Search results for "Instrumentation"
showing 10 items of 4914 documents
Radon and material radiopurity assessment for the NEXT double beta decay experiment
2015
Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM
Experimental signatures of extreme optical fluctuations in lumped Raman fiber amplifiers
2012
International audience; In this work, we experimentally investigate several temporal and spectral methods to highlight extreme fluctuations which can develop during the Raman amplification of an ultrashort pulse train. Forward and backward pumping schemes are compared to dual pass configurations.
The effect of energy-dependent detector efficiency in electron spectroscopic methods: XPS, AES and DCEMS
1993
Systematic studies were performed to investigate the distorting effect of the electron energy dependence of the channeltron detector efficiency on the shape of data distributions in electron spectroscopy. In agreement with earlier results for electron energies up to 3 keV, it was found that a virtually energy-independent shape of the electron distribution might be achieved even in a very broad range of electgron energies (up to 15 keV) by appropriate selection of the operational high voltage of a channeltron. However, the efficieny of channeltrons was also found to depend on count rates, indicating one of the principal difficulties in comparing distribution recorded under different experime…
Peak shape for a quadrupole mass spectrometer: comparison of computer simulation and experiment
2000
Abstract Computer simulations of ion trajectories have been used to evaluate the performance of a quadrupole mass spectrometer. Consideration has been given to realistic fields modeled on a commercial system as well as experimental distributions with respect to ion entry position, axial and radial velocity and relative phase of the quadrupole field. Determination of the mass filter acceptance-area as a function of the mass setting yields mass peak shapes with a dynamic range of more than seven orders of magnitude and thus provides estimates for abundance sensitivity. Results from these simulations are found to give excellent agreement with experimental measurements for different elements in…
Two-color ionization of hydrogen by short intense pulses
2010
Photoelectron energy spectra resulting by the interaction of hydrogen with two short pulses having carrier frequencies, respectively, in the range of the infrared and XUV regions have been calculated. The effects of the pulse duration and timing of the X-ray pulse on the photoelectron energy spectra are discussed. Analysis of the spectra obtained for very long pulses show that certain features may be explained in terms of quantum interferences in the time domain. It is found that, depending on the duration of the X-ray pulse, ripples in the energy spectra separated by the infrared photon energy may appear. Moreover, the temporal shape of the low frequency radiation field may be inferred by …
Finely tunable laser based on a bulk silicon wafer for gas sensing applications
2016
In this work a very simple continuously tunable laser based on an erbium ring cavity and a silicon wafer is presented. This laser can be tuned with very fine steps, which is a compulsory characteristic for gas sensing applications. Moreover the laser is free of mode hopping within a spectral range sufficiently wide to match one of the ro-vibrational lines of a target molecule. Here the proposed laser reached, at ∼1530 nm, a continuous tuning range of around 950 pm (>100 GHz) before mode hopping occurred, when a silicon wafer of 355 μm thickness was used. Additionally, the laser can be finely tuned with small tuning steps of <12 pm, achieving a resolution of 84.6 pm °C-1 and by using a therm…
Color centers and structural damage in LiF induced by 150 MeV Kr ions
2012
Color centers and evolution of structure defects were investigated in LiF crystals irradiated at room temperature with 150 MeV 84Kr ions with a beam current of 10nA/cm2 in the fluence range 1011 - 1014 ions/cm2 at the cyclotron accelerator DC-60 (Astana, Kazakhstan). At the fluence of 1011 ions/cm2, SEM imaging revealed mainly formation of etchable ion tracks. Above this fluence, severe structural modifications in the irradiated layer were observed which include the ion-induced formation of dislocations and grains with nano-scale dimensions. The role of fluence in the concentration of electronic color centers and structural modifications is discussed.
Spectral characterization of laser-accelerated protons with CR-39 nuclear track detector
2018
CR-39 nuclear track material is frequently used for the detection of protons accelerated in laser-plasma interactions. The measurement of track densities allows for determination of particle angular distributions, and information on the kinetic energy can be obtained by the use of passive absorbers. We present a precise method of measuring spectral distributions of laser-accelerated protons in a single etching and analysis process. We make use of a one-to-one relation between proton energy and track size and present a precise calibration based on monoenergetic particle beams. While this relation is limited to proton energies below 1 MeV, we show that the range of spectral measurements can b…
Differential study of substituted and unsubstituted cobalt phthalocyanines for gas sensor applications
2011
Abstract The conductivity of CoPc (cobalt phthalocyanine) and Co[(SO3Na)2,3Pc] was measured under a flow of two different gases (NH3 and O3), during exposure/recovery cycles. It appears that the relative responses are linearly related to the concentration, in the 20–200 ppb range for O3 and in the 20–200 ppm range for NH3. Observed during time, the sensing parameters allow a qualitative understanding of the kinetics. The comparative study of those products under both different gases gave interesting results for sensor applications. Whereas CoPc is sensitive to both gases, its sulfonated counterpart is only sensitive to NH3.
Thermal properties of ferroelectric 0.7PbNi1/3Nb2/3O3–0.3PbTiO3ceramics
2013
A study of heat capacity as function of temperature of the 0.7PbNi1/3Nb2/3O3–0.3PbTiO3 solid solution within the 120–800 K range is reported. Broad anomalies on the curve of heat capacity are revealed in the 250–450 K and 450–650 K intervals peaking at 520 K and a λ-anomaly at T ≈ 225 K. Results are discussed with account for dielectric and structural data.