Charged Current Measurements Research Articles

Synergy between DUNE and T2HKK to probe invisible neutrino decay

We address the consequence of invisible neutrino decay within the framework of two long base-line neutrino experiments: T2HKK (Tokai-to-Hyper-Kamiokande-to-Korea) and DUNE (Deep Underground Neutrino experiment). Our primary objective is to bring out the aspects of CC (charged current) and NC (neutral current) measurements at DUNE in the context of invisible neutrino decay. We find that the inclusion of NC measurements with the CC measurements enhances its ability to constrain invisible neutrino decay. Further, the synergy between DUNE and T2HKK improves the constraints on invisible neutrino decay. At 3σ C.L. (confidence level) the derived constraint is τ3/m3 ≥ 6.21 × 10−11 s/eV. Additionally, if nature prefers ν3 to be unstable and the decay width is τ3/m3 = 2.2 × 10−11 s/eV, this combination can exclude the no-decay scenario at more than 5σ C.L. Although the CP sensitivity is not much hindered in the presence of invisible neutrino decay, the measurements of θ23 and the ability to resolve octant of θ23 is significantly influenced in these individual experiments. In the presence of invisible neutrino decay, the synergy between DUNE and T2HKK can exclude the wrong octant somewhat more effectively than either experiment alone.

Extraction of the strong coupling with HERA and EIC inclusive data

Sensitivity to the strong coupling αS(MZ2)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\alpha _S(M^2_Z)$$\\end{document} is investigated using existing Deep Inelastic Scattering data from HERA in combination with projected future measurements from the Electron Ion Collider (EIC) in a next-to-next-to-leading order QCD analysis. A potentially world-leading level of precision is achievable when combining simulated inclusive neutral current EIC data with inclusive charged and neutral current measurements from HERA, with or without the addition of HERA inclusive jet and dijet data. The result can be obtained with substantially less than one year of projected EIC data at the lower end of the EIC centre-of-mass energy range. Some questions remain over the magnitude of uncertainties due to missing higher orders in the theoretical framework.

A New Approach for Optimizing a Bipolar Charge Transport Model for Dielectric Materials: Theoretical Framework

A bipolar charge transport model with two levels of traps (shallow and deep traps) is employed to describe and investigate the dynamic behavior of the space charge in low-density polyethylene (LDPE). This kind of model requires some initial experimental conditions alongside a set of parameters. An optimization method is used in order to provide the best precision for model parameters. Furthermore, the sensitivity of these parameters has been analyzed using an approach based on Sobol's method. In essence, this paper proposes a specific protocol that contributes to producing a global set of parameters able to provide the best approximate fit between experimental and simulated results. Net charge density is measured by the pulse electro-acoustic method (PEA) along with what is known as external charging current measurements. The simulated data are obtained by a bipolar charge transport model, which is developed for low-sensity polyethylene.

Non-Unitarity at DUNE and T2HK with charged and neutral current measurements

Neutral current (NC) measurements play an important role in exploring new physics scenarios at long-baseline neutrino oscillation experiments. We find that combining NC measurements of the proposed Deep Underground Neutrino Experiment (DUNE) with its charged current (CC) measurements enhances the bounds on some of the non-unitarity parameters. Combining DUNE with the T2HK experiment improves the bounds further. We show that even in the averaged out regime of light sterile neutrinos, the NC events are different from the heavy sterile case in the leading order. It is observed that NC measurements at DUNE provide much better constraints on the α 33 parameter than the CC measurements.

Numerical Optimization Applying Trust Region Algorithm to Optimize Parameters Related to Charge Transport Model in LDPE

Recently, a numerical model has been developed for describing bipolar charge transport with two levels of traps (shallow and deep traps) in low density polyethylene (LDPE). This paper presents an optimization method, which is based on trust region algorithm. However, the enterprise has to be done with laying out the determination of physical parameters pertaining to bipolar charge transport model. Experimental data that have been used are net density charge measured by the pulse electro acoustic method (PEA) along with what is known as external charging current measurements. Simulated data are computed by the bipolar charge transport model, which is developed for LDPE. In essence, this paper sheds the light on the advanced algorithm that can give rise to a unique set of parameters for the model. Parameters will be reckoned using two different cost functions depending on current density and charge density data's. Conclusions on the best-to-use cost function are presented.

Electrical and physicochemical properties and transient charging currents in mineral and vegetable oils mixtures

The present work aims at investigating the possibility of mixtures between naphthenic transformer mineral oil (MO) and natural ester olive oil (VO). Ten mixture ratios between the two non-inhibited oils have been constituted. The variations of the electrical and physicochemical checking parameters (density, color number, water content, acidity, breakdown voltage and dissipation factor) are first analyzed and discussed in comparison with their initial values and those recommended by standards. Then, DC fields are applied during 3000 s and isothermal charging current measurements are made. The two original oils are both uninhibited, new and contain water contents in the limits of their saturation levels. The study reveals a favor for the vegetable oil and mixtures up to 15 % of mineral oil, especially with regard to breakdown voltage and charging current behavior. On the other hand, the addition of VO amounts until 15% improves significantly all the properties of the MO in spite of the high water amounts contained in the base VO.

Evidence for electron-based ion generation in radio-frequency ionization.

Radio-frequency ionization (RFI) is a novel ionization method coupled to mass spectrometry (MS) for analysis of semi-volatile and volatile organic compounds (VOCs). Despite the demonstrated capabilities of RFI MS for VOC analysis in both positive- and negative-ion modes, mechanism of RFI is not completely understood. Improved understanding of the ion generation process in RFI should expand its utility in MS. Here, we studied the possibility of electron emission in RFI using both direct charged particle current measurements and indirect electron detection in a 9.4-T Fourier transform-ion cyclotron resonance (FT-ICR) mass spectrometer. We show that RF-generated electrons can be trapped in the ICR cell and, subsequently, reacted with neutral hexafluorobenzene (C6 F6 ) molecules to generate C6 F6 (●-) . Intensity of observed C6 F6 (●-) species correlated with the number of trapped electrons and decreased as a function of electron quenching period. We also measured the electron attachment rate constant of hexafluorobenzene using a post-RF electron trapping experiment. Measured electron attachment rate constant of hexafluorobenzene (1.19 (±0.53) × 10(-9) cm(3) molecule(-1) s(-1) ) for post-RF FT-ICR MS agreed with the previously reported value (1.60 (±0.30) × 10(-9) cm(3) molecule(-1) s(-1) ) from low-pressure ICR MS measurements. Experimental results from direct and indirect electron measurements suggest that RFI process involves RF-generated electrons under ultrahigh vacuum conditions.

A New Model of Outer Belt Electrons for Dielectric Internal Charging (MOBE-DIC)

The outer electron belt poses a significant radiation hazard to spacecraft due to internal charging and dose effects. We present a new user-friendly model to characterise the worst-case environment built on data from the Giove-A spacecraft. We use instrument data based on a novel technique of direct charging current measurements, uncontaminated by protons and unaffected by dead-time, to create the model. The model provides integral or differential electron flux spectra with the following input parameters: percentile 90%, 99% or 100%; L-shell range 3-8; Magnetic Latitude ( B/B 0 ) range 1-100; Energy range 0.5-3 MeV. Comparisons with other models and independent data sets show that our “Model of Outer Belt Electrons for Dielectric Internal Charging” (MOBE-DIC) provides a sound worst-case specification for mission planners and design engineers. We find that, in medium Earth orbit particularly, MOBE-DIC indicates a harder electron spectrum than either AE9 or FLUMIC.

A 128-channel picoammeter system and its application on charged particle beam current distribution measurements.

A 128-channel picoammeter system is constructed based on instrumentation amplifiers. Taking advantage of a high electric potential and narrow bandwidth in DC energetic charged beam measurements, a current resolution better than 5 fA can be achieved. Two sets of 128-channel strip electrodes are implemented on printed circuit boards and are employed for ion and electron beam current distribution measurements. Tests with 60 keV O(3+) ions and 2 keV electrons show that it can provide exact boundaries when a positive charged particle beam current distribution is measured.

Online estimation of lithium-ion battery capacity using sparse Bayesian learning

Lithium-ion (Li-ion) rechargeable batteries are used as one of the major energy storage components for implantable medical devices. Reliability of Li-ion batteries used in these devices has been recognized as of high importance from a broad range of stakeholders, including medical device manufacturers, regulatory agencies, patients and physicians. To ensure a Li-ion battery operates reliably, it is important to develop health monitoring techniques that accurately estimate the capacity of the battery throughout its life-time. This paper presents a sparse Bayesian learning method that utilizes the charge voltage and current measurements to estimate the capacity of a Li-ion battery used in an implantable medical device. Relevance Vector Machine (RVM) is employed as a probabilistic kernel regression method to learn the complex dependency of the battery capacity on the characteristic features that are extracted from the charge voltage and current measurements. Owing to the sparsity property of RVM, the proposed method generates a reduced-scale regression model that consumes only a small fraction of the CPU time required by a full-scale model, which makes online capacity estimation computationally efficient. 10 years' continuous cycling data and post-explant cycling data obtained from Li-ion prismatic cells are used to verify the performance of the proposed method.

Effect of fluorination on the surface electrical properties of epoxy resin insulation

Epoxy samples were surface fluorinated in a laboratory vessel using a F2/N2 gas mixture to suppress surface charge accumulation. Attenuated total reflection infrared analyses indicate that the fluorination led to substantial variations in chemical composition and structure of the sample surface layer. Measurement results of surface properties indicate that surface conductivity and wettability or polarity were dramatically increased by the fluorination. A very likely decrease in charge trap depth and the adsorbed water on the surface in air are responsible for the high surface conductivity. As a result, charge cannot accumulate on the fluorinated surface even at room temperature, rapidly transporting along the surface. Surface charging current measurements further show a much larger steady state current flowing along the fluorinated surface, suggesting much lower dynamic surface potential or charge density during charging, compared with those for the original surface.

Significant suppression of surface charge accumulation on epoxy resin by direct fluorination

Prepared epoxy sheets were surface fluorinated in a laboratory vessel using a F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> mixture with 12.5% F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> by volume at 50 oC and 0.1 MPa (1000 mbar) for 10 min to suppress surface charge accumulation on the epoxy sheet. Attenuated total reflection infrared analyses indicate that the fluorination led to substantial changes in chemical composition and structure of the sheet surface layer. The thickness of the fluorinated layer was determined to be 0.42 μm by SEM observation of the cross-section of the fluorinated sheet, and its SEM image shows that the fluorination also resulted in an increase in surface roughness. As a result, the deposited corona charge cannot be stored on the fluorinated surface even at room temperature, compared with a stable surface charge of the nonfluorinated (original) epoxy sample which has deep surface charge traps as indicated by the open-circuit thermally stimulated discharge current measurement. The measurements of surface conductivity and contact angle and the calculation of surface energy reveal that the fluorination gave rise to dramatic increases in surface conductivity and surface wettability and polarity. A very likely substantial decrease in depth of charge traps in the fluorinated surface layer and the adsorbed water on the fluorinated surface are responsible for the high surface conductivity of the fluorinated epoxy sheet. Surface charging current measurements further show a large steady state current flowing along the fluorinated surface during corona charging, compared with the almost zero steady state current of the original sample. This therefore suggests a lower steady state surface potential and a smaller dynamic surface charge accumulation of the fluorinated sample during the charge.

Influence of fluorination time on surface charge accumulation on epoxy resin insulation

In order to suppress surface charge accumulation on the epoxy resin insulation and to investigate the influence of treatment time on the charge accumulation, epoxy samples are surface fluorinated for the different times of 10 min, 30 min and 60 min in a laboratory vessel using an F2/N2 mixture. Attenuated total reflection infrared analyses and the observations of the cross section and the surface of the samples by SEM indicate the increases in degree of fluorination, thickness and compactness of the fluorinated layer, and the decrease in surface roughness, with treatment time increasing. Compared with the deep surface charge traps and stable surface charge of the unfluorinated (original) sample, as indicated by the open-circuit thermally stimulated discharge current measurement, the fluorinated surface cannot store the charge. The corona charges deposited on the sample surfaces fluorinated for 10 min, 30 min or 60 min rapidly decay to zero in about 2 min, 10 min or 15 mi at room temperature respectively, showing a slowed-down release of charge with fluorination time. The measurements of surface conductivity and contact angle and the calculation of surface energy reveal that fluorination gives rise to dramatic increases in surface conductivity, surface wettability and polarity, while they decrease with treatment time. The significant increase in surface conductivity of the fluorinated sample is attributed to a very likely substantial decrease in trap depth and the adsorbed water on the fluorinated surfac. Surface charging current measurements further show that large steady state current flows along the fluorinated surface during corona charging, in comparison with the almost zero steady state current for the original sample. This implies that the fluorinated sample has much lower surface charge accumulation in the period of charging, than the original sample.

Mastering picocoulombs in the 1890s: The Curies’ quartz–electrometer instrumentation, and how it shaped early radioactivity history

This paper describes the instrumentation developed by Pierre and Jacques Curie in the 1880s to perform very precise charge and low current measurements. Using this set-up, which is nearly as precise as most present digital electronic charge measurement apparatuses, Jacques Curie established the absorption current law for insulating materials. A detailed analysis is made of the experimental path followed by Marie Curie from the choice of her research subject to her first discoveries, using the same Curie quartz–electrometer set-up. From the Curie “discovery notebooks” and a modern reconstitution of this experiment, it is possible to reconstruct what were her main experimental difficulties concerning the measurements of the picoampere leakage currents produced by the radioactive rays. We will underline that the availability for Marie Curie of a precise ready-to-use electrostatic measurement technique played an important, if not decisive, part in her career and her research. A more general issue addressed here is that laboratory techniques are not only a prerequisite of modern scientific work, but in a great part influence knowledge production.

Transient charging current measurements and modelling in silicon nanocrystal floating gate devices

Nanocrystals-based memories are promising candidates for the scaling of Flash memories in the next decade. However, tools to specify where the carriers are actually stored are still needed in order to optimize the elaboration processes of the nanocrystals. This article presents a model which may be used to extract the physical parameters of the objects in which the carriers are charged. These parameters are extracted from transient current measurements which may be performed by most conventional static ammeters. The model is based on the study of an equivalent circuit followed by a finite elements analysis of the memory device. This technique has been used to study MOS capacitors containing silicon nanocrystals obtained by annealing LPCVD silicon rich oxide layers. Our model was found to predict all the transient features observed in the current. It quantitatively determined that in average, one electron is charged into 3–5 nm diameter nanocrystals having a density of 0.84–1.5 × 10 12 cm −2. These parameters are very close to the size and the density which have been targeted during the elaboration process.

H1 INCLUSIVE CROSS-SECTION MEASUREMENTS AND AN EXTRACTION OF PARTON DISTRIBUTION FUNCTIONS

An extraction of the parton distributions of the proton by a next-to-leading order QCD fit in the framework of the Standard Model is presented. The fit implements a novel decomposition of the quark species into up- and down-type quark distributions, which is the key to enable a determination of flavor separated parton distributions from a single experiment. The fit is performed on the inclusive unpolarized neutral and charged current cross-section measurements by the H1 collaboration at HERA. The discussion of uncertainties of parton distribution functions is based upon but extends the QCD analysis published together with the H1 data.

Neutral and charged current cross sections and measurements of F2, xF3 and F L at high Q2 at HERA

Inclusive e+p cross sections for neutral and charged current deep inelastic scattering have been determined by the H1 and ZEUS collaborations at HERA. The data were recorded in 1999 and 2000 at a center of mass energy of 318 GeV with an integrated luminosity of 65.2 pb–1 and 60.9 pb–1, respectively. Taking into account previously published e±p neutral current data the structure functions F2 and xF3 were extracted. F L was determined by extending the measurement to small scattered positron energies. The quark singlet distribution F2 CC was extracted for the first time at HERA by combining e+p and e–p charged current cross sections. All results are well described by Standard Model expectations. PACS: 13.60.Hb Total and inclusive cross sections (including deep-inelastic processes) – 14.20.Dh Protons and neutrons

Proton structure at high Q2

The results of inclusive charged and neutral current measurements at HERA are shown. The results cover a Q2 range of 100 to 30 000 GeV2 and Bjorken χ between 0.0013 and 0.65. Measurements of the proton structure functions F2 and χF3 are made, as well as the extraction f FL in the range 110 < Q2 <700 GeV2. Parton distribution functions are extracted from these data in a next to leading order QCD analysis.

If sterile neutrinos exist, how can one determine the total solar neutrino fluxes?

The ${}^{8}\mathrm{B}$ solar neutrino flux inferred from a global analysis of solar neutrino experiments is within 11% $(1\ensuremath{\sigma})$ of the predicted standard solar model value if only active neutrinos exist, but could be as large as 1.7 times the standard prediction if sterile neutrinos exist. We show that the total ${}^{8}\mathrm{B}$ neutrino flux (active plus sterile neutrinos) can be determined experimentally to about 10% $(1\ensuremath{\sigma})$ by combining charged current measurements made with the KamLAND reactor experiment and with the SNO CC solar neutrino experiment, provided the LMA neutrino oscillation solution is correct and the simulated performance of KamLAND is valid. Including also SNO NC data, the sterile component of the ${}^{8}\mathrm{B}$ neutrino flux can be measured by this method to an accuracy of about 12% $(1\ensuremath{\sigma})$ of the standard solar model flux. Combining Super-Kamiokande and KamLAND measurements and assuming the oscillations occur only among active neutrinos, the ${}^{8}\mathrm{B}$ neutrino flux can be measured to 6% $(1\ensuremath{\sigma});$ the total flux can be measured to an accuracy of about 9%. The total ${}^{7}\mathrm{Be}$ solar neutrino flux can be determined to an accuracy of about 28% $(1\ensuremath{\sigma})$ by combining measurements made with the KamLAND, SNO, and gallium neutrino experiments. One can determine the total ${}^{7}\mathrm{Be}$ neutrino flux to a $1\ensuremath{\sigma}$ accuracy of about 11% or better by comparing data from the KamLAND experiment and the BOREXINO solar neutrino experiment provided both detectors work as expected. The $\mathrm{pp}$ neutrino flux can be determined to about 15% using data from the gallium, KamLAND, BOREXINO, and SNO experiments.

Space charge and external circuit current measurements in LDPE films during breakdown tests

Space charge dynamics in low density polyethylene films were observed by the pulsed electroacoustic (PEA) method throughout breakdown tests at various temperatures. To clarify the relationship between space charge and breakdown, we developed a PEA system with a current measurement unit. The applied voltage was increased up to 300 kV mm-1 in 150 ms to investigate a short time breakdown. Space charge profiles were measured at 1 ms intervals, and the external current was simultaneously measured. A significant positive charge propagating into the specimen was observed immediately before the breakdown at 90°C. These measurements revealed that the positive charge behaviour is strongly related to the breakdown.