Vapor Detection, Classification, and Quantification Performance Using Arrays of Conducting Polymer Composite Chemically Sensitive Resistors

We describe a method for generating a variety of chemically diverse, broadly responsive, low power vapor sensors. A key to our ability to fabricate chemically diverse sensing elements is the preparation of processable, air stable films of electrically conducting organic polymers. An array of such sensing elements produces a chemically reversible, diagnostic pattern of electrical resistance changes upon exposure to different odorants. Such conducting polymer elements are simply prepared and are readily modified chemically to respond to a broad range of analytes. In addition, these sensors yield a fairly rapid, low power, de electrical signal in response to the vapor of interest, and their signals are readily integrated with software or hardware-based neural networks for purposes of analyte identification. Principle component analysis has demonstrated that such sensors can identify and quantify different airborne organic solvents, and can yield information on the components of gas mixtures

Prospect studies for Higgs Boson pair production to bbyy final state at the HL-LHC with the ATLAS detector

By the end of the HL-LHC era, before 2040, the ATLAS experiment aims to increase the size of the dataset from $\sim$300fb$^{-1}$, acquired at the end of LHC running, up to $\sim$3000fb$^{-1}$. The large dataset expected after HL-LHC operation increases the likelihood of seeing rare processes such as the $H \rightarrow HH \rightarrow b\bar{b}\gamma\gamma$ decay channel. This channel is one of the most promising for measuring the Higgs boson self-coupling. To mimic the expected ATLAS detector response to various physics objects at the HL-LHC, upgrade performance functions are constantly developed and updated. A recent update to these functions included the addition of a considerably more realistic estimate of the expected material budget of the ITk, as well as dedicated functions for both the 50$\times$50$\mu$m$^2$ and 25$\times$100$\mu$m$^2$ pixel sensor geometries. A Boosted Decision Tree method was applied to the $H \rightarrow HH \rightarrow b\bar{b}\gamma\gamma$ channel to determine the effects of these changes. It was shown that the more realistic material budget and dedicated 50$\times$50$\mu$m$^2$ functions result in a significance for observing this channel of 3.10$\pm$0.13. Comparable results are obtained when using either a pixel sensor geometry of 25$\times$100$\mu$m$^2$ or reducing the radius of the innermost pixel layer

Array-based carbon black-polymer composite vapor detectors for detection of DNT in environments containing complex analyte mixtures

Thin films of carbon black-organic polymer composites have been deposited across two metallic leads, with sorption of vapors producing swelling-induced resistance changes of the detector films. To identify and classify vapors, arrays of such vapor sensing elements have been constructed in which each element of the array contains a different polymer as the insulating phase and a common conductor, carbon black, as the conducting phase. The differing gas-solid partition coefficients for the various polymers of the detector array produce a pattern of differential resistance changes that is used to classify vapors and vapor mixtures. The performance of this detector array system towards 2,4-dinitrotoluene, the predominant signature in the vapor phase above land mines, in the presence high concentrations of water or of acetone has been evaluated

Characterization of the Temporal Response Profile of Carbon Black−Polymer Composite Detectors to Volatile Organic Vapors

The relative differential resistance responses of carbon black−poly(ethylene-co-vinyl acetate) (PEVA) composite vapor detectors were evaluated in response to short rise time (<2 ms for a 17 ms pulse length) square pulses of acetone, n-hexane, methanol, 2-propanol, or toluene, in a background of synthetic air. The use of ultrathin films, along with a rapid vapor delivery system, facilitated measurement of the rapid time response available from this exemplary carbon black−polymer composite chemiresistive film for the detection of common organic vapors. Detectors formed from very thin (<200 nm) PEVA−carbon black composites produced steady-state responses within 17 ms upon exposure to methanol and produced steady-state responses within 90 ms upon exposure to toluene, acetone, and n-hexane. In accord with Fickian diffusion, the response times of the relative differential resistance of PEVA−carbon black detectors to analyte exposures were proportional to the square of the film thickness, l, in the range 510 ≤ l ≤ 5700 nm. Additionally, the relative differential resistance versus time profiles of PEVA−carbon black detectors were well fit by a simple finite difference model based on Fickian analyte diffusion, using a single analyte diffusion coefficient, for a variety of different film thicknesses and analyte concentrations

Progress in use of carbon-black-polymer composite vapor detector arrays for land mine detection

Thin films of carbon black-organic polymer composites have been deposited across two metallic leads, with swelling- induced resistance changes of the films signaling the presence of vapors. To identify and classify vapors, arrays of such vapor sensing elements have been constructed. Each element contained a different organic polymer as the insulating phase. The differing gas-solid partition coefficients for the various polymers of the detector array produced a pattern of resistance changes that was used to classify vapors and vapor mixtures. The performance of this system towards DNT, the predominant signature in the vapor phase above land miens, has been evaluated in detail, with robust detection demonstrated in the laboratory in less than 5 s in air at DNT levels in the low ppb range

Preparation and Properties of Vapor Detector Arrays Formed from Poly(3,4-ethylenedioxy)thiophene−Poly(styrene sulfonate)/Insulating Polymer Composites

Poly(3,4-ethylenedioxy)thiophene−poly(styrene sulfonate) (PEDOT−PSS) was used as the conductive component in a matrix of chemically different insulating polymers to form an array of vapor detectors. Such composites produced larger relative differential resistance responses when exposed to polar analytes than did the corresponding carbon black filled polymer composite detectors. However, the PEDOT−PSS composites produced smaller responses than carbon black composites when exposed to nonpolar analytes. The resolving power of a PEDOT−PSS detector array was compared to that of a carbon black composite array for a broadly construed set of organic vapors. The PEDOT−PSS array exhibited better, on average, discrimination between pairs of polar analytes and polar/nonpolar analytes than did the carbon black composite array. The carbon black composite array outperformed the PEDOT−PSS array in discriminating between nonpolar compounds. The addition of PEDOT−PSS composites to an array of carbon black composite detectors therefore can produce improved overall discrimination in a vapor sensor system when used in tasks to differentiate between of a broad set of analyte vapors

Array-based carbon black-polymer composite vapor detectors for detection of DNT in environments containing complex analyte mixtures

Thin films of carbon black-organic polymer composites have been deposited across two metallic leads, with sorption of vapors producing swelling-induced resistance changes of the detector films. To identify and classify vapors, arrays of such vapor sensing elements have been constructed in which each element of the array contains a different polymer as the insulating phase and a common conductor, carbon black, as the conducting phase. The differing gas-solid partition coefficients for the various polymers of the detector array produce a pattern of differential resistance changes that is used to classify vapors and vapor mixtures. The performance of this detector array system towards 2,4-dinitrotoluene, the predominant signature in the vapor phase above land mines, in the presence high concentrations of water or of acetone has been evaluated

Progress in use of carbon-black-polymer composite vapor detector arrays for land mine detection

Thin films of carbon black-organic polymer composites have been deposited across two metallic leads, with swelling- induced resistance changes of the films signaling the presence of vapors. To identify and classify vapors, arrays of such vapor sensing elements have been constructed. Each element contained a different organic polymer as the insulating phase. The differing gas-solid partition coefficients for the various polymers of the detector array produced a pattern of resistance changes that was used to classify vapors and vapor mixtures. The performance of this system towards DNT, the predominant signature in the vapor phase above land miens, has been evaluated in detail, with robust detection demonstrated in the laboratory in less than 5 s in air at DNT levels in the low ppb range