Large-scale Scientific Facilities Research Articles

Constrained multi-objective optimization of helium liquefaction cycle

The helium cryo-plant is an indispensable subsystem for the application of low temperature superconductors in large-scale scientific facilities. However, it is important to note that the cryo-plant requires stable operation and consumes a substantial amount of electrical power for its operation. Additionally, the construction of the cryo-plant incurs significant economic costs. To achieve the necessary cooling capacity while reducing power consumption and ensuring stability and economic feasibility, constrained multi-objective optimization is performed using the interior point method in this work. The Collins cycle, which uses liquid nitrogen precooling, is selected as the representative helium liquefaction cycle for optimization. The discharge pressure of the compressor, flow ratio of turbines, and effectiveness of heat exchangers are taken as decision parameters. Two objective parameters, cycle exergy efficiency, ?ex,cycle, and liquefaction rate, ?L , are chosen, and the wheel tip speed of turbines and UA of heat exchangers are selected as stability and economic cost constraints, respectively. The technique for order of preference by similarity to the ideal solution (TOPSIS) is utilized to select the final optimal solution from the Pareto frontier of constrained multi-objective optimization. Compared to the constrained optimization of ?ex,cycle, the TOPSIS result increases the ?L by 23.674%, but there is an 8.162% reduction in ?ex,cycle. Similarly, compared to the constrained optimization of ?L, the TOPSIS result increases the ?ex,cycle by 57.333%, but a 10.821% reduction in ?L is observed. This approach enables the design of helium cryo-plants with considerations for cooling capacity, exergy efficiency, economic cost, and stability. Furthermore, the wheel tip speed and UA of heat exchangers of the solutions in the Pareto frontier are also studied.

A new era is emerging at scientific user facilities.

Global scientific exchange has been profoundly perturbed by the COVID-19 pandemic, altering user travel behaviours and accelerating the use of remote access. Combined with the advent of artificial intelligence (AI), these trends together can change how large-scale user scientific facilities are used by the community and managed by operators.

Progress in analytical methods for the interaction between nanomaterials and biomolecules based on large-scale scientific facilities

Progress in analytical methods for the interaction between nanomaterials and biomolecules based on large-scale scientific facilities

Research on the newest GaN-Based solid-state power amplifier for CiADS project

Institute of Modern Physics (IMP), Chinese Academy of Sciences is the first domestic institute to widely apply solid-state power amplifier (SSPA) to linear accelerator project from China Accelerator Driven Sub-critical System (C-ADS) project started since 2011. Until now, SSPA design has already been considered for two large-scale scientific facilities in Guangdong Province of southeast China: China initiative Accelerator Driven System (CiADS) and High Intensity Heavy-ion Accelerator Facility (HIAF). The SSPA was developed rapidly due to the reliable technologies of LDMOS-based (laterally diffused metal oxide semiconductor) power amplifiers.With the maturation of GaN (Gallium Nitride) technology, GaN-based amplifiers have been studied in the field of accelerators since 2020. Last year, IMP made new progress with GaN SSPA, measuring power modules at three fundamental frequency points of 162.5 MHz, 325 MHz, and 650 MHz. The first 50 kW rack with GaN SSPA was measured at 650 MHz in IMP, and its modules offer huge advantages of 40% output power and 8% efficiency compared to the newest LDMOS at the same frequency, which holds a fascination for our project.Until the beginning of 2023, the prototype power modules on three frequency points were completed and tested. This paper will detail the design development of GaN technology and its technical characteristics.

Development of cold compressors for a 500 W@2 K superfluid helium refrigeration system

A superfluid helium refrigeration system is a necessity for the cooling equipment in many large-scale scientific facilities. As an essential device, a type of cold compressor is designed and manufactured in this paper. It mainly consists of motor, bearings, compressor components, and heat insulation. After conducting tests at both ambient temperature and low temperature, the target of long-term stable operation at 500 W@2 K was finally achieved. The structure and test results of the cold compressor are summarized. The isentropic efficiencies of cold compressors were between 50% and 70%, and the heat leakage was less than 40 W.

Cloud–Edge Hybrid Computing Architecture for Large-Scale Scientific Facilities Augmented with an Intelligent Scheduling System

Synchrotron radiation sources are widely used in interdisciplinary research, generating an enormous amount of data while posing serious challenges to the storage, processing, and analysis capabilities of the large-scale scientific facilities worldwide. A flexible and scalable computing architecture, suitable for complex application scenarios, combined with efficient and intelligent scheduling strategies, plays a key role in addressing these issues. In this work, we present a novel cloud–edge hybrid intelligent system (CEHIS), which was architected, developed, and deployed by the Big Data Science Center (BDSC) at the Shanghai Synchrotron Radiation Facility (SSRF) and meets the computational needs of the large-scale scientific facilities. Our methodical simulations demonstrate that the CEHIS is more efficient and performs better than the cloud-based model. Here, we have applied a deep reinforcement learning approach to the task scheduling system, finding that it effectively reduces the total time required for the task completion. Our findings prove that the cloud–edge hybrid intelligent architectures are a viable solution to address the requirements and conditions of the modern synchrotron radiation facilities, further enhancing their data processing and analysis capabilities.

Field test study on the evaluation of the microvibration controlling capacity of a mass concrete layer

Microvibration induced by natural disturbance and human activities has an adverse effect on the operation of the large-scale and ultraprecise facilities in the world. Under such circumstances, a passive vibration control method is generally deployed for such vibration-sensitive facilities, taking the High Energy Photo Source (HEPS) in Beijing as an example, a 3 m-thick mass concrete layer forming a ring foundation was cast at the facility, where a 1 m-thick reinforced concrete slab (RC slab) lies. Since microvibration control plays a crucial role in the operation of such large-scale scientific and ultraprecise facilities and few studies have been reported for large-scale concrete layer as antimicrovibration devices, this paper presents four field tests in Beijing, China, to evaluate the vibration control capacity of a mass concrete layer. Based on a large number of field tests, the effect of applying the concrete layer is discussed, and a reference is provided for the construction of similar facilities. The vibration signals, generated by shock excitation and ambient excitation, are measured through a highly sensitive and high-accuracy vibration acquisition system. It is concluded that the existence of the 1 m-thick RC slab has little influence on the microvibration signal frequency distribution in the vertical direction and that the signals from the concrete layer and subsoil differ by approximately 10 Hz in the vertical direction while differing by approximately 5 Hz in the horizontal direction. The microvibration control ability of the concrete layer is favorable in a higher frequency band over 20 ~ 30 Hz and more than 50% attenuation can be gained through the concrete layer; however, the microvibration control ability is not significant below 20 ~ 30 Hz. The vibration levels across different heights of the concrete layer section are the same. To prevent adverse vibration disturbance below 20 ~ 30 Hz, it is suggested that the traffic and road surface conditions should be taken into consideration when choosing the construction location. In addition, a long-term monitoring shows that 75% vibration energy at the site is firmly related to the construction activities which are approximately 1.4 km from the site.

Research advances on X-ray pixel detectors

<p indent="0mm">Advanced light sources, represented by synchrotron radiation facilities, are important platforms for multi-discipline research. Several large-scale scientific facilities are under construction or being scheduled, including the High Energy Photon Source (HEPS), Shanghai high repetition rate XFEL and extreme light facility (SHINE), Hefei Light Source, and so on. This shows that they are the strategic directions from the national demands. However, detector technologies of the light source beamlines became the bottleneck problem for a long time. Among them, the X-ray pixel detector is a typical representative. Unfortunately, systematic studies were fully blank in this field in China before, and products were totally foreign-monopolized. To break through the dilemma, Wei Wei and his team made pioneer studies in the X-ray pixel detector field in China, and achieved two stages of key results through long-term research. (1) Realized the breakthrough and filled in the blanks in the field of high-end detectors for synchrotron radiation: Brought out the first domestic silicon pixel detector prototype machine, while the performance of the full system reached the level of advanced international products; the sub-project successfully passed the national acceptance inspection of HEPS-TF (High Energy Photon Source-Test Facility); the detector has been delivered for customer applications, while customers’ achievements have already begun to emerge. During the development work, key techniques of pixel detectors have been broken through, especially the techniques of pixel IC chips, sensors, and advanced packaging. Meanwhile, key technology localization has also been achieved and various innovations have been made. This proved the work generally solved the problem of “being strangled” in the field of pixel detectors. (2) Aiming at the international frontier: Led the development of the fine pitch pixel detector. Its spatial resolution reached the same level as the state-of-the-art research of the world, and filled in the blanks in the domestic field; Wei Wei proposed a novel 4-D detection mode and implemented it in the field of synchrotron radiation for the first time; a series of prototype chips were successfully developed for large-scale scientific facilities including vertex detectors for particle physics experiments, free-electron lasers, and so on. The work preliminarily realized “paralleling” with international studies while promoted from “pursuing”. The breakthrough of those key technologies can make beamlines in future light sources capable to realize customized detector design. Therefore, the restrictions from foreign products can be freed and a large number of national funds can be saved. Moreover, it also makes it possible to promote the beamline capabilities, or even explore brand new experimental methodologies to realize original innovations.

The performance regulation optimization and engineering application of a domestic helium liquefier

<p indent="0mm">The superconducting magnets and the superconducting cavities are the key devices of large-scale scientific facilities, such as the HL-LHC in the CERN, the ITER, the EAST, the CiADS, and so on. A stable and reliable cold source such as the liquid helium (–269°C) is required to keep the superconducting magnets and the superconducting cavities working. Therefore, a helium liquefier or a helium refrigerator working at <sc>4.5 K</sc> is necessary for them. Research on high-field-strength superconducting dipole magnets used in future high-energy particle colliders is developed in the Institute of High Energy Physics of the Chinese Academy of Sciences. High-field-strength superconducting dipole magnets have large thermal loads and long test durations, which need large amount of liquid helium for their performance tests. Therefore, the long-term operating economy, stability, and reliability of the refrigeration system are highly required. The engineering application of using a helium liquefier for producing liquid helium to cool down superconducting dipole magnets has not been realized in China yet. Meanwhile, the price of the imported helium liquefiers is usually too high and the supply cycles are too long. Fortunately, a domestic helium liquefier has been developed by the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences. This paper will realize the engineering application of the domestic helium liquefier applied to the superconducting dipole magnet test platform for the first time. In order to meet the test requirements of high-field-strength superconducting dipole magnets, a performance regulation and optimization of the first domestic helium liquefier is studied. It realizes the optimal control of the cold-box cooling process and the Dewar cooling process, saves the power consumption of the compressor by 12.3% and 25.2% respectively, and significantly improves the economy of the helium liquefier. After the commissioning of the liquefier, the helium liquefier realizes the automatic control adjustment function to adapt to variable loads in different operating conditions. And the specific energy consumption of the helium liquefier under each load state is analyzed. Without considering the consumption of liquid nitrogen, the minimum specific energy consumption of the helium liquefier is <sc>2.4 kW h/L</sc> when the liquefier works with the full load. Through control optimization and experimental testing, the helium liquefier successfully realizes the joint operation with the user-end superconducting dipole magnet test platform, and passed the long-term operation reliability test. At present, the helium liquefier has run stably for more than two months, produced more than <sc>35000 L</sc> of liquid helium, promoting the first domestic accelerator high-field superconducting dipole magnet to achieve a breakthrough in the new index of the magnetic field strength of <sc>12.47 T.</sc> It’s the first time for the domestic helium liquefier applying to the superconducting dipole magnet test platform, and this engineering application can be further promoted in future.

Compact reversed Cherenkov radiation oscillator with high efficiency

An all-metal metamaterial slow-wave structure (MSWS), which comprises a hollow circular waveguide loaded by periodically arranged complementary electric split-ring resonators (CeSRRs), is proposed. Due to the CeSRRs with the characteristics of both subwavelength and strong resonance, the MSWS has both compact size and high interaction impedance relative to conventional SWS. Based on the reversed Cherenkov radiation in the MSWS, a compact reversed Cherenkov radiation oscillator (RCRO) with high efficiency is developed. The measured electronic efficiency is 19.54%, and measured output power is 10.16 kW at 2.221 GHz under the conditions that the beam voltage is 26 kV, the beam current is 2.0 A, and axial magnetic flux density is ∼962 G. The experimental results clearly show that the brand-new RCRO can be applied to large-scale scientific facilities, medical imaging, microwave heating, microwave disinfection and sterilization, and so on.

Physics model-informed Gaussian process for online optimization of particle accelerators

High-dimensional optimization is a critical challenge for operating large-scale scientific facilities. We apply a physics-informed Gaussian process (GP) optimizer to tune a complex system. Typical GP models learn from past observations to make predictions, but this reduces their applicability to systems where there is limited relevant archive data. Instead, here we use a fast approximate model from physics simulations to design the GP model. The GP is then employed to make inferences from sequential online observations in order to optimize the system. Simulation and experimental studies were carried out to demonstrate the method for online control of a storage ring. Our method is a simple prescription to construct a custom GP model, including correlations between the high-dimensional input space, while encoding the physical response of a system. The ability to inform the machine-learning model with physics, without relying on the availability and range of prior data, may have wide applications in science.

Research and Evaluation of RoCE in IHEP Data Center

With more and more large-scale scientific facilities are built, more and more HPC requirements are needed in IHEP. RDMA is a technology that allows servers in a network to exchange data in main memory without involving the processor, cache or operating system of either server, which can provide high bandwidth and low latency. There are two RDMA technologies which were InfiniBand and a relative newcomer called RoCE – RDMA over Converged Ethernet. This paper introduces the RoCE technology, we research and compare the performance of both IB and RoCE in IHEP data center, and we also evaluate the application scenarios of RoCE which can support our future technology selection in HEPS. In the end, we present our future plan.

Convergence of artificial intelligence and high performance computing on NSF-supported cyberinfrastructure

Significant investments to upgrade and construct large-scale scientific facilities demand commensurate investments in R&D to design algorithms and computing approaches to enable scientific and engineering breakthroughs in the big data era. Innovative Artificial Intelligence (AI) applications have powered transformational solutions for big data challenges in industry and technology that now drive a multi-billion dollar industry, and which play an ever increasing role shaping human social patterns. As AI continues to evolve into a computing paradigm endowed with statistical and mathematical rigor, it has become apparent that single-GPU solutions for training, validation, and testing are no longer sufficient for computational grand challenges brought about by scientific facilities that produce data at a rate and volume that outstrip the computing capabilities of available cyberinfrastructure platforms. This realization has been driving the confluence of AI and high performance computing (HPC) to reduce time-to-insight, and to enable a systematic study of domain-inspired AI architectures and optimization schemes to enable data-driven discovery. In this article we present a summary of recent developments in this field, and describe specific advances that authors in this article are spearheading to accelerate and streamline the use of HPC platforms to design and apply accelerated AI algorithms in academia and industry.

Data Cyberinfrastructure for End-to-End Science

Large-scale scientific facilities provide a broad community of researchers and educators with open access to instrumentation and data products generated from geographically distributed instruments and sensors. This paper discusses key architectural design, deployment, and operational aspects of a production cyberinfrastructure for the acquisition, processing, and delivery of data from large scientific facilities using experiences from the National Science Foundation's Ocean Observatories Initiative. This paper also outlines new models for data delivery and opportunities for insights in a wide range of scientific and engineering domains as the volumes and variety of data from facilities grow.

Diffuser design and experimental research of a large-scale chilled water storage system

ABSTRACT Naturally stratified technology is the most economical and effective method in chilled water storage technique and its core is the design of water diffuser. The better the performance of diffuser and the higher the efficiency of chilled water storage is. With the development of science and technology, many large-scale scientific facilities come into being, most of which need to be equipped with large-scale water storage system and run in the extreme operating conditions. If these water storage systems adopt the naturally stratified technology, it is necessary to optimize the design of the diffuser to achieve an ideal storage efficiency, which can not only save energy but also guarantee the operation of the facilities. The water storage system of Steady High Magnetic Field Facilities is one of the representative water storage systems with large flow rate and large temperature difference. By establishing the discrete equation of heat conduction, the results show that the convection doping related to the design of the diffuser is the primary factor affecting the thickness of thermocline. It was also verified by experiments that the large-scale chilled water storage device with well-designed octagonal diffuser and uniform flow orifice can achieve ideal storage efficiency under the operation conditions of large flow rate and large temperature difference.

On the prospects for an integrated approach to the legal regulation of scientific projects of the “megascience” class

Scientific projects of the “megascience” class are large-scale scientific facilities that require the attraction of significant human, material and financial resources. Given these features, they are most often realized by sharing costs between several states interested in implementing projects. The involvement of foreign participants in Russian scientific projects of the “megascience” class leads to the need to comply with the requirements of the legislation of the Russian Federation, which do not take into account the specifics of projects of the “megascience” class, in particular the organization of the stay of foreign scientists, engineers, their labor activities, import and export of scientific equipment, personnel training and others. In this regard, the report considers options for an integrated approach to the legal regulation of scientific projects of the “megascience” class in order to improve their implementation mechanisms and make them more attractive to foreign participation.

The prototype of equipment protection system based on Ethernet POWERLINK for HALS

Abstract The Hefei Advanced Light Source (HALS) is brought forward to be a new diffraction limited storage ring (DLSR) light source. The technical pre-research project for the HALS is in progress. As an critical part of the project, a prototype of the equipment protection system (EPS) is developed to study the interlock protection for components of the light source. The prototype of the EPS is a distributed system based on Gigabit Ethernet POWERLINK (EPL) under EPICS architecture. A PC is used as the master managing node (MN), and 10 FPGA-based controllers is employed for the slave controlled nodes (CNs). EPL is used for the communication between the MN and CNs. This paper reports the design and results of a series of performance tests of the prototype system. The test results indicate that the prototype system can run stably with a communication cycle time 275 μ s , and the maximum global response time is about 870 μ s . This system is a feasible solution for the EPS of large-scale scientific facilities. In the further studies, the response time is expected to be further reduced by choosing high-speed photo couplers and properly arranged input signals.

Research on the Spatial Layout of Science Park based on Large-scale Scientific Facilities: A Case Study of Spallation Neutron Source

A large-scale scientific facility is an essential driving force for innovation in science and technology in the country. A reasonably spatial layout for the development of a science park is a vital assurance for its function positioning. Furthermore, the function of the science park determines the setting of related industries and the way of spatial layout. Based on the first-hand information of the Harwell Campus in England, this paper first analyzes the functions of the Spallation Neutron Source, a benchmark science park, and then determines the internal space elements about the positioning function. Finally, based on the spatial distribution theory and the analysis of the spatial layouts of benchmark international science parks such as Harwell Campus in England, Silicon Valley and Oak Bridge in the United States, and Proton Accelerator Research Complex in Japan, the paper proposes layouts for setting up external resource-embedded and internal center proliferation projects.

Design of a High-Efficiency S-band Klystron with a Multi-cell Output Cavity

As large-scale scientific facilities develop, the klystron efficiency becomes an important issue to reduce high operating costs. We are developing high-efficiency klystrons for the Pohang Light Source-II (PLS-II) and the Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL) at the Pohang Accelerator Laboratory (PAL). The newly developed klystrons should have the same specifications, including perveance and overall length, to replace existing ones. Under these limited conditions, we designed the klystrons based on a multi-cell output cavity to improve the power-conversion efficiency significatly. We simulated the beam-dynamics using the Field Charge Interaction (FCI) code with a MATLAB script to find the optimum design parameters for high efficiency. We have determined the design parameters, such as cell tuning frequencies, inter-cell distances, couplings between cells and the Qe of the last cell, of the multi-cell output cavity.

Automatic data archiving and visualization at HLS-II

The control system of Hefei Light Source II (HLS-II) is a distributed system based on the experimental physics and industrial control system (EPICS). It is necessary to maintain the central configuration files for the existing archiving system. When the process variables in the control system are added, removed, or updated, the configuration files must be manually modified to maintain consistency with the control system. This paper presents a new method for data archiving, which realizes the automatic configuration of the archiving parameters. The system uses microservice architecture to integrate the EPICS Archiver Appliance and RecSync. In this way, the system can collect all the archived meta-configuration from the distributed input/output controllers and enter them into the EPICS Archiver Appliance automatically. Furthermore, we also developed a web-based GUI to provide automatic visualization of real-time and historical data. At present, this system is under commissioning at HLS-II. The results indicate that the new archiving system is reliable and convenient to operate. The operation mode without maintenance is valuable for large-scale scientific facilities.