Recent improvements in straw neutron detectors for large-scale neutron science instruments

2020 ◽  
Vol 22 (2-3) ◽  
pp. 353-369
Author(s):  
Jeffrey L. Lacy ◽  
Athanasios Athanasiades ◽  
Christopher S. Martin ◽  
Richard Nguyen ◽  
Stephen Davenport ◽  
...  
Keyword(s):  
Homeland Security ◽  
Large Scale ◽  
Detection Efficiency ◽  
Experimental Studies ◽  
Rate Capability ◽  
High Sensitivity ◽  
High Rate ◽  
Readout System ◽  
Thin Walls ◽  
Number Of Layers

Modified boron-coated straw (BCS) detector configurations are introduced, in order to improve detection efficiency, and reduce the number of layers required to match the response of high-pressure 3He tubes, in large-scale neutron science instruments. A new 7-straw design employing thin-walled aluminum tubes facilitates operation in vacuum, and substantially reduces the scattering material by a factor of 5 compared with the flow-through design of the Multi-Grid detector. Another design introduces 18 radial walls inside each straw, coated on both sides with enriched boron carbide, to increase the coated wall perimeter 4.3 times. The so-called Pie straw offers a significant benefit in detection efficiency compared with round straws used in LoKI. An example of such a straw having 18 septa is explored in modeling and experimental studies, that can potentially reduce the number of layers needed in large-scale instruments like LoKI by a factor of 2.8. In a parallel development, a totally new configuration of boron-coated detectors is introduced, aimed to address the need for high spatial resolution, and high-rate capability in single crystal diffractometers, like MaNDi and TOPAZ at the SNS, and in neutron reflectometers. The proposed structure is a close-packed array of rectangular cells, each fabricated by wrapping copper foil having a coating of 10B4C on one side and electroplated tin on the other side, around precisely machined rectangular bars. The array is pressed together and then vacuum brazed together. The resulting structure is quite strong and precise in geometry. This so-called Microcell Straw Array can be configured with channel dimensions as small as 0.5 mm × 2.5 mm. Due to its ultra thin walls (25 μm) secondary scattering of neutrons is minimized. It is sealed inside a fully welded thin aluminum containment vessel that allows convenient operation in vacuum. A mature low power readout system capable of an estimated count rate of 22 MHz in a 15 × 15 cm2 detector is also proposed. The improvements are the result of recent advances in BCS design, spurred by the development of compact, high-sensitivity monitors for homeland security and military applications.

scholarly journals Large High-Efficiency Thermal Neutron Detectors Based on the Micromegas Technology

Universe ◽  
2018 ◽  
Vol 4 (12) ◽  
pp. 134 ◽  
Author(s):  
Georgios Tsiledakis ◽  
Alain Delbart ◽  
Daniel Desforge ◽  
Ioanis Giomataris ◽  
Thomas Papaevangelou ◽  
...  
Keyword(s):  
Thermal Neutron ◽  
Large Scale ◽  
High Efficiency ◽  
Detection Efficiency ◽  
Rate Capability ◽  
High Rate ◽  
Thermal Neutrons ◽  
Neutron Detectors ◽  
Electron Multiplier ◽  
Detection Techniques

Due to the so-called 3He shortage crisis, many detection techniques for thermal neutrons are currently based on alternative converters. There are several possible ways of increasing the detection efficiency for thermal neutrons using the solid neutron-to-charge converters 10B or 10B4C. Here, we present an investigation of the Micromegas technology. The micro-pattern gaseous detector Micromegas was developed in the past years at Saclay and is now used in a wide variety of neutron experiments due to its combination of high accuracy, high rate capability, excellent timing properties, and robustness. A large high-efficiency Micromegas-based neutron detector is proposed for thermal neutron detection, containing several layers of 10B4C coatings that are mounted inside the gas volume. The principle and the fabrication of a single detector unit prototype with overall dimension of ~15 × 15 cm2 and its possibility to modify the number of 10B4C neutron converter layers are described. We also report results from measurements that are verified by simulations, demonstrating that typically five 10B4C layers of 1–2 μm thickness would lead to a detection efficiency of 20% for thermal neutrons and a spatial resolution of sub-mm. The high potential of this novel technique is given by the design being easily adapted to large sizes by constructing a mosaic of several such detector units, resulting in a large area coverage and high detection efficiencies. An alternative way of achieving this is to use a multi-layered Micromegas that is equipped with two-side 10B4C-coated gas electron multiplier (GEM)-type meshes, resulting in a robust and large surface detector. Another innovative and very promising concept for cost-effective, high-efficiency, large-scale neutron detectors is by stacking 10B4C-coated microbulk Micromegas. A prototype was designed and built, and the tests so far look very encouraging.

scholarly journals NASICON-Structured NaTi2(PO4)3 for Sustainable Energy Storage

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Mingguang Wu ◽  
Wei Ni ◽  
Jin Hu ◽  
Jianmin Ma
Keyword(s):  
Energy Storage ◽  
Large Scale ◽  
Low Cost ◽  
Rate Capability ◽  
Sodium Ion ◽  
High Rate ◽  
Storage Technologies ◽  
Scale Grid ◽  
Hybrid Capacitors ◽  
Aqueous Batteries

Abstract Several emerging energy storage technologies and systems have been demonstrated that feature low cost, high rate capability, and durability for potential use in large-scale grid and high-power applications. Owing to its outstanding ion conductivity, ultrafast Na-ion insertion kinetics, excellent structural stability, and large theoretical capacity, the sodium superionic conductor (NASICON)-structured insertion material NaTi2(PO4)3 (NTP) has attracted considerable attention as the optimal electrode material for sodium-ion batteries (SIBs) and Na-ion hybrid capacitors (NHCs). On the basis of recent studies, NaTi2(PO4)3 has raised the rate capabilities, cycling stability, and mass loading of rechargeable SIBs and NHCs to commercially acceptable levels. In this comprehensive review, starting with the structures and electrochemical properties of NTP, we present recent progress in the application of NTP to SIBs, including non-aqueous batteries, aqueous batteries, aqueous batteries with desalination, and sodium-ion hybrid capacitors. After a thorough discussion of the unique NASICON structure of NTP, various strategies for improving the performance of NTP electrode have been presented and summarized in detail. Further, the major challenges and perspectives regarding the prospects for the use of NTP-based electrodes in energy storage systems have also been summarized to offer a guideline for further improving the performance of NTP-based electrodes.

HIERARCHICAL Li4Ti5O12 MICROSPHERES AS A HIGH POWER ANODE MATERIAL FOR LITHIUM ION BATTERIES

2013 ◽  
Vol 01 (04) ◽  
pp. 1340013
Author(s):  
HONGJUN LUO ◽  
HONGSEN LI ◽  
LAIFA SHEN ◽  
PING NIE ◽  
JIE WANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Large Scale ◽  
Discharge Rate ◽  
Rate Capability ◽  
Lithium Ion ◽  
Cycling Performance ◽  
Electrochemical Analysis ◽  
High Rate ◽  
Diffraction Field ◽  
Hydrothermal Route

In this paper, hierarchical Li 4 Ti 5 O 12 microspheres were successfully synthesized in a large scale via a facile hydrothermal route. X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy were used to characterize the obtained Li 4 Ti 5 O 12 microspheres and the results indicate that the monodispersed Li 4 Ti 5 O 12 microspheres with ca. 2 μm in diameter was assembled by well-crystalline nanoparticles. Electrochemical analysis indicated that the Li 4 Ti 5 O 12 microspheres have superior rate capability and cycling performance. At the charge–discharge rate of 0.2, 1, 2, 5, 10 and 20 C, the discharge capacities of Li 4 Ti 5 O 12 microspheres are 169.2, 163.5, 158.3, 136.4, 117.6 and 94.3 mAh g−1, respectively. Excellent capacity retention of 98.7% was achieved after 100 cycles at 1 C rate and it can still maintained 91% even at high rate of 10 C.

scholarly journals Stable aqueous aluminum-manganese photoelectrochemical cells with high-rate and high-efficiency abilities

2021 ◽  
Author(s):  
Shuqiang Jiao ◽  
Xuefeng Zhang ◽  
Wei-li Song ◽  
Mingyong Wang ◽  
Jiguo Tu ◽  
...  
Keyword(s):  
Energy Density ◽  
Large Scale ◽  
High Efficiency ◽  
Rate Capability ◽  
High Energy ◽  
High Rate ◽  
High Energy Density ◽  
Energy Storage Devices ◽  
Slow Kinetics ◽  
Aqueous Aluminum

Abstract Aqueous aluminum-ion batteries (AAIBs) are potential candidates for large-scale energy storage devices for their advantages of high energy density, resource abundance, low cost, safety, and environmental friendliness. Due to various redox procedures, good reversibility, and high discharge potential, the aqueous aluminum-manganese oxide battery has drawn wide attention, while the critical issues induced from slow kinetics and undesired soluble Mn2+ lead to slow charging, poor rate capability, and low energy density. However, there is very limited progress for performance improvement via conventional chemical or physical modification approaches. To overcome these challenges, an efficient photo-regulation strategy has been proposed in terms of direct radiating visible light on the cell during the galvanostatic charging and discharging. The efficient separation and transmission of photoelectrons in the photo positive electrode dramatically improves the dynamics, and fast charging and enhanced rate performance could be achieved. Photo-oxidation behavior can effectively promote the conversion of soluble Mn2+, thus further enhancing the energy density of the as-assembled aluminum-manganese battery. Furthermore, a photo-conversion efficiency of up to 1.2% has been acquired. Based on the photo-regulation strategy, the mechanism of the photoelectrochemical coupling system has been understood, which opens a promising route for achieving photoelectrochemical batteries with high energy density and fast charge.

Two-dimensional ultrathin ZnCo2O4 nanosheets: general formation and lithium storage application

2015 ◽  
Vol 3 (18) ◽  
pp. 9556-9564 ◽  
Author(s):  
Youqi Zhu ◽  
Chuanbao Cao ◽  
Junting Zhang ◽  
Xingyan Xu
Keyword(s):  
Transition Metal ◽  
Large Scale ◽  
Storage Capacity ◽  
Rate Capability ◽  
High Rate ◽  
Two Dimensional ◽  
High Rate Capability ◽  
Lithium Storage ◽  
Excellent Cycling Stability ◽  
General Method

2D multicomponent transition-metal oxide nanosheets are synthesized on a large scale via a general method. Ultrathin ZnCo2O4 nanosheets exhibit high lithium storage capacity, excellent cycling stability, and good high-rate capability.

scholarly journals Electrochemical Investigation of Phenethylammonium Bismuth Iodide as Anode in Aqueous Zn2+ Electrolytes

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 656
Author(s):  
Stylianos Daskalakis ◽  
Mingyue Wang ◽  
Claire J. Carmalt ◽  
Dimitra Vernardou
Keyword(s):  
Large Scale ◽  
Specific Capacity ◽  
Research Work ◽  
Rate Capability ◽  
Chemical Vapor ◽  
High Rate ◽  
New Class ◽  
Bismuth Iodide ◽  
Aqueous Battery ◽  
Safety And Stability

Despite the high potential impact of aqueous battery systems, fundamental characteristics such as cost, safety, and stability make them less feasible for large-scale energy storage systems. One of the main barriers encountered in the commercialization of aqueous batteries is the development of large-scale electrodes with high reversibility, high rate capability, and extended cycle stability at low operational and maintenance costs. To overcome some of these issues, the current research work is focused on a new class of material based on phenethylammonium bismuth iodide on fluorine doped SnO2-precoated glass substrate via aerosol-assisted chemical vapor deposition, a technology that is industrially competitive. The anode materials were electrochemically investigated in Zn2+ aqueous electrolytes as a proof of concept, which presented a specific capacity of 220 mAh g−1 at 0.4 A g−1 with excellent stability after 50 scans and capacity retention of almost 100%.

scholarly journals Nitrogen- and Oxygen-Containing Three-Dimensional Hierarchical Porous Graphitic Carbon for Advanced Supercapacitor

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1540 ◽  
Author(s):  
Yunyan Zhao ◽  
Honghu Wang ◽  
Jing Liu ◽  
Jinghao Liu ◽  
Guicun Li ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Rate Capability ◽  
Porous Graphitic Carbon ◽  
Graphitic Carbon ◽  
Nickel Acetate ◽  
High Rate ◽  
Electrochemical Performances ◽  
Promising Alternative ◽  
Hierarchical Porous

Three-dimensional hierarchical porous graphitic carbon (HPGC) were synthesized via one-step carbonization-activation and a catalytic strategy. The method can not only improve the graphitization degree of carbon materials, but also offer plentiful interfaces for charge accumulation and short paths for ion/electron transport. Polypyrrole, potassium hydroxide, and nickel acetate were used as the carbon precursors, activating agent, and catalyst, respectively. The retraction and dissolution of Ni caused the change of pore size in the material and led to the interconnected micro/nano holes. Nickel acetate played a significant role in enhancing the electrical conductivity, introducing pseudocapacitance, and promoting ion diffusion. In the supercapacitor, HPGC electrode exhibited a remarkable specific capacitance of 336.3 F g−1 under 0.5 A g−1 current density and showed high rate capability, even with large current densities applied (up to 50 A g−1). Moreover, HPGC showed optimal cycling stability with 97.4% capacitance retention followed by 3000 charge-discharge cycles. The excellent electrochemical performances coupled with a facile large-scale synthesis procedure make HPGC a promising alternative for supercapacitors.

Analysis and design of suitable model structures for activated sludge tanks with circulating flow

1999 ◽  
Vol 39 (4) ◽  
pp. 55-60 ◽  
Author(s):  
J. Alex ◽  
R. Tschepetzki ◽  
U. Jumar ◽  
F. Obenaus ◽  
K.-H. Rosenwinkel
Keyword(s):  
Activated Sludge ◽  
Large Scale ◽  
Wastewater Treatment Plants ◽  
Treatment Plant ◽  
High Sensitivity ◽  
Suitable Model ◽  
Model Structure ◽  
Analysis And Design ◽  
Hydraulic Behaviour ◽  
Model Structures

Activated sludge models are widely used for planning and optimisation of wastewater treatment plants and on line applications are under development to support the operation of complex treatment plants. A proper model is crucial for all of these applications. The task of parameter calibration is focused in several papers and applications. An essential precondition for this task is an appropriately defined model structure, which is often given much less attention. Different model structures for a large scale treatment plant with circulation flow are discussed in this paper. A more systematic method to derive a suitable model structure is applied to this case. Results of a numerical hydraulic model are used for this purpose. The importance of these efforts are proven by a high sensitivity of the simulation results with respect to the selection of the model structure and the hydraulic conditions. Finally it is shown, that model calibration was possible only by adjusting to the hydraulic behaviour and without any changes of biological parameters.

scholarly journals Leisure Time Sports Activities and Life Satisfaction: Deeper Insights Based on a Representative Survey from Germany

2020 ◽  
Author(s):  
Michael Mutz ◽  
Anne K. Reimers ◽  
Yolanda Demetriou
Keyword(s):  
Life Satisfaction ◽  
Large Scale ◽  
Leisure Time ◽  
Organizational Context ◽  
Experimental Studies ◽  
Well Being ◽  
Activity Level ◽  
Leisure Satisfaction ◽  
General Life Satisfaction ◽  
Sports Activities

Abstract Observational and experimental studies show that leisure time sporting activity (LTSA) is associated with higher well-being. However, scholars often seem to assume that 1) LTSA fosters “general” life satisfaction, thereby ignoring effects on domain satisfaction; 2) the effect of LTSA on well-being is linear and independent of a person’s general activity level; 3) the amount of LTSA is more important than the repertoire of LTSA, i.e. the number of different activities; 4) all kinds of LTSA are equal in their effects, irrespective of spatial and organisational context conditions. Using data from the German SALLSA-Study (“Sport, Active Lifestyle and Life Satisfaction”), a large-scale CAWI-Survey (N = 1008) representing the population ≥ 14 years, the paper takes a closer look on these assumptions. Findings demonstrate that LTSA is associated with general life satisfaction and domain-specific satisfaction (concerning relationships, appearance, leisure, work and health), but that the relationship is most pronounced for leisure satisfaction. Associations of sport with life satisfaction, leisure satisfaction and subjective health are non-linear, approaching an injection point from which on additional LTSA is no longer beneficial. Moreover, findings lend support to the notion that diversity in LTSA matters, as individuals with higher variation in sports activities are more satisfied. Finally, results with regard to spatial and organizational context suggest that outdoor sports and club-organized sports have additional benefits.

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