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In this article, the ongoing development progress of the polarized neutron technique developments at the China Spallation Neutron Source (CSNS) is presented. The general goal of establishing polarized neutron capability in parallel to CSNS beamline construction is also explained. The key instrument development projects of developing the Spin-Exchange Optical Pumping (SEOP) 3 He systems, polarized neutron devices, and their application on neutron beamlines are demonstrated. Performance parameters of the developed techniques are also discussed.

The Radio Frequency Quadrupole (RFQ) was conditioned at the European Spallation Source during spring 2021. We used part of the conditioning time to estimate the accelerating potential within the RFQ analyzing the x-rays bremsstrahlung radiation emitted by the electrons released and accelerated in the RFQ. The results of these measurements are in good agreement with the theoretical prediction.

We present the ICONE project which proposes to build a HiCANS source in France. The aim of the ICONE project is to be able to provide the French neutron user community sufficient instrumental capacity to continue performing neutron scattering experiments for their research programs. The baseline goal is to offer performances equivalent to a medium power research reactor or spallation source (such as Orphée or ISIS). We consider that such a machine would fulfil the needs of at least two-thirds of the users which not require ultimate performances but simply beam-time to perform their experiments. We also describe the experimental work ongoing at Saclay around the various technologies necessary to build a HiCANS.

Coal–gas outburst is a complex dynamic phenomenon in underground coal mines that has occurred frequently over the past 150 years. This phenomenon has seriously restricted the efficient development of coal resources and it poses a great threat to global energy security. Physical simulation experiments under different conditions that considered the coal–rock combination structure and gas adsorptivity were carried out by using a true triaxial coal–gas outburst experimental system, and the experiments controlled for the type of adsorbable gas, the presence (or absence) of a roof and the gas pressure. The influence of the coal–rock structure and gas adsorptivity on the disaster occurrence conditions and dynamic response characteristics was discussed, and the gas–solid-coupling disaster-inducing mechanisms of coal–gas outburst under unloading were obtained. The results show that outburst pulverized coal does not present an obvious sorting performance under the experimental conditions of this work. All the outburst holes are characterized by small openings and large cavities. Coal walls around the holes are damaged by spallation, and the strength of the outburst holes is low, but relatively stable. Stronger gas adsorptivity and greater gas pressure correspond to more intense outburst dynamic effects. Moreover, greater outburst intensity corresponds to more obvious coal spallation characteristics. Whether there is roof or not has no significant effect on the sweeping and handling of thrown pulverized coal. Compared with the condition without roof, the existence of a roof will promote an increase in the outburst intensity and more obvious spallation damage of the outburst coal. The coal–gas outburst process includes four stages: outburst occurrence, rapid development, deceleration development and outburst termination. The research results have certain guiding significance for studies on the mechanism of coal–gas outburst.

To fully realize the potential application of spalled thermal barrier coating systems (TBCs) in gas turbine blades, it is essential to evaluate the service behavior of TBCs and the critical spallation size for safety servicing. For this purpose, the evaluation of the localized spallation of TBCs under high-temperature gas was investigated experimentally and numerically. Thermal insulation experiments and a conjugate heat transfer numerical algorithm were used to clarify the over-temperature phenomenon, temperature distributions, the relevant flow characteristics of the high-temperature gas in the localized spallation region of TBCs, and the influencing mechanisms that consider the spallation width were identified. The results suggested that when the spallation width was less than 10 μm, the temperature in the TBCs did not change due to the weak impression of gas. When the spallation width exceeded the security coefficient of about 3 mm, the TBCs were difficult to service safely due to the impact of high-temperature gas. Furthermore, the concept of an over-temperature coefficient was proposed to describe the over-temperature damage and a nonlinear fitting equation was obtained to reveal and predict the evolution of the over-temperature coefficient. The over-temperature coefficient may serve as a valuable metric in determining the performance degradation of TBCs.

The coherent elastic scattering of neutrinos off nuclei has eluded detection for four decades, even though its predicted cross section is by far the largest of all low-energy neutrino couplings. This mode of interaction offers new opportunities to study neutrino properties and leads to a miniaturization of detector size, with potential technological applications. We observed this process at a 6.7σ̃ confidence level, using a low-background, 14.6-kilogram CsI[Na] scintillator exposed to the neutrino emissions from the Spallation Neutron Source at Oak Ridge National Laboratory. Characteristic signatures in energy and time, predicted by the standard model for this process, were observed in high signal-to-background conditions. Improved constraints on nonstandard neutrino interactions with quarks are derived from this initial data set.

This paper reports the results of thermal spallation experiments on specially dried shale samples with 3 bedding orientations (0°, 45° and 90°) under 3 flame temperatures (899 °C, 1243 °C and 1559 °C) and the 3D thermal elastic finite element modelling. Under open flame heating, continuous spallation is observed with ejection of various spalls and popping sounds. After a period of spallation, tensile fractures are formed in the samples and grow perpendicular to the heating surface, except for a sample with bedding orientation of 90° under the low temperature. Increasing flame temperature promotes ejection, popping sounds and spallation rate, but reduces the spallation starting time, spallation duration, depression diameter and depression depth. The model shows that heating induces compressive stress in the surface layer and tensile stresses beneath it. The tensile stress is found to be sufficient to generate large tensile fractures. The ratio between the induced compressive and tensile stresses increases with increasing spallation depth but little affected by the flame temperature. The spallation compressive stress increases with temperature from 29 to 51% of the uniaxial compressive strength. This stress is shown to be sufficient to cause buckling of thin layers separated from the bulk of the rock. The size of the buckling layer is smaller than the size of the spallation zone leading to a mosaic pattern seen on the surface after spallation. The results are important for further understanding of the mechanism of thermal spallation of rocks as well as large scale spallation-like processes in the Earth’s crust.

At the European Spallation Source (ESS), two hydrogen moderators, where the nuclear heating is estimated to be 6.7 kW at 5 MW proton beam power, are installed above a rotating target wheel. The cryogenic moderator system (CMS) circulates subcooled liquid hydrogen through the moderators. Dynamic and static heat loads are removed by a large-scale 20 K helium refrigeration system, the Target Moderator Cryoplant (TMCP), with a cooling capacity of 30.3 kW at 15 K. Installation of the CMS was completed in May 2024, and preliminary commissioning was subsequently conducted at 17 K using helium, prior to hydrogen operation and without connecting the moderators. In this study, the CMS cool-down process was examined to aid in the development of an automated operation control system, and the operational parameters were optimized.

The European Spallation Source (ESS) in Lund, Sweden, is designed to become the most powerful accelerator driven spallation neutron source in the world. ESS is currently under construction, and the first beam on target is planned for the beginning of 2026, with first user operation expected to start in 2026. As a key component of the neutron production, which was developed, built and tested at the Institute of Technology and Engineering, (ITE) of Forschungszentrum Juelich GmbH, the cryogenic moderator slows down high-energy neutrons released from the spallation target. To gain maximum neutron brightness for condensed and soft matter research, an optimized low dimension liquid para-hydrogen moderator has been developed. Hydrogen with a pressure around 10 bar, a temperature around 20 K and a para-hydrogen fraction of at least 0.995 will be utilized to interact with neutrons in a unique moderator vessel arrangement. This paper describes the engineering design, manufacturing and installation of the low dimension liquid para-hydrogen moderator for the ESS.

After more than 20 years of operation, the cold compressor technology in use at the Spallation Neutron Source (SNS) is obsolete, and replacement parts and service are no longer available. SNS has partnered with Jefferson Lab to design and construct a replacement sub-atmospheric cold box outfitted with modern cold compressor technology. The general design follows from Jefferson Lab’s experience on other recent sub-atmospheric cold box projects. Design decisions are backed by thorough engineering analysis to ensure technical requirements are met in a cost-effective manner. Conceptual design of the replacement cold box has been completed, and will be summarized in this paper. It features five cold compressors with an operating flow range of 80-140 g/s, and includes piping and valving to support cold compressor maintenance without interrupting flow circulation to the load. The approach to thermal shielding, insulation, and integration of the upgraded cold compressor hardware into the existing SNS control system will also be addressed.