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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Investigation of Pt and Pd Modified WO{sub 3} and ZnO Based Thin Film Sensors for Ethanol Sensing

Ethanol sensors based on different WO{sub 3} and ZnO structures are studied in the present work. The XRD and SEM processes are used to characterize the sensing layer’s surface morphology which reveals the presence of nanoparticle in sensing layer. Further reducing the nanoparticle diameter by the addition of palladium (Pd) and platinum (Pt) for both the sensors (ZnO and WO{sub 3}) gives good results on sensitivity, operating temperature, response time and recovery time. Nanoparticle diameter for undoped WO{sub 3}, Pd-modified WO{sub 3} and Pt-modified WO{sub 3} based sensors is 11.8, 6 and 5.4 nm, whereas nanoparticle diameter for undoped, Pd-modified and Pt-modified ZnO based sensors is 20, 14 and 11 nm, respectively. Analysis of dynamic response of the sensors when exposed to different concentrations of ethanol vapour (from 500 to 10,000 ppm) and various temperatures indicate the improvement in sensitivity up to 77.2% for WO{sub 3} and 74.6% for ZnO based sensors.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2019

Real-Time and Online Monitoring of Glucose Contents by Using Molecular Imprinted Polymer-Based IDEs Sensor

A highly sensitive, selective, reversible, and reusable glucose sensor is developed by using molecularly imprinted polymer-based artificial receptors onto interdigital transducer. Sensor receptors were synthesized through bulk imprinting technology by using styrene as monomer, ethylene glycol dimethacrylate (EGDMA) as cross-linker, and AIBN as free radical initiator. Topography of the synthesized receptors was investigated by scanning electron microscopy (SEM). Fabricated sensor showed concentration-dependent linear and reversible response with lower limit of detection of 30 ppb and upper limit of detection ~ 500 ppm. Furthermore, newly fabricated sensor is highly selective towards its analyte of interest in the presence of other competing agents, and the regeneration of sensor response has been assessed with the percentage error of less than 2% under the period of 1 year at room temperature and pressure conditions. The reported sensor may have potential technological applications in the field of medical diagnostics, food, and pharmaceutical industry.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

A propagation-based fault detection and discrimination method and the optimization of sensor deployment

Industrial processes can be affected by faults having a serious impact on operation when not promptly detected and diagnosed. Here in this paper, a propagation-based fault detection and discrimination(PFDD) method is proposed to develop a strategy for fault diagnosis while in the design phase of a system. The PFDD method constructs the system model using the Integrated System Fault Analysis(ISFA) technique. Based on the system model, the propagation of hardware and software faults are simulated qualitatively. Given the results of the simulation, the process by which a fault propagates can be characterized using the qualitative features of system variables including the deviation of the system variables from their expected values, the variation of the system variables over time, and the order in which each variable is influenced during the propagation of the fault. The strategy by which a fault can be detected and discriminated is defined using those features. The PFDD method supports the detection and discrimination of faults in both steady states and transient states. Based on the PFDD method, the optimization of sensor deployment in a system is discussed. A brute force algorithm is developed to examine the system’s capability at diagnosing faults and the cost of sensor deployment for all possible configurations of sensors. The optimal sensor deployment strategy can be derived accordingly. However, the brute force method is only applicable to small-scale systems due to its high computational cost. A genetic algorithm is used to optimize sensor deployment in large-scale systems. The PFDD and sensor deployment optimization methods are applied to the Experimental Breeder Reactor II (EBR-II) for verification.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2018

Research of sensing characteristic and dynamic measurement of graphene oxides modified flexible arrayed RuO2 chlorine ion sensor

Highlights: • Sensitivity of the flexible arrayed RuO2/GO chlorine ion sensor was improved with optimal GO concentration, which could increase the reaction area between the chlorine ion and chlorine sensing membrane. • The electrochemical impedance spectroscopy (EIS) and atomic force microscope (AFM) were utilized to explain the relationships among the electron transfer resistance, GO modified amount and sensitivity. • The 30 μL/min flow rate of dynamic measurement for flexible arrayed RuO2/0.010 wt% GO chlorine ion sensor was obtained the best sensitivity and linearity 66.673 mV/pCl and 0.998, respectively. - Abstract: In this study, we used the graphene oxide (GO) solution, in which the concentration was from 0.005 wt% to 0.500 wt%, to modify the flexible arrayed ruthenium dioxide (RuO{sub 2}) chlorine ion sensor. It is found that the flexible arrayed RuO{sub 2}/0.010 wt% GO chlorine ion sensor had the best sensitivity (44.445 mV/pCl) and the linearity was 0.971. The electrochemical impedance spectroscopy (EIS) and atomic force microscope (AFM) were utilized to explain the relationships among the electron transfer resistance, GO modified amount and sensitivity. After that, we used the flexible arrayed RuO{sub 2}/0.010 wt% GO chlorine ion sensor and the microfluidic measurement system to investigate the dynamic sensing characteristics with different flow rates from 5 μL/min to 40 μL/min. According to the experimental results, the best sensitivity and linearity of flexible arrayed RuO{sub 2}/0.010 wt% GO chlorine ion sensor were 66.673 mV/pCl and 0.992 at 30 μL/min.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Low cost fabrication of highly sensitive ethanol sensor based on Pd-doped α-Fe2O3 porous nanotubes

Highlights: • Novel porous tubular nanostructures of α-Fe{sub 2}O{sub 3} are proposed. • The sensor based on 3.0 wt% Pd-doped α-Fe{sub 2}O{sub 3} porous nanotubes exhibited superior gas-sensing properties to ethanol. • The detection limit of the sensor for ethanol gas is as low as 0.1 ppm at 240 °C. • The sensor possesses an excellent reproducibility and good linearity (0.1–400 ppm) in ethanol detection. - Abstract: Pure and Pd-doped α-Fe{sub 2}O{sub 3} porous nanotubes (PNTs) are synthesized by a facile electrospinning approach. Different Pd dopant concentrations are introduced to investigate the dopant’s role in sensing performance. The structures and chemical compositions of the as-prepared products are examined using a series of characterization methods including XRD, EDS, SEM, TEM, XPS and BET. The gas-sensing properties of the sensor based on above PNTs are studied. And the results reveal that, compared with pure α-Fe{sub 2}O{sub 3}, the 3.0 wt% Pd-doped α-Fe{sub 2}O{sub 3} PNTs sensors exhibit superior performance in ethanol detection (at 240 °C). The highest sensitivity reaches 65.4 for 50 ppm ethanol and the detection limit is as low as 0.1 ppm. In addition, the sensors also show excellent selectivity, good long-term stability and as well as rapid response/recovery time (8 s/30 s, respectively) to ethanol. The improvement of sensing performance is mainly attributed to the dramatic sensitization of the additional Pd components.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Fast and low concentration detection of liquefied petroleum gas by Au-activated ZnO sensor

Highlights: • As-synthesized and Au-activated ZnO samples are studied as an LPG sensor. • The operating temperature of ZnO sensor decreases after activation by Au layer. • LPG sensitivity of ZnO sensor shows a significant enhancement after activation. • The Au-activated ZnO sensor is able to quick response to LPG. - Abstract: The development of a reliable and fast liquefied petroleum gas (LPG) sensor due to its highly inflammable and explosive nature is crucial to ensure a safe and healthy environment. In this research, as-synthesized and Au-activated nanostructured ZnO were prepared and investigated as an LPG sensor. The samples were structurally and morphologically characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). LPG sensitivity of the sample shows a significant enhancement after activation with the Au layer. The results also show that the Au-activated sample is able to detect the LPG in the range of 100–1000 ppm (and more concentrations) with the response time of 33-18 S that can be remarkable compared to the previous reports attributed to different materials and technologies.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2022

Electrochemically decorated gold nanoparticles on CVD graphene ChemFET sensor for the highly sensitive detection of As(III)

Here, in this paper, we report a novel reusable receptor-free chemically sensitive field-effect transistor (ChemFET) sensor for the sensitive detection of As(III) using electrochemical doping of Au nanoparticles (AuNPs)-chemical vapour deposition (CVD) graphene (Gr) sensing film (AuNPs-Gr). The sensor consists of a single-gap gold electrode and a single layer of CVD graphene as a conducting/sensing channel decorated with a thin layer of electrochemically deposited AuNPs to catalyze the electroreduction of As(III) ions onto the sensing channel. A new detection strategy was proposed by measuring the resistance change rate of the AuNPs-Gr sensing channel modified between the source electrode and drain electrode, wherein the resistance change was caused by the electrochemical doping of As(0). The results indicated that the electrochemical doping of As(0) onto the sensing channel led to an increase in resistance through the doping interaction among As(0), AuNPs and graphene, enabling the proposed sensor to have an extraordinary detection performance with a high sensitivity. Moreover, the proposed sensor can be recycled by removing the As(0) deposited on the sensing film with the aid of a simple electrochemical oxidization process. Additionally, the mechanism of the sensing strategy based on the electrochemical n-doping of As(0) into the AuNPs-Gr sensing film was investigated using a top liquid gate electrode. The As(III) concentration detected by the AuNPs-Gr ChemFET sensor was as low as 0.001 μg/L, demonstrating that such sensors with a compatible sensing strategy can be used to detect As(III) with high sensitivity, easy fabrication, fast response and can be recycled.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

State-of-the-art and evolution of UFSD sensors design at FBK

Over the past few years, there has been growing interest in the development of silicon sensors able to simultaneously measure accurately the time of passage and the position of impinging charged particles. In this contribution, a review of the progresses in the design of UFSD (Ultra-Fast Silicon Detectors) sensors, manufactured at the FBK (Fondazione Bruno Kessler) Foundry, aiming at tracking charged particles in 4 dimensions, is presented. The state-of-the-art UFSD sensors, with excellent timing capability, are planned to be used in both ATLAS and CMS experiments detector upgrade, in order to reduce the background due to the presence of overlapping events in the same bunch crossing. The latest results on sensors characterization including time resolution, radiation resistance and uniformity of the response are here summarized, pointing out the interplay between the design of the gain layer and the UFSD performances. The research is now focusing on the maximization of the sensor fill factor, to be able to reduce the pixel size, exploring the implementation of shallow trenches for the pixel isolation and the development of resistive AC-coupled UFSD sensors. In conclusion, a brief review on research paths tailored for detection of low energy X-rays or for low material budget applications is given.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Charge collection study with the ATLAS ITk prototype silicon strip sensors ATLAS17LS

The inner tracker of the ATLAS detector is scheduled to be replaced by a completely new silicon-based inner tracker (ITk) for the Phase-II of the CERN LHC (HL-LHC). The silicon strip detector covers the volume 40 < R < 100 cm in the radial and | z | < 300 cm in the longitudinal directions. The silicon sensors for the detector will be fabricated using the n + -on-p 6-inch wafer technology, for a total of 22,000 wafers. Here, intensive studies were carried out on the final prototype sensors ATLAS17LS fabricated by Hamamatsu Photonics (HPK). The charge collection properties were examined using penetrating 90 Sr β -rays and the ALIBAVA fast readout system for the miniature sensors of 1 cm × 1 cm in area. The samples were irradiated by protons in the 27 MeV Birmingham Cyclotron, the 70 MeV CYRIC at Tohoku University, and the 24 GeV CERN-PS, and by neutrons at Ljubljana TRIGA reactor for fluence values up to 2 × 10 15 n eq /cm 2 . The change in the charge collection with fluence was found to be similar to the previous prototype ATLAS12, and acceptable for the ITk. Sensors with two active thicknesses, 300 μ m (standard) and 240 μ m (thin), were compared and the difference in the charge collection was observed to be small for bias voltages up to 500 V. Some samples were also irradiated with gamma radiation up to 2 MGy, and the full depletion voltage was found to decrease with the dose. This was caused by the Compton electrons due to the 60 Co gamma radiation. To summarize, the design of the ATLAS17LS and technology for its fabrication have been verified for implementation in the ITk. We are in the stage of sensor pre-production with the first sensors already delivered in January of 2020.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2025

Autonomous sensor suite for evaluating fish-turbine interactions and environmental impacts in marine renewable energy and hydropower

Marine renewable energy (MRE) harnesses ocean-based resources such as waves, tides, currents, and thermal or salinity gradients for sustainable power generation. It has the potential to complement existing renewable resources, support remote communities, and contribute to decarbonization efforts. However, understanding the hydrodynamic forces created by MRE devices and their impacts on marine life is critical for responsible deployment. Here, to address these concerns, advanced sensor devices, including the Marine Sensor Fish (MSF), Sensor Fish Mini (SF Mini), and Flexible Sensor Fish (FSF), were developed to measure interactions between aquatic organisms and MRE systems. This paper details the design, manufacturing, calibration, and field deployment of these sensor suites, highlighting their ability to capture key physical stressors such as shear forces, pressure changes, and collision impacts. The MSF successfully evaluated turbine interactions at a tidal turbine in the Salish Sea, capturing data on turbulence, collision impact, and pressure gradients. The SF Mini validated hydrodynamic conditions in scaled hydraulic models, supporting computational fluid dynamics simulations. The FSF, with its flexible silicone body, measured species-specific impacts in turbulent environments. This research demonstrates the potential of Sensor Fish technology to advance sustainable marine energy systems by reducing biological impacts and informing environmentally sustainable designs.

Ecological impacts↗
DOE OSTI2021

Calibration and field deployment of low-cost sensor network to monitor underground pipeline leakage

Recent technological advances in methane detection have improved leak detection and repair. However, current methods to reliably measure methane concentrations rely on expensive instruments or demand significant labor input. There is interest in using affordable methane sensors that are responsive to ppmv level changes in methane concentrations in both urban and rural environments for monitoring underground natural gas pipeline leaks. This is especially relevant for situations where potentially significant leaks cannot be repaired immediately or smaller leaks that require long-term monitoring and further evaluation. In this work, a low-cost sensor unit, equipped with a metal oxide sensor, was designed, built, and calibrated over a wide range of methane concentrations and environmental conditions in preparation for field application. A network of these sensors was then installed at the test site and used to measure methane concentrations at ground level above known sub-surface natural gas emissions which emulated underground gas pipeline leaks. This low-cost sensor network measured over 4 days total for the two different known leakage rates. Results demonstrate that the sensors can continuously measure relative methane variability for extended periods but require calibration for a wide range of temperature and humidity conditions to properly determine absolute gas (i.e., methane) concentrations. Furthermore, when a regression analysis was conducted to evaluate the effects of meteorological parameters on methane concentration, air temperature and wind speed have strong impacts on the concentration. Overall, the network approach allows improved identification of leak location and monitoring of underground natural gas leaks.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Quantifying Acute Fuel and Respiration Dependent pH Homeostasis in Live Cells Using the mCherryTYG Mutant as a Fluorescence Lifetime Sensor

Intracellular pH plays a key role in physiology, and its measurement in living specimens remains a crucial task in biology. Fluorescent protein-based pH sensors have gained widespread use, but there is limited spectral diversity for multicolor detection, and it remains a challenge to measure absolute pH values. In this work we demonstrate that mCherryTYG is an excellent fluorescence lifetime pH sensor that significantly expands the modalities available for pH quantification in live cells. We first report the 1.09 Å X-ray crystal structure of mCherryTYG, exhibiting a fully matured chromophore. We next determine that it has an extraordinarily large dynamic range with a 2 ns lifetime change from pH 5.5 to 9.0. Critically, we find that the sensor maintains a pK a of 6.8 independent of environment, whether as the purified protein in solution or expressed in live cells. Furthermore, the lifetime measurements are robustly independent of total fluorescence intensity and scatter. We demonstrate that mCherryTYG is a highly effective sensor using time-resolved fluorescence spectroscopy on live-cell suspensions, which has been previously overlooked as an easily accessible approach for quantifying intracellular pH. As a red fluorescent sensor, we also demonstrate that mCherryTYG is spectrally compatible with the ATeam sensor and EGFP for simultaneous dual-color measurements of intracellular pH, ATP, and extracellular pH. In a proof-of-concept, we quantify acute respiration-dependent pH homeostasis that exhibits a stoichiometric relationship with the ATP-generating capacity of the carbon fuel choice in E. coli . Broadly speaking, our work presents a previously unemployed methodology that will greatly facilitate continuous pH quantification.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Exceptional NH 3 Detection by Cu(cyhdc) MOF Sensor Due to H 2 O Coadsorption

Metal–organic framework (MOF)-based electrical impedance sensors are a growing class of sensors that show utility in the detection of environmentally toxic gases. Detection of trace NH 3 has been particularly difficult to design due to the low electrical response of NH 3 . However, this has been circumvented by judiciously selecting a MOF that has enhanced electrical response to NH 3 due to coadsorption with predominant atmospheric gases such as water. Herein, an MOF Cu(cyhdc) based sensor has been successfully demonstrated for the enhanced detection of environmentally toxic NH 3 gas. The sensor shows a change in impedance when it is exposed to 5 ppm of NH 3 . At 20 °C, >30% relative humidity (RH) is necessary to elicit a change, with the response increasing with RH and reaching 3170× at 92% RH, producing the largest published response to NH 3 for a MOF direct electrical sensor. In the absence of water, no change is observed toward 5 ppm of NH 3 over 20–50 °C. Here, this electrical response is largely driven by huge decreases in the imaginary component of the impedance, attributed to increased capacitance at the surface of the MOF crystallites upon NH 3 and H 2 O coadsorption. Complementary structural and microstructural characterization proves that the Cu(cyhdc) crystalline structure and morphology remain intact under trace NH 3 and/or H 2 O adsorption. Despite extremely low NH 3 , loadings seen in TGA, XPS, and FT-IR confirm NH 3 and H 2 O adsorption, and changes to the metal-carboxylate IR peak positions are observed upon NH 3 adsorption. Concentrated primarily at the outer surfaces of the MOF crystallites, this NH 3 and H 2 O coadsorption effectively increases the surface capacitance across the Cu(cyhdc) powder and enables direct electrical detection of trace NH 3 . Together, these results demonstrate how coadsorption of specific molecules (H 2 O) can be used to enable the electrical detection of trace toxic gases that would otherwise not have produced a MOF sensor response.

ammonia↗
DOE OSTI2016

Optical arc sensor using energy harvesting power source

Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17 J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Cement sensors with acoustic bandgaps using carbon nanotubes

Cement is widely used in wellbores to stabilize the steel casing used in wellbore operations for oil and gas production, enhanced geothermal systems and carbon sequestration, and to limit fluid movement between sub-surface strata. Flaws such as microcracks in wellbore cement can lead to leakage along the wellbore compromising wellbore integrity. There is an increasing need for methods to monitor cement crack propagation in wellbore environments. In this study, we develop and report the first cementitious sensors capable of exhibiting high frequency acoustic bandgaps (ABGs) using carbon nanotubes (CNTs). Computational simulations of a sensor unit cell are used to design cement-multi walled carbon nanotubes (MWCNTs) sensors that show a wide bandgap. When the cement-MWCNTs sensors is embedded in cement specimens, bandgaps were measured experimentally under 300 kHz and under 600 kHz, consistent with the computationally predicted bandgaps in the range of 290–360 kHz, 410–460 kHz and 515–585 kHz. These bandgap features were absent in homogeneous cement specimens. X-ray tomographic reconstructions showed microscopic debonding at cement-MWCNTs sensor interface. Frequency response analysis of a three-dimensional computational model indicated a shift of frequency of minimum transmission due to the interface debonding, but no perturbation of bandgap response was observed. Here, the cement-MWCNTs sensors developed in this study show the potential of a packed CNT inclusion material in cementitious matrix to create ABGs in a cement matrix.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Quench detection using Hall sensors in high-temperature superconducting CORC ® -based cable-in-conduit-conductors for fusion applications

Advanced magnet systems for fusion applications would greatly benefit from the use of high-temperature superconductors (HTS). These materials allow fusion magnets to operate at higher magnetic fields, allowing for more compact fusion machines, and allow for operation at elevated temperatures, enabling demountable coils that provide access for maintenance of the fusion reactor. Quench detection remains a major challenge in the protection of HTS magnets that are vulnerable to localized conductor burnout due to their low quench propagation velocities. One of the methods explored is the use of Hall sensors that are incorporated in or near the magnet terminations that can detect local field variations that occur as a result of current redistribution within the conductor to bypass a hotspot within the magnet winding. This method is potentially well suited for Cable in Conduit Conductors, such as those made from Conductor on Round Core (CORC) cables, in which sub-cables containing HTS tapes are connected to the terminations at a low resistance. Here, to demonstrate the technique, a CORC ® triplet consisting of three sub-cables, rated for 4 kA operation at 77 K, was manufactured and Hall sensors were used to measure local field variations next to the terminations due to current redistribution between the cables. The Hall response was compared to voltages that developed over the cables and terminations as a local hotspot was applied to different cables in the triplet. It was found that the Hall sensors were faster and more sensitive than voltage contact measurements and were able to reliably detect current redistribution of only a few amperes caused by a hotspot, well before the triplet exceeded its critical current. The method also allowed the detection of heater-induced hotspots during high ramp rates of 2 kA s<:sup>–1 relevant for fusion applications. Hall sensors have a distinct benefit of being less sensitive to inductive pickup of AC interference compared to voltage contact measurements that make quench detection through voltage measurements in magnets especially challenging. The method can also be used for diagnostic measurements of current redistribution caused by other sources such as inhomogeneous current injection from faulty joints, or localized conductor damage. The Hall sensors are likely capable of detecting the onset of a quench that may occur a far distance away from the sensor location, presenting a breakthrough in HTS quench detection that potentially removes one of the remaining barriers to reliable operation of large HTS magnet systems.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Probing the role of CNTs in Pt nanoparticle/CNT/graphene nanohybrids H 2 sensors

Abstract In the carbon nanotubes film/graphene heterostructure decorated with catalytic Pt nanoparticles using atomic layer deposition (Pt-NPs/CNTs/Gr) H 2 sensors, the CNT film determines the effective sensing area and the signal transport to Gr channel. The former requires a large CNT aspect ratio for a higher sensing area while the latter demands high electric conductivity for efficient charge transport. Considering the CNT’s aspect ratio decreases, while its conductivity increases ( i.e. , bandgap decreases), with the CNT diameter, it is important to understand how quantitatively these effects impact the performance of the Pt-NPs/CNTs/Gr nanohybrids sensors. Motivated by this, this work presents a systematic study of the Pt-NPs/CNTs/Gr H 2 sensor performance with the CNT films made from different constituent CNTs of diameters ranging from 1 nm for single-wall CNTs, to 2 nm for double-wall CNTs, and to 10–30 nm for multi-wall CNTs (MWCNTs). By measuring the morphology and electric conductivity of SWCNT, DWCNT and MWCNT films, this work aims to reveal the quantitative correlation between the sensor performance and relevant CNT properties. Interestingly, the best performance is obtained on Pt-NPs/MWCNTs/Gr H 2 sensors, which can be attributed to the compromise of the effective sensing area and electric conductivity on MWCNT films and illustrates the importance of optimizing sensor design.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Strain Measurement in the Spallation Target Using High-Radiation-Tolerant Fiber Sensors

We describe the measurement of fast dynamic strains in the mercury target module of the spallation neutron source using customized high-radiation-tolerant fiber-optic strain sensors. The sensors are made from fluorine-doped single-mode optical fibers that demonstrated high radiation tolerance at 1300 nm. A digital phase demodulation scheme is employed in the signal interrogation system, which enables high bandwidth measurement and has an excellent adaptability to sensor output power fluctuations and sensor gap variations. Fast transient strain waveforms induced by high-energy, high-intensity proton pulses are successfully measured. Here, the sensors have survived radiation doses of 10 9 Gy. Both measurement bandwidth and radiation tolerance of the sensors are an order of magnitude higher than their commercial counterparts.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗