenic coolers is more reasonable due to much better mechanical properties and similar values of cooling capacity.

Origins Space Telescope integration and testing

I describe the plans, flows, key facilities, test beds, pathfinders, simulators, and ground support equipment that could be used to fully integrate, functionally test, and qualify the Origins Space Telescope (Origins). The Origins observatory consists of the spacecraft bus module and the cryogenic payload module, which comprises the telescope and three science instruments. The telescope is a three-mirror anastigmat and is composed of four mirrors: three with optical power (the elliptical primary, hyperbolic secondary, and elliptical tertiary mirrors) and a flat field-steering mirror. The three science instruments spanning the wavelength range 2.8 to 588 μm provide the powerful new spectroscopic and imaging capabilities required to achieve the scientific objectives. The Origins Survey Spectrometer uses six gratings in parallel to take multibeam spectra simultaneously across the 25- to 588-μm window through long slits enabling deep three-dimensional extragalactic surveys. The far-IR imager/polarimeter provides imaging and polarimetric measurement capabilities at 50 and 250 μm. Its fast mapping enables rapid follow-up of transient or variable sources and efficient monitoring campaigns. The mid-infrared spectrometer simultaneously provides spectroscopy over 2.8 to 20 μm with exquisite stability and precision (<5 ppm between 2.8 and 10 μm, <20 ppm between 11 to 20 μm). All the instruments are delivered for integration and test fully qualified and calibrated. The integration and test program implemented at each level of assembly is discussed as well as the separation of thermal vacuum testing between the hot and cold zones of the observatory.

Low-Inductance High-Voltage Input of Pulsed Power to the Cryogenic Module of the Septum Magnet for the NICA Collider

A design for a device for pulsed-power input to the cryogenic module of a septum magnet of the NICA collider is presented. This design allows the input inductance to be minimized at acceptable heat fluxes from the resistive heating and temperature gradient.

Oxygen storage module with physisorption technology for closed-circuit respirators

The new Cryogenic Flux Capacitor (CFC) technology employs nano-porous aerogel composites to store large quantities of fluid molecules in a physisorbed solid-state condition at moderate pressures and cryogenic temperatures. By its design architecture, a CFC device can be “charged” and “discharged” quickly and on demand according to standby/usage requirements. One of three main application areas is the CFC-Life for breathing air or oxygen supply to meet new demands in life support systems. Through the Liquid Oxygen Storage Module (LOXSM) Project, the National Institute for Occupational Safety and Health, and Cryogenics Test Laboratory have partnered to test the feasibility of applying the CFC technology to Closed-Circuit Escape Respirators (CCER), or respirators operating on the closed-circuit principle in general. The envisioned Cryogenic Oxygen Storage Module (COSM) is an innovative concept to store oxygen in solid-state form, according to physisorption processes at any cryogenic temperature, and deliver it as a gas using the CFC as the core storage element. Gaseous oxygen would be admitted into the breathing loop of the CCER by introducing heat into the storage module. Potentially replacing the gaseous or chemical based oxygen supply used in today’s closed-circuit respirators, the COSM is a high capacity, conformal, small-size solution for future life support equipment of all kinds. In particular, are the CCER devices that must to be carried on the person, ready to be quickly deployed and used for escape in an emergency. Initial test data for physisorption of oxygen in aerogel materials and CFC core modules are presented. The basic operational parameters for charging and discharging are summarized through prototype testing of the cryogenic oxygen storage module.

Cryogenic Thermoelectric Cooler for Operating Temperatures below 90 K

The possibility of fabricating thermoelectric coolers for operating temperatures below 90 K is considered. It is impossible to use the standard thermoelectric-cell scheme consisting of two semiconductor legs of n-type and p-type conductivity connected into an in-series electrical circuit for these temperatures. There is only one effective n-type thermoelectric material based on Bi–Sb solid solutions for the region of cryogenic temperatures. For this case, thermoelectric cells with a thermoelectric n-type leg and passive leg based on a high-temperature superconductor (HTSC) are investigated. The design of a thermoelectric cooler (module) consisting of thermoelectric n-type legs (extruded Bi0.91Sb0.09 crystals) and passive HTSC-based legs (YBa2Cu3O7 –x) is proposed. A magnetic field is used to increase the thermoelectric figure of merit ZT of the module. The maximal temperature drop between the hot and cold sides ΔT > 13.5 K and maximal cooling capacity Qc > 0.36 W are attained for the cryogenic module at a hot side temperature of Th = 80 K, current consumption of I = 6.4 A, and voltage of U = 0.10 V.

Hydraulic adjustment of the two-phase helium forced flow cooled superconducting magnets of the SIS100 heavy ion synchrotron for FAIR

The fast ramped superconducting heavy ion synchrotron SIS100 is the core component of the international FAIR project at GSI in Darmstadt. The magnet system of the SIS100 consists of the superconducting dipoles, quadrupoles and corrector magnets assembled in cryogenic modules. In order to maximize the beam intensity the SIS100 main dipoles will operate up to 1.9 T with 4 T/s with a high repetition rate of up to 1 Hz. The various configurations of parallel cooling circuits must be hydraulically adjusted in respect to their dynamic heat load for a wide spread of operation cycles. We present the results of dynamic heat loss measurements for the different types of magnets as well as the procedure of their hydraulic adjustment.

Криогенный термоэлектрический модуль для рабочего интервала температур ниже 90 K

It is considered the possibility of creating thermoelectric coolers for operating temperatures below 90 K. For these temperatures it is not possible to use a standard circuit of a thermoelement, consisting of two n- and p-semiconductor legs, connected in a series electrical circuit. In the area of cryogenic temperatures there is only an effective thermoelectric material of n-type conductivity, based on solid solutions Bi−Sb. In this case thermoelements composed of thermoelectric n-type leg and a passive leg, based on high temperature superconductor (HTSC) were studied. A thermoelectric cooler (module), consisting of six n-type legs (extruded crystals Bi0.91Sb0.09 ) and passive legs based on HTSC (YBa2Cu3O(7−x) ) films was designed. A magnetic field was used to increase thermoelectric figure of merit ZT of the cryogenic module. For created cryogenic module at hot side temperature Th = 80 K, a current I = 6.4 A and a voltage U = 0.10 V the maximum value of temperature drop &gt; 13.5 K and a maximum cooling capacity Qc &gt; 0.36 W were achieved.

Superconducting cavity material for the European XFEL

Analysis of the strategy for superconducting cavity material procurement and quality management is done on the basis of the experience with the cavity production for the European x-ray free electron laser (EXFEL) facility. An adjustment of the material specification to EXFEL requirements, procurement of material, quality control (QC), documentation, and shipment to cavity producers have been worked out and carried out by DESY. A multistep process of qualification of the material suppliers included detailed material testing, single- and nine-cell cavity fabrication, and cryogenic radiofrequency tests. Production of about 25 000 semi-finished parts of high purity niobium and niobium-titanium alloy in a period of three years has been divided finally between companies Heraeus, Tokyo Denkai, Ningxia OTIC, and PLANSEE. Consideration of large-grain (LG) material as a possible option for the EXFEL has resulted in the production of one cryogenic module consisting of seven (out of eight) LG cavities. LG materials fulfilled the EXFEL requirements and showed even 25% to 30% higher unloaded quality factor. A possible shortage of the required quantity of LG material on the market led, however, to the choice of conventional fine-grain (FG) material. Eddy-current scanning (ECS) has been applied as an additional QC tool for the niobium sheets and contributed significantly to the material qualification and sorting. Two percent of the sheets have been rejected, which potentially could affect up to one-third of the cavities. The main imperfections and defects in the rejected sheets have been analyzed. Samples containing foreign material inclusions have been extracted from the sheets and electrochemically polished. Some inclusions remained even after 150 μm surface layer removal. Indications of foreign material inclusions have been found in the industrially fabricated and treated cavities and a deeper analysis of the defects has been performed.

4C modeling of the supercritical helium loop HELIOS in isobaric configuration

Superconducting magnets for tokamak fusion reactors are subject to highly variable loads due to the intrinsically pulsed operation of the machine. The refrigerator should, on the contrary, work under conditions as stable as possible and should be sized based on the averaged loads. In this paper, the cryogenic circuit module of the 4C (Cryogenic Circuit Conductor and Coil) code is used to analyze the isobaric configuration of the HELIOS (HElium Loop for hIgh lOads Smoothing) facility at CEA Grenoble, France. The 4C model is validated against experimental data from the isobaric HELIOS configuration: the computed evolution of temperature, pressure and mass flow rate at different circuit locations shows a good agreement with the measurements for two different pulsed heat load scenarios, with and without regulation. The advantages of the (somewhat more complicated) isobaric configuration vs. the isochoric configuration in terms of heat load smoothing are highlighted. 4C simulations are used to propose a new HELIOS layout with helium charging and discharging lines located in such a way that the HELIOS performance in the isobaric configuration is optimized. The paper confirms the importance of the isobaric configuration for a tokamak cryogenic circuit, as well as the accuracy of 4C in modeling the HELIOS operation, even in the presence of complex regulation.

Cryogenic Power Conversion Systems: The next step in the evolution of power electronics technology

In transportation applications, lower weight and volume of the power conversion systems is very important to achieve high power density, high efficiency, and superior performance. The thermal management of these power conversion units plays a significant role in reducing the weight and volume. The use of superconductive motors/generators, degaussing coils, energy storage modules, and cables has been considered to increase power density and efficiency. High-temperature superconducting (HTS) components combined with cryogenic power converters will provide significant benefits in the electrification of transportation and high power density power conversion systems. Cryogenic power converter modules offer other promising benefits over their room temperature counterparts in terms of reduced size and weight (i.e., increased power density) and improved efficiency, switching speed, and reliability. Such an integration could result in significant weight and space savings for next-generation mass transportation systems. In this article, the current research on cryogenic power electronics and superconducting motors/generators is discussed for future aircraft and ships.