Electroionization study of ethane: ionization and appearance energies, ion-pair formations and negative ions

1987 ◽  
Vol 65 (6) ◽  
pp. 1424-1432 ◽  
Author(s):  
Pierre Plessis ◽  
Paul Marmet
Keyword(s):  
Signal To Noise Ratio ◽  
Negative Ions ◽  
Ion Pair ◽  
High Signal ◽  
Threshold Region ◽  
Text Fragment ◽  
Ratio Data ◽  
Singly Charged ◽  
Fragment Production ◽  
Monoenergetic Electron Beam

Threshold region ionization efficiency curves of ethane, of all singly charged fragments consisting of at least one carbon atom, and of [Formula: see text] and [Formula: see text] are presented and analysed. An energy filtered monoenergetic electron beam apparatus capable of producing very high signal-to-noise ratio data was used to study these ions. The C2H6 ionization energy is evaluated to be 11.57 ± 0.02 eV and structures due to competition with [Formula: see text] fragment production are observed at higher energy in the [Formula: see text] curve. As a result of the high apparatus sensitivity several of the measured appearance energies are lower (some by several eV) than previously reported. [Formula: see text], [Formula: see text], and [Formula: see text] ion pair formations are observed. The [Formula: see text] ion pair formation, previously reported by several studies, is shown to be obscured by the isotopic [Formula: see text] fragment signal.

Electroionization study of ethylene: ionization and appearance energies, ion-pair formations, and negative ions

1987 ◽  
Vol 65 (2) ◽  
pp. 165-172 ◽  
Author(s):  
Pierre Plessis ◽  
Paul Marmet
Keyword(s):  
Electron Impact ◽  
Negative Ions ◽  
High Sensitivity ◽  
Ion Pair ◽  
Common Mechanism ◽  
Threshold Region ◽  
Monoenergetic Electron ◽  
Text Fragment ◽  
First Time ◽  
Very High

Monoenergetic electron-impact threshold ionization and appearance curves of very high sensitivity of ethylene and all fragments containing at least one carbon atom are analyzed in detail. Ionization or appearance energies are measured for all ions, including the [Formula: see text] fragment. Structures are observed in the immediate [Formula: see text] threshold region, which are attributed to hot bands and to Rydberg autoionizing states. [Formula: see text],[Formula: see text] and [Formula: see text] ion-pair formations are reported for the first time. Simultaneous production of positive and negative ions is seen to be a common mechanism by electron impact. Appearance energies of some fragments are several electron volts lower than those of previous works.

Electroionization study of ethylene: structures in the ionization and appearance curves

1987 ◽  
Vol 65 (7) ◽  
pp. 803-807 ◽  
Author(s):  
Pierre Plessis ◽  
Paul Marmet
Keyword(s):  
Carbon Atom ◽  
High Signal ◽  
Signal To Noise ◽  
Monoenergetic Electron ◽  
Text Production ◽  
Text Fragment ◽  
First Time ◽  
Fragmentation Processes ◽  
Fragment Production ◽  
Very High

Ionization-efficiency curves with very high signal-to-noise ratios for ethylene and all fragments consisting of at least one carbon atom are presented and analyzed. The curves are produced by monoenergetic electron impact and extend up to 10 eV above threshold. Most of the structures observed thus far by this method for these regions are reported here for the first time. Competition between [Formula: see text] production and [Formula: see text] and [Formula: see text] fragment production is clearly seen in the respective curves. Features occurring at the same energy in several of the curves indicate that these are due to a common progenitor, particularly the [Formula: see text] complex. The appearance of different fragmentation processes accounts for the onset-type structure found in some of the fragment-ion curves.

scholarly journals TDCOSMO

2020 ◽  
Vol 642 ◽  
pp. A193 ◽  
Author(s):  
M. Millon ◽  
F. Courbin ◽  
V. Bonvin ◽  
E. Buckley-Geer ◽  
C. D. Fassnacht ◽  
...  
Keyword(s):  
Time Delays ◽  
Signal To Noise Ratio ◽  
Light Curves ◽  
High Signal ◽  
Max Planck ◽  
Signal To Noise ◽  
Ratio Data ◽  
Final Measurement ◽  
Measured Time ◽  
Noise Ratio

We present six new time-delay measurements obtained from Rc-band monitoring data acquired at the Max Planck Institute for Astrophysics (MPIA) 2.2 m telescope at La Silla observatory between October 2016 and February 2020. The lensed quasars HE 0047−1756, WG 0214−2105, DES 0407−5006, 2M 1134−2103, PSJ 1606−2333, and DES 2325−5229 were observed almost daily at high signal-to-noise ratio to obtain high-quality light curves where we can record fast and small-amplitude variations of the quasars. We measured time delays between all pairs of multiple images with only one or two seasons of monitoring with the exception of the time delays relative to image D of PSJ 1606−2333. The most precise estimate was obtained for the delay between image A and image B of DES 0407−5006, where τAB = −128.4−3.8+3.5 d (2.8% precision) including systematics due to extrinsic variability in the light curves. For HE 0047−1756, we combined our high-cadence data with measurements from decade-long light curves from previous COSMOGRAIL campaigns, and reach a precision of 0.9 d on the final measurement. The present work demonstrates the feasibility of measuring time delays in lensed quasars in only one or two seasons, provided high signal-to-noise ratio data are obtained at a cadence close to daily.

Ionization and dissociative ionization of CO2 by electron impact

1977 ◽  
Vol 55 (21) ◽  
pp. 1889-1897 ◽  
Author(s):  
N. Bussières ◽  
P. Marmet
Keyword(s):  
Kinetic Energy ◽  
Electron Impact ◽  
Signal To Noise Ratio ◽  
Ion Pair ◽  
Pair Formation ◽  
Negative Ion ◽  
High Signal ◽  
Signal To Noise ◽  
Fragment Ions ◽  
Zero Kinetic Energy

Using a very sensitive apparatus with a high signal-to-noise ratio, new structures are observed in the ionization curve of CO2 by electron impact in the first 10 V above the ionization threshold. Neutral and negative ion levels are observed and related to npσu and npπu series converging to Ā, [Formula: see text], and [Formula: see text] levels of CO2+. Data for the fragment ions CO+, O+, and C+ are also presented; it is shown that they can be formed with zero kinetic energy. No ion pair formation can be detected at threshold.

Excited states of HI and DI and their negative ions between 10 and 20 eV

1988 ◽  
Vol 66 (7) ◽  
pp. 564-569
Author(s):  
P. Marmet ◽  
Hamid Nasrallah
Keyword(s):  
Excited States ◽  
Signal To Noise Ratio ◽  
Rydberg States ◽  
Negative Ions ◽  
Ionization Efficiency ◽  
High Signal ◽  
Signal To Noise ◽  
Noise Ratio ◽  
The Impact ◽  
Very High

The ionization-efficiency curves of HI and DI, obtained by the impact of monoenergetic electrons between 10 and 20 eV, are presented with a very high signal-to-noise ratio. Several new Rydberg states between the 2Π(3/2) and 2Π(1/2) limits and also below the 2Σ+ limit have been identified. Also, the first two 6s and 6p Rydberg levels with configuration (5sσ)1(5pσ)2(5pπ)4nlλ have been observed at 17.3 and 18.6 eV, respectively. The results obtained in DI confirm the structures observed in HI.

A compact guided-wave EMAT with pulsed electromagnet for ferromagnetic tube inspection

2020 ◽  
Vol 64 (1-4) ◽  
pp. 951-958
Author(s):  
Tianhao Liu ◽  
Yu Jin ◽  
Cuixiang Pei ◽  
Jie Han ◽  
Zhenmao Chen
Keyword(s):  
Power Plants ◽  
Signal To Noise Ratio ◽  
Small Diameter ◽  
Performance Testing ◽  
Guided Wave ◽  
High Signal ◽  
Receiver Coil ◽  
Signal To Noise ◽  
Corrosion Defects

Small-diameter tubes that are widely used in petroleum industries and power plants experience corrosion during long-term services. In this paper, a compact inserted guided-wave EMAT with a pulsed electromagnet is proposed for small-diameter tube inspection. The proposed transducer is noncontact, compact with high signal-to-noise ratio and unattractive to ferromagnetic tubes. The proposed EMAT is designed with coils-only configuration, which consists of a pulsed electromagnet and a meander pulser/receiver coil. Both the numerical simulation and experimental results validate its feasibility on generating and receiving L(0,2) mode guided wave. The parameters for driving the proposed EMAT are optimized by performance testing. Finally, feasibility on quantification evaluation for corrosion defects was verified by experiments.

Application of Novel Low Current OBIRCH Amplifier and Nanoprobing to Identify Subtle Leakages in Advanced Node Technologies

2018 ◽  
Author(s):  
Satish Kodali ◽  
Liangshan Chen ◽  
Yuting Wei ◽  
Tanya Schaeffer ◽  
Chong Khiam Oh
Keyword(s):  
Signal To Noise Ratio ◽  
Semiconductor Industry ◽  
Fault Isolation ◽  
Ring Oscillator ◽  
High Signal ◽  
The Novel ◽  
Resistance Change ◽  
Three Samples ◽  
Relative Threshold ◽  
First Time

Abstract Optical beam induced resistance change (OBIRCH) is a very well-adapted technique for static fault isolation in the semiconductor industry. Novel low current OBIRCH amplifier is used to facilitate safe test condition requirements for advanced nodes. This paper shows the differences between the earlier and novel generation OBIRCH amplifiers. Ring oscillator high standby leakage samples are analyzed using the novel generation amplifier. High signal to noise ratio at applied low bias and current levels on device under test are shown on various samples. Further, a metric to demonstrate the SNR to device performance is also discussed. OBIRCH analysis is performed on all the three samples for nanoprobing of, and physical characterization on, the leakage. The resulting spots were calibrated and classified. It is noted that the calibration metric can be successfully used for the first time to estimate the relative threshold voltage of individual transistors in advanced process nodes.

scholarly journals VS2 as saturable absorber for Q-switched pulse generation

Nanophotonics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 2569-2576 ◽  
Author(s):  
Lu Li ◽  
Lihui Pang ◽  
Qiyi Zhao ◽  
Yao Wang ◽  
Wenjun Liu
Keyword(s):  
Saturable Absorber ◽  
Nonlinear Optical ◽  
Modulation Depth ◽  
Signal To Noise Ratio ◽  
Transition Metal Dichalcogenides ◽  
Laser Cavity ◽  
Pulse Generation ◽  
High Signal ◽  
Power Pulse ◽  
Metal Dichalcogenides

AbstractTransition metal dichalcogenides have been widely utilized as nonlinear optical materials for laser pulse generation applications. Herein, we study the nonlinear optical properties of a VS2-based optical device and its application as a new saturable absorber (SA) for high-power pulse generation. Few-layer VS2 nanosheets are deposited on the tapered region of a microfiber to form an SA device, which shows a modulation depth of 40.52%. After incorporating the microfiber-VS2 SA into an Er-doped fiber laser cavity, passively Q-switched pulse trains could be obtained with repetition rates varying from 95 to 233 kHz. Under the pump power of 890 mW, the largest output power and shortest pulse duration are measured to be 43 mW and 854 ns, respectively. The high signal-to-noise ratio of 60 dB confirms the excellent stability of the Q-switching state. To the best of our knolowdge, this is the first illustration of using VS2 as an SA. Our experimental results demonstrate that VS2 nanomaterials have a large potential for nonlinear optics applications.

scholarly journals Detection and localization of multiple small damages in beam

2021 ◽  
Vol 13 (1) ◽  
pp. 168781402098732
Author(s):  
Ayisha Nayyar ◽  
Ummul Baneen ◽  
Syed Abbas Zilqurnain Naqvi ◽  
Muhammad Ahsan
Keyword(s):  
Frequency Response ◽  
Natural Frequencies ◽  
Signal To Noise Ratio ◽  
Moving Average ◽  
A Priori ◽  
Damage Index ◽  
High Signal ◽  
Frequency Range ◽  
Spatial Locality ◽  
System Frequency

Localizing small damages often requires sensors be mounted in the proximity of damage to obtain high Signal-to-Noise Ratio in system frequency response to input excitation. The proximity requirement limits the applicability of existing schemes for low-severity damage detection as an estimate of damage location may not be known  a priori. In this work it is shown that spatial locality is not a fundamental impediment; multiple small damages can still be detected with high accuracy provided that the frequency range beyond the first five natural frequencies is utilized in the Frequency response functions (FRF) curvature method. The proposed method presented in this paper applies sensitivity analysis to systematically unearth frequency ranges capable of elevating damage index peak at correct damage locations. It is a baseline-free method that employs a smoothing polynomial to emulate reference curvatures for the undamaged structure. Numerical simulation of steel-beam shows that small multiple damages of severity as low as 5% can be reliably detected by including frequency range covering 5–10th natural frequencies. The efficacy of the scheme is also experimentally validated for the same beam. It is also found that a simple noise filtration scheme such as a Gaussian moving average filter can adequately remove false peaks from the damage index profile.

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