Weak line water vapor spectrum in the 13 200–15 000 cm−1 region

New Fourier transform spectra of water vapor are presented in the range 6500–16 400 cm−1 obtained using pathlengths of up to 800 m and long integration times. These spectra have a significantly higher signal-to-noise than previous measurements in this wavenumber range. Wavenumbers, absolute intensities and self-broadening coefficients, all with associated uncertainties, are presented for 3604 lines in the region 13 200–15 000 cm−1. Analysis of these lines using variational linelists, along with other unassigned lines from previous studies, has been conducted. This leads to 952 new line assignments to transitions involving 35 different vibrational states of H216O. A smaller number of lines are assigned to H218O and H217O

Weak line water vapor spectrum in the 11,787–13,554 cm−1 region

Long-pathlength Fourier transform spectra of water vapor recorded previously by Schermaul et al. (J. Mole. Spectrosc. 211, 169 (2002)) are analyzed in the range 11 787–13 554 cm−1. Wavenumbers, absolute intensities, and self-broadening coefficients, with associated uncertainties, are presented for 2137 lines. Analysis of these lines using variational linelists has been conducted leading to the assignment of 1906 of the new lines to 23 different upper vibrational states in the 3ν+δ, 4ν, and 4ν+δ polyads, a further 19 lines are ascribed to H218O. Comparisons are made with the HITRAN database

A Laser Frequency Comb System for Absolute Calibration of the VTT Echelle Spectrograph

A wavelength calibration system based on a laser frequency comb (LFC) was developed in a co-operation between the Kiepenheuer-Institut f\"ur Sonnenphysik, Freiburg, Germany and the Max-Planck-Institut f\"ur Quantenoptik, Garching, Germany for permanent installation at the German Vacuum Tower Telescope (VTT) on Tenerife, Canary Islands. The system was installed successfully in October 2011. By simultaneously recording the spectra from the Sun and the LFC, for each exposure a calibration curve can be derived from the known frequencies of the comb modes that is suitable for absolute calibration at the meters per second level. We briefly summarize some topics in solar physics that benefit from absolute spectroscopy and point out the advantages of LFC compared to traditional calibration techniques. We also sketch the basic setup of the VTT calibration system and its integration with the existing echelle spectrograph.Comment: 9 pages, 2 figures; Solar Physics 277 (2012

The Imaging Magnetograph eXperiment (IMaX) for the Sunrise balloon-borne solar observatory

The Imaging Magnetograph eXperiment (IMaX) is a spectropolarimeter built by four institutions in Spain that flew on board the Sunrise balloon-borne telesocope in June 2009 for almost six days over the Arctic Circle. As a polarimeter IMaX uses fast polarization modulation (based on the use of two liquid crystal retarders), real-time image accumulation, and dual beam polarimetry to reach polarization sensitivities of 0.1%. As a spectrograph, the instrument uses a LiNbO3 etalon in double pass and a narrow band pre-filter to achieve a spectral resolution of 85 mAA. IMaX uses the high Zeeman sensitive line of Fe I at 5250.2 AA and observes all four Stokes parameters at various points inside the spectral line. This allows vector magnetograms, Dopplergrams, and intensity frames to be produced that, after reconstruction, reach spatial resolutions in the 0.15-0.18 arcsec range over a 50x50 arcsec FOV. Time cadences vary between ten and 33 seconds, although the shortest one only includes longitudinal polarimetry. The spectral line is sampled in various ways depending on the applied observing mode, from just two points inside the line to 11 of them. All observing modes include one extra wavelength point in the nearby continuum. Gauss equivalent sensitivities are four Gauss for longitudinal fields and 80 Gauss for transverse fields per wavelength sample. The LOS velocities are estimated with statistical errors of the order of 5-40 m/s. The design, calibration and integration phases of the instrument, together with the implemented data reduction scheme are described in some detail.Comment: 17 figure

Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

Détection, par voie spectroscopique, de l’acétylène et de l’éthane dans l’atmosphère terrestre, à partir d’observations solaires infrarouges au sol

peer reviewe

Line width and line shape analysis in the inductively coupled plasma by high resolution Fourier transform spectrometry

High resolution Fourier transform spectrometry has been used to perform line width and line shape analysis of eighty-one iron I emision lines in the spectral range 290 to 390nm originating in the normal analytical zone of an inductively coupled plasma. Computer programs using non-linear least squares fitting techniques for line shape analysis were applied to the fully resolved spectra to determine Gaussian and Lorentzian components of the total observed line width. The effect of noise in the spectrum on the precision of the line fitting technique was assessed, and the importance of signal to noise ratio for line shape analysis is discussed. Translational (Doppler) temperatures were calculated from the Gaussian components of the line width and were found to be on the order of 6300/sup 0/K. The excitation temperature of iron I was also determined from the same spectral data by the spectroscopic slope method based on the Einstein-Boltzmann expression for spectral intensity and was found to be on the order of 4700/sup 0/K. 31 references

Precision Fe I and Fe II wavelengths in the red and infra-red spectrum of the iron-neon hollow cathode lamp

Wavelengths and wavenumbers are presented for 290 lines in the spectrum of the Iron-Neon hollow cathode lamp. The lines are all strong, stable, well resolved lines in Fe I or Fe II; the range covered is from 424 nm to 4.2 $\mu$m (23600 to 2354  cm$^{-1}$). The measurements were made by Fourier transform spectrometry with a wavenumber precision of $\pm 0.0003$ cm$^{-1}$ or better. The absolute accuracy, based on visible region Ar II standards, varies from 0.001 cm$^{-1}$ at 20000 cm$^{-1}$ to 0.0005 cm$^{-1}$ at 2300 cm$^{-1}$. The absolute scale used is the same as that employed in earlier work, covering the range from 17350 to 55000 cm$^{-1}$. The intensities, damping parameters (Lorentzian component of line profile) and observed signal to noise ratios of the lines are also tabulated. Auxiliary experiments showed that lines of large Doppler width or high damping parameter suffer significant wavenumber shifts; such lines have been excluded from the list. It is also shown that the wavenumbers of unbroadened lines are the same in large (950 mA, 4 mB) and small (20 mA, 10 mB) hollow cathode lamps

Quadrupole transitions of the 1←0 band of N2 observed in a high resolution atmospheric spectrum

Using a high resolution atmospheric absorption spectrum recorded at Kitt Peak with the solar Fourier transform spectrometer, it has been possible to observe the quadrupole transitions S7 to S16 of the 1 ← 0 band of N2. The analysis of the equivalent widths and of the central depths of these lines has enabled us to determine the derivative of the quadrupole moment (∂Q/∂r)e = (0.94 ± 0.05) ea 0 and to estimate the broadening coefficient by air γ0N2-air = 0.06 ± 0.02 cm-1 atm.-1 at 296 K. Finally the assignment of telluric lines between 2 391.5 and 2 467 cm-1 is also given.Un spectre d'absorption à haute résolution de l'atmosphère terrestre enregistré à Kitt Peak à l'aide d'un spectromètre par transformation de Fourier a permis d'observer les transitions quadrupolaires S7 à S16 de la bande 1 ← 0 de N2. L'analyse des largeurs équivalentes et des profondeurs centrales de ces raies conduit, d'une part à la détermination de la dérivée du moment quadrupolaire (∂Q/∂r)e = (0,94 ± 0,05) ea0 et d'autre part, à une estimation du coefficient d'élargissement par l'air γ0N2-air = 0,06 ± 0,02 cm -1 atm.-1 à 296 K. En outre l'identification des raies telluriques observées entre 2 391,5 et 2 467 cm-1 est donnée