The mean life of the positive muon at rest was accurately measured in a zero magnetic fleld with a pulsed beam and found to be 2.1973 plus or minus 0.0003 mu s. (auth)

A measurement of the lifetime and capture rate of negative muons in various elements is reported. The timing system was calibrated in terms of the accurately known positive muon lifetime. The values obtained are in reasonable agreement with previous experimental data, and have a comparable accuracy. ...

Accurate atomic lifetime data are useful for terrestrial and astrophysical plasma diagnostics. At accuracies higher than those required for these applications, lifetime measurements test atomic structure theory in ways complementary to spectroscopic energy determinations. At the highest level of accuracy, the ...

Accurate atomic lifetime data are useful for terrestrial and astrophysical plasma diagnostics. At accuracies higher than those required for these applications, lifetime measurements test atomic structure theory in ways complementary to spectroscopic energy determinations. At the highest level of accuracy, the ...

A new experiment is described which avoids the neutron problem by comparing accurately the mu exp - and mu exp + lifetimes in liquid hydrogen. In addition by comparing the lifetime of neutrons from mu capture and electrons from mu decay, uncertainties abo...

A standard lifetime value is needed in Cl-36 for the analysis of GRID data. The lifetime values reported in the literature are not sufficiently accurate and reliable for this purpose. The lifetime of the 1.959 MeV state in Cl-36 was measured to be 68 + or...

A number of recent atomic lifetime measurements on multiply charged ions have reported uncertainties lower than 1%. Such a level of accuracy challenges theory, which is a good thing. However, a few lessons learned from earlier precision lifetime measurements on atoms and singly charged ions suggest that one should ...

The DIRAC experiment aims to measure the lifetime of ?+?- atoms in the ground state with 10% precision, using the 24 GeV/c proton beam of the CERN Proton Synchrotron. As the value of the above lifetime of order 10-15s is dictated by a strong interaction at low energy, the precise measurement of this quantity ...

Using collinear fast beam cw dye laser modulation spectroscopy, accurate lifetimes in Th II have been measured. Together with known branching ratios, these lifetimes have allowed the determination of absolute oscillator strengths for Th II. This element is of astrophysical interest as a chronometer for stellar and ...

Radiative lifetimes of 24 levels in Nd II have been measured with a laser-ion beam technique using intracavity excitation. Several levels were found to have a different lifetime than earlier reported. The measured lifetimes were used to correct old gf-values deduced from arc spectra. These new ...

Zylon composite fiber strands under tension demonstrate decreasing lifetime with increased load. The creep rupture experiment aims to accurately measure this load-lifetime relationship. The experiment found that a log-log plot of load compared to lifetime demonstrates an overall trend that ...

A number of recent atomic lifetime measurements on multiply charged ions have reported uncertainties lower than 1%. Such a level of accuracy challenges theory, which is a good thing. However, a few lessons learned from earlier precision lifetime measurements on atoms and singly charged ions suggest to remain ...

Radiative lifetimes measured by time-resolved laser-induced fluorescence are reported for 40 odd-parity levels and 36 even-parity levels of singly ionized terbium. The odd-parity levels range in energy from 29000 to 40000 cm{minus}1 and those of even-parity from 21000 to 37000 cm{minus}1. These lifetimes, with one exception, are ...

Lifetimes, oscillator strengths and hyperfine structures in Ho II are measured. Accurate atomic structure data are of importance for element identification in stellar atmospheres as well as in atomic structure studies. Lifetimes of 3 excited levels, all observed in stellar spectra, have been ...

... FLUORESCENT LIFETIME MEASUREMENTS OF RARE EARTH ELEMENTS ... vii Page 10. FLUORESCENT LIFETIME MEASUREMENTS ...

A careful measurement of the lifetime of the first 2 +T=1 state in 42Sc has allowed an accurate experimental test of isospin purity in the A=42 isobaric analogs by using the isospin formalism. A lifetime of 69 (18) fs has been determined, giving an isoscalar matrix element of 6.8 (8) W.u. Previous ...

A careful measurement of the lifetime of the first 2{sub T=1}{sup +} state in {sup 42}Sc has allowed an accurate experimental test of isospin purity in the A=42 isobaric analogs by using the isospin formalism. A lifetime of 69 (18) fs has been determined, giving an isoscalar matrix element of 6.8 (8) W.u. Previous ...

The current work is part of an ongoing study of radiative properties of rare earth neutral atoms motivated by research needs in several disparate fields including astrophysics, laser chemistry and lighting technology. Time-resolved laser-induced fluorescence on a slow atomic beam has been used to measure radiative lifetimes, accurate ...

Radiative lifetimes of nine of the levels np 4P5/20, np 4D7/2,5/20 and np 2D5/20 in the homologous ions Ar II (n = 4), Kr II (n = 5) and Xe II (n = 6) have been measured with the beam-laser method. The measured lifetimes are compared with lifetime values from other experimental and theoretical ...

Accurate lifetime measurements were performed by dye laser excitation to investigate the predissociation of the electronically excited NH/ND (c 1Pi) state. The lifetime of ND (c, v prime = 0, J prime = 1) is 500 +/- 10 ns, a value close to the purely radiative lifetime of the rotationless ...

The lifetimes of atomic inner-shell vacancies are uniquely related, through the uncertainty principle, to widths of the corresponding atomic energy levels. In many cases, atomic level widths can be measured quite accurately by x-ray photoelectron spectros...

A complex of setups for measuring the lifetime of excited states of nuclei by the method of delayed electron-gamma and gamma-gamma coincidences in the range 10 exp -10 -10 exp -6 s is presented. The methods allowing for a substantial increase in the accur...

The positron annihilation lifetime spectroscopy (PALS) using a low energy flux generator may provide a reasonably accurate technique for measuring molecular weights of linear polymers and characterization of thin polyimide films in terms of their dielectr...

Reference is made to studies by Biemont et al. (1982) and Kwiatkowski et al. (1982), in which 'modern' radiative lifetimes obtained by laser excitation were used to refine and update solar abundance values. The same procedure is extended here to Ru I. Radiative lifetimes are measured by laser excitation for 12 levels of Ru I. The ...

We report a precision measurement of the cesium 6P3/2 excited-state lifetime. Two collimated, counterpropagating thermal Cs beams cross perpendicularly to femtosecond pulsed laser beams. High timing accuracy is achieved from having excitation and ionization laser pulses which originate from the same mode-locked laser. Using pulse selection we vary the ...

All models of lasing action require knowledge of the physical parameters involved, of which many can be measured or estimated. The value of the terminal level lifetime is an important parameter in modeling many high power laser systems since the terminal level lifetime can have a substantial impact on the extraction efficiency of the ...

All models of lasing action require knowledge of the physical parameters involved, of which many can be measured or estimated. The value of the terminal level lifetime is an important parameter in modeling many high power laser systems since the terminal level lifetime can have a substantial impact on the extraction efficiency of the ...

Fluorescence spectroscopy and imaging methods, including fluorescence lifetime sensing, are being developed for noninvasive tissue diagnostics. The purpose of this study was to identify and quantify those factors affecting the accurate recovery of fluorophore lifetimes from inhomogeneous tissues in vivo. A Monte Carlo code was ...

After remarkable reduction in the Z1/2 center in n-type 4H-SiC epilayers, the measured carrier lifetimes can be severely affected by other recombination paths. Impacts of carrier recombination at the surface as well as in the substrate are investigated in detail by using numerical simulation based on a diffusion equation. The simulation reveals that a very ...

Nanosecond-pulse-width lasers, such as nitrogen lasers, are relatively inexpensive and are commonly used for biological and biomedical applications. Because the laser pulse width is comparable to fluorophore excited-state lifetimes (�1 -- 10 ns), deconvolution of the temporal system response is needed for accurate lifetime ...

... Accession Number : AD0407559. Title : PRECISION LIFETIME MEASUREMENT ON POSITIVE AND NEGATIVE MUONS. ...

... for recombination are included together with a ... for measuring carrier lifetime. ... Descriptors : *CHARGE CARRIERS, PHOTOCONDUCTIVITY, BAND ...

Two series of selectively deuterated cryptates with the lanthanoids Yb and Nd have been synthesized, and the luminescence lifetimes for the corresponding near-IR emission bands have been measured. Global fitting of these lifetime data combined with structural analysis allows for the accurate quantification of the ...

We use the configuration-interaction method and many-body perturbation theory to perform accurate calculations of energy levels, transition amplitudes, and lifetimes of low-lying states of barium and radium. Calculations for radium are needed for the planning of measurements of parity- and time-invariance-violating effects which are ...

A new positron annihilation lifetime spectrometer consisting of a start ?-ray detector, a stop ?-ray detector, a digital oscilloscope, and a positron detector, which is a plastic scintillator coupled to a photomultiplier tube, is described. A 22Na source is placed between the positron detector and a sample to be studied. ?-ray signals related to positrons annihilating in the ...

Radiative lifetimes, accurate to �5%, have been measured for 153 levels of neutral cerium using time-resolved laser-induced fluorescence (TRLIF) on a slow beam of cerium atoms. Of the 153 levels studied, 150 are even parity and 3 are odd parity. The levels range in energy from 16 869 to 28 557 cm?1. This set of Ce I ...

On the basis of the application of a number of accurately known oscillator strengths to a least-squares fit, it is possible to obtain the coefficients of a function whose intensity, I, is taken from such tabulations as that of Meggers et al. (1975). Recently measured lifetimes are presently used to obtain an improved formula for ...

We studied the fluorescence properties of several potential picosecond lifetime standards suitable for two-photon excitation from a Ti : sapphire femtosecond laser. The fluorescence emission of the selected fluorophores (rose bengal, pyridine 1, and LDS 798) covered the visible to near-infrared wavelength range from 550 to 850 nm. We suggest that these compounds can be used to ...

A new and accurate method for measuring lifetimes of excited ionic states is described. The method employs selective laser excitation and rapid Doppler tuning to convert the spontaneous exponential decay of the excited state into a spatial variation of fluorescence intensity. The technique has been tested on the 6p /sup 2/P/sub ...

A spectrograph with continuous wavelength resolution has been integrated into a frequency-domain fluorescence lifetime-resolved imaging microscope (FLIM). The spectral information assists in the separation of multiple lifetime components, and helps resolve signal cross-talking that can interfere with an accurate analysis of multiple ...

The two-parameter Weibull distribution has been widely adopted to model the lifetime statistics of dielectric breakdown under constant voltage, but recent lifetime testing for high-k gate dielectrics has revealed a systematic departure from Weibull statistics, evocative of lifetime statistics for small quasibrittle structures under ...

Microwave photoconductive decay is widely used to measure the recombination lifetime in semiconductors and is generally considered to be a low-injection technique. Here, the authors examine the technique in detail from both a theoretical and experimental perspective. When the skin or penetration depth is much less than the sample thickness, the ...

Fluorescence lifetime imaging microscopy (FLIM) is now routinely used for dynamic measurements of signaling events inside living cells, including detection of protein-protein interactions. An understanding of the basic physics of fluorescence lifetime measurements is required to use this technique. In this ...

Fluorescence lifetime imaging microscopy (FLIM) is now routinely used for dynamic measurements of signaling events inside living cells, including detection of protein-protein interactions. An understanding of the basic physics of fluorescence lifetime measurements is required to use this technique. In this ...

The technique of time-resolved laser-induced fluorescence is the best method for lifetime measurements because it is largely free from systematic errors that undermine other methods. Lifetime measurements have been performed using time-resolved laser-induced fluorescence on atom and ion beams of many refractory ...

Visualizing and quantifying protein-protein interactions is a recent trend in biomedical imaging. The current advances in fluorescence microscopy coupled with the development of new fluorescent probes provide the tools to study protein interactions in living specimens. Spectral bleed-through or cross talk is a problem in one- and two-photon microscopy to recognize whether one is observing the ...

We extend the technique of fluorescence resonance energy transfer (FRET) by introducing a luminescent terbium chelate as a donor and an organic dye, tetramethylrhodamine, as an acceptor. The results are consistent with a F�rster theory of energy transfer, provided the appropriate parameters are used. The use of lanthanide donors, in general, and this pair, in particular, has many advantages over ...

The authors extend the technique of fluorescence resonance energy transfer (FRET) by introducing a luminescent terbium chelate as a donor and an organic dye, tetramethylrhodamine, as an acceptor. The results are consistent with a Foerster theory of energy transfer, provided the appropriate parameters are used. The use of lanthanide donors in general, and this pair in particular, has many ...

The scattering lengths of a two pion system are the golden magnitudes to test the QCD predictions in the low energy sector. The DIRAC (PS-212) experiment at CERN will obtain a particular combination of the S-wave isospin 0 and 2 scattering lengths by measuring the lifetime of pionium, the hydrogen-like ?+?- atom. This measurement tests ...

A time-resolved confocal fluorescence spectroscopy system is built to measure the fine structure and localized biochemistry of epithelial tissue. It is found that the autofluorescence excited at 405 nm is sensitive to the cellular metabolism and can be used to sense the metabolic status of epithelial tissue. The decay of autofluorescence excited at 405 nm can be ...

By directly measuring the donor fluorescence lifetime as a function of acceptor concentration in the

... Accession Number : ADA229865. Title : Fluorescent Lifetime Measurements of Rare Earth Elements in Gallium Arsenide. ...

... Title : FLUORESCENCE LIFETIME MEASUREMENTS BY TIME CORRELATED SINGLE PHOTON COUNTING. Descriptive Note : Technical rept.,. ...

Lifetimes of states in at least one of the M1 bands in each nucleus from 193-197Pb have been determined through Doppler-Shift Attenuation Method experiments performed with the Gammasphere array. The nuclei were populated under similar conditions allowing accurate relative measurements of the state lifetimes. The ...

A method for the determination of the surface recombination velocity of cylindric vias for the application in back-contacted silicon solar cells is proposed. By applying a theoretical framework for the lifetime dependence on dislocation density, the measured minority carrier lifetime as a function of via density can be described ...

guide, LED Luminaire Lifetime: Recommendations for Testing and Reporting (PDF 666 KB), details specific guidance for accurate reporting of lifetime. Additional metrics...

In the most accurate cold neutron beam determination of the neutron lifetime based on the absolute counting of decay protons, the largest uncertainty was attributed to the absolute determination of the capture flux of the cold neutron beam. Currently an experimental effort is underway at the National Institute of Standards and Technology (NIST) that will ...

Accurate lifetimes have been measured for low-lying levels in 22Ne, 28Si and 31P by bombarding 4He implanted targets with beams of 19F and 28Si ions. Mean lifetimes determined by fitting Doppler-broadened ?-ray lineshapes were (Ex in MeV, ? in ps): 22Ne (1.275, 5.15 +/- 0.31; 3.357, 0.324 +/- 0.009), 28Si (1.779, ...

Singlet delta oxygen lifetime in deuterated basic hydrogen peroxide was measured. The contributing bimolecular rate constants were measured as a function of temperature. The measured lifetime of 20 microseconds compared favorably to the lifetime of 24 microseconds arrived ...

Singlet delta oxygen lifetime in deuterated basic hydrogen peroxide was measured. The contributing bimolecular rate constants were measured as a function of temperature. The measured lifetime of 20 microseconds compared favorably to the lifetime of 24 mic...

There is a desire to characterize plastically deformed regions in structures to monitor their integrity. Of particular importance is the accurate prediction of the lifetime of damaged pipelines due to outside force. In order to accurately predict the remaining life it is essential to accurately determine the degree ...

Precision measurements of atomic lifetimes are important to the analysis of data from many areas of physics and provide fundamental atomic structure information. Scientists in the fields of astrophysics, geophysics, and plasma fusion all depend on oscillator strengths to determine the relative abundances of elements. Assessing the operation of discharge ...

Natural radiative lifetime measurements have been performed for 70 odd-parity highly excited levels of neutral barium in the energy range from 308 15.512 to 417 59.93 cm{sup -1} by a time-resolved laser-induced fluorescence technique in a laser-produced plasma. The lifetime values measured in this paper are in the ...

Natural radiative lifetime measurements have been performed for 70 odd-parity highly excited levels of neutral barium in the energy range from 308 15.512 to 417 59.93 cm-1 by a time-resolved laser-induced fluorescence technique in a laser-produced plasma. The lifetime values measured in this paper are in the range ...

Accurate measurement of the lifetime of the neutron (which is unstable to beta decay) is important for understanding the weak nuclear force and the creation of matter during the Big Bang. Previous measurements of the neutron lifetime have mainly been limited by certain systematic errors; ...

We report the first accurate determination of mobility-lifetime products, ..mu..tau, in thin films of a Cu-ternary chalcopyrite by photoconductivity and ambipolar diffusion length measurements. We found that for Cu-deficient, nearly intrinsic CuGaSe/sub 2/ at an illumination of about 0.25 AM1 the hole's ..mu..tau is 6 x 10/sup ...

This paper presents a novel, history-based, statistical technique for online battery lifetime prediction. The approach first takes a one-time, full cycle, voltage measurement of a constant load, and uses it to transform the partial voltage curve of the current workload into a form with robust predictability. Based on the transformed history curve, we ...

Financial support of this research project has lead to advances in the study of atomic structure through precision measurements of atomic lifetimes, energy splittings, and transitions energies. The interpretation of data from many areas of physics and chemistry requires an accurate understanding of atomic structure. For example, ...

The 1979 Intercosmos-19 experiment was carried out several years following the decay of the artificial radiation belt, so the measured distribution function and the radial diffusion coefficients came from the natural electrons. The diffusion coefficients were first estimated in a previous study (Mineev and Elisarov, 1996). Here, a more accurate ...

Principle of frequency -domain method to implement fluorescence lifetime imaging is introduced in the paper. Referred to the excitation light, the fluorescence light has a phase shift and a reduced modulation degree. Both the phase and the modulation can be used to determine the fluorescence lifetime. However, phase measurements are ...

An optical remote sensor for temperature and pressure was constructed by affixing a ruby crystal to the tip of a single optical fiber. The temperature and pressure information is encoded onto the fluorescent signal back-scattered from the fibertip. Such an optical system is immune to electromagnetic noise. Changes in the lifetime of the emission are associated only with ...

The DARPA-NRL Laser Program is concerned with the development of laser technology of electronic state lasers and associated physics. In particular the development of the XeF laser has been emphasized. Experimental and theoretical efforts were made to understand and improve laser performance. The radiative lifetime of XeF was measured by photolytic ...

The DARPA-NRL Laser Program is concerned with the development of laser technology of electronic state lasers and associated physics. In particular the development of the XeF laser has been emphasized. Experimental and theoretical efforts were made to understand and improve laser performance. The radiative lifetime of XeF was measured by photolytic ...

Contents: Excited-Ion Lifetimes using Penning-Ionizing Collisions, Radiative and Predissociative Lifetimes of the A2E+ State of OH.

The positron lifetime technique for monitoring changes in material properties is described. Examples of positron lifetime measurements in metals and nonmetals are given. Experiments performed on fatigued and thermally degraded materials indicate that the ...

Latest and best measurements of physical quantities involved in complete calculation of the charge exchange lifetime of mirroring magnetospheric ions are coalesced and summarized. It is critical that the charge exchange lifetimes for ions be known as accu...

Aims: We measure transition probabilities for Cr II transitions from the z 4H_J, z 2D_J, y 4F_J, and y 4G_J levels in the energy range 63 000 to 68 000 cm-1. Methods: Radiative lifetimes were measured using time-resolved laser-induced fluorescence from a laser-produced plasma. In addition, branching fractions were determined from ...

We report direct measurement of H2 Q-branch Raman coherence lifetimes using time-resolved picosecond coherent anti-Stokes Raman scattering (ps-CARS). A custom-built, high-peak-power, nearly transform-limited ps laser system offers an ideal combination of frequency and temporal resolution for such measurements. The coherence ...

Transition probabilities of 1191 spectral lines in the first spectra of Nb, Rh, Hf, Ta, and W are determined by accurate measurements of radiative lifetimes and branching ratios. The lifetimes are measured by the time-resolved laser-induced fluorescence on an atomic beam. The atomic beam source ...

Haze formation on reticle continues to be a significant problem for the semiconductor industry. Haze can be formed on the outside pellicle and on the quartz back side of the reticle. Major component of the haze is known to be aluminum sulfate that comes from the reticle cleaning process. The reticle materials, the exposure wavelength, roughness of photomask and this haze will affect the resolution ...

The DIRAC experiment aims to measure the lifetime of pi]+[pi- atoms in the ground state with 10% precision, using the 24 GeV/c proton beam of the CERN Proton Synchrotron. As the value of the above lifetime of order 10-15s is dictated by a strong interaction at low energy, the precise measurement of this quantity ...

... the effective photon lifetime in ... SERVICE LIFE), *PHOTONS, *CAVITY RESONATORS ... SENSITIVITY, LASER BEAMS, PRECISION, REFLECTIVITY ...

... OF ELECTRON FREE LIFETIME AND TRAPPING FACTOR IN HIGH PURITY CADMIUM SULFIDE, CADMIUM SULFIDE/SELENIDE AND ...

The measurements at CDF of the masses and lifetimes of weakly decaying B hadrons are described. 11 refs., 2 figs.

The PAMELA (Payload for Antimatter Matter Exploration and Light nuclei Astrophysics) experiment is a satellite-borne apparatus that performes measurements of the cosmic radiation with a particular focus on antiparticles and light nuclei. Accurate measurements of the elemental composition of cosmic rays are required in order to ...

... AD0244448. Title : A PROCEDURE FOR THE ACCURATE MEASUREMENT OF INFRARED DICHROISM OF ORIENTED FILMS. ...

... Title : A METHOD OF ACCURATELY MEASURING DYNAMIC STABILITY DERRIVATIVES IN TRANSONIC AND SUPERSONIC WIND TUNNELS,. ...

Fluorescence resonance energy transfer (FRET), in which a fluorescent donor molecule transfers energy via a nonradiative dipole-dipole interaction to an acceptor molecule (which is usually a fluorescent molecule), is a standard spectroscopic technique for measuring distances in the 10-70 Angstrom range. We have used a luminescent europium chelate as donor and an organic dye, ...

A single-shot, lifetime-based pressure-sensitive paint (PSP) technique is proposed as a pressure sensor for applications requiring high pressure sensitivity on a moving model such as a rotor blade. The method is based on a single pulse of high-energy excitation light and a double-frame exposure on an interline transfer charge-coupled device camera for recording luminescent ...

The spectrum of singly ionized titanium was analyzed by photographic spectral recordings of the light from a hollow cathode. Classified lines in the region 1200 A to 11000 A and term values are reported. Lifetime of the 3p 5 5p levels in neutral argon were measured by the high frequency deflection technique considering the trapping of radiation from the ...

Accurate lifetimes measured by means of the cascade-free method based on laser excitation of a fast ion beam preexcited in a carbon foil are reported for four 2 p 3 d levels in NII. The lifetime results are: ?(2 p 3 d 3 D {1/0})=0.209�0.007 ns, ?(2 p 3 d 3 D {2/0})=0.219�0.007 ns, ?(2 p 3 d 3 D ...

Partial Contents: Introduction; Overview of existing lifetime measurement techniques; Measurement of fluorescence lifetimes: a system identification approach; Numerical and electrical simulations; The fluorescence experiments; The fluorescence measurement...

We review B{sup +} and B{sup 0} mean lifetime measurements, including direct measurements and determination of the lifetime ratio via measurements of the ratios of branching ratios. We present world averages.

The nanosatellite UNICubeSAT is described, carrying a Broglio Drag Balance Instrument for neutral thermosphere density in situ measurements. The aim of the mission is to contribute to the development of accurate thermosphere models, achieving in situ, real time measurements of atmosphere density, that could be exploited for global ...

The electrostatic breakdown of polymeric materials is important in the design and lifetimes of power line, spacecraft, computational systems, and electronic military components. The key parameters in determining material lifetime include the applied temperature and electric field and the material parameters (Gibbs free energy and density of states). This ...

The ?-ray spectra of 20 resonances in the 35Cl(p, ?)36Ar reaction have been measured with a Ge(Li) detector. Branching ratios and energies of the resonances and of 29 bound states have been determined. Two new doublets have been found at Ex = 7.14 and 7.25 MeV. The reaction Q-value has been determined as Qo = 8506.9+/-0.3 keV; this value was used to deduce ...

Context. In a very recent measurement Gurell et al. (2009, A&A, 508, 525) commented that while the theoretical lifetime of a 4G5.5 is approximately one tenth of the lifetime of b 2H5.5 the corresponding measurement shows this to be close to one fifth. This large discrepancy is attributed to the effect of ...

... Title : NONDESTRUCTIVE MEASUREMENT OF MINORITY CARRIER LIFETIMES IN SI WAFERS USING FREQUENCY DEPENDENCE OF AC ...

... Descriptors : *CHARGE CARRIERS, *TRANSISTORS, MEASUREMENT, CHARGE CARRIERS, SURFACE PROPERTIES, PHOTOCONDUCTIVITY ...

... Descriptors : *CHARGE CARRIERS, *PHOTOCONDUCTIVITY, * SEMICONDUCTORS, *GERMANIUM, *SILICON, MEASUREMENT, CHARGE ...

The positron lifetime technique for monitoring changes in material properties is described. Examples of positron lifetime measurements in metals and nonmetals are given. Experiments performed on fatigued and thermally degraded materials indicate that the positron lifetime spectrum is sensitive to these material ...

The beam lifetime of the 1.3 GeV storage ring TLS (Taiwan Light Source) at SRRC was studied. Contributions of the gas scattering lifetime and Touschek scattering lifetime were measured. Effects of insertion devices, RF energy acceptance, chromaticity sett...

A tandem photoconductive switch, producing nearly rectangular electrical pulses with variable duration from 25 ps to 1 ns, was used for accurate turn-on delay measurements of a laser diode. Maximum electrical pulse amplitude was 75 V and both rise and fall times were 15 ps. The shortest delay recorded was 60 ps. The carrier lifetime at ...

The ability to accurately measure the mobility of particles at low concentrations in small volumes is very useful for a broad range of applications. The coupling of micro- and nano-fluidic devices and confocal microscopy offers an efficient and rapid technique for multiplexed single molecule detection and analysis. Microfluidic channels at micron and ...

The interpretation of room temperature phosphorescence studies of proteins requires an understanding of the mechanisms governing the tryptophan triplet-state lifetimes of residues fully exposed to solvent and those deeply buried in the hydrophobic core of proteins. Since solvents exposed tryptophans are expected to behave similarly to indole free in solution, it is important ...

To predict accurately the leakage currents in silicon-on-insulator transistors (SOI), the minority carrier generation lifetime in the body region and the surface generation velocity at the body/buried interface must be known. It is demonstrated in this paper that both these quantities can be found from the application of charge-time and capacitance-time ...

The beam lifetime of the 1.3 GeV storage ring TLS (Taiwan Light Source) at SRRC was studied. Contributions of the gas scattering lifetime and Touschek scattering lifetime were measured. Effects of insertion devices, RF energy acceptance, chromaticity setting, transverse emittance coupling strength, bunch length, ...

Time-resolved fluorescence optical tomography allows 3-dimensional localization of multiple fluorophores based on lifetime contrast while providing a unique data set for improved resolution. However, to employ the full fluorescence time measurements, a light propagation model that accurately simulates weakly diffused and multiple ...

High-quality oscillator strengths are needed to convert the amount of interstellar absorption into an accurate abundance from data acquired with the Hubble Space Telescope and the Far Ultraviolet Spectroscopic Explorer. In order to help clarify the appropriate values to use for ultraviolet transitions in Cu II, we report lifetimes from our beam-foil ...

? rays were measured at several angles in both singles and coincidence mode in the Sn119(?,n?)Te122 reaction at 15 MeV on a thick target. Lifetimes of excited states in Te122 were determined from a Monte Carlo Doppler shift attenuation method (DSAM) analysis of the Doppler broadened lines shapes of ? rays de-exciting the levels. A comparison of several ...

The commercial availability of boron-loaded organic scintillators has led to the development of neutron detectors that operate as ``electronically'' black, totally absorbing spectrometers. The key to the enhanced spectroscopy is the delayed capture of nearly thermalized neutrons by 10B that can occur within a few microseconds after the energy pulse from prompt proton recoils. ...

Recent measurements of the B hadron lifetime from PEP and PETRA experiments are presented. These measurements firmly establish that the B lifetime is long (approx.1 psec), implying that the mixing between the third generation of quarks and the lighter quarks is much weaker that the mixing between the first two ...

We report the measurement of the lifetime of the D sup 0 meson. The direct observation of the decay vertex distribution in the process D sup 0 -> K sup - pi sup + was made using a vertex chamber installed in the HRS detector at PEP. The measured lifetime ...

Lifetime measurements with various detectors at PEP and PETRA are discussed, with emphasis on an experiment with the SLAC-LBL Mark II detector. This was the first to introduce a vertex detector for more precise lifetime measurements. A two-lepton study in...

The generation and propagation of fluorescence light within biological tissue offers the potential for biomedical diagnostics and analyte sensing. Arising from an exogenous fluorescent dye injected as a contrast agent or immobilized in a polymer implant, the fluorescent decay kinetics can be sensitive to the tissue??s biochemical environment, providing quantitative in vivo information of the ...

The compact scintillator device WILLI, set up in IFIN-HH Bucharest (44� 26' N latitude and 26� 04' E longitude), has been used for measurements of the charge ratio in the atmospheric muon flux. The experimental method, based on the observation of the reduced effective lifetime of negative muons stopped in matter, as compared with the ...

An extensive body of data supports a relation between acute exposures to ambient ozone and the occurrence of various acute respiratory symptoms and changes in measures of lung function. In contrast, relatively few data are available on the human health effects that result from long-term exposure to ambient ozone, Current efforts to study long-term ozone-related health effects ...

In an attempt to achieve accurate quantification of DNA levels in cell nuclei, we studied the influence of salt concentration on the fluorescence of cell nuclei complexed with Hoechst-33258 (Hoe) fluorochrome. The fluorescence of cell nuclei was compared with that of extracted DNA as well as that of nucleosome core. Conformational changes in these complexes were examined by ...

We report the first observation, together with a mechanism for such an observation, of a steplike feature in the pulsed field ionization photoelectron measurement of CH4(C2H2), marking the 0 K dissociation threshold for the formation of CH3(+) + H(C2H(+) + H) from CH4(C2H2). The nonexistence of a step in the spectrum for C 2H4 at its dissociation threshold for C2H2(+) ...