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As a part of R&D work for the high intensity proton linac of China Accelerator Driven Sub-critical System project, a superconducting half-wave cavity with a frequency of 162.5 MHz and an optimal beta of 0.15 (HWR015) has been developed at Institute of Modern Physics (IMP), Chinese Academy of Sciences. In this paper, the design and test results will be described in detail. We introduced a new stiffening strategy for the HWR cavity, the simulation results show that the cavity has much lower frequency sensitivity coefficient (df/dp), Lorentz force detuning coefficient (KL), and can achieve more stable mechanical properties. The performance of the HWR cavity operated in cryostat will be also reported.

Thin film of selendia tin (SnSe) is made by the method of closed selenisation. Measurement of alternating current for samples in the form of enclosed structures with aluminum electrodes (Al/SnSe/Al) is carried out in the cryostat chamber at an intermediate temperature in the cryostat chamber at a temperature between (228-373) K. The parameters measured are capacitance for frequencies less than 50kHz, capacitance decreases, with respect to frequency and increases with temperature, whereas at frequencies greater than 50 kHz the capacity is fixed. The dielectric constant of the film is er = 12.13, calculated from the graph of capacitance with respect to the thickness of the sample (1/d).

Superconducting multipole insertion devices (wigglers and undulators) used to generate synchrotron radiation significantly increase the photon flux, especially in the hard spectral region. Over the past 35 years, more than 25 superconducting wigglers for leading centers of synchrotron radiation have been created at the BINP. A cryogenic system based on cryocoolers has been developed, which makes is possible to operate superconducting insertion devices for several years without consuming liquid helium. In this paper, the characteristics of various superconducting insertion devices created at the BINP are presented. The design features and recent advances in the development of the magnetic and cryogenic system with liquid and indirect cooling are discussed.

Myocardial tissue in optimal cutting temperature (OCT) fixation and cryostat sectioning was tested as a means of storing and preparing tissue for myofilament function analysis in relation to conventional liquid nitrogen freezing and dissection. Actomyosin interaction, Ca2+ force activation, and passive compliance were tested. The study concluded that OCT storage and cryostat sectioning do not interfere with the actomyosin cross-bridge dynamics or Ca2+ activation but that absolute tension values suffer and may not be investigated by this method.

The first of series (FoS) multiplet built for the Super-FRS at GSI/FAIR was delivered to a dedicated magnet test facility at CERN. After a series of tests at room temperature, it was cooled down to 4.5 K and is now under cold powering test. The commissioning of the CERN test facility is performed in parallel with the magnet testing. The quadrupole and the sextupole magnet enclosed in the cryostat module are superferric magnets with a large aperture diameter of 380 mm. The yoke length of the quadrupole magnet and the sextupole magnet is 1200 mm and 500 mm, respectively. The features of the magnets are vacuum impregnated racetrack coils made of Nb-Ti conductor and a maximum integrated gradient of 11.4 T/m × m for the quadrupole magnet and 20 T/m 2 × m for the sextupole magnet, respectively. This paper presents the design issues of the magnets, especially of the quadrupole magnet, an overview of a qualification process of the multiplets, and preliminary test results.

A series of high temperature superconducting (HTS) flux pumps have been developed to achieve the persistent current mode (PCM) operation for HTS magnets. However, most of the HTS flux pumps work with a small operating air gap, or with an iron core, the extra heat load brought by the conventional components deployed in the cryogenic environment is inevitable. To address this problem, in this study, in conjunction with the wireless power transfer (WPT) approach and transformer-rectifier type HTS flux pump, we have proposed a contactless self-regulating HTS flux pump. A circuit model and a 2D H-formulation finite-element model have been built for better understanding this system. Furthermore, a basic prototype was proposed to experimentally validate this concept. The measured results indicate that this method has the potential to charge the HTS magnet with all the conventional constituents outside the cryostat, and the operating frequency could be very low to evade inducing large eddy current as well as losses on the cryostat wall.

Currently, feasibility studies on fully turboelectric propulsion systems for electric aircrafts are being conducted worldwide. A fully superconducting rotating machine can realize fully turboelectric propulsion systems with light weight and high power density. In the simple casing model considered in a previous study, the field winding forms a large percentage of the generator weight. Therefore, to reveal the relationship between the operation temperature of the field winding and output power density, we compared an inner cryostat model having a field winding operation temperature of 20 K with the simple casing model having a field winding operation temperature of 64 K in terms of the output power density, efficiency, and increasing temperature. The stator and rotor rooms of the inner cryostat model were insulated by introducing the vacuum layer. The inner cryostat casing structure can have a lower refrigerant gas temperature, e.g., 20 K. Consequently, the temperature of the simple model increased from 5.4 to 7.1 K and that of the inner cryostat model increased from 3.0 to 6.1 K. The simple and inner cryostat models’ power densities were 18.8 and 21.7 kW/kg, respectively. Both models achieved 99% efficiency. No major difference was observed between both models in terms of efficiency and output power density.

JT-60SA is a fusion experiment tokamak device with superconducting magnets to be built in Japan. As a unique feature of the JT-60SA cryodistribution system, the main cryogenic transfer line from the helium refrigerator directly inserts into the tokamak cryostat at 12.4 m height, and then it branches to 12 distribution units separately placed around the tokamak through headers in the cryostat. This configuration contributes to the maximization of plasma volume and installation flexibility for heating and measurement devices of plasma experiments but causes complicated cooling paths and severe conditions on a mechanical design due to the seismic event and the thermal contraction. In this work, we represent the system design of JT-60SA cryodistribution and several component designs in these severe conditions.

We have finalized the design of a full-scale tabletop 1.5-T/90-mm MgB $_2$ finger MRI magnet system for osteoporosis screening based on our preliminary test results of small coils and superconducting joints. The magnet will operate in persistent mode at 10 K with an additional 5 K temperature margin. The magnet design which includes six main coils and an iron shield satisfies the required specification of a field intensity of 1.5 T, homogeneity of $\leq$ 5 ppm over a 20-mm diameter of spherical volume, and a fringe field of $\leq$ 5 gauss at 0.5 m in radius from the magnet center. An active protection method using external heaters will be applied to prevent a local hot spot in the MgB $_2$ windings from being overheated when quench occurs. Active shield transverse and axial gradient coils for this tabletop osteoporosis MRI, having primary and shield coil pairs, are designed to minimize stray fields that can induce eddy currents on nearby metal surface and thus imaging artifacts. This paper covers design and analysis of: 1) the main coils and iron shield; 2) coil former; 3) quench protection; and 4) active shield gradient coils. We also discuss design changes of the cryostat and equipment plan for the overall system. The magnet system will be completed and then, equipped with other MRI hardware components including an in-house-made gradient coil assembly and RF coils for demonstration of 1.5-T finger MRI in 2020.

A versatile test facility capable of providing cryogenic-electro-magnetic multifield was constructed for field-dependent and mechanical property measurements of superconducting wires/tapes at Lanzhou University of China. It firstly realized a continuous variation of cryogenic temperature from 4.2 K to 77 K (∼5 K/min) and a transport current from 0–1000 A (∼1 A/min) in a background magnetic field of 3.5 T. Aiming at improvements of samples in a larger scope, the facility was upgraded on several sub-systems, for example, the background superconducting magnet, variable-temperature cryogenic and mechanical loading and control system. This paper presents the latest upgrading of the multifield test facility. A semi-open split NbTi magnet with a combined cooling system was newly fabricated to generate a transverse background filed up to 5 T in a relatively larger test space of ∅100 mm × H800 mm. To improve the cryogenic system for refrigeration, a compact cryostat of cylinder-like vacuum Dewar vessel with a visible window, cooled by a Gifford–McMahon (GM) cryocoolers, was constructed. The continuous temperature variations from 4 to 353 K (∼10 K/min) and a high transport current application 0–1000 A (∼3 A/min) for testing superconducting wires/tapes were achieved. Additionally, a data acquisition system with accurate and synchronous measurements of multifield including current, temperature, strain, and AC losses was enhanced. Some tests illustrated that the upgrading of sub-systems and extend of operation range for the test facility were well improved. It will contribute to the progress in understanding design issues for superconducting wires/tapes under intense multiple fields.

According to the so-called Primakoff effect, axions and axion-like particles can transform into photons in the presence of a strong magnetic field. To continue the search for these hypothetical particles, a new helioscope called the International Axion Observatory IAXO, and its subscale but fully functional demonstrator Baby-IAXO, are being designed. To increase the detector's sensitivity by a factor of 10 compared to the present CAST helioscope, the experiment needs a stronger magnetic field and in a much larger volume. The superconducting magnet of Baby-IAXO features two 10 m long flat racetrack coils spaced by 0.8 m, arranged in a common coil configuration and generating an average magnetic field of 2.1 T in the two 700 mm detection bores positioned in between the coils. The cold mass structure based on using mainly Al6061-T651, is designed to guarantee pre-stress of the coils during curing and sustain the magnetic loads by the Lorentz force. At ultimate current of 12 kA, the repelling force between the two coils is 33 MN. Furthermore, the supporting structure has to keep the coils in position as they are in an unstable equilibrium in the plane parallel to the racetracks. To support the cold mass in the cryostat, an arrangement of rods was chosen in order to minimize the cryogenic load. The system is composed of 16 titanium rods, which in addition to supporting the expected force loads also keeps the magnet centered. The total mass of the magnet is 35 t comprising an 18 t cold mass and a 15 t cryostat. The magnet is installed on an elevated 360° rotating platform further constraining the cryostat design. Here the mechanical design of cold mass, cold mass supporting system and cryostat of the Baby-IAXO magnet are presented.

In magnetic resonance imaging (MRI), pulsed magnetic gradient fields induce eddy currents in surrounding conducting components of the MRI scanner. These eddy currents distort MRI image and introduce thermal load in cryostat. Ohmic heating of superconducting magnet due to eddy currents changes the operating temperature of magnet, which can lead to system quench. Numerical simulation of these eddy current is important to compensate/control their adverse effects. In this paper, a coupled circuit network method is outlined to model eddy currents in a superconducting magnet that induced by z-gradient coil. According to the axial symmetry, the cylindrical cryostat vessels are divided into several concentric slices with a finite thickness. Each slice is modeled as a series circuit composed of a resistor and an inductor, and inductively coupled with other slices and gradient coil. To improve the calculation efficiency, the Eigen matrix technique is used to simplify the coupled differential matrix equation. The undesired eddy current effects including time-varying secondary magnetic field and power losses are analyzed. In addition, the eddy current behavior due to mechanical errors of gradient coil is discussed. Compared with the simulation results of ideal gradient coil design, the misalignment between primary and secondary layer of z-gradient coil can cause asymmetric secondary magnetic field along z-axis and further introduce $B_{0}$ -shift in imaging area.

Generally, in a high temperature superconducting (HTS) generator, a large magnetic air gap exists because of needed space for a cryostat or non-magnetic cores in the HTS generators. Consequently, the inductance becomes lower than conventional generators. As a result, the short circuit current becomes as high as more than 10 times the rated current. The design of the mechanical structure of a generator is very challenging to endure a high force and torque at the HTS field coils. Therefore, a performance evaluation system (PES) is required to test the HTS field coil and support structures of the generator. In this paper, the design and feasibility study of a PES for and HTS field coil of large-scale HTS generator are presented. The 10 MW class HTS generator and PES was designed based on the electromagnetic analysis results obtained using the finite element method. The torque and force of the HTS field coil were analyzed. As a result, the HTS field coil can be practically tested using the proposed PES whether the structure of the coil can withstand the high torque and force of the generator. The proposed PES design and short-circuit analysis results can be effectively used for the development of large-scale HTS wind power generation systems.

The Grenoble Hybrid magnet is a modular platform applying resistive and superconducting technologies to deliver various continuous high magnetic field and flux configurations. They range from 43 T in 34 mm diameter with 24 MW down to 9 T in 800 mm with the superconducting coil 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 future is considered and needs to be assessed by further dedicated studies. The key design parameters are recalled including the specifically developed superconducting conductor, the large bore outsert coil, the cryostat with the eddy-current shield and the cryogenic infrastructure. Most of the equipment of the hybrid magnet outsert has been built, tested and delivered to LNCMI-Grenoble, where integration and assembly is ongoing. The dedicated material development program initiated for the innermost resistive insert is in progress. The status of the project is given together with the main problems encountered and solved. The commissioning of the overall hybrid magnet system will start in 2020 and will be followed possibly by the first run of a new axion dark matter search experiment in preparation.

Cryogenic bypass diodes have been installed in all superconducting dipole magnets (1232) and quadrupole magnets (392) of the Large Hadron Collider (LHC) at CERN, and operated during the physics runs since 2009. The bypass diodes are a fundamental ingredient of the quench protection system for those main dipoles and quadrupoles magnets. The diodes are located inside the magnet cryostats, operating in superfluid helium and exposed to ionizing radiation. The connection between the superconducting magnet and the bypass diode is made through a mechanical clamping system and copper bus bars. Since their first installation, all LHC diodes have undergone at least two full thermal cycles (from 1.9 K to room temperature and back to superfluid helium temperature). The evolution of electrical parameters as well as improvements and modifications made over a period of 10 years are reviewed in this paper. With CERN preparing for LHC's High Luminosity era, the long-term strategy for cold diodes is presented, based on the overall results and experience gathered so far, including the studies related to the tolerance with respect to the radiation doses and neutron fluences expected.

In this article, a structural integrity assessment of ITER Torus Cryo-Pump Housing (TCPH) is presented. TCPH is a penetration structure located on the cryostat cylinder whose main function is to accommodate and support the Torus Cryo-Pump (TCP), connect it to the vacuum vessel (VV), and provide tritium confinement and primary vacuum boundary. The design of the TCPH structure was finalized during the final design review (FDR). After the FDR, based on the manufacturing feasibility study, changes in the design were proposed to facilitate the nondestructive examination of weld joints. To qualify the proposed changes, structural integrity assessment was performed as per Section VIII Div. 2 Part 5 of ASME code by finite-element analysis using ANSYS software. The structural and thermal assessment was done as per TCPH load specification for protection against plastic collapse, local failure, ratcheting, buckling, and fatigue to perform the structural integrity of the TCPH. The results obtained from the integrity assessment qualified the design criteria. Margins available over allowable stress values for plastic collapse, local failure, and ratcheting are 20%, 19%, and 30%, respectively. A buckling factor of 79 was achieved with a minimum allowable value of 13.42. For fatigue, a usage fraction of 0.516 was obtained against allowable maximum value of 1. Thus, the design with proposed changes was qualified and incorporated.

A crucial part of the closed fuel cycle of future fusion power plants will be isotope separation, which takes place in a cryogenic distillation refraction column, where all six hydrogen isotopologu...

Objective: To present the technical design and demonstrate the feasibility of a multi-channel on-scalp magnetoencephalography (MEG) system based on high critical temperature (high- ${T}_\text{c}$ ) superconducting quantum interference devices (SQUIDs). Methods: We built a liquid nitrogen-cooled cryostat that houses seven YBCO SQUID magnetometers arranged in a dense, head-aligned array with minimal distance to the room-temperature environment for all sensors. We characterize the performance of this 7-channel system in terms of on-scalp MEG utilization and present recordings of spontaneous and evoked brain activity. Results: The center-to-center spacing between adjacent SQUIDs is 12.0 and 13.4 mm and all SQUIDs are in the range of 1-3 mm of the head surface. The cryostat reaches a base temperature of $\sim$ 70 K and stays cold for $>$ 16 h with a single 0.9 L filling. The white noise levels of the magnetometers is 50–130 fT/Hz1/2 at 10 Hz and they show low sensor-to-sensor feedback flux crosstalk ( $ 0.6%). We demonstrate evoked fields from auditory stimuli and single-shot sensitivity to alpha modulation from the visual cortex. Conclusion: All seven channels in the system sensitively sample neuromagnetic fields with mm-scale scalp standoff distances. The hold time of the cryostat furthermore is sufficient for a day of recordings. As such, our multi-channel high- ${T}_\text{c}$ SQUID-based system meets the demands of on-scalp MEG. Significance: The system presented here marks the first high- ${T}_\text{c}$ SQUID-based on-scalp MEG system with more than two channels. It enables us to further explore the benefits of on-scalp MEG in future recordings.

A measuring complex for recording events by single-photon superconducting detectors based on NbN structures is presented; low-noise high-frequency HEMT transistors are used as cryogenic amplifiers in it.

The influence of the cooling method on thermal stability is a non-trivial aspect for superconducting material to be used in several applications, for example, in photon detection. Indeed, a wasteful cooling can induce quenches in the device that can lead to false counts. So far, the efficient cooling has been realized by immersion of the superconducting device in a liquid He bath. However, cheaper cryogen-free (CF) cooling techniques are now commercially available, as well as cryocoolers are becoming the only way to obtain a cooling environment in the liquid He shortage. Here we consider three different cooling methods: one is by liquid He in a standard cryostat and the other two are a dynamic or a static He gas cooling in a CF cryostat. Then, we are able to evaluate the performance of the cooling method by the impact on current-voltage curves at very high bias currents. In particular, we acquire current-voltage characteristics on ultra-thin microbridges made by two different superconducting materials commonly used in detectors fabrication, which are NbN and NbTiN. Here, the flux-flow instability (FFI) phenomenon is used as a tool to determine the influence of the three different cooling techniques on the voltage stability of the devices under current biasing. It results that the CF cooling method has performance comparable to liquid He bath. This finding supports the spread of the CF technique for applications, and it validates the FFI as a tool to test superconducting materials.

The 1-ton-scale CUORE detector is made of 988 $${{{\hbox {TeO}}}}_2$$ crystals operated as cryogenic bolometers at a working temperature of $$\sim 10{{{\hbox { mK}}}}$$ . In order to provide the necessary cooling power at 4 K stage, a total of five pulse tube (PT) refrigerators are used. The PTs make the cryogenic system reliable and stable, but have the downside that mechanical vibrations at low frequencies (1.4 Hz and related harmonics) are injected into the experimental apparatus. An active noise cancellation technique has been developed in order to reduce such effect by taking advantage from the coherent interference of the pressure oscillations originated by the different PTs. The technique that will be presented consists in controlling the relative phases of the pressure waves running inside the CUORE PT lines, in order to achieve the lowest detector noise. By reducing the power of PT harmonics by a factor up to $$10^4$$ , it drastically suppresses the overall noise RMS on the CUORE detector. In the following, we demonstrate the reliability and effectiveness of the technique, showing that the optimization of the detector noise level is possible in different experimental conditions.

The high thermal conductivity of single-walled carbon nanotubes (SWCNTs) has gained much attention for their applications in potential thermal devices. Here, we investigate anharmonic effects, originated from phonon interactions, of SWCNT bundles by temperature dependent Raman imaging using our home-built mini cryostat system. The cryostat system is small enough to be mounted on a piezo scanner that suppresses thermal drift, enabling Raman imaging at different temperatures. We obtained Raman spectral images of several SWCNT bundles with a spatial resolution of a few hundred nanometers at different temperatures. We found that different bundles show different temperature dependences of Raman peak intensity, shift, and width. The temperature dependence was further elucidated by considering the sample topography observed by atomic force microscopy, where bundle effects seem to play an important role to influence the anharmonicity. The temperature-dependent Raman analysis based on spatially resolved imaging will be a powerful tool to investigate anharmonic effects of advanced carbon nanomaterials as well as to realize in situ visualization of thermal properties for future thermal devices.

A vertically loaded cryostat with a shaft diameter of 80 mm based on a GM SRDK415D cryocooler for operation in the temperature range of 4–300 K is described. This cryostat can operate both in vertical and horizontal positions, almost without losing the final temperature. The time-temperature curves of the sample chamber in the temperature range of 4–150 K in the vertical and horizontal positions of the cryostat are presented. The temperature is adjusted using the controller. Before the experiment, the 25-mbar pressure of heat exchange helium gas is set in the shaft. The cryostat is designed for operation at the NERA spectrometer of the IBR-2 reactor at the Laboratory of Neutron Physics of the Joint Institute for Nuclear Research.

Dielectric waveguides have potential as transmission lines in subterahertz (sub-THz) applications due to their low-loss. A new application of a rectangular dielectric waveguide (RDW) for a THz superconducting receiver system for radio astronomy is investigated and demonstrated for the first time. The RDW can be used to transmit sub-THz local oscillator (LO) signals into the cryostat for driving the superconductor insulator superconductor mixer, with very low heat transfer. A series of RDWs with different lengths are fabricated. The measured average attenuation constants of the RDW are 0.034 and 0.069 dB/mm at 3.4 and 300 K measurement environments over 240–300 GHz, respectively. The double-sideband system noise temperature of the receiver system is also measured. With this LO signal feeding system, there is only 0.69 mW thermal transfer power from the 300 to the 3.4 K cold stage. Compared to traditional pumping signal feeding schemes, such as the horn-to-horn structure and beam splitter method, this approach outperforms the traditional schemes in terms of feeding flexibility, insertion loss, and thermal isolation for the cryostat. The proposed RDW can be widely applied to superconducting receivers for radio astronomy in the future.

The accelerator-driven subcritical system (ADS) is the internationally recognized key technology of nuclear waste problem treatment, of which superconducting proton linac is an important part. With the support of the strategic science and technology pilot project of the Chinese Academy of Sciences, the Institute of High Energy Physics of the Chinese Academy of Sciences took the lead in the research of 325 MHz superconducting proton linac, which is called ADS Injector I. The superconducting accelerator part of ADS Injector I mainly consists of 14 spoke-type superconducting cavities with β 0.12. At the same time, the research work of various cavities with different β values and different frequencies is also carried out to lay the technical and technological foundation for ADS main accelerator. The only way to determine whether the superconducting cavity can reach the design target and whether it can be installed into the cryostat is the vertical test at cryogenic. As the only way to test the microwave performance of the superconducting cavity at low temperature, the vertical test can accurately test the acceleration gradient Eacc and the corresponding quality factor Q0 of the superconducting cavity. The design and construction of the superconducting cavity vertical test facility is based on the practical needs of the pilot project and the long-term development of the superconducting accelerator. This paper mainly introduces the design and construction of the cryogenic vertical test system for the superconducting cavity of ADS Injector I, including the system scheme design, process design, heat load analysis, 2 K superfluid helium obtaining method, system commissioning and operation, etc. The static heat leakage at 2 K of the 2 K superfluid helium vertical test system of ADS Injector I is 1.624 W, which has reached the international advanced level. The 2 K superfluid helium vertical test system of ADS Injector I after constructed not only meets the test requirements of ADS pilot project, but also conducts 4 K and 2 K vertical tests for other different types of superconducting cavities and relevant cryogenic experiments.

The predictable quantum efficient detector (PQED) is a primary standard of optical power, which utilizes two custom-made induced-junction photodiodes that are mounted in a wedged trap configuration for the reduction of reflectance losses. PQED photodiodes of p-type and n-type were characterized for their dark current dependence on reverse bias voltage at room temperature. As simulations predict that the dark current will decrease exponentially with temperature, the temperature dependence of dark current for the n-type photodiodes was also measured. Two n-type induced-junction photodiodes were assembled inside a liquid nitrogen cryostat. The results from the dark current measurements indicate that the cooled n-type photodiodes are suitable for measuring optical fluxes in the few photon regime. A photon flux of approximately 7,000,000 photons per second was measured using the PQED at a cryogenic temperature with a relative standard uncertainty of 0.15%. The results support the utilization of the PQED as a primary standard of optical power in single and few photon applications.

The effect of vacuum degradation in cryostat of a gamma spectrometer on the steady-state temperature of thermal shield and its efficiency are analyzed in this study. Considering the thermal load du...

A versatile, modular in situ high-intensity monochromatic illumination set-up installed on a standard Q-band ESR spectrometer equipped with a cryostat and probe head for measurements at cryogenic temperatures, which can be easily assembled from commercially available optical components is presented. Using as monochromatic light sources pig-tailed laser diodes (LDs) or fiber-coupled light-emitting diodes (LEDs), a high efficiency of the light transfer (more than 95%) through an optical guide inserted in the sample holder is achieved in the sample area of the microwave cavity. With various LEDs and LDs, one can perform ESR in situ illumination experiments from UV to far-IR, in both cw and pulse mode. Its operation is illustrated with an experiment revealing the presence of certain ESR silent defects in oxygen-doped floating-zone ultrapure Si samples irradiated at room temperature with high-energy–high-fluence electron beams and pulse annealed up to 300 °C. New information is obtained by comparing the ESR spectra recorded at T = 120 K, without and with 1.06 µm across-the-gap in situ illumination.

The basic circuit diagrams of cryogenic installations that can ensure the necessary temperature operation conditions of power cables on the basis of high-temperature superconductors are considered. Formulas for calculating the energy consumed for cooling the cable by means of closed- and open-type cryogenic installations are determined. The hydraulic losses determining the energy expenditures for pumping the cryoagent in the cable cryostat with corrugated shells are analyzed. The components of the power required to compensate for the losses in transmitting electric energy via a superconducting cable are determined. As a result, a procedure for calculating energy expenditures for cryogenic installations in different cycles of their operation is proposed. The hydraulic friction coefficient in the flexible cryostat shells is determined. The available empirical relations for estimating the hydraulic friction coefficient in a flexible cryostat are compared with one another.

Superconducting MRI magnet is the most exhaustive commercial application of superconductivity and helium cryogenics. Cryocooler based Zero-Boil-Off (ZBO) technique is inevitable for the present-day scanner. An MRI cryostat for a 1.5T MRI magnet has been designed with the ZBO technique using a fin-based helium recondenser. A cryocooler based test rig has been developed to characterize the performance of the helium recondenser made of OFHC copper. A two-stage GM cryocooler is used to cool the thermal shield and the helium recondenser. Four liters of liquid helium has been produced using the same heat exchanger. The recondensation test of the heat exchanger is performed up to 6 psi of bath pressure. At 1psi, the recondensation capacity is found to be ~1.5W. This paper briefly discusses the experimental details of the recondensation test along with an analytical calculation.

—Arrays of planar annular antennas in the 345 GHz range with integrated superconductor–insulator–normal metal–insulator–superconductor (SINIS) bolometers have been developed, fabricated, and experimentally investigated. To increase the absorption efficiency, the source signal was matched with the array using a back-to-back horn and a counter-reflector. The efficiency of the receiving structure was studied depending on the direction of irradiation—through the substrate and from the antenna—as well as on the thickness of the substrate. The methods for normalizing a received signal using a reference channel outside and inside a cryostat is described. The best results were obtained by irradiating the array from the antenna with a substrate thickness equivalent to a quarter wavelength in the dielectric and sputtering of the rear side with a gold film (counterreflector). The effective matching band in the main range was more than 50 GHz; the volt–watt sensitivity reaches 109 V/W.

A Superconducting (SC) resonator (QWR) designed to operate at 113.6 MHz with geometry beta of 0.055 is under development for the post-acceleration of Rare Isotope Beam (RIB) at VECC, Kolkata. The QWR section of the post accelerator is composed of two cryostat module each containing four hermetically sealed QWRs having separate vacuum from cryostat. Each QWR module will accelerate beam up to q/A=1/7 with accelerating gradient of 5.0 MV/m in CW mode. In this paper, the design of the QWR has been reported considering issues like sufficient operational margin, beam dynamical requirements, mechanical fabrication, etc. The simulations performed with FEM code show that the tuning system can adjust and compensate the frequency drift due to external vibrations and helium pressure fluctuation during operation. In order to minimize the undesirable beam steering effect due to vertical component of electric field, studies has been made to optimally position QWRs inside cryostat.

A new type of miniature negative temperature coefficient (NTC) thermistors has been developed and manufactured with Mn-Ni-Cu-Fe oxides. The prepared NTC thermistors were calibrated in the temperature range from 77 K to 300 K with 1 μA exciting currents. The automatic calibration apparatus as well as thermometric characteristics, stability, calibration equations and interchangeability of the manufactured thermistors were investigated. A mean fit equation was obtained: 1/T = 8.60 × 10−4 + 6.54 × 10−4 ln(R/Rref) + 2.46 × 10−5 ln(R/Rref)2 + 9.48 × 10−7 ln(R/Rref)3 − 2.16 × 10−8 ln(R/Rref)4. All the prepared NTC thermistors agreed with this fit with an error of 1.5 K. If the greater accuracy is required, a calibration is necessary, and the calibration accuracy is estimated to be ±10 mK.

The past few decades have seen major developments in the design and operation of cryogenic particle detectors. This technology offers an extremely good energy resolution - comparable to semiconductor detectors - and a wide choice of target materials, making low temperature calorimetric detectors ideal for a variety of particle physics applications. Rare event searches have continued to require ever greater exposures, which has driven them to ever larger cryogenic detectors, with the CUORE experiment being the first to reach a tonne-scale, mK-cooled, experimental mass. CUORE, designed to search for neutrinoless double beta decay, has been operational since 2017 at a temperature of about 10 mK. This result has been attained by the use of an unprecedentedly large cryogenic infrastructure called the CUORE cryostat: conceived, designed and commissioned for this purpose. In this article the main characteristics and features of the cryogenic facility developed for the CUORE experiment are highlighted. A brief introduction of the evolution of the field and of the past cryogenic facilities are given. The motivation behind the design and development of the CUORE cryogenic facility is detailed as are the steps taken toward realization, commissioning, and operation of the CUORE cryostat. The major challenges overcome by the collaboration and the solutions implemented throughout the building of the cryogenic facility will be discussed along with the potential improvements for future facilities. The success of CUORE has opened the door to a new generation of large-scale cryogenic facilities in numerous fields of science. Broader implications of the incredible feat achieved by the CUORE collaboration on the future cryogenic facilities in various fields ranging from neutrino and dark matter experiments to quantum computing will be examined., Comment: 45 pages, 14 figures

This paper investigates different possibilities of measurement and control of pressure in the cryostat filled with liquid nitrogen. Laboratory designed membrane pressure regulator for automatic control of pressure in the range from 0.9 to 1.3 bar gauge in the cryostat is presented. The performance of the special purpose regulator is evaluated through measurement of pressure deviations from set-point value and their effect on thermal conditions in the cryostat. Results are compared to values obtained using manual pressure regulator.

The Einstein Telescope is Europe’s next generation gravitational-wave detector. To develop all necessary technology, four research facilities have emerged across Europe: The Amaldi Research Center (ARC) in Rome (Italy), ETpathfinder in Maastricht (The Netherlands), SarGrav in the Sos Enattos mines on Sardinia (Italy) and E-TEST in Liége (Belgium) and its surroundings. The ARC pursues the investigation of a large cryostat, equipped with dedicated low-vibration cooling lines, to test full-scale cryogenic payloads. The installation will be gradual and interlaced with the payload development. ETpathfinder aims to provide a low-noise facility that allows the testing of full interferometer configurations and the interplay of their subsystems in an ET-like environment. ETpathfinder will focus amongst others on cryogenic technologies, silicon mirrors, lasers and optics at 1550 and 2090 nm and advanced quantum noise reduction schemes. The SarGrav laboratory has a surface lab and an underground operation. On the surface, the Archimedes experiment investigates the interaction of vacuum fluctuations with gravity and is developing (tilt) sensor technology for the Einstein Telescope. In an underground laboratory, seismic characterisation campaigns are undertaken for the Sardinian site characterisation. Lastly, the Einstein Telecope Euregio meuse-rhine Site & Technology (E-TEST) is a single cryogenic suspension of an ET-sized silicon mirror. Additionally, E-TEST investigates the Belgian–Dutch–German border region that is the other candidate site for Einstein Telescope using boreholes and seismic arrays and hydrogeological characterisation. In this article, we describe the Einstein Telescope, the low-frequency part of its science case and the four research facilities.

We present a cryogenic ion trapping system designed for large scale quantum simulation of spin models. Our apparatus is based on a segmented-blade ion trap enclosed in a 4 K cryostat, which enables us to routinely trap over 100 $^{171}$Yb$^+$ ions in a linear configuration for hours due to a low background gas pressure from differential cryo-pumping. We characterize the cryogenic vacuum by using trapped ion crystals as a pressure gauge, measuring both inelastic and elastic collision rates with the molecular background gas. We demonstrate nearly equidistant ion spacing for chains of up to 44 ions using anharmonic axial potentials. This reliable production and lifetime enhancement of large linear ion chains will enable quantum simulation of spin models that are intractable with classical computer modelling., Comment: 16 pages, 11 figures

We present the results of theoretical and experimental studies of the resonant properties of a single cell of a receiving system based on cold-electron bolometers (CEBs) with a double-slot antenna and curved coplanar lines, which is intended for receiving a signal in the range 220–240 GHz with a bandwidth of 5%. The resonant properties of a CEB located on the cryostat plate with a temperature of 0.3 K, are measured using an oscillator based on high-temperature superconductor (HTS) of yttrium barium copper oxide (YBCO), placed inside the same cryostat on a plate with a temperature of 4 K, which allows one to obtain smooth amplitude-frequency characteristics.

In order to quickly and economically achieve low temperatures, the process of obtaining them in home universal liquid-flow cryostats using liquid helium and nitrogen is considered. To control the level of a cryoagent, an original capacitive system for measuring the level of different liquid cryoagents has been designed, which has no analogs in the world. It has been experimentally shown that the most optimal and economical way to obtain low temperatures is to pump cryoagent vapors directly from the working chamber of the cryostat., З метою швидкого i економного досягнення низьких температур розглянуто процес їх отримання у вiтчизняних унiверсальних рiдинно-протiчних крiостатах з використанням рiдкого гелiю та азоту. Для контролю рiвня крiоагента розроблено оригiнальну ємнiсну систему вимiрювання рiвня рiзних типiв рiдкого крiоагента, яка немає аналогiв у свiтi. Експериментально показано, що найоптимальнiшим i найекономнiшим шляхом отриманння низьких температур є вiдкачка парiв крiоагента безпосередньо з робочої камери крiостата.

This paper presents effects of lithium (Li) and magnesium (Mg) dopants on the dielectric properties of ZnO ceramics with emphasis on ferroelectricity prospects of co-doped samples with Zn0.7Li0.28Mg0.02O compositions. Ceramics with average relative density ∼97% were produced by solid-state-reaction of mechanically activated powder precursors using 1000 °C for 2 h sintering conditions. Room temperature A.C. conductivity σ a . c ( ω ) and temperature-frequency (T-ω) dependence of dielectric permittivity ( e ′ ) and loss ( e ″ ) of the samples are measured within temperature range from −100 to 150 °C in air and in a vacuum cryostat with liquid nitrogen coolant. Undoped ZnO σ a . c ( ω ) data exhibits a nearly insensitive dependence to the ω while that of doped samples show significant ω dependence and higher σ a . c ( ω ) values than undoped ZnO ceramics. Anomalous e ′ and e ″ peaks were observed in Zn0.7Li0.28Mg0.02O specimens around TC of −25 °C during cooling and −10 °C during heating measurements in air. However, dielectric properties of the same Zn0.7Li0.28Mg0.02O ceramics obtained in vacuum cryostat and from undoped ZnO ceramics in air and in vacuum cryostat did not reveal any e ′ and e ″ transition peaks at low temperature.

We present the results of the experimental and theoretical study of the resonant properties and noise of a single cell of a receiving system based on cold-electron bolometers (CEB) with a double-folded slot antenna and coplanar lines. The system was designed to receive signals at 220/240 GHz frequencies with a 5% bandwidth. In measurements, we used the samples of the double-folded slot antennas with slot lengths of 162 um and coplanar line lengths from 185 to 360 um. Measurements of the resonance properties of CEB located at 0.3 K cryostat plate were carried out using a generator based on a high-temperature YBCO Josephson junction located inside the same cryostat at 4 K plate. This arrangement made it possible to obtain smooth amplitude-frequency characteristics with a clearly defined peak of a 15–21 GHz bandwidth at different frequencies. Based on these results, 2-D array of double-folded slot antennas with CEBs as 220/240 GHz LSPE channel prototype was calculated.The absorption efficiency of the array has reached 81% and 77% for 220 and 240 GHz channels, respectively.

Synchrotron-radiation-based (SR-based) Mossbauer spectroscopy was applied to 193Ir 73 keV transition. Measuring the spectra of Ir metal and IrO2 at 7 K was performed to evaluate the spectrometer employing He-closed-cycle cryostats. The SR-based Mossbauer spectroscopy on 193Ir 73 keV Mossbauer transition was applied to investigate the physical properties of an intermediate valence iridium oxide Ca5Ir3O12. Efficiency of measuring spectra on operation modes of a synchrotron radiation facility was also discussed.

A large bore “High-Temperature Superconductor Cable Test Facility Magnet” for testing advanced cables and inserts in high transverse field is in its design phase. This magnet will be the core component of a facility for developing conductors and accelerator magnets operating above 15 T, an enabling technology for next-generation fusion devices using magnetic confinement of plasma and for future energy frontier colliders. The procurement of Nb3Sn conductor, fabrication of cables, winding of coils, and assembly of the dipole magnet will be done at Lawrence Berkeley National Laboratory (LBNL) and the test pit and cryostat will be constructed at Fermi National Accelerator Laboratory. This article will present the conductor element of the LBNL project, specifically cable design parameters (based on the Bruker OST RRP $^{\bigcirc \!\!\!\! {\hbox{R}}}$ Nb3Sn superconducting wire) and the development phase cable fabrication experience. Challenges of the cable fabrication will be discussed. The wire and cable planned for this magnet are similar to those under study for the Future Circular Collider and other large facility magnets. The successful fabrication of the development cable has positive implications for these other projects.