bluuebunny/crossref_metadata_2025_split huggingface dataset:
Failure analysis of leaks due to cracks in hydrogen transfer lines of ESS cryogenic moderator
Authors: Tatsumoto H , Lyngh D , Arnold P , Segerup M , Tereszkowski P , Beßler Y 
Published: June 2022

Abstract
The ESS cryogenic Moderator System (CMS) has been designed to slow down the high-energy neutrons by means of two hydrogen moderators (to be increased to four in the future) by using forced flow of subcooled liquid hydrogen with a temperature of 17 K at 1.0 MPa. A liquid hydrogen leak is considered the most severe failure for the CMS. A leak scenario from the transfer line to its vacuum envelope through a crack have been analyzed and the expected results will be presented in this paper. An analysis code has been developed and calculated the pressure and temperature changes in the CMS process line and its vacuum envelope. The effect of the crack sizes is clarified. The consequential temperature changes along the vacuum envelope as well as the pressure drops were calculated. The required size of the safety relief device in the hydrogen transfer line and its vacuum envelope have thereby been determined and implemented.
Design of a hydrogen vent line for ESS cryogenic moderator system
Authors: Tatsumoto H , Lyngh D , Arnold P , Segerup M , Tereszkowski P , Beßler Y 
Published: June 2022

Abstract
The ESS cryogenic moderator system (CMS) circulates subcooled liquid hydrogen at 17 K and 1 MPa to remove nuclear heating at two hydrogen moderators. All the hydrogen will be safely released to the atmosphere on the roof top of the Target building through a hydrogen vent line (HVL) with a total length of 36 m. Two-phase hydrogen would flow through the HVL because the hydrogen expands by isenthalpic process. The HVL has been designed to avoid decreasing the wall penetration temperature below 253 K and to be sized big enough to limit the backpressure below the design pressure. One-dimensional transient thermohydraulic analysis code that can treat two-phase flow heat transport behavior has been developed. A natural convection heat transfer from air to the cold surface is considered. In this work, the wall temperature reductions and the pressure drop along the HVL during release of cryogenic hydrogen are analyzed. The size and thickness of the HVL have been verified based on the analysis results.
43+T Grenoble hybrid magnet: Commissioning tests of the current leads and cryogenic satellite producing the pressurized superfluid He at 1.8 K
Authors: Pugnat P , Barbier R , Berriaud C , Boujet T , Graffin P , Grandclément C , Hervieu B , Jousset J , Juster F P , Molinié F , Pelloux M , Pfister R , Ronayette L , Yildiz E 
Published: June 2022

Abstract
The Grenoble Hybrid magnet is a modular platform using resistive and superconducting technologies to produce various continuous high magnetic field and flux configurations for the scientific community. They range from 43 T in 34 mm diameter with 24 MW electrical power to 9 T in 800 mm diameter when the superconducting coil is used alone. Thanks to the ongoing upgrade of the electrical power installation of LNCMI-Grenoble up to 30 MW and possibly to 36 MW, the possibility to increase the total field up to 45-46 T in the near future is foresee and deeply studied. The key design parameters will be briefly recalled including the specifically developed Nb-Ti/Cu conductor, the large bore outsert superconducting coil, the magnet cryostat with its structure including the eddy-current shield, the cryogenic line for the interconnection with the cryogenic satellite and the fully dedicated 150 l/h He liquefaction plant. All components of the hybrid magnet platform have been built, tested and delivered to LNCMI-Grenoble, where integration and assembly are ongoing. The status of the project will be given with focus to the recent commissioning tests of the cryogenic satellite producing the pressurized superfluid He at 1.8 K as well as to the successful powering tests of the specially developed current leads at ultimate current and under fully degraded cooling conditions simulating the worst-case accidental scenario.
The GTLT cryocooler, a low temperature variant of CryoTel® GT
Authors: Kim Yongsu , Mansfield Doug 
Published: June 2022

Abstract
The CryoTel® GT is an integral Stirling cryocooler with 16 W of lift capacity at 77 K with a nominal input power of 240 W. The GT has been a Sunpower legacy product since it was brought to commercialization in 2005. The contact-free operation of the moving components by using Sunpower’s gas bearings technology results in a long lifetime of the cooler, achieving an MTTF of over 200,000 hrs. Typical no-load temperature of GT is around 36 K. Sunpower used an advanced regenerator to improve the performance and was able to provide cooling lift below 35 K. Although the advanced regenerator effectively improved the cooler performance, overall cryocooler cost went up substantially due to the costly special processes and materials for the regenerator. Looking for a cost-effective alternative, Sunpower applied optimization techniques and developed a regenerator design improving its performance at lower temperature. To reduce the conduction loss of the cold finger, an alternative material for stainless steel was selected. Its material cost is a little higher than stainless and the thermal conductivity is between titanium and stainless. It is weldable into the transition using the same methods and geometry as the current stainless cold finger which is a huge benefit. Sunpower built 6 units and achieved an average no-load temperature of 26.5 K, about 9 K colder no-load temperature than standard GT, at the same input power. This low temperature variant of GT is named as GTLT and we are moving to add the GTLT as a commercial product.
Final design of the cryostat for the high luminosity LHC magnets
Authors: Ramos D , Vande Craen A , Prin H , Leclercq Y , Williams L , Struik M , Barlow G , Riu Martinez O , Wong Luis B , Parma V , Savary F , Todesco E 
Published: June 2022

Abstract
The high luminosity LHC project (HL-LHC) aims at increasing proton collisions by a factor of ten whilst extending physics exploitation until 2035. Its performance will rely on new focusing quadrupoles, beam separation dipoles and corrector magnets with large apertures to be installed on both sides of the ATLAS and CMS experiments. A dedicated cryostat design of about 1 m in diameter was developed for operation of these magnets at 1.9 K, comprising the required cryogenic circuits, interconnects, supports, insulation, and instrumentation systems. Six cryostats with various lengths in the range of 8 to 11 m are required on each side of the interaction points to house the triplet magnets, correctors and the first separation dipole. These cryostats will be linked through flexible interconnects to form a continuous vacuum insulation and cryogenic system of about 60 m in length. The second rearmost separation dipole requires a stand-alone cryostat of 15 m in length but nevertheless features common design principles. We present the design of these cryostats, from a conceptual stage towards the final design. Assembly aspects are also addressed, including a modular approach affording flexibility and simplification of the manufacturing and assembly processes.
A cryostat for a 6 T conduction-cooled, no-insulation multi-pancake HTS solenoid
Authors: Barkas J , Zhai Y , Safabakhsh M 
Published: June 2022

Abstract
There is a growing requirement for high-field (>20 T) magnets capable of continuous operation, driven by the needs of both fundamental research and technological advance, particularly in application to an eventual pilot plant for magnetic confinement fusion. Even with HTS windings, such magnets will still require cryogenic cooling, and liquid helium (LHe) immersion, the typical solution to this problem, adds significantly to the operating expenses of such facilities. This reality makes cryogen-free cooling systems a necessity in future high-field magnet systems. The Princeton Plasma Physics Laboratory (PPPL) is exploring conduction-cooling systems of HTS pancake solenoids for a scanning tunneling microscopy (STM) facility at Princeton University, and potentially also for the central solenoid of the Fusion Nuclear Science Facility (FNSF). To these ends, PPPL is designing a cryostat to evaluate the thermal stability of a 5-6 T, 30 double-pancake (DP) REBCO insert coil of 40 mm ID / 70 mm OD, and smaller prototypes, operated in self-field with conduction cooling provided by a 2-stage GM cryocooler. The current design is expected to achieve 1st and 2nd stage temperatures of 44 K and 4-10 K, respectively, with the resistivity of DP-DP solder joints being the principal source of uncertainty in 2nd stage temperature predictions.
Feasibility study of capacitance based quench detection technique for HTS power transmission cables
Authors: Hassan Harris K. , Sagar Pankaj , Singh Gour Abhay , V Rao V. 
Published: June 2022

Abstract
2nd Generation High Temperature Superconducting (2G HTS) tapes are replacing the conventional Low Temperature Superconducting (LTS) wires in various felds of applied superconductivity, especially in the power transmission applications. Transients in the electrical grid can result in the loss of superconductivity leading to thermal runaway. This phenomenon is known as quench. To avoid catastrophic consequences, timely detection of quench is imperative. However, the HTS materials possess a low Normal Zone Propagation Velocity (NZPV) compared to LTS materials during quench. This property combined with a low electromagnetic shielding makes the conventional voltage tap detection technique unreliable for HTS power transmission cables. A capacitance based quench detection technique is proposed and its feasibility is studied. A variation in the permittivity of the cryogenic fuid and the dielectric can be observed in association with the heat generation during faults. This can be refected as the variation in the measured capacitance between cryostat and cable former. In this study, this capacitance is computed using the FEM model of HTS cable operating at various temperatures along with diferent vapour liquid ratios of cryogen. The results of this work can be extended into experiments for quench detection in HTS power transmission cables.
Cryogenic design of the crab cavity modules for the High Luminosity LHC at CERN
Authors: Brodzinski K , Capatina O , Capelli T , Claudet S , Delprat L 
Published: June 2022

Abstract
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.
Improvement of Magnet and Cavities cooling at Heavy Ion or Rare Isotopes Accelerators due to Application of sub-cooled Superfluid Helium
Authors: Putselyk S 
Published: June 2022

Abstract
Several modern Heavy Ion or Rare Iosotopes Accelerator uses superconducting (sc) cavities for an acceleration of the beam particles. Operation of sc magnets with higher magnetic fields and improved field gradients also leads to a better beam focusing (also called “beam optics”) and improves the overall accelerator compactness. In many accelerators, like XFEL, SNS, LCLS-II, HIE-ISOLDE, ATLAS, ISAC-II/ARIEL, SPIRAL-2, FLASH, Jlab-FEL/ERL, the operation is limited either by cooling capability of sc cavities or refrigeration capacities. In most of the cases, increasing of refrigerator capacities is a challenging task due to available free space or investments, and, therefore, improvement of cavity cooling due to increasing of a quality factor (Q
0) or heat transfer at cavity surfaces is considered. Application of a sub-cooled superfluid (sf) helium gives several advantages, like higher heat flux densities, longer time for onset of a film boiling regime and shorter recovery time, reduced Kapitza resistances, etc. In the present paper, application of sub-cooled superfluid helium for cooling of cavities with half and quarter-wave resonators, which are typically applied at Heavy Ion and Rare Isotopes Accelerators or sometimes at electron and proton ones, is considered. In order to limit the present discussion, its application to FRIB-style cryomodules is discussed in details.
Flow of Neon-Nitrogen-Hydrocarbon mixture through adiabatic capillary tube at cryogenic temperatures
Authors: Parmar Darshit , Atrey M. D. 
Published: June 2022

Abstract
Capillary tubes are widely used in J-T refrigerators owing to their simplicity, easy operation, and zero maintenance. J-T refrigerators are mainly used for domestic and commercial refrigeration and air conditioning and hence the study on flow through capillary tubes is highly focused on conventional refrigerants at relatively higher temperatures. The present work is an extension of previous work done by the authors and focuses on the flow of refrigerant mixtures consisting of neon, nitrogen, and hydrocarbons at cryogenic temperatures for the capillary tube of a J-T cryocooler. The mass flow rate through the capillary tube is studied experimentally by changing refrigerant mixture composition and inlet temperature to the capillary tube. A mathematical model is developed based on a length feedback loop to predict the mass flow rate through the capillary tubes using the homogenous flow model. The model is found to predict mass flow rate through the capillary tube with an average error of 10 % for almost all the experimental values.
Numerical simulation of sinusoidal corrugated fins and serrated fins performance at low temperature
Authors: Zhu Z G , Wang H , Zhang Q Y , Zou Z Y 
Published: June 2022

Abstract
Due to promoting the disturbance of fluid and high heat transfer performance, sinusoidal wavy fins and serrated fins are used in plate fin heat exchangers (PFHE) for cryogenic system. In order to compare their flow and heat transfer performance difference at low temperature, this article adopts the numerical simulation method to investigate the flow and heat transfer characteristics of normal-temperature and low-temperature helium in corrugated wavy fin and serrated fin channels. The influence of different temperature and Reynolds numbers on the fin performance are analyzed. The results can provide theoretical guidance for the optimal design of cryogenic PFHE.
Friction stir welding of AISI 316LN high strength austenitic stainless steel for cryogenic application
Authors: Aviles Santillana I , Debeux J , Meyer M , Muddamallappa M , Polo Picazo A , Robe H , Rodriguez Castro E , Sgobba S , Weiss KP 
Published: June 2022

Abstract
Friction stir welding (FSW) is a solid state joining process that uses the heat generated by the friction of a rotating tool and the base material to join materials together. Due to the fact that the material is never melted, and that extensive plastic deformation is introduced in the weld seam, a unique set of properties is achieved. The technique has been extensively used to join aluminium and aluminium alloys, but very few developments are reported on high strength austenitic stainless steel, which is the material of choice for many high energy physics and fusion magnets. This paper contains a comprehensive microstructural and mechanical characterization, including at cryogenic temperature, of an 8 mm thick high strength austenitic stainless steel plates. The steel grade is the high alloy version of AISI 316LN (identified as 1.4429 or -X2CrNiMoN17-13-3 according to European standards). Special attention was given to cryogenic elastic – plastic J – integral testing of the weld seam. To the authors’ knowledge, this is the first time fracture toughness at cryogenic temperature on friction stir welded 1.4429 has been measured.
Niobium rod quality and its impact on the production of Nb3Sn strand for the Divertor Tokamak Test Facility toroidal coils
Authors: Smathers D. , Flanigan J. , Kim J. , Sim K. 
Published: June 2022

Abstract
Niobium Tin cable is being used in the high field magnets in the Divertor Tokamak Test Facility under construction by ENEA in Italy. Kiswire Advanced Technology was selected to provide 55 tonnes of high-performance Niobium Tin wire for the 18 Toroidal Field Coils. The conductor design is based on a 0.82mm Nb3Sn strand similar to that provided for the ITER TF coils. H. C. Starck Solutions provided the pure Nb rod and Ta sheet for their conductor design. The enhanced strand requirement has both a minimum current (320 A at 12 Tesla) and maximum hysteresis loss (± 3T cycle 1000mJ/cc) and a Cu/Non-Cu of 1:1. To achieve the current and hysteresis loss reliably, the niobium rod must maintain its shape throughout the drawing process. The n value requirement (>20) is a good indication of niobium filament uniformity while the RRR requirement (>100) is a good indication of tantalum barrier performance. The HCSS rod supplied to KAT provided consistently high Ic (>320A at 12 Tesla), low hysteresis loss and the Ta sheet provided very good RRR values. We report here the consistency of more than 11 tonnes of HCSS Nb rod properties for chemistry, hardness, grain size and wire performance.
Neutron irradiation effect on critical current and critical temperature of Nb3Sn wire
Authors: Nishimura Arata , Hishinuma Yoshimitsu 
Published: June 2022

Abstract
The ITER project is ongoing in France, and it is expected that a lot of high energy neutrons will be generated, and some neutrons will reach to superconducting magnets. To keep the safe and stable operation of the superconducting magnets, the neutron irradiation data must be piled up and the mechanisms of the irradiation effect must be investigated. A 15.5 T superconducting magnet and a variable temperature insert were installed in a radiation control area at Oarai centre in Tohoku University, and the superconducting properties of the irradiated Nb3Sn wires have been evaluated. The critical current was improved once and drastically dropped after irradiation of 1023 n/m2, and the critical temperature degraded monotonically, and the critical magnetic field decreased around 17 T after the irradiation of 1023 n/m2. The mechanism of the irradiation effect was discussed based on a flux pinning concept.
3D Modelling and Validation of the Optimal Pitch in Commercial CORC Cables
Authors: Fareed M. U. , Kapolka M. , Robert B. C. , Clegg M. , Ruiz H. S. 
Published: June 2022

Abstract
Conductor on a rounded core (CORC®) cables with current densities beyond 300 A/mm-2 at 4.2 K, and a capacity to retain around 90 % of critical current after bending to a diameter of 3.5 cm, make them a strong candidate for high field power applications and magnets. In this paper, we present a full 3D-FEM model based upon the so-called H-formulation for commercial CORC® cables manufactured by Advanced Conductor Technologies LLC. The model presented consists of tapes ranging from 1 up to 3 SuperPower 4mm-width tapes in 1 single layer and at multiple pitch angles. By varying the twist pitch, local electromagnetic characteristics such as the current density distribution along the length and width are visualized. Measurements of macroscopical quantities such as AC-losses are disclosed in comparison with available experimental measurements. We particularly focused on the influence of the twist pitch by comparing the efficiency and performance of multiple cables, critically assessing the optimal twist pitch angle.
Influence of cooling temperature on load-carrying performance of a radial HTS magnetic bearing
Authors: Guan Xiang , Zou Yincai , Bian Xing , Shang Jin , Wu Jihao , Li Qing 
Published: June 2022

Abstract
High temperature superconducting (HTS) magnetic bearing can operate in the harsh environment of low temperature and negative pressure with low loss and self-stability. Therefore, it has been gradually applied in flywheel energy storage, cryogenic liquid pump, cold compressor and some other cryogenic rotating machinery. The load-carrying performance of HTS magnetic bearing is affected by the cooling temperature of HTS directly. In this paper, the linear model is used to modify the temperature dependence to evaluate the influence of cooling temperature on load-carrying performance quantitatively, and the results are analyzed and displayed from the aspects of maximum levitation force, levitation stiffness and hysteresis effect. The research results of this paper have practical significance for the design and safe operation of HTS levitation system.
Electrical characterization of a 1200V GaN HEMT at cryogenic temperatures
Authors: Hossain Md Maksudul , Wei Yuqi , Rashid Arman-Ur , Sweeting Rosten , Alan Mantooth H. 
Published: June 2022

Abstract
The cryogenic operation of power converters integrated with the superconducting electric machines can leverage the lower parasitic, lower core material, and insulation requirement to reduce weight and increase power density in aerospace applications. To that end, Gallium Nitride High Electron Mobility Transistor (GaN HEMT) has recently proven to be the most viable option for the cryogenic converter operation. However, the topology selection and optimization are greatly influenced by the current/voltage rating of the power devices. Although series connected HEMTs can increase the blocking voltage, the dynamic voltage imbalance issue stemming from device parameter fluctuations, the larger number of required isolated gate driver makes the need for single high blocking voltage devices more compelling. This is even more pronounced in GaN due to its higher operating frequency which stems from the lower input capacitance. Although 900V cascode GaN HEMTs are now commercially available, single-chip high voltage HEMTs are attractive due to their zero reverse recovery charge, and lower package bonding parasitics. In this paper, a 1200V enhancement-mode GaN HEMT from GaNPower International has been characterized at cryogenic temperature. A 63% decrease has been demonstrated in the on-resistance, Rds(on) from room temperature to -150°C. The threshold voltage shows a 1.2x increase from room temperature to cryogenic temperature (-178°C). The transconductance (Gfs) shows a 1.34x increase for a temperature difference of 175°C. The results translate to a lower conduction loss and a faster switching speed and unfold further possibility of GaN in cryogenic converter applications.