WorldWideScience

Sample records for emission spectra

  1. X-ray absorption spectra and emission spectra of plasmas

    International Nuclear Information System (INIS)

    Peng Yonglun; Yang Li; Wang Minsheng; Li Jiaming

    2002-01-01

    The author reports a theoretical method to calculate the resolved absorption spectra and emission spectra (optically thin) of hot dense plasmas. Due to its fully relativistic treatment incorporated with the quantum defect theory, it calculates the absorption spectra and emission spectra for single element or multi-element plasmas with little computational efforts. The calculated absorption spectra of LTE gold plasmas agree well with the experimental ones. It also calculates the optical thin emission spectra of LTE gold plasmas, which is helpful to diagnose the plasmas of relevant ICF plasmas. It can also provide the relevant parameters such as population density of various ionic stages, precise radiative properties for ICF studies

  2. Emissive spectra of shock-heated argon

    International Nuclear Information System (INIS)

    Tang Jingyou; Gu Yan; Peng Qixian; Bai Yulin; Li Ping

    2003-01-01

    To study the radiant properties of argon under weak shock compression, an aluminum target filled with gaseous argon at ambient states was impacted by a tungsten alloy projectile which was launched from a two-stage light gun to 2.00 km/s. The radiant signals of single shock-compressed argon were recorded by a six-channel pyrometer and oscilloscopes, which varied with time linearly for the five channels from 405 nm to 700 nm and exponentially for the channel 800 nm, and the corresponding velocity of shock wave was determined to be 4.10 ± 0.09 km/s. By the present experiment, it has been shown that the absorbability of the shock-heated argon is low for visual light and the optical depths of argon gas turn from thin to thick as wavelengths gradually increase. The time-resolved spectra in the rising-front of the radiant signal in the re-shocked argon were recorded by means of an OMA, and strong emissive spectrum bands near 450 nm light-wave length but no linear spectrum were found. The emissive spectrum properties of shock-compression argon were qualitatively explained by the state parameters and ionization degree

  3. Emission Spectra of Hydrogen-Seeded Helium Arcjets

    National Research Council Canada - National Science Library

    Welle, R

    2000-01-01

    .... This work reports on a recent set of experiments in which emission spectra of the plume of a helium arcjet were acquired and analyzed to obtain information on the internal energy modes of the arcjet...

  4. Cancerous tissue mapping from random lasing emission spectra

    International Nuclear Information System (INIS)

    Polson, R C; Vardeny, Z V

    2010-01-01

    Random lasing emission spectra have been collected from both healthy and cancerous tissues. The two types of tissue with optical gain have different light scattering properties as obtained from an average power Fourier transform of their random lasing emission spectra. The difference in the power Fourier transform leads to a contrast between cancerous and benign tissues, which is utilized for tissue mapping of healthy and cancerous regions of patients

  5. Chemical effects in x-ray emission spectra

    International Nuclear Information System (INIS)

    Fernandes, N.G.

    1982-01-01

    The chemical bond influence in X-ray emission spectra of hafnium, iodine, iron, sulphur, aluminium and magnesium is detected. The position of one X-ray emission line is determined by three methods: parabolic profile; Gaussian distribution and extra-heavy maximum. (author)

  6. Classification spectra of Sanduleak and Stephenson emission-line stars

    International Nuclear Information System (INIS)

    Allen, D.A.

    1978-01-01

    Low dispersion slit spectra of 89 emission-line stars are described; these stars were originally located and classified by Sanduleak and Stephenson in an objective-prism survey. The new data broadly confirm the classification scheme adopted by Sanduleak and Stephenson. In particular most of the large number of symbiotic stars they classified have been confirmed and others found. Many of these contain strong, broad emission bands in their red spectra. Two new Wolf-Rayet stars, one new planetary nebula and two new bipolar reflection nebulae involving hidden emission-line stars have been found. (author)

  7. Classification spectra of Sanduleak and Stephenson emission-line stars

    Energy Technology Data Exchange (ETDEWEB)

    Allen, D A [Anglo-Australian Observatory, Epping (Australia)

    1978-09-01

    Low dispersion slit spectra of 89 emission-line stars are described; these stars were originally located and classified by Sanduleak and Stephenson in an objective-prism survey. The new data broadly confirm the classification scheme adopted by Sanduleak and Stephenson. In particular most of the large number of symbiotic stars they classified have been confirmed and others found. Many of these contain strong, broad emission bands in their red spectra. Two new Wolf-Rayet stars, one new planetary nebula and two new bipolar reflection nebulae involving hidden emission-line stars have been found.

  8. Optical emission line spectra of Seyfert galaxies and radio galaxies

    International Nuclear Information System (INIS)

    Osterbrock, D.E.

    1978-01-01

    Many radio galaxies have strong emission lines in their optical spectra, similar to the emission lines in the spectra of Seyfert galaxies. The range of ionization extends from [O I] and [N I] through [Ne V] and [Fe VII] to [Fe X]. The emission-line spectra of radio galaxies divide into two types, narrow-line radio galaxies whose spectra are indistinguishable from Seyfert 2 galaxies, and broad-line radio galaxies whose spectra are similar to Seyfert 1 galaxies. However on the average the broad-line radio galaxies have steeper Balmer decrements, stronger [O III] and weaker Fe II emission than the Seyfert 1 galaxies, though at least one Seyfert 1 galaxy not known to be a radio source has a spectrum very similar to typical broad-line radio galaxies. Intermediate-type Seyfert galaxies exist that show various mixtures of the Seyfert 1 and Seyfert 2 properties, and the narrow-line or Seyfert 2 property seems to be strongly correlated with radio emission. (Auth.)

  9. Thermoluminescence emission spectra and optical bleaching of oligoclase

    International Nuclear Information System (INIS)

    Bos, A.J.J.; Piters, T.M.; Ypma, P.J.

    1994-01-01

    Thermoluminescence (TL) spectra of oligoclase samples have been recorded in the temperature range from 300 to 700 K and the wavelength range from 300 to 850 nm. Like other feldspars, oligoclase produces blue (peaking at 460 nm) and red (peaking at 765 nm) emission bands. The maximum of the red emission occurs 20 K lower than that of the blue band. Optical bleaching was performed at wavelengths varying from 360 to 800 nm. Bleaching of artificially irradiated oligoclase causes a decrease of the TL signal. The bleaching efficiency increases with decreasing wavelength. Bleaching does not only influence the height of the glow curve but also the shape. An interesting observation is that the ratio of the blue and red band intensities is not affected by a bleaching procedure. No evidence has been found that bleaching influences the shape of the emission spectra. The correlation between the blue and red bands is discussed. (Author)

  10. Nonclassical polarization effects in fluorescence emission spectra from microdroplets

    Science.gov (United States)

    Arnold, S.; Goddard, N. L.; Hill, S. C.

    1999-12-01

    We report a pronounced nonclassical polarization effect on the shape of fluorescence emission spectra from isolated microdroplets containing a dilute solution of soluble fluors or a dilute layer of surfactant fluors. We see different spectral shapes for 90° scattering when comparing between IVV, IVH, IHH, IHV. However, we measure the largest difference in spectral shape in the surfactant case, with the incident polarization directed toward the detector (IHV vs IHH). Imaging reveals that the emission in this case principally arises from two distinct regions near the surface of the droplet, which are diametrically opposed and along the axis of the incident laser beam. The effect appears to be the direct result of coupling between molecular emission moments and electromagnetic modes of the droplet. It is not the molecule which radiates but the molecule microvessel. Directional emission is sensitive to the polarization of the electromagnetic mode which is stimulated by the coupling.

  11. Theory of X-ray absorption and emission spectra

    International Nuclear Information System (INIS)

    Mukoyama, Takeshi

    2004-01-01

    Theoretical studies on X-ray absorption and emission spectroscopy are discussed. Simple expressions for X-ray emission rate and X-ray absorption cross section are presented in the dipole approximation. Various atomic models to obtain realistic wave functions and theoretical calculations for X-ray absorption cross sections and X-ray emission rates are described. In the case of molecules and solids, molecular orbital methods for electronic structures and molecular wave functions are discussed. The emphasis is on the procedures to obtain the excited-state and continuum wave functions for molecules and to calculate the multi-center dipole matrix elements. The examples of the calculated X-ray absorption and emission spectra are shown and compared with the experimental results

  12. Study of aluminum emission spectra in astrophysical plasmas

    International Nuclear Information System (INIS)

    Jin Zhan; Zhang Jie

    2001-01-01

    High temperature, high density and strong magnetic fields in plasmas produced by ultra-high intensity and ultrashort laser pulses are similar to the main characteristics of astrophysical plasmas. This makes it possible to simulate come astrophysical processes at laboratories. The author presents the theoretic simulation of aluminum emission spectra in astrophysical plasmas. It can be concluded that using laser produced plasmas, the authors can obtain rich information on astrophysical spectroscopy, which is unobservable for astronomer

  13. Emission spectra of dimethoxybenzenes by controlled electron impact

    International Nuclear Information System (INIS)

    Ogawa, Teiichiro; Imasaka, Totaro; Toyoda, Minoru; Tsuji, Masaharu; Ishibashi, Nobuhiko

    1975-01-01

    The emission spectra of o-, m-, and p-dimethoxybenzenes under controlled electron impact excitation (200 eV) were measured in the 220 - 450 nm region at very low pressures. The photoemissions of the excited parent species and such fragment species as H, CH, CO, and CO + were observed and assigned. The relative intensities of the photoemissions of the parent species were compared with those of the fluorescence spectra (photoexcitation) in an n-hexane solution. The excited parent species, H, and CH were concluded to be produced in one-electron processes; however, the CO + species were assumed to be produced in both one- and two-electron processes, and the relative contributions are evaluated. It was concluded that the rate of the predissociation of o-dimethoxybenzene was faster than those of the other two isomers, and the observed characteristics of o-dimethoxybenzene had something to do with this faster rate. (auth.)

  14. Polarization of electron cyclotron emission spectra in LHD

    International Nuclear Information System (INIS)

    Vries, P.C. de; Nagayama, Y.; Kawahata, K.; Inagaki, S.; Sasao, H.; Nagasaki, K.

    1999-07-01

    Electron cyclotron emission (ECE) can be used to determine the electron temperature profile in magnetized plasmas. The complex structure of the magnetic field configuration in the Large Helical Device (LHD), which has a large shear, complicates the analysis of the ECE spectrum. In a sheared magnetic field the propagation of X and O-mode polarization through the plasma are coupled, causing mode conversion and polarization rotation. Mode scrambling is also caused by wall reflections. In this report, this mode conversion in LHD is numerically analyzed. It was found that at low density mode conversion scrambles the ECE spectra. However, at higher density (n eo > 1.0·10 19 m -3 ) the polarization mode is found to rotate with the sheared magnetic field, yielding only a negligible mode conversion. Wall reflections are found to depolarize the ECE spectrum. Notwithstanding the LHD magnetic configuration, it is shown that temperature profiles could be revealed from the ECE spectra. (author)

  15. Emission spectra of gaseous avalanches and their time structure

    International Nuclear Information System (INIS)

    Fraga, M.M.; Lima, E.P. de; Marques, R.F.; Policarpo, A.J.P.L.; Alves, M.A.F.; Salete, M.; Leite, S.C.P.

    1993-01-01

    Following previous measurements in argon/methane mixtures, the authors now report on the emission spectra of argon/ethane and methane/ethane mixtures, in the region from 120 to 450 nm, for a single wire chamber working in the proportional and/or self-quenching streamer modes. Identification of radicals and fragments is attempted. The time evolution of VUV light, relevant to photon feedback processes, is presented for the CI lines at 156.1 and 165.7nm in argon/methane, argon/ethane and methane/ethane mixtures

  16. Spontaneous emission spectra from a staggered-array undulator

    International Nuclear Information System (INIS)

    Shimada, Shigeki; Okada, Kouji; Masuda, Kai; Sobajima, Masaaki; Yoshikawa, Kiyoshi; Ohnishi, Masami; Yamamoto, Yasushi; Toku, Hisayuki

    1997-01-01

    A staggered-array undulator set inside the superconducting solenoid coils is shown to be able to provide high undulator fields larger than the longitudinal magnetic fields, a small undulator period, easy tunability through the solenoid coil current, and compact and easy fabrication. The overall performance characteristics of this undulator were studied mainly with respect to iron and aluminum disk widths, and spontaneous emission spectra through the numerical calculations. The maximum undulator field is found to be obtained for the ratio of the aluminum disk width to the undulator period of 0.45. The line widths (FWHM) of the spontaneous emission spectra, however, do not show N w -1 dependence on the number of the undulator period N w for practical beams with a Gaussian distribution, compared with for a single electron. The energy spread among various parameters is seen to play an important role in reducing the FWHM with increase of N w . The large tunability of the wavelength is proved to cover 6-10 mm by changing the solenoid magnetic field from 0.4 T to 1.6 T. (author)

  17. OSL, TL and IRSL emission spectra of sedimentary quartz and feldspar samples

    International Nuclear Information System (INIS)

    Lomax, Johanna; Mittelstraß, Dirk; Kreutzer, Sebastian; Fuchs, Markus

    2015-01-01

    This contribution presents a variety of different luminescence emission spectra from sedimentary feldspar and quartz samples under various stimulation modes. These are green stimulated quartz (OSL-) spectra, quartz TL spectra, feldspar IRSL and post-IR IRSL spectra. A focus was set at recording OSL and IRSL spectra at elevated stimulation temperatures such as routinely applied in luminescence dating. This was to test whether optical stimulation at elevated temperatures results in a shift of emission peaks. For OSL emissions of quartz, this has so far not been tested. In case of feldspar emissions, post-IR IRSL conditions, hence IRSL emissions at a low temperature, directly followed by high temperature post-IRSL emissions, are explicitly investigated. All spectra were recorded using a new system incorporated into a Lexsyg luminescence reader. Thus, this study, besides presenting new spectral data, also serves as a feasibility study for this new device. It is shown that (a) the new device is capable of automatically measuring different sorts of spectra, also at elevated temperatures, (b) known thermally and optically stimulated peak emissions of quartz and feldspar are confirmed, (c) obtained IRSL and OSL spectra indicate that there is no significant relation between peak emission and stimulation temperature. - Highlights: • We have measured OSL, IRSL and TL emission spectra of sedimentary quartz and feldspar samples. • Spectral analyses were performed at elevated stimulation temperatures. • Emission spectra show very little variation with stimulation temperatures.

  18. Emission line spectra of Herbig-Haro objects

    International Nuclear Information System (INIS)

    Brugel, E.W.; Boehm, K.H.; Mannery, E.

    1981-01-01

    Spectrophotometric data have been obtained for 12 Herbig-Haro nebulae with the multichannel spectrometer on the Mt. Palomar 5.08 m telescope and with the image intensified dissector scanner on the Kitt Peak 2.13 m telescope. Optical emission line fluxes are presented for the following Herbig-Haro objects: H-H 1 (NW), H-H 1 (SE), H-H 2A, H-H 2G, H-H 2H, H-H 3, H-H 7, H-H 11, H-H 24A, H-H 30, H-H 32, and H-H 40. Values for the electron temperature and electron density have been determined for 10 of these condensations. Significant inhomogeneities in the line-forming regions of these H-H objects are indicated by the derived N/sub e/-T/sub e/ diagrams. Empirical two-component density models have been constructed to interpret the emission line spectra of the five brightest condensations. Slightly less satisfactory homogeneous models are presented for the remaining five objects

  19. Fluorescence of Bacteria, Pollens, and Naturally Occurring Airborne Particles: Excitation/Emission Spectra

    National Research Council Canada - National Science Library

    Hill, Steven C; Mayo, Michael W; Chang, Richard K

    2009-01-01

    The fluorescence intensity as a function of excitation and emission wavelengths (EEM spectra) was measured for different species of bacteria, biochemical constituents of cells, pollens, and vegetation...

  20. Quantitative analysis of directional spontaneous emission spectra from light sources in photonic crystals

    International Nuclear Information System (INIS)

    Nikolaev, Ivan S.; Lodahl, Peter; Vos, Willem L.

    2005-01-01

    We have performed angle-resolved measurements of spontaneous-emission spectra from laser dyes and quantum dots in opal and inverse opal photonic crystals. Pronounced directional dependencies of the emission spectra are observed: angular ranges of strongly reduced emission adjoin with angular ranges of enhanced emission. It appears that emission from embedded light sources is affected both by the periodicity and by the structural imperfections of the crystals: the photons are Bragg diffracted by lattice planes and scattered by unavoidable structural disorder. Using a model comprising diffuse light transport and photonic band structure, we quantitatively explain the directional emission spectra. This work provides detailed understanding of the transport of spontaneously emitted light in real photonic crystals, which is essential in the interpretation of quantum optics in photonic-band-gap crystals and for applications wherein directional emission and total emission power are controlled

  1. Classification of hydromagnetic emissions based on frequency--time spectra

    International Nuclear Information System (INIS)

    Fukunishi, H.; Toya, T.; Koike, K.; Kuwashima, M.; Kawamura, M.

    1981-01-01

    By using 3035 hydromagnetic emission events observed in the frequency range of 0.1--2.0 Hz at Syowa (Lapprox.6), HM emissions have been classified into eight subtypes based on their spectral structures, i.e., HM whistler, periodic HM emission, HM chorus, HM emission burst, IPDP, morning IPDP, Pc 1--2 band, and irregular HM emission. It is seen that each subtype has a preferential magnetic local time interval and also a frequency range for its occurrence. Morning IPDP events and irregular HM emissions occur in the magnetic morning hours, while dispersive periodic HM emissions and HM emission bursts occur around magnetic local noon, then HM chorus emissions occur in the afternoon hours and IPDP events occur in the evening hours. Furthermore, it is noticed that the mid-frequencies of these emissions vary from high frequencies in the morning hours to low frequencies in the afternoon hours. On the basis of these results, the generation mechanisms of each subtype are discussed

  2. Study of atomic and molecular emission spectra of Sr by laser induced breakdown spectroscopy (LIBS).

    Science.gov (United States)

    Bhatt, Chet R; Alfarraj, Bader; Ayyalasomayajula, Krishna K; Ghany, Charles; Yueh, Fang Y; Singh, Jagdish P

    2015-12-01

    Laser Induced Breakdown Spectroscopy (LIBS) is an ideal analytical technique for in situ analysis of elemental composition. We have performed a comparative study of the quantitative and qualitative analysis of atomic and molecular emission from LIBS spectra. In our experiments, a mixture of SrCl2 and Al2O3 in powder form was used as a sample. The atomic emission from Sr and molecular emission from SrCl and SrO observed in LIBS spectra were analyzed. The optimum laser energies, gate delays, and gate widths for selected atomic lines and molecular bands were determined from spectra recorded at various experimental parameters. These optimum experimental conditions were used to collect calibration data, and the calibration curves were used to predict the Sr concentration. Limits of detection (LODs) for selected atomic and molecular emission spectra were determined.

  3. Influence of pure dephasing on emission spectra from single photon sources

    DEFF Research Database (Denmark)

    Næsby Rasmussen, Andreas; Skovgård, Troels Suhr; Kristensen, Philip Trøst

    2008-01-01

    We investigate the light-matter interaction of a quantum dot with the electromagnetic field in a lossy microcavity and calculate emission spectra for nonzero detuning and dephasing. It is found that dephasing shifts the intensity of the emission peaks for nonzero detuning. We investigate the char......We investigate the light-matter interaction of a quantum dot with the electromagnetic field in a lossy microcavity and calculate emission spectra for nonzero detuning and dephasing. It is found that dephasing shifts the intensity of the emission peaks for nonzero detuning. We investigate...

  4. Neutron emission spectra of excited 126–140Sn nuclei

    International Nuclear Information System (INIS)

    Aggarwal, Mamta; Rajasekaran, M.

    2004-01-01

    We investigate one-neutron and two-neutron emission from 132 Sn and its neighboring isotopes due to thermal excitation. The rotational states of 132 Sn at different temperatures are investigated. The effects of separation energy and thermal excitation energy on neutron emission probability are studied. (author)

  5. Infrared spectra of peculiar emission-line stars

    International Nuclear Information System (INIS)

    Andrillat, Yvette; Houziaux, Leo

    1975-01-01

    230A/mm spectra of HD51585, V1016Cyg, HBV475 and XXOph between 8,000 and 11,000A are described. Important spectral variations have been noted between 1974 and 1975. Satisfactory identifications cannot be proposed for lines at 9,180 and 9,204A [fr

  6. Imaging Emission Spectra with Handheld and Cellphone Cameras

    Science.gov (United States)

    Sitar, David

    2012-01-01

    As point-and-shoot digital camera technology advances it is becoming easier to image spectra in a laboratory setting on a shoestring budget and get immediate results. With this in mind, I wanted to test three cameras to see how their results would differ. Two undergraduate physics students and I used one handheld 7.1 megapixel (MP) digital Cannon…

  7. Emission spectra of alkali-metal (K,Na,Li)-He exciplexes in cold helium gas

    International Nuclear Information System (INIS)

    Enomoto, K.; Hirano, K.; Kumakura, M.; Takahashi, Y.; Yabuzaki, T.

    2004-01-01

    We have observed emission spectra of excimers and exciplexes composed of a light alkali-metal atom in the first excited state and 4 He atoms [K*He n (n=1-6), Na * He n (n=1-4), and Li * He n (n=1,2)] in cryogenic He gas (the temperature 2 K -1 . Differently from exciplexes with heavier alkali-metal atoms, the spectra for the different number of He atoms were well separated, so that their assignment could be made experimentally. Comparing with the spectra of K * He n , we found that the infrared emission spectrum of the K atom excited in liquid He was from K*He 6 . To confirm the assignment, we have also carried out ab initio calculation of adiabatic potential curves and peak positions of the emission spectra of the exciplexes

  8. An experimental investigation on the properties of laser-induced plasma emission spectra

    International Nuclear Information System (INIS)

    Tang Xiaoshuan; Li Chunyan; Ji Xuehan; Feng Eryin; Cui Zhifeng

    2004-01-01

    The authors have measured the time-resolved emission spectra produced by Nd: YAG laser induced Al plasma with different kinds of buffer gas (He, Ar, N 2 and Air). The dependence of emission spectra line intensity and Stark broadening on the time delay, kinds and pressure of buffer gas are studied. The results show that the atomic emission line intensity reaches maximum at 3 μs time delay, the Stark broadening increases with increasing the pressure of buffer gas, and decreases with increasing time delay. The Stark broadening in Ar buffer gas is largest among the four different kinds of buffer gas. (author)

  9. Emission spectra of yttrium vanadate doped with bismuth and dysprosium

    International Nuclear Information System (INIS)

    Pawar, B.V.; Patil, R.N.

    1975-01-01

    The fluorescence spectra of YVO 4 :Bi and YVO 4 :Bi:Dy phosphors under X-rays and ultra-violet radiation have been studied. The observations on the phosphors with constant Bi 3+ and varying Dy 3+ concentration can be attributed to radiationless transfer of energy from Bi 3+ to Dy 3+ coupled with non-radiative losses due to self-quenching at higher level of Dy 3+ concentration. While the observations on the phosphors with constant Dy 3+ and varying Bi 3+ concentration indicate that there is radiationless transfer from Bi 3+ to Dy 3+ under X-ray or UV irradiation. (author)

  10. Qualitative analysis of the rare earth element by simulation of inductively coupled plasma emission spectra

    International Nuclear Information System (INIS)

    Hashimoto, M.S.; Tobishima, Taeko; Kamitake, Seigo; Yasuda, Kazuo.

    1985-01-01

    The emission lines for qualitative analysis of rare earth elements by a simulation technique of ICP spectra were proposed. The spectra were simulated by employing a Gaussian (or a Lorentzian at high concentrations) profile. The simulated spectra corresponded quite well with the observed ones. The emission lines were selected so that the interference was as small as possible. The present qualitative analysis is based on a pattern recognition method where observed intensity ratios of the emission lines in each element are compared with those of a single analyte element. The qualitative analysis was performed for twelve standard solutions containing a single rare earth element and for eight standard solutions containing an element other than rare earth elements. The selection of the emission lines and the algorithm of the present qualitative analysis were justified. (author)

  11. Coherent manipulation of spontaneous emission spectra in coupled semiconductor quantum well structures.

    Science.gov (United States)

    Chen, Aixi

    2014-11-03

    In triple coupled semiconductor quantum well structures (SQWs) interacting with a coherent driving filed, a coherent coupling field and a weak probe field, spontaneous emission spectra are investigated. Our studies show emission spectra can easily be manipulated through changing the intensity of the driving and coupling field, detuning of the driving field. Some interesting physical phenomena such as spectral-line enhancement/suppression, spectral-line narrowing and spontaneous emission quenching may be obtained in our system. The theoretical studies of spontaneous emission spectra in SQWS have potential application in high-precision spectroscopy. Our studies are based on the real physical system [Appl. Phys. Lett.86(20), 201112 (2005)], and this scheme might be realizable with presently available techniques.

  12. Gamma-ray emission spectra from spheres with 14 MeV neutron source

    International Nuclear Information System (INIS)

    Yamamoto, Junji; Kanaoka, Takeshi; Murata, Isao; Takahashi, Akito; Sumita, Kenji

    1989-01-01

    Energy spectra of neutron-induced gamma-rays emitted from spherical samples were measured using a 14 MeV neutron source. The samples in use were LiF, Teflon:(CF 2 ) n , Si, Cr, Mn, Co, Cu, Nb, Mo, W and Pb. A diameter of the sphere was either 40 or 60 cm. The gamma-ray energy in the emission spectra covered the range from 500 keV to 10 MeV. Measured spectra were compared with transport calculations using the nuclear data files of JENDL-3T and ENDF/B-IV. The agreements between the measurements and the JENDL-3T calculations were good in the emission spectra for the low energy gamma-rays from inelastic scattering. (author)

  13. Emission spectra from super-critical rippled plasma density profiles illuminated by intense laser pulses

    International Nuclear Information System (INIS)

    Ondarza R, R.; Boyd, T.J.M.

    2000-01-01

    High-order harmonic emission from the interaction of intense femtosecond laser pulses with super-critical plasmas characterized by a rippled density profile at the vacuum-plasma interface has been observed from particle-in-cell (PIC) simulations. A plasma simulation box several laser wavelengths in extent was prepared with a rippled density of a fraction of a laser wavelength. Emission spectra at the very initial stage of the interaction were recorded with spectral characteristics dissimilar to those previously reported in the literature. The reflected light spectra were characterized by a strong emission at the plasma line and by a series of harmonics at multiples of the ripple frequency. Harmonic spectra were obtained for different values of the plasma ripple frequency. In all cases the harmonics were emitted at the precise multiple harmonic number of the ripple frequency. Another important feature apparent from the simulations was that the emission peaks appeared to havea complex structure as compared with those for unrippled plasmas. For the cases when the plasma was rippled the peaks that corresponded to the multiples of the rippled density typically showed a double peak for the first few harmonics. The reflected emission plots for the main laser pulse showed strong emission at the plasma frequency and at multiples of that frequency as reported by the authors in the literature. (Author)

  14. Study of Ultraviolet Emission Spectra in ZnO Thin Films

    Directory of Open Access Journals (Sweden)

    Y. M. Lu

    2013-01-01

    Full Text Available Photoluminescence (PL of ZnO thin films prepared on c-Al2O3 substrates by pulsed laser deposition (PLD are investigated. For all samples, roomtemperature (RT spectra show a strong band-edge ultraviolet (UV emission with a pronounced low-energy band tail. The origin of this UV emission is analyzed by the temperature dependence of PL spectra. The result shows that the UV emission at RT contains different recombination processes. At low temperature donor-bound exciton (D0X emission plays a major role in PL spectra, while the free exciton transition (FX gradually dominates the spectrum with increasing temperatures. It notes that at low temperature an emission band (FA appears in low energy side of D0X and FX and can survive up to RT. Further confirmation shows that the origin of the band FA can be attributed to the transitions of conduction band electrons to acceptors (e, A0, in which the acceptor binding energy is estimated to be approximately 121 meV. It is concluded that at room temperature UV emission originates from the corporate contributions of the free exciton and free electrons-to-acceptor transitions.

  15. Fourier transform infrared emission spectra of atomic rubidium: g- and h-states

    Czech Academy of Sciences Publication Activity Database

    Civiš, Svatopluk; Ferus, Martin; Kubelík, Petr; Chernov, Vladislav E.; Zanozina, Ekaterina M.

    2012-01-01

    Roč. 45, č. 17 (2012), s. 175002 ISSN 0953-4075 R&D Projects: GA AV ČR IAAX00100903 Institutional support: RVO:61388955 Keywords : Fourier transform infrared emission spectra * atomic rubidium * physical chemistry Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.031, year: 2012

  16. A Spectral Library of Emissivity Spectra for MERTIS on BepiColombo

    Science.gov (United States)

    Maturilli, A.; Helbert, J.; Varatharajan, I.; D'Amore, M.; Hiesinger, H.

    2018-05-01

    At PSL we measured emissivity spectra in vacuum for a suite of Mercury surface analogues for temperatures from 100°C to >400°C. The spectral library is completed by reflectance on samples fresh and post-heating (0.2 to 200 µm spectral range).

  17. Modification of Optical Properties of Seawater Exposed to Oil Contaminants Based on Excitation-Emission Spectra

    Science.gov (United States)

    Baszanowska, E.; Otremba, Z.

    2015-10-01

    The optical behaviour of seawater exposed to a residual amount of oil pollution is presented and a comparison of the fluorescence spectra of oil dissolved in both n-hexane and seawater is discussed based on excitation-emission spectra. Crude oil extracted from the southern part of the Baltic Sea was used to characterise petroleum properties after contact with seawater. The wavelength-independent fluorescence maximum for natural seawater and seawater artificially polluted with oil were determined. Moreover, the specific excitation-emission peaks for natural seawater and polluted water were analysed to identify the natural organic matter composition. It was found that fluorescence spectra identification is a promising method to detect even an extremely low concentration of petroleum residues directly in the seawater. In addition, alien substances disturbing the fluorescence signatures of natural organic substances in a marine environment is also discussed.

  18. VNIR Reflectance and MIR Emissivity Spectra of Ordinary Chondrite Meteorites Under Simulated Asteroid Surface Conditions

    Science.gov (United States)

    Gemma, M.; Shirley, K.; Glotch, T. D.; Ebel, D. S. S.

    2017-12-01

    Recent missions have revealed much about the nature of many Near-Earth asteroids, including the NEAR-Shoemaker target 433 Eros and Hayabusa target 25142 Itokawa. Both asteroids appear to have mineralogy consistent with ordinary chondrite meteorites. Laboratory spectral analysis of well-constrained meteorite samples can be employed as a reference tool to characterize and constrain data from current and future asteroid studies. A sample set of ordinary chondrite meteorites was chosen from the collection at the American Museum of Natural History. Six meteorites, spanning groups H, L, and LL, were prepared at four different size fractions (25-63 μm, 63-90 μm, 90-125 μm, 125-250 μm) in an attempt to mimic regolith known to exist on asteroids such as 433 Eros and 25142 Itokawa. At the Center for Planetary Exploration at Stony Brook University, spectra of the ordinary chondrite material were measured under simulated asteroid surface conditions ( 10-6 mbar, 150 K chamber temperature, low intensity illumination). The samples were used in two experiments: one measuring visible and near-infrared (VNIR) reflectance spectra at a series of temperatures, and the other measuring mid-infrared (MIR) emissivity spectra. The emissivity measurements require accurate simulation of the thermal environment within asteroid regolith, achieved by inducing a thermal gradient within the sample that results in a surface brightness temperature around 323 K (similar to the surface of 25142 Itokawa). Mid-IR emissivity spectra were collected for each sample at a surface temperature of 323 K, and reflectance spectra were collected in increments of 10 K, over the range 283 K to 373 K. Preliminary VNIR spectra show spreads similar to those seen in Hinrichs and Lucey (2002). Preliminary MIR emissivity spectra suggest that under asteroid surface conditions, the position of the Christiansen feature shifts to shorter wavelengths and emissivity is lower in the Reststrahlen bands when compared to

  19. Energy spectra of neutrons accompanying the emission fission of 238U

    International Nuclear Information System (INIS)

    Smirenkin, G.N.; Lovchikova, G.N.; Trufanov, A.M.; Svirin, M.I.; Polyakov, A.V.; Vinogradov, V.A.; Dmitriev, V.D.; Boykov, G.S.

    1996-01-01

    The spectra of fission neutrons emitted from 238U are measured for the first time by the time-of-flight method at incident-neutron energies of 16.0 and 17.7 MeV. Analysis of the neutron spectra shows that experimental results at incident-neutron energies of 14.7, 16.0, and 17.7 MeV (above the threshold of chance fission) differ significantly from those obtained at a neutron energy of 2.9 MeV (below the threshold of chance fission). Owing to the prefission emission of neutrons, the observed spectra of neutrons from emission fission exhibit a characteristic growth of the neutron yield in both hard and soft sections of the spectrum of secondary neutrons. This growth manifests itself as a step in the first case and as a rise in the second case, where it results in a noticeable excess of neutrons over the statistical-model predictions for E<2 MeV. The first feature in the spectra of neutrons from emission fission can be associated with the nonequilibrium decay of an excited fissile nucleus. On the contrary, the origin of the second feature has yet to be clarified. Additional measurements of angular distributions of secondary neutrons may prove helpful in this respect

  20. Energy spectra and asymmetry of charged particle emission in the muon minus capture by nuclei

    International Nuclear Information System (INIS)

    Balandin, M.P.; Grebenyuk, V.M.; Sinov, V.G.; Konin, A.D.

    1978-01-01

    Energy spectra of separated-by-mass single-charged particles at the capture of 130 MeV negative muons by carbon, oxygen, magnesium and sulphur have been measured. The experimental results are compared with the theoretical calculations at the assumption of preequilibrium decay of collective states described by the hydrodynamical model. The measurement of asymmetry of charged particle emission in sulphur and megnesium was carried out by hte method of muon spin precession in a magnetic field. Theoretical curves describe correctly the exponential spectra character, but the yields obtained are 2-3 times less than the experimental results

  1. Photoluminescence emission spectra of Makrofol® DE 1-1 upon irradiation with ultraviolet radiation

    Directory of Open Access Journals (Sweden)

    M. El Ghazaly

    Full Text Available Photoluminescence (PL emission spectra of Makrofol® DE 1-1 (bisphenol-A based polycarbonate upon irradiation with ultraviolet radiation of different wavelengths were investigated. The absorption-and attenuation coefficient measurements revealed that the Makrofol® DE 1-1 is characterized by high absorbance in the energy range 6.53–4.43 eV but for a lower energy than 4.43 eV, it is approximately transparent. Makrofol® DE 1-1 samples were irradiated with ultraviolet radiation of wavelength in the range from 250 (4.28 eV to 400 (3.10 eV nm in step of 10 nm and the corresponding photoluminescence (PL emission spectra were measured with a spectrofluorometer. It is found that the integrated counts and the peak height of the photoluminescence emission (PL bands are strongly correlated with the ultraviolet radiation wavelength. They are increased at the ultraviolet radiation wavelength 280 nm and have maximum at 290 nm, thereafter they decrease and diminish at 360 nm of ultraviolet wavelength. The position of the PL emission band peak was red shifted starting from 300 nm, which increased with the increase the ultraviolet radiation wavelength. The PL bandwidth increases linearly with the increase of the ultraviolet radiation wavelength. When Makrofol® DE 1-1 is irradiated with ultraviolet radiation of short wavelength (UVC, the photoluminescence emission spectra peaks also occur in the UVC but of a relatively longer wavelength. The current new findings should be considered carefully when using Makrofol® DE 1-1 in medical applications related to ultraviolet radiation. Keywords: Photoluminescence spectra, Makrofol® DE 1-1, UV–vis spectrophotometry, Attenuation coefficient, Ultraviolet radiation

  2. Mid-infrared emission and Raman spectra analysis of Er(3+)-doped oxyfluorotellurite glasses.

    Science.gov (United States)

    Chen, Fangze; Xu, Shaoqiong; Wei, Tao; Wang, Fengchao; Cai, Muzhi; Tian, Ying; Xu, Shiqing

    2015-04-10

    This paper reports on the spectroscopic and structural properties in Er(3+)-doped oxyfluorotellurite glasses. The compositional variation accounts for the evolutions of Raman spectra, Judd-Ofelt parameters, radiative properties, and fluorescent emission. It is found that, when maximum phonon energy changes slightly, phonon density plays a crucial role in quenching the 2.7 μm emission generated by the Er(3+):(4)I11/2→(4)I13/2 transition. The comparative low phonon density contributes strong 2.7 μm emission intensity. The high branching ratio (18.63%) and large emission cross section (0.95×10(-20)  cm(2)) demonstrate that oxyfluorotellurite glass contained with 50 mol.% TeO2 has potential application in the mid-infrared region laser.

  3. EMISSION LINES BETWEEN 1 AND 2 keV IN COMETARY X-RAY SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, Ian; Christian, Damian J. [Department of Physics and Astronomy, California State University, 18111 Nordhoff Street, Northridge, CA 91330 (United States); Bodewits, Dennis [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Dennerl, Konrad [Max-Planck-Institut fuer extraterrestrische Physik, Postfach 1312, D-85741 Garching Germany (Germany); Lisse, Carey M. [Planetary Exploration Group, Space Department, Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Rd, Laurel, MD 20723 (United States); Wolk, Scott J., E-mail: ian.ewing.794@my.csun.edu, E-mail: daman.christian@csun.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2013-01-20

    We present the detection of new cometary X-ray emission lines in the 1.0-2.0 keV range using a sample of comets observed with the Chandra X-Ray Observatory and ACIS spectrometer. We have selected five comets from the Chandra sample with good signal-to-noise spectra. The surveyed comets are C/1999 S4 (LINEAR), C/1999 T1 (McNaught-Hartley), 153P/2002 (Ikeya-Zhang), 2P/2003 (Encke), and C/2008 8P (Tuttle). We modeled the spectra with an extended version of our solar wind charge exchange (SWCX) emission model. Above 1 keV, we find Ikeya-Zhang to have strong emission lines at 1340 and 1850 eV which we identify as being created by SWCX lines of Mg XI and Si XIII, respectively, and weaker emission lines at 1470, 1600, and 1950 eV formed by SWCX of Mg XII, Mg XI, and Si XIV, respectively. The Mg XI and XII and Si XIII and XIV lines are detected at a significant level for the other comets in our sample (LS4, MH, Encke, 8P), and these lines promise additional diagnostics to be included in SWCX models. The silicon lines in the 1700-2000 eV range are detected for all comets, but with the rising background and decreasing cometary emission, we caution that these detections need further confirmation with higher resolution instruments.

  4. Physical aspects of electron emission spectra shape for ferroelectrics-electrets

    International Nuclear Information System (INIS)

    Kolesnikov, V.V.; Kozakov, A.T.

    2002-01-01

    One introduces a theoretical approach establishing a link between the peculiarities of spectrum of electron emission from ferroelectrics-electrets and the behavior of potential at a specimen surface. From these points of view one analyzes physical nature of the key peculiarities in the experimental spectra. One points out strong effect of electret charge relaxation on their shape due to bifurcation (branching) of peculiarities in a spectrum. A complex shape of spectrum of electron emission from ferroelectrics-electrets results from peculiarities of distribution of electrical field and polarization along their surface [ru

  5. EVIDENCE FOR SECONDARY EMISSION AS THE ORIGIN OF HARD SPECTRA IN TeV BLAZARS

    International Nuclear Information System (INIS)

    Zheng, Y. G.; Kang, T.

    2013-01-01

    We develop a model for the possible origin of hard, very high energy (VHE) spectra from a distant blazar. In the model, both the primary photons produced in the source and secondary photons produced outside it contribute to the observed high-energy γ-ray emission. That is, the primary photons are produced through the synchrotron self-Compton process, and the secondary photons are produced through high-energy proton interactions with background photons along the line of sight. We apply the model to a characteristic case of VHE γ-ray emission in the distant blazar 1ES 1101-232. Assuming suitable electron and proton spectra, we obtain excellent fits to the observed spectra of this blazar. This indicated that the surprisingly low attenuation of the high-energy γ-rays, especially the shape of the VHE γ-ray tail of the observed spectra, can be explained by secondary γ-rays produced in interactions of cosmic-ray protons with background photons in intergalactic space.

  6. Emission spectra of Rb*Hen exciplexes in a cold 4He gas

    International Nuclear Information System (INIS)

    Hirano, K.; Enomoto, K.; Kumakura, M.; Takahashi, Y.; Yabuzaki, T.

    2003-01-01

    We report on the systematic observation of emission spectra of Rb * He n exciplexes (n=1,2,...,6), realized by exciting Rb atoms to the 5 2 P states (Rb * ) in a cold 4 He gas. The observed broad spectral components are assigned to Rb * He n (n=1-6) using theoretical spectra obtained from ab initio potential curves. The dynamics of the exciplex formation is discussed, based on the observed temperature dependence of the spectra. The He gas density dependence of the spectra of Rb * He is understood as a change in the population distribution over the vibrational levels. The present results are compared with our previous work with Cs [K. Enomoto et al., Phys. Rev. A 66, 042505 (2002)], and differences are explained in terms of the difference in the fine-structure splitting. Furthermore, we show the emission spectrum observed after the excitation of Rb in liquid He and conclude that it is the fluorescence from the exciplex Rb * He 6

  7. Surface defect assisted broad spectra emission from CdSe quantum dots for white LED application

    Science.gov (United States)

    Samuel, Boni; Mathew, S.; Anand, V. R.; Correya, Adrine Antony; Nampoori, V. P. N.; Mujeeb, A.

    2018-02-01

    This paper reports, broadband photoluminescence from CdSe quantum dots (QDs) under the excitation of 403 nm using fluorimeter and 403 nm CW laser excitation. The broad spectrum obtained from the colloidal quantum dots was ranges from 450 nm to 800 nm. The broadness of the spectra was attributed to the merging of band edge and defect driven emissions from the QDs. Six different sizes of particles were prepared via kinetic growth method by using CdO and elemental Se as sources of Cd and Se respectively. The particle sizes were measured from TEM images. The size dependent effect on broad emission was also studied and the defect state emission was found to be predominant in very small QDs. The defect driven emission was also observed to be redshifted, similar to the band edge emission, due to quantum confinement effect. The emission corresponding to different laser power was also studied and a linear relation was obtained. In order to study the colour characteristics of the emission, CIE chromaticity coordinate, CRI and CCT of the prepared samples were measured. It is observed that, these values were tunable by the addition of suitable intensity of blue light from the excitation source to yield white light of various colour temperatures. The broad photoluminescence spectrum of the QDs, were compared with that of a commercially available white LED. It was found that the prepared QDs are good alternatives for the phosphor in phosphor converted white LEDs, to provide good spectral tunability.

  8. VIRTIS on Venus Express thermal emission spectra near 1μm

    Science.gov (United States)

    Mueller, Nils; Tsang, Constantine; Helbert, Joern; Smrekar, Suzanne; Piccioni, Giuseppe; Drossart, Pierre

    2016-10-01

    Thermal emission from the surface of Venus is observable through narrow spectral windows close to 1μm. Surface temperature is strongly constrained by surface elevation, due to the thick and dense atmosphere. The data from Visible and InfraRed Thermal Imaging Spectrometer VIRTIS on Venus Express together with altimetry constrain surface emissivity. In VIRTIS observations at 1.02μm, strongly deformed highland plateaus (tesserae) appear to have a lower emissivity consistent with continental crust, an interpretation that implies existence of an early ocean. Comparison between the Magellan stereo digital elevation model (DEM) and altimetry shows that the altimetry height error in rough tesserae greatly exceeds the formal error. In the one tesserae outlier covered by altimetry, DEM, and VIRTIS, the height error could account for the observed emissivity variation. The radiances observed at 1.10 and 1.18μm have a different response to topography, mostly due to spectrally varying absorption in the overlying atmospheric column. Thus if the tesserae have the same emissivity as volcanic plains, its spectrum should be the same as that of plains of the correct surface elevation. In order to investigate this statistically, we create a database of all long exposure duration VIRTIS spectra in the range of 1 - 1.4μm. The spectra are corrected for the ubiquitous straylight from the dayside, based on analysis of spectra showing deep space. Because the 1.10 and 1.18μm peaks are narrow compared to the variation of instrument spectral registration, we fit each spectrum with a synthetic spectrum from an atmospheric radiative transfer model, using wavelength offset and bandwidths as parameters in addition to atmospheric variables. This dataset of ~28 million thermal emission spectra spans a wide range of southern latitudes and night local times, and thus may be useful for studies beyond the question of surface emissivity. A portion of this research was conducted at the Jet Propulsion

  9. Lifetime-vibrational interference effects in resonantly excited x-ray emission spectra of CO

    Energy Technology Data Exchange (ETDEWEB)

    Skytt, P.; Glans, P.; Gunnelin, K. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    The parity selection rule for resonant X-ray emission as demonstrated for O{sub 2} and N{sub 2} can be seen as an effect of interference between coherently excited degenerate localized core states. One system where the core state degeneracy is not exact but somewhat lifted was previously studied at ALS, namely the resonant X-ray emission of amino-substituted benzene (aniline). It was shown that the X-ray fluorescence spectrum resulting from excitation of the C1s at the site of the {open_quotes}aminocarbon{close_quotes} could be described in a picture separating the excitation and the emission processes, whereas the spectrum corresponding to the quasi-degenerate carbons could not. Thus, in this case it was necessary to take interference effects between the quasi-degenerate intermediate core excited states into account in order to obtain agreement between calculations and experiment. The different vibrational levels of core excited states in molecules have energy splittings which are of the same order of magnitude as the natural lifetime broadening of core excitations in the soft X-ray range. Therefore, lifetime-vibrational interference effects are likely to appear and influence the band shapes in resonant X-ray emission spectra. Lifetime-vibrational interference has been studied in non-resonant X-ray emission, and in Auger spectra. In this report the authors discuss results of selectively excited soft X-ray fluorescence spectra of molecules, where they focus on lifetime-interference effects appearing in the band shapes.

  10. Photoluminescence emission spectra of Makrofol® DE 1-1 upon irradiation with ultraviolet radiation

    Science.gov (United States)

    El Ghazaly, M.; Aydarous, Abdulkadir

    Photoluminescence (PL) emission spectra of Makrofol® DE 1-1 (bisphenol-A based polycarbonate) upon irradiation with ultraviolet radiation of different wavelengths were investigated. The absorption-and attenuation coefficient measurements revealed that the Makrofol® DE 1-1 is characterized by high absorbance in the energy range 6.53-4.43 eV but for a lower energy than 4.43 eV, it is approximately transparent. Makrofol® DE 1-1 samples were irradiated with ultraviolet radiation of wavelength in the range from 250 (4.28 eV) to 400 (3.10 eV) nm in step of 10 nm and the corresponding photoluminescence (PL) emission spectra were measured with a spectrofluorometer. It is found that the integrated counts and the peak height of the photoluminescence emission (PL) bands are strongly correlated with the ultraviolet radiation wavelength. They are increased at the ultraviolet radiation wavelength 280 nm and have maximum at 290 nm, thereafter they decrease and diminish at 360 nm of ultraviolet wavelength. The position of the PL emission band peak was red shifted starting from 300 nm, which increased with the increase the ultraviolet radiation wavelength. The PL bandwidth increases linearly with the increase of the ultraviolet radiation wavelength. When Makrofol® DE 1-1 is irradiated with ultraviolet radiation of short wavelength (UVC), the photoluminescence emission spectra peaks also occur in the UVC but of a relatively longer wavelength. The current new findings should be considered carefully when using Makrofol® DE 1-1 in medical applications related to ultraviolet radiation.

  11. Excitation-emission spectra and fluorescence quantum yields for fresh and aged biogenic secondary organic aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Ji; Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey A.

    2013-05-10

    Certain biogenic secondary organic aerosols (SOA) become absorbent and fluorescent when exposed to reduced nitrogen compounds such as ammonia, amines and their salts. Fluorescent SOA may potentially be mistaken for biological particles by detection methods relying on fluorescence. This work quantifies the spectral distribution and effective quantum yields of fluorescence of SOA generated from two monoterpenes, limonene and a-pinene, and two different oxidants, ozone (O3) and hydroxyl radical (OH). The SOA was generated in a smog chamber, collected on substrates, and aged by exposure to ~100 ppb ammonia vapor in air saturated with water vapor. Absorption and excitation-emission matrix (EEM) spectra of aqueous extracts of aged and control SOA samples were measured, and the effective absorption coefficients and fluorescence quantum yields (~0.005 for 349 nm excitation) were determined from the data. The strongest fluorescence for the limonene-derived SOA was observed for excitation = 420+- 50 nm and emission = 475 +- 38 nm. The window of the strongest fluorescence shifted to excitation = 320 +- 25 nm and emission = 425 +- 38 nm for the a-pinene-derived SOA. Both regions overlap with the excitation-emission matrix (EEM) spectra of some of the fluorophores found in primary biological aerosols. Our study suggests that, despite the low quantum yield, the aged SOA particles should have sufficient fluorescence intensities to interfere with the fluorescence detection of common bioaerosols.

  12. Neutrino emission spectra of collapsing degenerate stellar cores - Calculations by the Monte Carlo method

    International Nuclear Information System (INIS)

    Levitan, Iu.L.; Sobol, I.M.; Khlopov, M.Iu.; Chechetkin, V.M.

    1982-01-01

    The variation of the hard part of the neutrino emission spectra of collapsing degenerate stellar cores with matter having a small optical depth to neutrinos is analyzed. The interaction of neutrinos with the degenerate matter is determined by processes of neutrino scattering on nuclei (without a change in neutrino energy) and neutrino scattering on degenerate electrons, in which the neutrino energy can only decrease. The neutrino emission spectrum of a collapsing stellar core in the initial stage of the onset of opacity is calculated by the Monte Carlo method: using a central density of 10 trillion g/cu cm and, in the stage of deep collapse, for a central density of 60 trillion g/cu cm. In the latter case the calculation of the spectrum without allowance for effects of neutrino degeneration in the central part of the collapsing stellar core corresponds to the maximum possible suppression of the hard part of the neutrino emission spectrum

  13. High resolution krypton M/sub 4,5/ x-ray emission spectra

    International Nuclear Information System (INIS)

    Perera, R.C.C.; Hettrick, M.C.; Lindle, D.W.

    1987-10-01

    High resolution M/sub 4,5/ (3d → 4p) x-ray emission spectra from a krypton plasma were measured using a recently developed grazing-incidence reflection-grating monochromator/spectrometer with very high flux rates at extreme ultraviolet and soft x-ray wave lengths. The nominal resolving power of the instrument, E/ΔE, is about 300 in this energy range (∼80 eV). Three dipole-allowed 3d → 4p emission lines were observed at 80.98 eV, 80.35 eV and 79.73 eV. A broad peak at about 82.3 eV is tentatively assigned to transitions resulting from Kr 2+ , and effects of excitation energy on M/sub 4,5/ x-ray emission were observed. 9 refs., 3 figs., 1 tab

  14. Life-time resolved emission spectra in CdCl2 crystals

    International Nuclear Information System (INIS)

    Kawabata, S.; Nakagawa, H.; Kitaura, M.

    2005-01-01

    The emission spectrum of CdCl 2 is composed of ultraviolet (UV) and yellow (Y) bands peaking at 3.70 and 2.30 eV, respectively. In order to determine the initial states of the Y-luminescence, decay curves of the Y-emission were measured at 8K by varying emission energy in the range from 1.64 eV to 3.13 eV. The observed decay curves are composed of two or three exponential components. The values of lifetime for them were 900, 460 and 60 μs. The emission spectrum for each decay component, i.e., life-time resolved emission spectrum, was analyzed by the observed decay curves. The emission spectrum for the component of 460 μs lifetime exhibits a dominant band at 2.30 eV and a satellite band at 3.03 eV. The emission spectrum for the component of 60 μs lifetime is reproduced by the three Gaussian bands peaking at 2.21, 2.65 and 2.87 eV. For the component of 900 μs lifetime, only a single band appears at 1.73 eV. The origin of the emission bands in life-time resolved emission spectra is briefly discussed, and the initial states of Y-luminescence are explained by the excited states of a [Cd 2+ Cl - 6 ] 4- complex molecular ion. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Life-time resolved emission spectra in CdI2 crystals

    International Nuclear Information System (INIS)

    Kawabata, Seiji; Nakagawa, Hideyuki

    2007-01-01

    The emission spectrum of CdI 2 is composed of ultraviolet (UV), green (G) and yellow (Y and Y') bands peaking at 3.38, 2.50, 2.16 and 2.25 eV, respectively. In order to determine the initial states of the Y- and G-luminescence, decay curves have been measured at 6 and 80 K by varying emission energy. The observed decay curves are composed of two or three exponential components. These decay components were named τ 1 , τ 2 , τ 3 , τ 3' and τ 4 . The emission spectrum for each decay component, i.e., the life-time resolved emission spectrum, was constructed from the observed decay curves. At 6 K, three bands at 2.12, 2.49 and 2.64 eV are obtained for τ 1 , τ 2 and τ 3 components, respectively. At 80 K, a dominant band for the τ 4 component and a weak band for the τ 3' component appear on the same energy position at 2.25 eV. The origin of each emission band in the life-time resolved emission spectra will be briefly discussed

  16. Electron-electron correlation, resonant photoemission and X-ray emission spectra

    International Nuclear Information System (INIS)

    Parlebas, J.C.; Kotani, Akio; Tanaka, Satoshi.

    1991-01-01

    In this short review paper we essentially focus on the high energy spectroscopies which involve second order quantum processes, i.e., resonance photoemission, Auger and X-ray emission spectroscopies, denoted respectively by RXPS, AES and XES. First, we summarize the main 3p-RXPS and AES results obtained in Cu and Ni metals; especially we recall that the satellite near the 3p-threshold in the spectra, which arises from a d-hole pair bound state, needs a careful treatment of the electron-electron correlation. Then we analyze the RXPS spectra in a few Ce compounds (CeO 2 , Ce 2 O 3 and CeF 3 ) involving 3d or 4d core levels and we interpret the spectra consistently with the other spectroscopies, such as core XPS and XAS which are first order quantum processes. Finally within the same one-impurity model and basically with the same sets of parameters, we review a theory for the Ce 5p→3d XES, as well as for the corresponding RXES, where (1) the incident X-ray is tuned to resonate with the 3d→4f transition and (2) the X-ray emission due to the 5p→3d transition is actually observed. The paper ends with a general discussion. (author) 77 refs

  17. Method of fission product beta spectra measurements for predicting reactor anti-neutrino emission

    Energy Technology Data Exchange (ETDEWEB)

    Asner, D.M.; Burns, K.; Campbell, L.W.; Greenfield, B.; Kos, M.S., E-mail: markskos@gmail.com; Orrell, J.L.; Schram, M.; VanDevender, B.; Wood, L.S.; Wootan, D.W.

    2015-03-11

    The nuclear fission process that occurs in the core of nuclear reactors results in unstable, neutron-rich fission products that subsequently beta decay and emit electron antineutrinos. These reactor neutrinos have served neutrino physics research from the initial discovery of the neutrino to today's precision measurements of neutrino mixing angles. The prediction of the absolute flux and energy spectrum of the emitted reactor neutrinos hinges upon a series of seminal papers based on measurements performed in the 1970s and 1980s. The steadily improving reactor neutrino measurement techniques and recent reconsiderations of the agreement between the predicted and observed reactor neutrino flux motivates revisiting the underlying beta spectra measurements. A method is proposed to use an accelerator proton beam delivered to an engineered target to yield a neutron field tailored to reproduce the neutron energy spectrum present in the core of an operating nuclear reactor. Foils of the primary reactor fissionable isotopes placed in this tailored neutron flux will ultimately emit beta particles from the resultant fission products. Measurement of these beta particles in a time projection chamber with a perpendicular magnetic field provides a distinctive set of systematic considerations for comparison to the original seminal beta spectra measurements. Ancillary measurements such as gamma-ray emission and post-irradiation radiochemical analysis will further constrain the absolute normalization of beta emissions per fission. The requirements for unfolding the beta spectra measured with this method into a predicted reactor neutrino spectrum are explored.

  18. Emission spectra of photoionized plasmas induced by intense EUV pulses: Experimental and theoretical investigations

    Science.gov (United States)

    Saber, Ismail; Bartnik, Andrzej; Skrzeczanowski, Wojciech; Wachulak, Przemysław; Jarocki, Roman; Fiedorowicz, Henryk

    2017-03-01

    Experimental measurements and numerical modeling of emission spectra in photoionized plasma in the ultraviolet and visible light (UV/Vis) range for noble gases have been investigated. The photoionized plasmas were created using laser-produced plasma (LPP) extreme ultraviolet (EUV) source. The source was based on a gas puff target; irradiated with 10ns/10J/10Hz Nd:YAG laser. The EUV radiation pulses were collected and focused using grazing incidence multifoil EUV collector. The laser pulses were focused on a gas stream, injected into a vacuum chamber synchronously with the EUV pulses. Irradiation of gases resulted in a formation of low temperature photoionized plasmas emitting radiation in the UV/Vis spectral range. Atomic photoionized plasmas produced this way consisted of atomic and ionic with various ionization states. The most dominated observed spectral lines originated from radiative transitions in singly charged ions. To assist in a theoretical interpretation of the measured spectra, an atomic code based on Cowan's programs and a collisional-radiative PrismSPECT code have been used to calculate the theoretical spectra. A comparison of the calculated spectral lines with experimentally obtained results is presented. Electron temperature in plasma is estimated using the Boltzmann plot method, by an assumption that a local thermodynamic equilibrium (LTE) condition in the plasma is validated in the first few ionization states. A brief discussion for the measured and computed spectra is given.

  19. Changes of soft X-ray emission spectra of oxygen and copper in high Tc superconductors

    International Nuclear Information System (INIS)

    Fukushima, Sei; Gohshi, Yohichi; Kohiki, Shigemi; Saitoh, Naoki

    1989-01-01

    X-ray induced soft X-ray emission spectroscopy is one of the bulk analysis methods used to characterize high-Tc superconductor. In this report, some observations on the changes in O Kα and Cu L spectra of thin layer LnBa 2 Cu 3 O 7-δ (Ln=Er,Gd) samples are presented. From the measurement of O Kα, no discernible difference was found between those of Gd compounds which were composed single phase or not. It may be said that the electronic structure of p state localized on the O is not sensitive to the change of Tc or zero-resistance temperature. From the measurement of Cu L spectra, it was found that Cu Lα of only Gd containing compounds has a low energy shoulder

  20. Emission spectra from AlN and GaN doped with rare earth elements

    International Nuclear Information System (INIS)

    Choi, Sung Woo; Emura, Shuichi; Kimura, Shigeya; Kim, Moo Seong; Zhou Yikai; Teraguchi, Nobuaki; Suzuki, Akira; Yanase, Akira; Asahi, Hajime

    2006-01-01

    Luminescent properties of GaN and AlN based semiconductors containing rare earth metals of Gd and Dy are studied. Cathodoluminescent spectra from AlGdN show a clear and sharp peak at 318 nm following LO phonon satellites. Photoluminescence spectra from GaDyN by the above-gap excitation also show several peaks in addition to the broad luminescence band emission. For GaGdN, the sharp PL peaks are also observed at 650 and 670 nm, and they are assigned to the intra-f orbital transitions by their time decay measurements. The broad band at around 365 nm for AlGdN, 505 nm for GaGdN and GaDyN are commonly observed. The origin of these broad bands is discussed

  1. Local secondary-electron emission spectra of graphite and gold surfaces obtained using the Scanning Probe Energy Loss Spectrometer (SPELS)

    International Nuclear Information System (INIS)

    Lawton, J J; Pulisciano, A; Palmer, R E

    2009-01-01

    Secondary-electron emission (SEE) spectra have been obtained with the Scanning Probe Energy Loss Spectrometer at a tip-sample distance of only 50 nm. Such short working distances are required for the best theoretical spatial resolution (<10 nm). The SEE spectra of graphite, obtained as a function of tip bias voltage, are shown to correspond to unoccupied states in the electronic band structure. The SEE spectra of thin gold films demonstrate the capability of identifying (carbonaceous) surface contamination with this technique.

  2. Local secondary-electron emission spectra of graphite and gold surfaces obtained using the Scanning Probe Energy Loss Spectrometer (SPELS)

    Energy Technology Data Exchange (ETDEWEB)

    Lawton, J J; Pulisciano, A; Palmer, R E, E-mail: R.E.Palmer@bham.ac.u [Nanoscale Physics Research Laboratory, School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom)

    2009-11-25

    Secondary-electron emission (SEE) spectra have been obtained with the Scanning Probe Energy Loss Spectrometer at a tip-sample distance of only 50 nm. Such short working distances are required for the best theoretical spatial resolution (<10 nm). The SEE spectra of graphite, obtained as a function of tip bias voltage, are shown to correspond to unoccupied states in the electronic band structure. The SEE spectra of thin gold films demonstrate the capability of identifying (carbonaceous) surface contamination with this technique.

  3. Identifying Student and Teacher Difficulties in Interpreting Atomic Spectra Using a Quantum Model of Emission and Absorption of Radiation

    Science.gov (United States)

    Savall-Alemany, Francisco; Domènech-Blanco, Josep Lluís; Guisasola, Jenaro; Martínez-Torregrosa, Joaquín

    2016-01-01

    Our study sets out to identify the difficulties that high school students, teachers, and university students encounter when trying to explain atomic spectra. To do so, we identify the key concepts that any quantum model for the emission and absorption of electromagnetic radiation must include to account for the gas spectra and we then design two…

  4. Modeling the complexity of acoustic emission during intermittent plastic deformation: Power laws and multifractal spectra.

    Science.gov (United States)

    Kumar, Jagadish; Ananthakrishna, G

    2018-01-01

    Scale-invariant power-law distributions for acoustic emission signals are ubiquitous in several plastically deforming materials. However, power-law distributions for acoustic emission energies are reported in distinctly different plastically deforming situations such as hcp and fcc single and polycrystalline samples exhibiting smooth stress-strain curves and in dilute metallic alloys exhibiting discontinuous flow. This is surprising since the underlying dislocation mechanisms in these two types of deformations are very different. So far, there have been no models that predict the power-law statistics for discontinuous flow. Furthermore, the statistics of the acoustic emission signals in jerky flow is even more complex, requiring multifractal measures for a proper characterization. There has been no model that explains the complex statistics either. Here we address the problem of statistical characterization of the acoustic emission signals associated with the three types of the Portevin-Le Chatelier bands. Following our recently proposed general framework for calculating acoustic emission, we set up a wave equation for the elastic degrees of freedom with a plastic strain rate as a source term. The energy dissipated during acoustic emission is represented by the Rayleigh-dissipation function. Using the plastic strain rate obtained from the Ananthakrishna model for the Portevin-Le Chatelier effect, we compute the acoustic emission signals associated with the three Portevin-Le Chatelier bands and the Lüders-like band. The so-calculated acoustic emission signals are used for further statistical characterization. Our results show that the model predicts power-law statistics for all the acoustic emission signals associated with the three types of Portevin-Le Chatelier bands with the exponent values increasing with increasing strain rate. The calculated multifractal spectra corresponding to the acoustic emission signals associated with the three band types have a maximum

  5. Time evolution, Lamb shift, and emission spectra of spontaneous emission of two identical atoms

    International Nuclear Information System (INIS)

    Wang Dawei; Li Zhenghong; Zheng Hang; Zhu Shiyao

    2010-01-01

    A unitary transformation method is used to investigate the dynamic evolution of two multilevel atoms, in the basis of symmetric and antisymmetric states, with one atom being initially prepared in the first excited state and the other in the ground state. The unitary transformation guarantees that our calculations are based on the ground state of the atom-field system and the self-energy is subtracted at the beginning. The total Lamb shifts of the symmetric and antisymmetric states are divided into transformed shift and dynamic shift. The transformed shift is due to emitting and reabsorbing of virtual photons, by a single atom (nondynamic single atomic shift) and between the two atoms (quasi-static shift). The dynamic shift is due to the emitting and reabsorbing of real photons, by a single atom (dynamic single atomic shift) and between the two atoms (dynamic interatomic shift). The emitting and reabsorbing of virtual and real photons between the two atoms result in the interatomic shift, which does not exist for the one-atom case. The spectra at the long-time limit are calculated. If the distance between the two atoms is shorter than or comparable to the wavelength, the strong coupling between the two atoms splits the spectrum into two peaks, one from the symmetric state and the other from the antisymmetric state. The origin of the red or blue shifts for the symmetric and antisymmetric states mainly lies in the negative or positive interaction energy between the two atoms. In the investigation of the short time evolution, we find the modification of the effective density of states by the interaction between two atoms can modulate the quantum Zeno and quantum anti-Zeno effects in the decays of the symmetric and antisymmetric states.

  6. Emission spectra of phosphor MgSO4 doped with Dy and Mn

    International Nuclear Information System (INIS)

    Zhang Chunxiang; Chen Lixin; Tang Qiang; Luo Daling; Qiu Zhiren

    2001-01-01

    Emission spectra of phosphor MgSO 4 doped with Dy and Dy/Mn were measured with an optical multichannel analyzer and a linear heating system whose temperature was controlled by a microcomputer. The emission spectrum bands at 480 nm and 580 nm of phosphor MgSO 4 doped with Dy were observed in the three dimensional (3D) glow curves. Compared with the 3D spectrum of CaSO 4 :Dy and the spectrum bands of MgSO 4 :Dy shows the same wavelengths which resulted from the quantum transitions among the energy levels of Dy 3 '+ ions. The intensities of the glow peaks in both spectrum bands (480 nm and 580 nm) of phosphor MgSO 4 doped with Dy/Mn were dramatically reduced except the 380 degree C glow peak

  7. Phosphorescent Molecularly Doped Light-Emitting Diodes with Blended Polymer Host and Wide Emission Spectra

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2013-01-01

    Full Text Available Stable green light emission and high efficiency organic devices with three polymer layers were fabricated using bis[2-(4′-tert-butylphenyl-1-phenyl-1H-benzoimidazole-N,C2′] iridium(III (acetylacetonate doped in blended host materials. The 1 wt% doping concentration showed maximum luminance of 7841 cd/cm2 at 25.6 V and maximum current efficiency of 9.95 cd/A at 17.2 V. The electroluminescence spectra of devices indicated two main peaks at 522 nm and 554 nm coming from phosphor dye and a full width at half maximum (FWHM of 116 nm. The characteristics of using blended host, doping iridium complex, emission spectrum, and power efficiency of organic devices were investigated.

  8. Bound-bound transitions in the emission spectra of Ba+-He excimer

    Science.gov (United States)

    Moroshkin, P.; Kono, K.

    2016-05-01

    We present an experimental and theoretical study of the emission and absorption spectra of the Ba+ ions and Ba+*He excimer quasimolecules in the cryogenic Ba-He plasma. We observe several spectral features in the emission spectrum, which we assign to the electronic transitions between bound states of the excimer correlating to the 6 2P3 /2 and 5 2D3 /2 ,5 /2 states of Ba+. The resulting Ba+(5 2DJ) He is a metastable electronically excited complex with orbital angular momentum L =2 , thus expanding the family of known metal-helium quasimolecules. It might be suitable for high-resolution spectroscopic studies and for the search for new polyatomic exciplex structures.

  9. Inferring physical properties of galaxies from their emission-line spectra

    Science.gov (United States)

    Ucci, G.; Ferrara, A.; Gallerani, S.; Pallottini, A.

    2017-02-01

    We present a new approach based on Supervised Machine Learning algorithms to infer key physical properties of galaxies (density, metallicity, column density and ionization parameter) from their emission-line spectra. We introduce a numerical code (called GAME, GAlaxy Machine learning for Emission lines) implementing this method and test it extensively. GAME delivers excellent predictive performances, especially for estimates of metallicity and column densities. We compare GAME with the most widely used diagnostics (e.g. R23, [N II] λ6584/Hα indicators) showing that it provides much better accuracy and wider applicability range. GAME is particularly suitable for use in combination with Integral Field Unit spectroscopy, both for rest-frame optical/UV nebular lines and far-infrared/sub-millimeter lines arising from photodissociation regions. Finally, GAME can also be applied to the analysis of synthetic galaxy maps built from numerical simulations.

  10. Photospheric Emission in the Joint GBM and Konus Prompt Spectra of GRB 120323A

    Energy Technology Data Exchange (ETDEWEB)

    Guiriec, S.; Kouveliotou, C. [Department of Physics, The George Washington University, 725 21st Street NW, Washington, DC 20052 (United States); Gehrels, N.; McEnery, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Hartmann, D. H., E-mail: sylvain.guiriec@nasa.gov [Department of Physics and Astronomy, Clemson University, Kinard Lab of Physics (United States)

    2017-09-10

    GRB 120323A is a very intense short gamma -ray burst (GRB) detected simultaneously during its prompt γ -ray emission phase with the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-ray Space Telescope and the Konus experiment on board the Wind satellite. GBM and Konus operate in the keV–MeV regime; however, the GBM range is broader toward both the low and the high parts of the γ -ray spectrum. Analyses of such bright events provide a unique opportunity to check the consistency of the data analysis as well as cross-calibrate the two instruments. We performed time-integrated and coarse time-resolved spectral analysis of GRB 120323A prompt emission. We conclude that the analyses of GBM and Konus data are only consistent when using a double-hump spectral shape for both data sets; in contrast, the single hump of the empirical Band function, traditionally used to fit GRB prompt emission spectra, leads to significant discrepancies between GBM and Konus analysis results. Our two-hump model is a combination of a thermal-like and a non-thermal component. We interpret the first component as a natural manifestation of the jet photospheric emission.

  11. Effects of the background environment on formation, evolution and emission spectra of laser-induced plasmas

    International Nuclear Information System (INIS)

    De Giacomo, A.; Dell'Aglio, M.; Gaudiuso, R.; Amoruso, S.; De Pascale, O.

    2012-01-01

    In this paper the most important features of Laser Induced Plasma (LIP) evolution were analyzed from the fundamental point of view, in order to point out the effects of background environment on the plasma emission spectra. In particular, the main differences between air and vacuum Laser-Induced Breakdown (LIBS) are discussed, as well as those arising in high-pressure gases and in liquid environment. As can be expected, the dynamics of the plasma is strongly dependent on the environment where the plasma itself expands, which can be exploited for several different applications, ranging from chemical analysis and process diagnostics to materials science. The effect of other experimental conditions, such as the state of aggregation of the irradiated target, and the effect of laser pulse duration are also briefly reviewed. - Highlights: ► General processes involved in laser ablation and plasma generation were reported. ► Effect of number density in the plasma on the spectra features was discussed. ► LIP in gases at different pressures, in liquids and in DP techniques was discussed. ► LIBS spectra in various environments and correlated applications were discussed.

  12. Modeling of aircraft exhaust emissions and infrared spectra for remote measurement of nitrogen oxides

    Directory of Open Access Journals (Sweden)

    K. Beier

    Full Text Available Infrared (IR molecular spectroscopy is proposed to perform remote measurements of NOx concentrations in the exhaust plume and wake of aircraft. The computer model NIRATAM is applied to simulate the physical and chemical properties of the exhaust plume and to generate low resolution IR spectra and synthetical thermal images of the aircraft in its natural surroundings. High-resolution IR spectra of the plume, including atmospheric absorption and emission, are simulated using the molecular line-by-line radiation model FASCODE2. Simulated IR spectra of a Boeing 747-400 at cruising altitude for different axial and radial positions in the jet region of the exhaust plume are presented. A number of spectral lines of NO can be identified that can be discriminated from lines of other exhaust gases and the natural atmospheric background in the region around 5.2 µm. These lines can be used to determine NO concentration profiles in the plume. The possibility of measuring nitrogen dioxide NO2 is also discussed briefly, although measurements turn out to be substantially less likely than those of NO. This feasibility study compiles fundamental data for the optical and radiometric design of an airborne Fourier transform spectrometer and the preparation of in-flight measurements for monitoring of aircraft pollutants.

  13. Modeling of aircraft exhaust emissions and infrared spectra for remote measurement of nitrogen oxides

    Directory of Open Access Journals (Sweden)

    K. Beier

    1994-08-01

    Full Text Available Infrared (IR molecular spectroscopy is proposed to perform remote measurements of NOx concentrations in the exhaust plume and wake of aircraft. The computer model NIRATAM is applied to simulate the physical and chemical properties of the exhaust plume and to generate low resolution IR spectra and synthetical thermal images of the aircraft in its natural surroundings. High-resolution IR spectra of the plume, including atmospheric absorption and emission, are simulated using the molecular line-by-line radiation model FASCODE2. Simulated IR spectra of a Boeing 747-400 at cruising altitude for different axial and radial positions in the jet region of the exhaust plume are presented. A number of spectral lines of NO can be identified that can be discriminated from lines of other exhaust gases and the natural atmospheric background in the region around 5.2 µm. These lines can be used to determine NO concentration profiles in the plume. The possibility of measuring nitrogen dioxide NO2 is also discussed briefly, although measurements turn out to be substantially less likely than those of NO. This feasibility study compiles fundamental data for the optical and radiometric design of an airborne Fourier transform spectrometer and the preparation of in-flight measurements for monitoring of aircraft pollutants.

  14. On-the-fly ab initio semiclassical dynamics: Emission spectra of oligothiophenes

    Science.gov (United States)

    Wehrle, Marius; Sulc, Miroslav; Vanicek, Jiri

    2014-03-01

    We employ the thawed Gaussian approximation (TGA) [E. J. Heller, J. Chem. Phys. 62, 1544 (1975)] within an on-the-fly ab initio (OTF-AI) scheme to calculate the vibrationally resolved emission spectra of oligothiophenes up to five rings. OTF-AI-TGA is efficient enough to treat all vibrational degrees of freedom on an equal footing even in case of 5-oligothiophene (105 vibrational degrees of freedom), thus obviating the need for the crude global harmonic approximation, popular for large system. The experimental emission spectra have been almost perfectly reproduced. In order to provide a deeper insight into the associated physical and chemical processes, we present a systematic approach to assess the importance and to analyze the mutual coupling of individual vibrational degrees of freedom during the dynamics. This allows us to explain the changes in the vibrational line shapes of the oligothiophenes with increasing number of rings. Furthermore, we observe the dynamical interplay between quinoid and aromatic characters of individual rings in the oligothiophene chain during the dynamics and confirm that the quinoid character prevails in the center of the chain. This research was supported by the Swiss NSF Grant No. 200021_124936/1 and NCCR Molecular Ultrafast Science & Technology (MUST), and by the EPFL.

  15. Spontaneous emission spectra and quantum light-matter interactions from a strongly coupled quantum dot metal-nanoparticle system

    DEFF Research Database (Denmark)

    Van Vlack, C.; Kristensen, Philip Trøst; Hughes, S.

    2012-01-01

    the dot to the detector, we demonstrate that the strong-coupling regime should be observable in the far-field spontaneous emission spectrum, even at room temperature. The vacuum-induced emission spectra show that the usual vacuum Rabi doublet becomes a rich spectral triplet or quartet with two of the four...

  16. Accounting for many-body correlation effects in the calculation of the valence band photoelectron emission spectra of ferromagnets

    International Nuclear Information System (INIS)

    Minar, J.; Chadov, S.; Ebert, H.; Chioncel, L.; Lichtenstein, A.; De Nadai, C.; Brookes, N.B.

    2005-01-01

    The influence of dynamical correlation effects on the valence band photoelectron emission of ferromagnetic Fe, Co and Ni has been investigated. Angle-resolved as well as angle-integrated valence band photoelectron emission spectra were calculated on the basis of the one-particle Green's function, which was obtained by using the fully relativistic Korringa-Kohn-Rostoker method. The correlation effects have been included in terms of the electronic self-energy which was calculated self-consistently within Dynamical Mean-Field Theory (DMFT). In addition a theoretical approach to calculate high-energy angle-resolved valence band photoelectron emission spectra is presented

  17. Interpretation of magnetic circular dichroism of X-ray emission spectra

    International Nuclear Information System (INIS)

    Takayama, Yasuhiro; Yoshida, Tetsuo; Nakamura, Satoshi; Sasaki, Naoya; Ishii, Hiroyoshi; Miyahara, Tsuneaki

    2006-01-01

    We have measured the dependence of the magnetic circular dichroism (MCD) of the X-ray emission spectra (XES) on the temperature and incident angle for a Gd thin film. The energy of the incident photon for the XES was 138.25eV, which corresponded to the resonant excitation to the 8 D 9/2 intermediate state. The dependence of the observed MCD on the temperature and incident angle was quite different from that of the magnetic moment estimated with a SQUID magnetometer. By considering the reflection, saturation effect, self-absorption effect and magnetic anisotropy of the thin film, the agreement of the two behaviors was considerably improved. This result shows that the revisions of the MCD of the XES are extremely important for the quantitative estimation of the magnetic moment from the MCD of the XES. (author)

  18. Fourier transform infrared emission spectra of MnH and MnD

    Science.gov (United States)

    Gordon, Iouli E.; Appadoo, Dominique R. T.; Shayesteh, Alireza; Walker, Kaley A.; Bernath, Peter F.

    2005-01-01

    Fourier transform infrared emission spectra of MnH and MnD were observed in the ground X7Σ + electronic state. The vibration-rotation bands from v = 1 → 0 to v = 3 → 2 for MnH and from v = 1 → 0 to v = 4 → 3 for MnD were recorded at an instrumental resolution of 0.0085 cm -1. Spectroscopic constants were determined for each vibrational level and equilibrium constants were found from a Dunham-type fit. The equilibrium vibrational constant ( ωe) for MnH was found to be 1546.84518(65) cm -1, the equilibrium rotational constant ( Be) is 5.6856789(103) cm -1 and the eqilibrium bond distance ( re) was determined to be 1.7308601(47) Å.

  19. Chemical environment effects on the Kβ emission spectra in P compounds

    International Nuclear Information System (INIS)

    Ceppi, S.; Tirao, G.; Stutz, G.; Riveros, J.A.

    2008-01-01

    Several clusters of PO 4 3- and P 2 O 7 4- were studied in different chemical environment by measuring the Kβ 1,3 , Kβ x and Kβ' lines from P-Kβ emission spectrum. The Kβ spectrum structures were analyzed from its relation with its chemical environment. In this paper, the cation influence and the cation substitution with H on satellite Kβ' line parameters were also studied. It was found that this line allows the light ligand atom to be identified and also the number of H bonds with the PO 4 3- cluster be characterized. Besides cation influence on the P-Kβ spectrum, it can be shown that this influence is smaller than the ligand atom and cation-H substitution. Theoretical spectra were obtained by using the DV-Xα method in order to compare it with the experimental data and to interpret the Kβ line structure in terms of molecular orbital theory

  20. Atomic Emission Spectra Diagnosis and Electron Density Measurement of Semiconductor Bridge (SCB) Plasma

    International Nuclear Information System (INIS)

    Feng Hongyan; Zhu Shunguan; Zhang Lin; Wan Xiaoxia; Li Yan; Shen Ruiqi

    2010-01-01

    Emission spectra of a semiconductor bridge (SCB) plasma in a visible range was studied in air. The electron density was measured in a conventional way from the broadening of the A1 I 394.4 nm Stark width. Based on the Saha equation, a system for recording the intensity of Si I 390.5 nm and Si II 413.1 nm was designed. With this technique, the SCB plasma electron density was measured well and accurately. Moreover, the electron density distribution Vs time was acquired from one SCB discharge. The individual result from the broadening of the Al I 394.4 nm Stark width and Saha equation was all in the range of 10 15 cm -3 to 10 16 cm -3 . Finally the presumption of the local thermodynamic equilibrium (LTE) condition was validated.

  1. Time resolved spectra in the infrared absorption and emission from shock heated hydrocarbons

    Science.gov (United States)

    Bauer, S. H.; Borchardt, D. B.

    1990-07-01

    We have extended the wavelength range of our previously constructed multichannel, fast recording spectrometer to the mid-infrared. With the initial configuration, using a silicon-diode (photovoltaic) array, we recorded light intensities simultaneously at 20 adjacent wavelengths, each with 20 μs time resolution. For studies in the infrared the silicon diodes are replaced by a 20 element PbSe (photoconducting) array of similar dimensions (1×4 mm/element), cooled by a three-stage thermoelectric device. These elements have useful sensitivities over 1.0-6.7 μm. Three interchangeable gratings in a 1/4 m monochromator cover the following spectral ranges: 1.0-2.5 μm (resolution 33.6 cm-1) 2.5-4.5 μm (16.8 cm-1) 4.0-6.5 μm (16.7 cm-1). Incorporated in the new housing there are individually controlled bias-power sources for each detector, two stages of analogue amplification and a 20-line parallel output to the previously constructed digitizer, and record/hold computer. The immediate application of this system is the study of emission and absorption spectra of shock heated hydrocarbons-C2H2, C4H4 and C6H6-which are possible precursors of species that generate infrared emissions in the interstellar medium. It has been recently proposed that these radiations are due to PAH that emit in the infrared upon relaxation from highly excited states. However, it is possible that such emissions could be due to shock-heated low molecular-weight hydrocarbons, which are known to be present in significant abundances, ejected into the interstellar medium during stellar outer atmospheric eruptions. The full Swan band system appeared in time-integrated emission spectra from shock heated C2H2 (1% in Ar; T5eq~=2500K) no soot was generated. At low resolution the profiles on the high frequency side of the black body maximum show no distinctive features. These could be fitted to Planck curves, with temperatures that declined with time from an initial high that was intermediate between T5 (no

  2. Bidimensional characterization of the emission spectra in a direct current atmospheric pressure glow discharge

    International Nuclear Information System (INIS)

    Orejas, Jaime; Pisonero, Jorge; Bordel, Nerea; Nelis, Thomas; Guillot, Philippe; Sanz-Medel, Alfredo

    2012-01-01

    An in-house atmospheric pressure glow discharge source, designed to be used as ionization/desorption source for ambient mass spectrometry, has been electrically characterized, and its optical emission spectra evaluated in detail. Electrical characterization showed that the plasma regime can vary from glow discharge to arc discharge depending on operating conditions (i.e. He flow rate and inter electrode distance). Furthermore, bidimensional images of the optical emission of some plasma species using filters as wavelength selectors, were registered from inside and outside the discharge chamber (inner region and afterglow region respectively), showing the spatial distribution of excited species (i.e. He*, N 2 + and O*). These distribution patterns are useful to study the chemistry of the discharge plasma, since different production pathways and different excitation energies affect the presence of these species in the plasma regions. - Highlights: ► An in-house APGD is characterized through electrical and OES measurements. ► Interelectrode distance had more effect on electric regime than He flow rate. ► Internal plume images showed differences on the production pathways for each species. ► Higher interelectrode distances and He flow rates showed better afterglow conditions.

  3. Bidimensional characterization of the emission spectra in a direct current atmospheric pressure glow discharge

    Energy Technology Data Exchange (ETDEWEB)

    Orejas, Jaime [University of Oviedo, Department of Physics, C/ Gonzazlez Quiros S/N, Mieres (Spain); Pisonero, Jorge, E-mail: pisonerojorge@uniovi.es [University of Oviedo, Department of Physics, C/ Gonzazlez Quiros S/N, Mieres (Spain); Bordel, Nerea [University of Oviedo, Department of Physics, C/ Gonzazlez Quiros S/N, Mieres (Spain); Nelis, Thomas [Bern University of Applied Sciences, Quellgasse 21, 2501 Bienne (Switzerland); Guillot, Philippe [DPHE, CUFR J. F. Champollion, Universite de Toulouse, Place de Verdun, Albi (France); Sanz-Medel, Alfredo, E-mail: asm@uniovi.es [University of Oviedo, Department of Physical and Analytical Chemistry, C/ Julian Claveria 8, Oviedo (Spain)

    2012-10-15

    An in-house atmospheric pressure glow discharge source, designed to be used as ionization/desorption source for ambient mass spectrometry, has been electrically characterized, and its optical emission spectra evaluated in detail. Electrical characterization showed that the plasma regime can vary from glow discharge to arc discharge depending on operating conditions (i.e. He flow rate and inter electrode distance). Furthermore, bidimensional images of the optical emission of some plasma species using filters as wavelength selectors, were registered from inside and outside the discharge chamber (inner region and afterglow region respectively), showing the spatial distribution of excited species (i.e. He*, N{sub 2}{sup +} and O*). These distribution patterns are useful to study the chemistry of the discharge plasma, since different production pathways and different excitation energies affect the presence of these species in the plasma regions. - Highlights: Black-Right-Pointing-Pointer An in-house APGD is characterized through electrical and OES measurements. Black-Right-Pointing-Pointer Interelectrode distance had more effect on electric regime than He flow rate. Black-Right-Pointing-Pointer Internal plume images showed differences on the production pathways for each species. Black-Right-Pointing-Pointer Higher interelectrode distances and He flow rates showed better afterglow conditions.

  4. Time resolved spectra in the infrared absorption and emission from shock heated hydrocarbons. [in interstellar medium

    Science.gov (United States)

    Bauer, S. H.; Borchardt, D. B.

    1990-01-01

    The wavelength range of a previously constructed multichannel fast recording spectrometer was extended to the mid-infrared. With the initial configuration, light intensities were recorded simultaneously with a silicon-diode array simultaneously at 20 adjacent wavelengths, each with a 20-micron time resolution. For studies in the infrared, the silicon diodes were replaced by a 20-element PbSe array of similar dimensions, cooled by a three-stage thermoelectric device. It is proposed that infrared emissions could be due to shock-heated low molecular-weight hydrocarbons. The full Swan band system appeared in time-integrated emission spectra from shock-heated C2H2; no soot was generated. At low resolution, the profiles on the high-frequency side of the black body maximum show no distinctive features. These could be fitted to Planck curves, with temperatures that declined with time from an initial high that was intermediate between T5 (no conversion) and T5(eq).

  5. Spontaneous emission spectra and simulating multiple spontaneous generation coherence in a five-level atomic medium

    International Nuclear Information System (INIS)

    Li Jiahua; Liu Jibing; Qi Chunchao; Chen Aixi

    2006-01-01

    We investigate the features of the spontaneous emission spectra in a coherently driven cold five-level atomic system by means of a radio frequency (rf) or microwave field driving a hyperfine transition within the ground state. It is shown that a few interesting phenomena such as spectral-line narrowing, spectral-line enhancement, spectral-line suppression, and spontaneous emission quenching can be realized by modulating the frequency and intensity of the rf-driving field in our system. In the dressed-state picture of the coupling and rf-driving fields, we find that this coherently driven atomic system has three close-lying levels so that multiple spontaneously generated coherence (SGC) arises. Our considered atomic model can be found in real atoms, such as rubidium or sodium, so a corresponding experiment can be done to observe the expected phenomena related to SGC reported by Fountoulakis et al. [Phys. Rev. A 73, 033811 (2006)], since no rigorous conditions are required

  6. Assisted Interpretation of Laser-Induced Fluorescence Spectra of Egg-Based Binding Media Using Total Emission Fluorescence Spectroscopy

    International Nuclear Information System (INIS)

    Anglos, D.; Nevin, A.

    2006-01-01

    Laser-induced fluorescence (LIF) spectroscopy can provide nondestructive, qualitative analysis of protein-based binding media found in artworks. Fluorescence emissions from proteins in egg yolk and egg white are due to auto fluorescent aromatic amino acids as well as other native and age-related fluorophores, but the potential of fluorescence spectroscopy for the differentiation between binding media is dependent on the choice of a suitable excitation wavelength and limited by problems in interpretation. However, a better understanding of emission spectra associated with LIF can be achieved following comparisons with total emission fluorescence spectra where a series of consecutive emission spectra are recorded over a specific range. Results using nanosecond UV laser sources for LIF of egg-based binding media are presented which are rationalised following comparisons with total emission spectra. Specifically, fluorescence is assigned to tryptophan and oxidation products of amino acids; in the case of egg yolk, fatty-acid polymerisation and age-related degradation products account for the formation of fluorophores.

  7. Nebular and auroral emission lines of [Cl III] in the optical spectra of planetary nebulae.

    Science.gov (United States)

    Keenan, F P; Aller, L H; Ramsbottom, C A; Bell, K L; Crawford, F L; Hyung, S

    2000-04-25

    Electron impact excitation rates in Cl III, recently determined with the R-matrix code, are used to calculate electron temperature (T(e)) and density (N(e)) emission line ratios involving both the nebular (5517.7, 5537.9 A) and auroral (8433.9, 8480.9, 8500.0 A) transitions. A comparison of these results with observational data for a sample of planetary nebulae, obtained with the Hamilton Echelle Spectrograph on the 3-m Shane Telescope, reveals that the R(1) = I(5518 A)/I(5538 A) intensity ratio provides estimates of N(e) in excellent agreement with the values derived from other line ratios in the echelle spectra. This agreement indicates that R(1) is a reliable density diagnostic for planetary nebulae, and it also provides observational support for the accuracy of the atomic data adopted in the line ratio calculations. However the [Cl iii] 8433.9 A line is found to be frequently blended with a weak telluric emission feature, although in those instances when the [Cl iii] intensity may be reliably measured, it provides accurate determinations of T(e) when ratioed against the sum of the 5518 and 5538 A line fluxes. Similarly, the 8500.0 A line, previously believed to be free of contamination by the Earth's atmosphere, is also shown to be generally blended with a weak telluric emission feature. The [Cl iii] transition at 8480.9 A is found to be blended with the He i 8480.7 A line, except in planetary nebulae that show a relatively weak He i spectrum, where it also provides reliable estimates of T(e) when ratioed against the nebular lines. Finally, the diagnostic potential of the near-UV [Cl iii] lines at 3344 and 3354 A is briefly discussed.

  8. ELECTROMAGNETIC EMISSION FROM LONG-LIVED BINARY NEUTRON STAR MERGER REMNANTS. II. LIGHT CURVES AND SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Siegel, Daniel M. [Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Am Mühlenberg 1, D-14476 Potsdam-Golm (Germany); Ciolfi, Riccardo, E-mail: daniel.siegel@aei.mpg.de, E-mail: riccardo.ciolfi@unitn.it [Physics Department, University of Trento, Via Sommarive 14, I-38123 Trento (Italy)

    2016-03-01

    Recent observations indicate that in a large fraction of binary neutron star (BNS) mergers a long-lived neutron star (NS) may be formed rather than a black hole. Unambiguous electromagnetic (EM) signatures of such a scenario would strongly impact our knowledge on how short gamma-ray bursts (SGRBs) and their afterglow radiation are generated. Furthermore, such EM signals would have profound implications for multimessenger astronomy with joint EM and gravitational-wave (GW) observations of BNS mergers, which will soon become reality thanks to the ground-based advanced LIGO/Virgo GW detector network. Here we explore such EM signatures based on the model presented in a companion paper, which provides a self-consistent evolution of the post-merger system and its EM emission up to ∼10{sup 7} s. Light curves and spectra are computed for a wide range of post-merger physical properties. We present X-ray afterglow light curves corresponding to the “standard” and the “time-reversal” scenario for SGRBs (prompt emission associated with the merger or with the collapse of the long-lived NS). The light curve morphologies include single and two-plateau features with timescales and luminosities that are in good agreement with Swift observations. Furthermore, we compute the X-ray signal that should precede the SGRB in the time-reversal scenario, the detection of which would represent smoking-gun evidence for this scenario. Finally, we find a bright, highly isotropic EM transient peaking in the X-ray band at ∼10{sup 2}–10{sup 4} s after the BNS merger with luminosities of L{sub X} ∼ 10{sup 46}–10{sup 48} erg s{sup −1}. This signal represents a very promising EM counterpart to the GW emission from BNS mergers.

  9. Bayesian electron density inference from JET lithium beam emission spectra using Gaussian processes

    Science.gov (United States)

    Kwak, Sehyun; Svensson, J.; Brix, M.; Ghim, Y.-C.; Contributors, JET

    2017-03-01

    A Bayesian model to infer edge electron density profiles is developed for the JET lithium beam emission spectroscopy (Li-BES) system, measuring Li I (2p-2s) line radiation using 26 channels with  ∼1 cm spatial resolution and 10∼ 20 ms temporal resolution. The density profile is modelled using a Gaussian process prior, and the uncertainty of the density profile is calculated by a Markov Chain Monte Carlo (MCMC) scheme. From the spectra measured by the transmission grating spectrometer, the Li I line intensities are extracted, and modelled as a function of the plasma density by a multi-state model which describes the relevant processes between neutral lithium beam atoms and plasma particles. The spectral model fully takes into account interference filter and instrument effects, that are separately estimated, again using Gaussian processes. The line intensities are inferred based on a spectral model consistent with the measured spectra within their uncertainties, which includes photon statistics and electronic noise. Our newly developed method to infer JET edge electron density profiles has the following advantages in comparison to the conventional method: (i) providing full posterior distributions of edge density profiles, including their associated uncertainties, (ii) the available radial range for density profiles is increased to the full observation range (∼26 cm), (iii) an assumption of monotonic electron density profile is not necessary, (iv) the absolute calibration factor of the diagnostic system is automatically estimated overcoming the limitation of the conventional technique and allowing us to infer the electron density profiles for all pulses without preprocessing the data or an additional boundary condition, and (v) since the full spectrum is modelled, the procedure of modulating the beam to measure the background signal is only necessary for the case of overlapping of the Li I line with impurity lines.

  10. Infrared and near infrared emission spectra of TeH and TeD

    Science.gov (United States)

    Yu, Shanshan; Shayesteh, Alireza; Fu, Dejian; Bernath, Peter F.

    2005-04-01

    The vibration-rotation emission spectra for the X2Π ground state and the near infrared emission spectra of the X2Π 1/2- X2Π 3/2 system of the TeH and TeD free radicals have been measured at high resolution using a Fourier transform spectrometer. TeH and TeD were generated in a tube furnace with a DC discharge of a flowing mixture of argon, hydrogen (or deuterium), and tellurium vapor. In the infrared region, for the X2Π 3/2 spin component we observed the 1-0, 2-1, and 3-2 vibrational bands for most of the eight isotopologues of TeH and the 1-0 and 2-1 bands for three isotopologues of TeD. For the X2Π 1/2- X2Π 3/2 transition, we observed the 0-0 and 1-1 bands for TeH and the 0-0, 1-1, and 2-2 bands for TeD. Except for a few lines, the tellurium isotopic shift was not resolved for the X2Π 1/2- X2Π 3/2 transitions of TeH and TeD. Local perturbations with Δ v = 2 between the two spin components of the X2Π state of TeH were found: X2Π 1/2, v = 0 with X2Π 3/2, v = 2; X2Π 1/2, v = 1 with X2Π 3/2, v = 3. The new data were combined with the previous data from the literature and two kinds of fits (Hund's case (a) and Hund's case (c)) were carried out for each of the 10 observed isotopologues: 130TeD, 128TeD, 126TeD, 130TeH, 128TeH, 126TeH, 125TeH, 124TeH, 123TeH, and 122TeH.

  11. Förster resonance energy transfer, absorption and emission spectra in multichromophoric systems. III. Exact stochastic path integral evaluation.

    Science.gov (United States)

    Moix, Jeremy M; Ma, Jian; Cao, Jianshu

    2015-03-07

    A numerically exact path integral treatment of the absorption and emission spectra of open quantum systems is presented that requires only the straightforward solution of a stochastic differential equation. The approach converges rapidly enabling the calculation of spectra of large excitonic systems across the complete range of system parameters and for arbitrary bath spectral densities. With the numerically exact absorption and emission operators, one can also immediately compute energy transfer rates using the multi-chromophoric Förster resonant energy transfer formalism. Benchmark calculations on the emission spectra of two level systems are presented demonstrating the efficacy of the stochastic approach. This is followed by calculations of the energy transfer rates between two weakly coupled dimer systems as a function of temperature and system-bath coupling strength. It is shown that the recently developed hybrid cumulant expansion (see Paper II) is the only perturbative method capable of generating uniformly reliable energy transfer rates and emission spectra across a broad range of system parameters.

  12. Theoretically predicted soft x-ray emission and absorption spectra of graphitic-structured BC2N

    Science.gov (United States)

    Muramatsu, Yasuji

    Theoretical B K, C K and N K x-ray emission/absorption spectra of three possible graphitic-structured BC2N clusters are predicted based on the B2p-, C2p-, and N2p- density-of-states (DOS) calculated by discrete variational (DV)-X[alpha] molecular orbital calculations. Several prominent differences in DOS spectral features among BC2Ns, h-BN, and graphite are confirmed from comparison of calculated B2p-, C2p-, and N2p-DOS spectra. These variations in the spectra allow BC2N structures to be positively identified by high-resolution x-ray emission/absorption spectroscopy in the B K, C K, and N K regions.

  13. Comparison of experimental and calculated neutron emission spectra and angular distributions

    International Nuclear Information System (INIS)

    Gruppelaar, H.; Akkermans, J.M.

    1980-06-01

    Experimental and calculated neutron emission spectra and angular distributions have been intercompared for 14.6-MeV neutron-induced reactions. The experimental data, measured by Hermsdorf et al., cover 34 elements in a large mass range. To calculate the differential neutron scattering cross sections a unified model of preequilibrium neutron emission was used, in which the generalized master equation of Mantzouranis et al. was solved with a fast exact matrix method, recently introduced by Akkermans. For the scattering kernel a three-term Legendre polynomial representation was adopted, which was either derived from the differential free nucleon-nucleon scattering cross section or fitted to obtain optimal agreement with the set of experimental data of Hermsdorf et al. The results of the last-mentioned calculation are quite acceptable in view of the fact that only two global parameters have been to describe the angular distributions of all experimental data. The report contains tables and graphs of the calculated Legendre coefficients and graphs of energy-averaged angular distributions for all 34 elements. It is further shown that improvements in the energy and angular distributions could be obtained by means of adjustment of the level-density parameters of the individual residual nuclei. Finally a short discussion is devoted to the problems of fitting angular distributions at backward angles by varying the model parameters or the specification of the initial condition. It is indicated that the so-called preequilibrium phase of the nuclear reaction actually consists of two different stages, the first one generating the forward-peaked angular distributions and the second one showing angular distributions symmetric about 90 0

  14. Computing the Absorption and Emission Spectra of 5-Methylcytidine in Different Solvents: A Test-Case for Different Solvation Models.

    Science.gov (United States)

    Martínez-Fernández, L; Pepino, A J; Segarra-Martí, J; Banyasz, A; Garavelli, M; Improta, R

    2016-09-13

    The optical spectra of 5-methylcytidine in three different solvents (tetrahydrofuran, acetonitrile, and water) is measured, showing that both the absorption and the emission maximum in water are significantly blue-shifted (0.08 eV). The absorption spectra are simulated based on CAM-B3LYP/TD-DFT calculations but including solvent effects with three different approaches: (i) a hybrid implicit/explicit full quantum mechanical approach, (ii) a mixed QM/MM static approach, and (iii) a QM/MM method exploiting the structures issuing from molecular dynamics classical simulations. Ab-initio Molecular dynamics simulations based on CAM-B3LYP functionals have also been performed. The adopted approaches all reproduce the main features of the experimental spectra, giving insights on the chemical-physical effects responsible for the solvent shifts in the spectra of 5-methylcytidine and providing the basis for discussing advantages and limitations of the adopted solvation models.

  15. Time-space distribution of laser-induced plasma parameters and its influence on emission spectra of the laser plumes

    International Nuclear Information System (INIS)

    Ershov-Pavlov, E.A.; Katsalap, K.Yu.; Stepanov, K.L.; Stankevich, Yu.A.

    2008-01-01

    A physical model is developed accounting for dynamics and radiation of plasma plumes induced by nanosecond laser pulses on surface of solid samples. The model has been applied to simulate emission spectra of the laser erosion plasma at the elemental analysis of metals using single- and double-pulse excitation modes. Dynamics of the sample heating and expansion of the erosion products are accounted for by the thermal conductivity and gas dynamic equations, respectively, supposing axial symmetry. Using the resulting time-space distributions of the plasma parameters, emission spectra of the laser plumes are evaluated by solving the radiation transfer equation. Particle concentration in consecutive ionization stages is described by the Saha equation in the Debye approximation. The population of excited levels is determined according to Boltzmann distribution. Local characteristics determining spectral emission and absorption coefficients are obtained point-by-point along an observation line. Voigt spectral line profiles are considered with main broadening mechanisms taken into account. The plasma dynamics and plume emission spectra have been studied experimentally and by the model. A Q-switched Nd:YAG laser at 1064 nm wavelength has been used to irradiate Al sample with the pulses of 15 ns and 50 mJ duration and energy, respectively. It has resulted in maximum power density of 0.8 MW/cm 2 on the sample surface. The laser plume emission spectra have been recorded at a side-on observation. Problems of the spectra contrast and of the elemental analysis efficiency are considered relying on a comparative study of the measurement and simulation results at the both excitation modes

  16. VUV emission spectra from binary rare gas mixtures near the resonance lines of Xe I and Kr I

    CERN Document Server

    Morozov, A; Gerasimov, G; Arnesen, A; Hallin, R

    2003-01-01

    Emission spectra of Xe-X (X = He, Ne, Ar and Kr) and of Kr-Y (Y = He, Ne and Ar) mixtures with low concentrations of the heavier gases (0.1-1%) and moderate total pressures (50-200 hPa) have been recorded near each of the two resonance lines of Xe and Kr in DC glow capillary discharges. The recorded intense emissions have narrow spectral profiles with FWHM of about 0.1 nm. The profiles are very similar in shape to profiles of known high resolution absorption spectra recorded at comparable gas pressures. A tentative identification of the emission structures is given, which involves transitions in heteronuclear molecules and quasimolecules between weakly-bound states.

  17. Spectra calculations in central and wing regions of CO2 IR bands between 10 and 20 μm. III: atmospheric emission spectra

    International Nuclear Information System (INIS)

    Niro, F.; Clarmann, T. von; Jucks, K.; Hartmann, J.-M.

    2005-01-01

    A theoretical model for the prediction of CO 2 absorption in both central and wing regions of infrared absorption bands was presented in the companion paper I. It correctly accounts for line-mixing effects and was validated by comparisons with laboratory spectra in the 600-1000 cm -1 region. This quality was confirmed using atmospheric transmissions measured by solar occultation experiments in the second paper. The present work completes these studies by now considering atmospheric emission in the 10-20 μm range. Comparisons are made between computed atmospheric radiances and measurements obtained using four different Fourier transform experiments collecting spectra for nadir, up-looking, as well as limb (from balloon and satellite) geometries. Our results confirm that using a Voigt model can lead to very large errors that affect the spectrum more than 300 cm -1 away from the center of the CO 2 ν 2 band. They also demonstrate the capability of our model to represent accurately the radiances in the entire region for a variety of atmospheric paths. This success opens interesting perspectives for the sounding of pressure and temperature profiles, particularly at low altitudes. Another benefit of the quality of the model should be an increased accuracy in the retrieval of atmospheric state parameters from broad features in the measured spectra (clouds, aerosols, heavy trace gases)

  18. MID-INFRARED ATOMIC FINE-STRUCTURE EMISSION-LINE SPECTRA OF LUMINOUS INFRARED GALAXIES: SPITZER/IRS SPECTRA OF THE GOALS SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Inami, H. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Armus, L.; Stierwalt, S.; Díaz-Santos, T.; Surace, J.; Howell, J.; Marshall, J. [Spitzer Science Center, California Institute of Technology, CA 91125 (United States); Charmandaris, V. [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, GR-71003 Heraklion (Greece); Groves, B. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Kewley, L. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Petric, A. [Department of Astronomy, California Institute of Technology, MS 320-47, Pasadena, CA 91125 (United States); Rich, J. [The Observatories, Carnegie Institute of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Haan, S. [CSIRO Astronomy and Space Science, Marsfield, NSW 2122 (Australia); Evans, A. S. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States); Mazzarella, J.; Lord, S. [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Appleton, P. [NASA Herschel Science Center, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Spoon, H. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Frayer, D. [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States); Matsuhara, H., E-mail: inami@noao.edu [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (Japan); and others

    2013-11-10

    We present the data and our analysis of mid-infrared atomic fine-structure emission lines detected in Spitzer/Infrared Spectrograph high-resolution spectra of 202 local Luminous Infrared Galaxies (LIRGs) observed as part of the Great Observatories All-sky LIRG Survey (GOALS). We readily detect emission lines of [S IV], [Ne II], [Ne V], [Ne III], [S III]{sub 18.7{sub μm}}, [O IV], [Fe II], [S III]{sub 33.5{sub μm}}, and [Si II]. More than 75% of these galaxies are classified as starburst-dominated sources in the mid-infrared, based on the [Ne V]/[Ne II] line flux ratios and equivalent width of the 6.2 μm polycyclic aromatic hydrocarbon feature. We compare ratios of the emission-line fluxes to those predicted from stellar photo-ionization and shock-ionization models to constrain the physical and chemical properties of the gas in the starburst LIRG nuclei. Comparing the [S IV]/[Ne II] and [Ne III]/[Ne II] line ratios to the Starburst99-Mappings III models with an instantaneous burst history, the emission-line ratios suggest that the nuclear starbursts in our LIRGs have ages of 1-4.5 Myr, metallicities of 1-2 Z{sub ☉}, and ionization parameters of 2-8 × 10{sup 7} cm s{sup –1}. Based on the [S III]{sub 33.5{sub μm}}/[S III]{sub 18.7{sub μm}} ratios, the electron density in LIRG nuclei is typically one to a few hundred cm{sup –3}, with a median electron density of ∼300 cm{sup –3}, for those sources above the low density limit for these lines. We also find that strong shocks are likely present in 10 starburst-dominated sources of our sample. A significant fraction of the GOALS sources (80) have resolved neon emission-line profiles (FWHM ≥600 km s{sup –1}) and five show clear differences in the velocities of the [Ne III] or [Ne V] emission lines, relative to [Ne II], of more than 200 km s{sup –1}. Furthermore, six starburst and five active galactic nucleus dominated LIRGs show a clear trend of increasing line width with ionization potential

  19. Analysis of the X-ray emission spectra of copper, germanium and rubidium plasmas produced at the Phelix laser facility

    Science.gov (United States)

    Comet, M.; Pain, J.-C.; Gilleron, F.; Piron, R.; Denis-Petit, D.; Méot, V.; Gosselin, G.; Morel, P.; Hannachi, F.; Gobet, F.; Tarisien, M.; Versteegen, M.

    2017-03-01

    We present the analysis of X-ray emission spectra of copper, germanium and rubidium plasmas measured at the Phelix laser facility. The laser intensity was around 6×1014 W.cm-2. The analysis is based on the hypothesis of an homogeneous plasma in local thermodynamic equilibrium using an effective temperature. This temperature is deduced from hydrodynamic simulations and collisional-radiative computations. Spectra are then calculated using the LTE opacity codes OPAMCDF and SCO-RCG and compared to experimental data.

  20. An interferometer experiment to explore the aspect angle dependence of stimulated electromagnetic emission spectra

    Directory of Open Access Journals (Sweden)

    Isham

    2005-01-01

    Full Text Available When the Earth's ionosphere is irradiated by a radiofrequency (RF electromagnetic wave of sufficiently high power density and tuned to match a natural E- or F-region plasma frequency, ionospheric magnetoionic wave modes may be excited and may generate RF electromagnetic sideband waves via nonlinear interactions. These secondary emissions, which may then escape from the ionosphere, have been termed stimulated electromagnetic emission or SEE. The frequency spectra of this radiation has been studied extensively, and a number of characteristic spectral features have been identified and in some cases related to particular plasma processes. The separation in frequency between the RF pump and the harmonics of the local electron gyrofrequency is critical in determining the amount of anomalous absorption suffered by the pump wave and the spectral properties of the stimulated sidebands. The pump can excite electrostatic waves which do not propagate away but can in some cases be observed via radio-wave scattering from the electron density fluctuations associated with them. These enhanced density fluctuations are created by processes commonly referred to as upper-hybrid and Langmuir turbulence. Langmuir turbulence has been the subject of 930-MHz scattering observations with antenna scanning through several pre-selected angles between the geographic and geomagnetic zenith directions, and a preference for pointing angles between the Spitze angle and geomagnetic field-aligned was identified. Other phenomena, such as the generation of enhanced electron temperatures and artificial aurora, have more recently been shown to have special behavior at similar angles, near but apparently not quite at field-aligned. In view of this evidence for angular structure in several pump-induced effects, in light of the rich variety of SEE phenomena strongly dependent on the geomagnetic field via the frequency interval between the pump and the gyrofrequency harmonics, and in

  1. An interferometer experiment to explore the aspect angle dependence of stimulated electromagnetic emission spectra

    Directory of Open Access Journals (Sweden)

    Isham

    2005-01-01

    Full Text Available When the Earth's ionosphere is irradiated by a radiofrequency (RF electromagnetic wave of sufficiently high power density and tuned to match a natural E- or F-region plasma frequency, ionospheric magnetoionic wave modes may be excited and may generate RF electromagnetic sideband waves via nonlinear interactions. These secondary emissions, which may then escape from the ionosphere, have been termed stimulated electromagnetic emission or SEE. The frequency spectra of this radiation has been studied extensively, and a number of characteristic spectral features have been identified and in some cases related to particular plasma processes. The separation in frequency between the RF pump and the harmonics of the local electron gyrofrequency is critical in determining the amount of anomalous absorption suffered by the pump wave and the spectral properties of the stimulated sidebands. The pump can excite electrostatic waves which do not propagate away but can in some cases be observed via radio-wave scattering from the electron density fluctuations associated with them. These enhanced density fluctuations are created by processes commonly referred to as upper-hybrid and Langmuir turbulence. Langmuir turbulence has been the subject of 930-MHz scattering observations with antenna scanning through several pre-selected angles between the geographic and geomagnetic zenith directions, and a preference for pointing angles between the Spitze angle and geomagnetic field-aligned was identified. Other phenomena, such as the generation of enhanced electron temperatures and artificial aurora, have more recently been shown to have special behavior at similar angles, near but apparently not quite at field-aligned. In view of this evidence for angular structure in several pump-induced effects, in light of the rich variety of SEE phenomena strongly dependent on the geomagnetic field via the frequency interval between the pump and the gyrofrequency harmonics, and in view

  2. Calculation of emission and absorption spectra of LTE plasma by the STA method

    International Nuclear Information System (INIS)

    Oreg, A.B.J.; Goldstein, W.H.

    1991-01-01

    Recent improvements in the Super Transition Array (STA) method for calculating Bound-Bound (BB) and Bound-Free (BF) emission and absorption spectra for LTE plasma are described and illustrated. The method accounts for all possible BB and BF radiative transitions in the plasma. Full detailed first order quantum relativistic treatment is used for calculating transition energies and probabilities. The enormous number of configurations are divided into sets of superconfigurations comprised of a collection of energetically grouped configurations to a specific one-electron transition is then represented by a Gaussian whose moments (total intensity, average energy and variance) are calculated accurately using a technique that bypasses the necessity of direct summation over all the levels involved. The calculation of these moments involves the populations of the configurations given by their statistical weights and the Boltzmann factor. For each configuration within the superconfiguration the authors use zeroeth order energies in the Boltzmann factor corrected by a superconfiguration averaged first order term. The structure of the spectrum is increasingly revealed by splitting each STA into a number of smaller STAs. When the spectrum converges it describes the detailed UTA structure, where each configuration-to-configuration array is represented by a separate Gaussian with first order energy in the Boltzmann factor. Convergence is reached with only a few thousand STAs, at most, which makes the calculations practical. It should be pointed out that in this treatment the STA moments are obtained by summing over all level-to-level transitions, rather than configuration-to-configuration average transitions. The authors also take into account orbital relaxation by calculating orbitals and energies for each superconfiguration in its own, optimized potential

  3. Transition probabilities of Ce I obtained from Boltzmann analysis of visible and near-infrared emission spectra

    Science.gov (United States)

    Nitz, D. E.; Curry, J. J.; Buuck, M.; DeMann, A.; Mitchell, N.; Shull, W.

    2018-02-01

    We report radiative transition probabilities for 5029 emission lines of neutral cerium within the wavelength range 417-1110 nm. Transition probabilities for only 4% of these lines have been previously measured. These results are obtained from a Boltzmann analysis of two high resolution Fourier transform emission spectra used in previous studies of cerium, obtained from the digital archives of the National Solar Observatory at Kitt Peak. The set of transition probabilities used for the Boltzmann analysis are those published by Lawler et al (2010 J. Phys. B: At. Mol. Opt. Phys. 43 085701). Comparisons of branching ratios and transition probabilities for lines common to the two spectra provide important self-consistency checks and test for the presence of self-absorption effects. Estimated 1σ uncertainties for our transition probability results range from 10% to 18%.

  4. Spatial-Resolved Measurement and Analysis of Extreme-Ultraviolet Emission Spectra from Laser-Produced Al Plasmas

    International Nuclear Information System (INIS)

    Cao Shi-Quan; Su Mao-Gen; Sun Dui-Xiong; Min Qi; Dong Chen-Zhong

    2016-01-01

    Extreme ultraviolet emission from laser-produced Al plasma is experimentally and theoretically investigated. Spatial-evolution emission spectra are measured by using the spatio-temporally resolved laser produced plasma technique. Based on the assumptions of a normalized Boltzmann distribution among the excited states and a steady-state collisional-radiative model, we succeed in reproducing the spectra at different detection positions, which are in good agreement with experiments. The decay curves about the electron temperature and electron density, as well as the fractions of individual Al ions and average ionization stage with increasing the detection distance are obtained by comparison with the experimental measurements. These parameters are critical points for deeply understanding the expanding and cooling of laser produced plasmas in vacuum. (paper)

  5. α particle induced scintillation in dense gaseous argon: emission spectra and temporal behavior of its ionic component

    International Nuclear Information System (INIS)

    Carvalho, M.J.; Klein, G.

    1980-01-01

    The scintillation induced by α particles in dense gaseous argon (above 1 atm) has been studied. The electric field dependence of the scintillation, shows that the second continuum (centred around 1270A) stems from the neutral as well as from the ionic species, initially created by the impinging particle. Intensity decay curves and emission spectra of these neutral excitation and ionic components were determined. Time constants suggest that the recombination mechanism is responsible for a delayed formation of the second continuum states, 1 Σ + sub(u) and 3 Σ + sub(u). The third continuum of the emission spectra, which spreads at longer wavelengths, from 1600A to 2800A, is field independent

  6. Measurement and analysis of double-differential neutron emission spectra in (P,N) and (α,N) reactions

    International Nuclear Information System (INIS)

    Okamoto, K.; Mehta, M.K.

    1988-05-01

    The second IAEA Research Co-ordination Meeting on Measurement and Analysis of Double-Differential Neutron Emission Spectra in (p,n) and (α,n) Reactions was convened by the IAEA Nuclear Data Section at the IAEA Headquarters in Vienna during 8-10 February, 1988. The main objectives of the Co-ordinated Research Project for which this meeting was held are (i) to extract systematic information about nuclear level densities as a function of excitation energy by analysing the neutron emission spectra from (p,n) and (α,n) reactions on properly selected targets and bombarding energy range, and (ii) to parametrize this information into appropriate phenomenological models to enable reliable extrapolation for general use of level density information in basic and applied nuclear physics related problems. Detailed conclusions and recommendations, together with a summary of the programme during 1988/1989 are attached in the Appendices

  7. INTEGRAL hard X-ray spectra of the cosmic X-ray background and Galactic ridge emission

    Science.gov (United States)

    Türler, M.; Chernyakova, M.; Courvoisier, T. J.-L.; Lubiński, P.; Neronov, A.; Produit, N.; Walter, R.

    2010-03-01

    Aims: We derive the spectra of the cosmic X-ray background (CXB) and of the Galactic ridge X-ray emission (GRXE) in the ~20-200 keV range from the data of the IBIS instrument aboard the INTEGRAL satellite obtained during the four dedicated Earth-occultation observations in early 2006. Methods: We analyze the modulation of the IBIS/ISGRI detector counts induced by the passage of the Earth through the field of view of the instrument. Unlike previous studies, we do not fix the spectral shape of the various contributions, but model instead their spatial distribution and derive for each of them the expected modulation of the detector counts. The spectra of the diffuse emission components are obtained by fitting the normalizations of the model lightcurves to the observed modulation in different energy bins. Because of degeneracy, we guide the fits with a realistic choice of the input parameters and a constraint for spectral smoothness. Results: The obtained CXB spectrum is consistent with the historic HEAO-1 results and falls slightly below the spectrum derived with Swift/BAT. A 10% higher normalization of the CXB cannot be completely excluded, but it would imply an unrealistically high albedo of the Earth. The derived spectrum of the GRXE confirms the presence of a minimum around 80 keV with improved statistics and yields an estimate of ~0.6 M⊙ for the average mass of white dwarfs in the Galaxy. The analysis also provides updated normalizations for the spectra of the Earth's albedo and the cosmic-ray induced atmospheric emission. Conclusions: This study demonstrates the potential of INTEGRAL Earth-occultation observations to derive the hard X-ray spectra of three fundamental components: the CXB, the GRXE and the Earth emission. Further observations would be extremely valuable to confirm our results with improved statistics.

  8. Experimental and theoretical studies of the VUV emission and absorption spectra of H2, HD and D2 molecules

    International Nuclear Information System (INIS)

    Roudjane, M.

    2007-12-01

    The aim of this thesis is to carry out an experimental study of the absorption and emission spectra of the D 2 and HD isotopes, with high resolution, in the VUV domain and to supplement it by a theoretical study of the excited electronic states involved in the observed transitions. The emission spectra of HD and D 2 are produced by Penning discharge source operating under low pressure and are recorded in the spectral range 78 - 170 nm. The recorded spectra contains more than 20.000 lines. The analysis of the spectrum consists in identifying and assigning the lines to the electronic transitions between energy levels of the molecule. The present analysis is based on our theoretical calculations of the ro-vibrational energy levels of the excited electronic states and the transition probabilities from these states towards the energy levels of the fundamental state. The theoretical results are obtained by resolving the coupled equations between the excited electronic states B 1 Σ u 1 , B' 1 Σ u 1 , C 1 Π u 1 and D 1 Π u 1 , taking into account the nonadiabatic couplings between these states, and they are obtained in the adiabatic approximation for the excited electronic states B''B-bar 1 Σ u + , D' 1 Π u 1 and D'' 1 Π u 1 . The equations are resolved using a modern method based on the discretization variables representation method. In addition, we have carried out a study of the absorption spectra of the HD and D 2 molecules

  9. Modification of erbium photoluminescence excitation spectra for the emission wavelength 1.54 μm in mesoscopic structures

    International Nuclear Information System (INIS)

    Gaponenko, N.V.; Unuchak, D.M.; Mudryi, A.V.; Malyarevich, G.K.; Gusev, O.B.; Stepikhova, M.V.; Krasilnikova, L.V.; Stupak, A.P.; Kleshcheva, S.M.; Samoilovich, M.I.; Tsvetkov, M.Yu.

    2006-01-01

    Photoluminescence excitation (PLE) spectra for the emission wavelength 1.54 μm were studied for erbium-doped xerogels embedded in artificial opals and porous anodic alumina films. Opals were chosen with photonic stop-band in green spectral range, where excitation of 1.54 μm occurs most efficiently. In comparison to the structure erbium-doped titania xerogel/porous anodic alumina/silicon the photoluminescence excitation spectra for 1.54 μm emission wavelength significantly changes for the same xerogels embedded in artificial opals. Enhancement of erbium-related 1.54 μm emission was observed from the structure Fe 2 O 3 xerogel/porous anodic alumina fabricated on silicon, having some incompletely anodized aluminium, under excitation with either the lasing source at 532 nm or xenon lamp. Evident difference in PLE spectra for erbium doped TiO 2 and Fe 2 O 3 xerogels in porous anodic alumina is observed

  10. Paradigms and challenges for bioapplication of rare earth upconversion luminescent nanoparticles: small size and tunable emission/excitation spectra.

    Science.gov (United States)

    Sun, Ling-Dong; Wang, Ye-Fu; Yan, Chun-Hua

    2014-04-15

    Rare earth (RE) materials, which are excited in the ultraviolet and emit in the visible light spectrum, are widely used as phosphors for lamps and displays. In the 1960's, researchers reported an abnormal emission phenomenon where photons emitted from a RE element carried more energy than those absorbed, owing to the sequential energy transfer between two RE ions--Yb(3+)-sensitized Er(3+) or Tm(3+)--in the solid state. After further study, researchers named this abnormal emission phenomenon upconversion (UC) emission. More recent approaches take advantage of solution-based synthesis, which allows creation of homogenous RE nanoparticles (NPs) with controlled size and structure that are capable of UC emission. Such nanoparticles are useful for many applications, especially in biology. For these applications, researchers seek small NPs with high upconversion emission intensity. These UCNPs have the potential to have multicolor and tunable emissions via various activators. A vast potential for future development remains by developing molecular antennas and energy transfer within RE ions. We expect UCNPs with optimized spectra behavior to meet the increasing demand of potential applications in bioimaging, biological detection, and light conversion. This Account focuses on efforts to control the size and modulate the spectra of UCNPs. We first review efforts in size control. One method is careful control of the synthesis conditions to manipulate particle nucleation and growth, but more recently researchers have learned that the doping conditions can affect the size of UCNPs. In addition, constructing homogeneous core/shell structures can control nanoparticle size by adjusting the shell thickness. After reviewing size control, we consider how diverse applications impose different requirements on excitation and/or emission photons and review recent developments on tuning of UC spectral profiles, especially the extension of excitation/emission wavelengths and the adjustment

  11. Simultaneous measurement of quantum yield ratio and absorption ratio between acceptor and donor by linearly unmixing excitation-emission spectra.

    Science.gov (United States)

    Zhang, C; Lin, F; DU, M; Qu, W; Mai, Z; Qu, J; Chen, T

    2018-02-13

    Quantum yield ratio (Q A /Q D ) and absorption ratio (K A /K D ) in all excitation wavelengths used between acceptor and donor are indispensable to quantitative fluorescence resonance energy transfer (FRET) measurement based on linearly unmixing excitation-emission spectra (ExEm-spFRET). We here describe an approach to simultaneously measure Q A /Q D and K A /K D values by linearly unmixing the excitation-emission spectra of at least two different donor-acceptor tandem constructs with unknown FRET efficiency. To measure the Q A /Q D and K A /K D values of Venus (V) to Cerulean (C), we used a wide-field fluorescence microscope to image living HepG2 cells separately expressing each of four different C-V tandem constructs at different emission wavelengths with 435 nm and 470 nm excitation respectively to obtain the corresponding excitation-emission spectrum (S DA ). Every S DA was linearly unmixed into the contributions (weights) of three excitation-emission spectra of donor (W D ) and acceptor (W A ) as well as donor-acceptor sensitisation (W S ). Plot of W S /W D versus W A /W D for the four C-V plasmids from at least 40 cells indicated a linear relationship with 1.865 of absolute intercept (Q A /Q D ) and 0.273 of the reciprocal of slope (K A /K D ), which was validated by quantitative FRET measurements adopting 1.865 of Q A /Q D and 0.273 of K A /K D for C32V, C5V, CVC and VCV constructs respectively in living HepG2 cells. © 2018 The Authors Journal of Microscopy © 2018 Royal Microscopical Society.

  12. Outer atmospheres of cool stars. XII - A survey of IUE ultraviolet emission line spectra of cool dwarf stars

    Science.gov (United States)

    Linsky, J. L.; Bornmann, P. L.; Carpenter, K. G.; Hege, E. K.; Wing, R. F.; Giampapa, M. S.; Worden, S. P.

    1982-01-01

    Quantitative information is obtained on the chromospheres and transition regions of M dwarf stars, in order to determine how the outer atmospheres of dMe stars differ from dM stars and how they compare with the outer atmospheres of quiet and active G and K type dwarfs. IUE spectra of six dMe and four dM stars, together with ground-based photometry and spectroscopy of the Balmer and Ca II H and K lines, show no evidence of flares. It is concluded, regarding the quiescent behavior of these stars, that emission-line spectra resemble that of the sun and contain emission lines formed in regions with 4000-20,000 K temperatures that are presumably analogous to the solar chromosphere, as well as regions with temperatures of 20,000-200,000 K that are presumably analogous to the solar transition region. Emission-line surface fluxes are proportional to the emission measure over the range of temperatures at which the lines are formed.

  13. Steep Hard-X-ray Spectra Indicate Extremely High Accretion Rates in Weak Emission-Line Quasars

    Science.gov (United States)

    Marlar, Andrea; Shemmer, Ohad; Anderson, Scott F.; Brandt, W. Niel; Diamond-Stanic, Aleksandar M.; Fan, Xiaohui; Luo, Bin; Plotkin, Richard; Richards, Gordon T.; Schneider, Donald P.; Wu, Jianfeng

    2018-06-01

    We present XMM-Newton imaging spectroscopy of ten weak emission-line quasars (WLQs) at 0.928 ≤ z ≤ 3.767, six of which are radio quiet and four which are radio intermediate. The new X-ray data enabled us to measure the hard-X-ray power-law photon index (Γ) in each source with relatively high accuracy. These measurements allowed us to confirm previous reports that WLQs have steeper X-ray spectra, therefore indicating higher accretion rates with respect to "typical" quasars. A comparison between the Γ values of our radio-quiet WLQs and those of a carefully-selected, uniform sample of 84 quasars shows that the first are significantly higher, at the ≥ 3σ level. Collectively, the four radio-intermediate WLQs have lower Γ values with respect to the six radio-quiet WLQs, as may be expected if the spectra of the first group are contaminated by X-ray emission from a jet. These results suggest that, in the absence of significant jet emission along our line of sight, WLQs constitute the extreme high end of the accretion rate distribution in quasars. We detect soft excess emission in our lowest-redshift radio-quiet WLQ, in agreement with previous findings suggesting that the prominence of this feature is associated with a high accretion rate. We have not detected signatures of Compton reflection, Fe Kα lines, or strong variability between two X-ray epochs in any of our WLQs.

  14. Ab-initio modeling of an iron laser-induced plasma: Comparison between theoretical and experimental atomic emission spectra

    International Nuclear Information System (INIS)

    Colgan, J.; Judge, E.J.; Kilcrease, D.P.; Barefield, J.E.

    2014-01-01

    We report on efforts to model the Fe emission spectrum generated from laser-induced breakdown spectroscopy (LIBS) measurements on samples of pure iron oxide (Fe 2 O 3 ). Our modeling efforts consist of several components. We begin with ab-initio atomic structure calculations performed by solving the Hartree–Fock equations for the neutral and singly ionized stages of Fe. Our energy levels are then adjusted to their experimentally known values. The atomic transition probabilities and atomic collision quantities are also computed in an ab-initio manner. We perform LTE or non-LTE calculations that generate level populations and, subsequently, an emission spectrum for the iron plasma for a range of electron temperatures and electron densities. Such calculations are then compared to the experimental spectrum. We regard our work as a preliminary modeling effort that ultimately strives towards the modeling of emission spectra from even more complex samples where less atomic data are available. - Highlights: • LIBS plasma of iron oxide • Ab-initio theoretical Modeling • Discussion of LTE versus non-LTE criteria and assessment • Boltzmann plots for Fe—determination of when LTE is a valid assumption • Emission spectra for Fe—comparison of theoretical modeling and measurement: good agreement obtained

  15. On the origin of excimer emission in electroluminescence and photoluminescence spectra of polyfluorenes

    International Nuclear Information System (INIS)

    Vacha, Martin; Ha, Jaekook; Sato, Hisaya

    2007-01-01

    We report a study on the differences in red-shifted excimer band in photoluminescence (PL) and electroluminescence (EL) spectra of thin films of a copolymer of dibutylfluorene and butylphenylphenoxazine. The relative intensity of the excimer band in PL spectra increases with temperature above the polymer glass transition, and with the intensity of the excitation light. In EL spectra, on the other hand, the relative excimer intensity is seen to decrease with increasing driving voltage. These opposite trends originate from the different nature of excitations in PL and EL spectra: photoexcitation directly creates singlet excitons while electric excitation proceeds via interaction of injected electrons and holes. In case of electric excitation, the observed results might be due to trap-assisted excimer formation

  16. Production and analysis of some atomic emission spectra in the vacuum ultraviolet

    International Nuclear Information System (INIS)

    Meijer, F.G.

    1979-01-01

    The development of technical facilities for spectra analysis are described including the design, construction and adjustment of a grazing incidence spectrograph for the extreme ultraviolet and the improvements in light sources. The investigations of the fifth and fourth spectra of tantalum, the analysis of the sixth spectrum of tungsten, the extension of the analysis of the fourth spectrum of hafnium and a start of the analysis of the seventh spectrum of rhenium are presented. (C.F.)

  17. Deconvolution of Thermal Emissivity Spectra of Mercury to their Endmember Counterparts measured in Simulated Mercury Surface Conditions

    Science.gov (United States)

    Varatharajan, I.; D'Amore, M.; Maturilli, A.; Helbert, J.; Hiesinger, H.

    2017-12-01

    The Mercury Radiometer and Thermal Imaging Spectrometer (MERTIS) payload of ESA/JAXA Bepicolombo mission to Mercury will map the thermal emissivity at wavelength range of 7-14 μm and spatial resolution of 500 m/pixel [1]. Mercury was also imaged at the same wavelength range using the Boston University's Mid-Infrared Spectrometer and Imager (MIRSI) mounted on the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii with the minimum spatial coverage of 400-600km/spectra which blends all rocks, minerals, and soil types [2]. Therefore, the study [2] used quantitative deconvolution algorithm developed by [3] for spectral unmixing of this composite thermal emissivity spectrum from telescope to their respective areal fractions of endmember spectra; however, the thermal emissivity of endmembers used in [2] is the inverted reflectance measurements (Kirchhoff's law) of various samples measured at room temperature and pressure. Over a decade, the Planetary Spectroscopy Laboratory (PSL) at the Institute of Planetary Research (PF) at the German Aerospace Center (DLR) facilitates the thermal emissivity measurements under controlled and simulated surface conditions of Mercury by taking emissivity measurements at varying temperatures from 100-500°C under vacuum conditions supporting MERTIS payload. The measured thermal emissivity endmember spectral library therefore includes major silicates such as bytownite, anorthoclase, synthetic glass, olivine, enstatite, nepheline basanite, rocks like komatiite, tektite, Johnson Space Center lunar simulant (1A), and synthetic powdered sulfides which includes MgS, FeS, CaS, CrS, TiS, NaS, and MnS. Using such specialized endmember spectral library created under Mercury's conditions significantly increases the accuracy of the deconvolution model results. In this study, we revisited the available telescope spectra and redeveloped the algorithm by [3] by only choosing the endmember spectral library created at PSL for unbiased model

  18. Neutron emission spectra and level density of hot rotating 132Sn

    International Nuclear Information System (INIS)

    Aggarwal, Mamta

    2008-01-01

    The neutron emission spectrum of the highly excited compound nuclear system 132 Sn is investigated at high spin. The doubly magic nucleus 132 Sn undergoes a shape transition at high angular momentum which affects the nuclear level density and neutron emission probability considerably. The interplay of temperature, shape, deformation and rotational degrees of freedom and their influence on neutron emission is emphasized. We predict an enhancement of nucleonic emission at those spins where the nucleus suffers a transition from a spherical to deformed shape. (author)

  19. The multi-resolution capability of Tchebichef moments and its applications to the analysis of fluorescence excitation-emission spectra

    Science.gov (United States)

    Li, Bao Qiong; Wang, Xue; Li Xu, Min; Zhai, Hong Lin; Chen, Jing; Liu, Jin Jin

    2018-01-01

    Fluorescence spectroscopy with an excitation-emission matrix (EEM) is a fast and inexpensive technique and has been applied to the detection of a very wide range of analytes. However, serious scattering and overlapping signals hinder the applications of EEM spectra. In this contribution, the multi-resolution capability of Tchebichef moments was investigated in depth and applied to the analysis of two EEM data sets (data set 1 consisted of valine-tyrosine-valine, tryptophan-glycine and phenylalanine, and data set 2 included vitamin B1, vitamin B2 and vitamin B6) for the first time. By means of the Tchebichef moments with different orders, the different information in the EEM spectra can be represented. It is owing to this multi-resolution capability that the overlapping problem was solved, and the information of chemicals and scatterings were separated. The obtained results demonstrated that the Tchebichef moment method is very effective, which provides a promising tool for the analysis of EEM spectra. It is expected that the applications of Tchebichef moment method could be developed and extended in complex systems such as biological fluids, food, environment and others to deal with the practical problems (overlapped peaks, unknown interferences, baseline drifts, and so on) with other spectra.

  20. Study of the structural characteristics of a group of natural silicates by means of their Kβ emission spectra

    International Nuclear Information System (INIS)

    Torres Deluigi, Maria Torres; Strasser, Edgardo N.; Vasconcellos, Marcos A.Z.; Riveros, Jose A.

    2006-01-01

    In this work, the Si Kβ and Al Kβ emission spectra of a group of natural silicates typical of a region in San Luis (Argentina) are described qualitatively within the frame of the Molecular Orbital (MO) theory. Since these spectra come from electron transitions from valence orbitals, they offer information on the chemical bonds that are present and on the molecular orbitals involved. The spectra were obtained by means of an electron microprobe. The energies, intensities and full-width at half-maximum (FWHM) of the lines that conform the silicon and aluminium Kβ spectra were quantified. It was observed that an increase in the number of oxygen ions shared by the tetrahedra (SiO 4 ) 4- caused a lineal increase in the FWHM of the Si Kβ 1,3 and Al Kβ 1,3 lines. This behavior is caused by the increase of the covalent character of the Si-O and Al-O bonds with the quantity of oxygen ions shared by the adjacent tetrahedra

  1. Lα1 satellites in X-ray emission spectra of higher - Z elements

    International Nuclear Information System (INIS)

    Poonia, S.

    2004-01-01

    Full text: The X-ray satellite spectra arising due to 2p 3/2 -1 3x -1 - 3x -1 3d -1 (x ≡ s, p, d) transition array, in elements with Z 74 to 92, have been calculated. While the energies of various transitions of the array have been determined by using available Hartree-Fock-Slater data on 1s -1 - 2p -1 3x -1 and 2p 3/2 -1 - 3x -1 , 3x' -1 Auger transition energies and their relative intensities have been estimated by considering cross - sections of singly ionized 2x -1 (x ≡ s, p) states and then of subsequent Coster-Kronig and shake off processes. The calculated spectra have been compared with the measured satellite energies in Lα1 spectra. Their intense peaks have been identified as the observed satellite lines. The one to one correspondence between the peaks in calculated spectra and the satellites in measured spectra has been established on the basis of the agreement between the separations in the peak energies and those in the measured satellite energies. It has been established that three satellites observed in the Lα 1 region of the X-ray spectra of various elements and named α', α ix and α x in order of increasing energy are mainly emitted by 2p 3/2 -1 3d -1 - 3d -2 transitions. It is observed that the satellite α' in all these spectra can be assigned to the superposition of 3 F 4 - 3 F 4 transition and that this must be most intense one out of all these satellites, contributing in order of decreasing intensity. The line α ix , has been assigned to mainly the 1 F 3 - 1 G 4 , 1 P 1 - 1 D 2 and 1 F 3 - 1 D 2 transitions. Finally, the satellite α x , reported in the spectra of elements with Z = 74-92, has been associated with the transition 3 D 3 - 3 F 4 . The possible contributions of other transitions of the 2p 3/2 -1 3x -1 - 3x -1 3d -1 (x ≡ s, p, d) array having appreciable intensities, have also been discussed

  2. Computer simulation of ICP spectra: A new tool for the study of excitation, emission, and line overlap

    International Nuclear Information System (INIS)

    Blades, M.W.; Burton, L.L.

    1986-01-01

    It is well known that the relatively high temperature of ICP sources provides an excitation environment relatively free from dissociation and vaporization interferences and, in addition, produces intense analyte line spectra and hence high analytical sensitivity. However, this feature also introduces the potential for spectral overlaps from sample concomitants. The degree to which an analyte spectral line intensity can be corrected for interfering spectral overlaps depends on many factors including spectrometer resolution, sample composition and ICP operating conditions. The authors have been using a computer program to assist them in the study of ICP analyte emission spectra. This program is being used to study the spectral distribution of line intensity information and also to do detailed investigations on spectral overlaps in complex sample mixtures. As input data the program uses tabulated wavelengths, transition probabilities (gA values), partition functions, excitation energies of the transitions, ionization energy, temperature, and Doppler and Stark linewidths

  3. Plasma Emission Spectra of Opuntia Nopalea Obtained with Microsecond Laser Pulses

    International Nuclear Information System (INIS)

    Ponce, L.; Flores, T.; Arronte, A.; Flores, A.

    2008-01-01

    Laser-induced Plasma Spectroscopy was performed during the spines ablation of Opuntia by using Nd:YAG microsecond laser pulses. The results show strong absorption in Glochids that causes the intense electronic noise on the spectra. This process is consider suitable for practical elimination of spines in alimentary products like opuntia

  4. Fluorescence of Bacteria, Pollens, and Naturally Occurring Airborne Particles: Excitation/Emission Spectra

    Science.gov (United States)

    2009-02-01

    35 Figure 29. EEM spectra of kaolin particles, dry...Warrington, PA. Glass beads were obtained from Peirce Chemical Co., Rockford, IL. Kaolin particles were obtained from Particle Information Services...solution concentration of 1 mg/ml. The samples were vortexed and pipetted vigorously to disperse aggregates. Stock bacteria solutions were diluted to a

  5. Optically stimulated luminescence emission spectra from feldspars as a function of sample temperature

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.

    1997-01-01

    samples have been measured at various sample temperatures. A small but consistent shift of the peak emission wavelength to shorter wavelengths at higher temperatures is observed. However, the magnitude of this shift is sufficiently small that it will not affect measurements of the thermal activation...... energy. A systematic difference is observed between the thermal activation energies measured when using different emission wavelengths. In particular, the thermal activation energy of the emission at 400 nm is typically 0.11 eV, while that at 570 nm from the same samples is 0.03-0.05 eV. Several possible...

  6. Spallation Neutron Emission Spectra in Some Amphoter Target Nuclei by Proton Beam Up to 140 MeV Energy

    International Nuclear Information System (INIS)

    Yildirim, G.

    2008-01-01

    In the present study, the (p,xn) reaction neutron-emission spectra for some amphoter target nuclei as 27 A l, 64 Z n, 120 S n, and 208 P b were investigated up to 140 MeV incident proton energy. The pre-equilibrium calculations were calculated by using the hybrid model, the geometry dependent hybrid model, the full exciton model and the cascade exciton model. The reaction equilibrium component was calculated with a traditional compound nucleus model developed by Weisskopf Ewing. Calculation results have been discussed and compared with the available experimental data in literature

  7. Retrieval of Tropospheric Profiles from IR Emission Spectra: Field Experiment and Sensitivity Study

    National Research Council Canada - National Science Library

    Theriault, J

    1993-01-01

    .... The goal of this project was the retrieval of atmospheric temperature and water vapor profiles and possibly over relevant information on clouds and aerosol properties from high resolution IR emission...

  8. GNASH: a preequilibrium, statistical nuclear-model code for calculation of cross sections and emission spectra

    International Nuclear Information System (INIS)

    Young, P.G.; Arthur, E.D.

    1977-11-01

    A new multistep Hauser--Feshbach code that includes corrections for preequilibrium effects is described. The code can calculate up to 60 decay reactions (cross sections and energy spectra) in one computation, and thereby provide considerable flexibility for handling processes with complicated reaction chains. Input parameter setup, problem output, and subroutine descriptions are given along with a sample problem calculation. A brief theoretical description is also included. 8 figures, 3 tables

  9. Emission from water vapor and absorption from other gases at 5-7.5 μm in Spitzer-IRS Spectra Of Protoplanetary Disks

    Energy Technology Data Exchange (ETDEWEB)

    Sargent, B. A. [Center for Imaging Science and Laboratory for Multiwavelength Astrophysics, Rochester Institute of Technology, 54 Lomb Memorial Drive, Rochester, NY 14623 (United States); Forrest, W.; Watson, Dan M.; Kim, K. H.; Richter, I.; Tayrien, C. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); D' Alessio, P.; Calvet, N. [Department of Astronomy, The University of Michigan, 500 Church Street, 830 Dennison Building, Ann Arbor, MI 48109 (United States); Furlan, E. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Green, J. [Department of Astronomy, University of Texas, 1 University Station, Austin, TX 78712 (United States); Pontoppidan, K., E-mail: baspci@rit.edu [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2014-09-10

    We present spectra of 13 T Tauri stars in the Taurus-Auriga star-forming region showing emission in Spitzer Space Telescope Infrared Spectrograph 5-7.5 μm spectra from water vapor and absorption from other gases in these stars' protoplanetary disks. Seven stars' spectra show an emission feature at 6.6 μm due to the ν{sub 2} = 1-0 bending mode of water vapor, with the shape of the spectrum suggesting water vapor temperatures >500 K, though some of these spectra also show indications of an absorption band, likely from another molecule. This water vapor emission contrasts with the absorption from warm water vapor seen in the spectrum of the FU Orionis star V1057 Cyg. The other 6 of the 13 stars have spectra showing a strong absorption band, peaking in strength at 5.6-5.7 μm, which for some is consistent with gaseous formaldehyde (H{sub 2}CO) and for others is consistent with gaseous formic acid (HCOOH). There are indications that some of these six stars may also have weak water vapor emission. Modeling of these stars' spectra suggests these gases are present in the inner few AU of their host disks, consistent with recent studies of infrared spectra showing gas in protoplanetary disks.

  10. Anatomy of the AGN in NGC 5548. IX. Photoionized emission features in the soft X-ray spectra

    Science.gov (United States)

    Mao, Junjie; Kaastra, J. S.; Mehdipour, M.; Gu, Liyi; Costantini, E.; Kriss, G. A.; Bianchi, S.; Branduardi-Raymont, G.; Behar, E.; Di Gesu, L.; Ponti, G.; Petrucci, P.-O.; Ebrero, J.

    2018-04-01

    The X-ray narrow emission line region (NELR) of the archetypal Seyfert 1 galaxy NGC 5548 has been interpreted as a single-phase photoionized plasma that is absorbed by some of the warm absorber components. This scenario requires those overlaying warm absorber components to have larger distance (to the central engine) than the X-ray NELR, which is not fully consistent with the distance estimates found in the literature. Therefore, we reanalyze the high-resolution spectra obtained in 2013-2014 with the Reflection Grating Spectrometer (RGS) aboard XMM-Newton to provide an alternative interpretation of the X-ray narrow emission features. We find that the X-ray narrow emission features in NGC 5548 can be described by a two-phase photoionized plasma with different ionization parameters (logξ = 1.3 and 0.1) and kinematics (vout = -50 and -400 km s-1), and no further absorption by the warm absorber components. The X-ray and optical NELR might be the same multi-phase photoionized plasma. Both X-ray and optical NELR have comparable distances, asymmetric line profiles, and the underlying photoionized plasma is turbulent and compact in size. The X-ray NELR is not the counterpart of the UV/X-ray absorber outside the line of sight because their distances and kinematics are not consistent. In addition, X-ray broad emission features that we find in the spectrum can be accounted for by a third photoionized emission component. The RGS spectrum obtained in 2016 is analyzed as well, where the luminosity of most prominent emission lines (the O VII forbidden line and O VIII Lyα line) are the same (at a 1σ confidence level) as in 2013-2014.

  11. Emission Lines in the Near-infrared Spectra of the Infrared Quintuplet Stars in the Galactic Center

    Energy Technology Data Exchange (ETDEWEB)

    Najarro, F. [Departamento de Astrofísica, Centro de Astrobiología (CSIC-INTA), Ctra. Torrejón a Ajalvir km 4, E-28850 Torrejón de Ardoz (Spain); Geballe, T. R. [Gemini Observatory, 670 North A’ohoku Place, Hilo, HI 96720 (United States); Figer, D. F. [Center for Detectors, Rochester Institute of Technology, 74 Lomb Memorial Drive, Rochester, NY 14623 (United States); Fuente, D. de la [Instituto de Astronomía, Unidad Académica en Ensenada, Universidad Nacional Autónoma de México, Ensenada 22860, México (Mexico)

    2017-08-20

    We report the detection of a number of emission lines in the 1.0–2.4 μ m spectra of four of the five bright-infrared dust-embedded stars at the center of the Galactic center’s (GC) Quintuplet Cluster. Spectroscopy of the central stars of these objects is hampered not only by the large interstellar extinction that obscures all of the objects in the GC, but also by the large amounts of warm circumstellar dust surrounding each of the five stars. The pinwheel morphologies of the dust observed previously around two of them are indicative of Wolf–Rayet colliding wind binaries; however, infrared spectra of each of the five have until now revealed only dust continua steeply rising to long wavelengths and absorption lines and bands from interstellar gas and dust. The emission lines detected, from ionized carbon and from helium, are broad and confirm that the objects are dusty late-type carbon Wolf–Rayet stars.

  12. Experimental and theoretical study on emission spectra of a nitrogen photoionized plasma induced by intense EUV pulses

    Directory of Open Access Journals (Sweden)

    Saber Ismail

    2018-01-01

    Full Text Available Spectral lines of low-temperature nitrogen photoionized plasma were investigated. The photoionized plasma was created in the result of irradiation N2 gas using laser plasma EUV radiation pulses. The source was based on a 10J/10ns Nd:YAG (λ = 1064 nm laser system and a gas puff target. The EUV radiation pulses were collected and focused using a grazing incidence multifoil EUV collector. The emission spectra were measured in the ultraviolet and visible (UV/Vis range. It was found that the plasma emission lines in the lower region of the UV range are relativley weak. Nonetheless, a part of the spectra contains strong molecular band in the 300 - 430 nm originated from second positive and first negative systems band transitions of nitrogen. These molecular band transitions were identified using a code for study the diatomic molecules, LIFBASE. The vibrational band of Δv = 0 and ±1 transitions were significantly populated than of that with Δv = ±2 and 3 transitions. A comparison of the calculated and measured spectrum is presented. With an assumption of a local thermodynamic equilibrium (LTE, the vibrational temperature was determined from the integrated band intensities with the help of the Boltzmann plot method and compared to the temperature predicted by SPECAIR and LIFBASE simulations. A summary of the results and the variations in the vibrational temperatures was discussed.

  13. Experimental and theoretical study on emission spectra of a nitrogen photoionized plasma induced by intense EUV pulses

    Science.gov (United States)

    Saber, Ismail; Bartnik, Andrzej; Skrzeczanowski, Wojciech; Wachulak, Przemyslaw; Jarocki, Roman; Fiedorowicz, Henryk; Limpouch, Jiri

    2018-01-01

    Spectral lines of low-temperature nitrogen photoionized plasma were investigated. The photoionized plasma was created in the result of irradiation N2 gas using laser plasma EUV radiation pulses. The source was based on a 10J/10ns Nd:YAG (λ = 1064 nm) laser system and a gas puff target. The EUV radiation pulses were collected and focused using a grazing incidence multifoil EUV collector. The emission spectra were measured in the ultraviolet and visible (UV/Vis) range. It was found that the plasma emission lines in the lower region of the UV range are relativley weak. Nonetheless, a part of the spectra contains strong molecular band in the 300 - 430 nm originated from second positive and first negative systems band transitions of nitrogen. These molecular band transitions were identified using a code for study the diatomic molecules, LIFBASE. The vibrational band of Δv = 0 and ±1 transitions were significantly populated than of that with Δv = ±2 and 3 transitions. A comparison of the calculated and measured spectrum is presented. With an assumption of a local thermodynamic equilibrium (LTE), the vibrational temperature was determined from the integrated band intensities with the help of the Boltzmann plot method and compared to the temperature predicted by SPECAIR and LIFBASE simulations. A summary of the results and the variations in the vibrational temperatures was discussed.

  14. Dynamics of hot spots in the DPF-78 plasma focus from x-ray spectra and REB emission

    International Nuclear Information System (INIS)

    Schmidt, H.; Wang, X.X.

    1995-01-01

    The X-ray emission from hot spots in the plasma focus DPF-78 was investigated with the help of two X-ray quartz crystal spectrometers of the Johann type and a 4 fold magnifying X-ray pinhole camera. In the experiments the working gas was chosen to be 300 Pa deuterium with 20 Pa argon admixture. X-ray spectra in the wavelength range from 3.55 angstrom to 4.0 angstrom, including H-like and He-like Argon lines, were recorded on Kodak DEF-2 film. From the spatially resolved spectra recorded side-on, a relative spectral shift between different hot spots of the same shot was often observed. The shift could be attributed to the Doppler shift. From spectral characteristics such as intensities and FWHM of Ar resonant and intercombination lines electron densities of up to 3 x 10 27 m -3 were determined. Radial dimensions of the hot spots ranging from about 140 microm to 300 microm were found from pinhole pictures applying the penumbra method. Usually two pulses of relativistic electron beams were observed using Cherenkov detectors in a magnetic spectrometer. The energy of the first pulse, which was emitted at the time of maximum compression, was higher than that of the second pulse. The measured FWHM of the REB pulses ranges from 3 ns to about 10 ns. The characteristics of the time-integrated X-ray spectra and the time resolved REB spectra and their dependence on the composition of the filling gas are discussed

  15. Determining misorientation of graphite grains from the angular dependence of X-ray emission spectra

    International Nuclear Information System (INIS)

    Belavin, V. V.; Okotrub, A. V.; Bulusheva, L. G.; Kotosonov, A. S.; Vyalykh, D. V.; Molodtsov, S. L.

    2006-01-01

    Angular-resolved X-ray absorption spectra were measured for pyrolytic graphite samples of various quality. A new approach to determining the misorientation of graphite grains in polycrystalline samples is proposed, which is based on calculations of the angular dependence of the relative intensity of a peak corresponding to the π* state for a normal distribution of grains. The experimental values are used to construct theoretical angular dependences using partial densities of the π* and σ* states determined from the nonempirical calculations for graphite

  16. Study of medical isotope production facility stack emissions and noble gas isotopic signature using automatic gamma-spectra analysis platform

    Science.gov (United States)

    Zhang, Weihua; Hoffmann, Emmy; Ungar, Kurt; Dolinar, George; Miley, Harry; Mekarski, Pawel; Schrom, Brian; Hoffman, Ian; Lawrie, Ryan; Loosz, Tom

    2013-04-01

    The nuclear industry emissions of the four CTBT (Comprehensive Nuclear-Test-Ban Treaty) relevant radioxenon isotopes are unavoidably detected by the IMS along with possible treaty violations. Another civil source of radioxenon emissions which contributes to the global background is radiopharmaceutical production companies. To better understand the source terms of these background emissions, a joint project between HC, ANSTO, PNNL and CRL was formed to install real-time detection systems to support 135Xe, 133Xe, 131mXe and 133mXe measurements at the ANSTO and CRL 99Mo production facility stacks as well as the CANDU (CANada Deuterium Uranium) primary coolant monitoring system at CRL. At each site, high resolution gamma spectra were collected every 15 minutes using a HPGe detector to continuously monitor a bypass feed from the stack or CANDU primary coolant system as it passed through a sampling cell. HC also conducted atmospheric monitoring for radioxenon at approximately 200 km distant from CRL. A program was written to transfer each spectrum into a text file format suitable for the automatic gamma-spectra analysis platform and then email the file to a server. Once the email was received by the server, it was automatically analysed with the gamma-spectrum software UniSampo/Shaman to perform radionuclide identification and activity calculation for a large number of gamma-spectra in a short period of time (less than 10 seconds per spectrum). The results of nuclide activity together with other spectrum parameters were saved into the Linssi database. This database contains a large amount of radionuclide information which is a valuable resource for the analysis of radionuclide distribution within the noble gas fission product emissions. The results could be useful to identify the specific mechanisms of the activity release. The isotopic signatures of the various radioxenon species can be determined as a function of release time. Comparison of 133mXe and 133Xe activity

  17. Studying the complex spectral line profiles in the spectra of hot emission stars and quasars .

    Science.gov (United States)

    Danezis, E.; Lyratzi, E.; Antoniou, A.; Popović, L. Č.; Dimitrijević, M. S.

    Some Hot Emission Stars and AGNs present peculiar spectral line profiles which are due to DACs and SACs phenomena. The origin and the mechanisms which are responsible for the creation of DACs/SACs is an important problem that has been studied by many researchers. This paper is a review of our efforts to study the origin and the mechanisms of these phenomena. At first we present a theoretic ad hoc picture for the structure of the plasma that surrounds the specific category of hot emission stars that present DACs or SACs. Then we present the mathematical model that we constructed, which is based on the properties of the above ad hoc theoretical structure. Finally, we present some results from our statistical studies that prove the consistency of our model with the classical physical theory.

  18. Investigation on the spatial evolution of the emission spectra in laser-induced Ni plasmas

    International Nuclear Information System (INIS)

    Du Chuanmei; Xu Ying; Zhang Mingxu

    2012-01-01

    In this paper, the spatial resolved emission spectrum of Ni atom in laser induced Ni plasma is measured in the wavelength region from 350 nm to 600 nm. The spatial evolution of the relative intensities and the Stark broadening of the 385.83 nm emission spectrum lines are also obtained. It is shown that Stark broadening and intensity of the spectrum lines increases firstly to its maximum and then de- creases along the direction of laser beam when the distance from the target surface is in the range from 0 to 2.5 mm. The maximum value of Stark broadening and relative intensity of the spectrum lines appear at 1.5 mm from the target surface. (authors)

  19. Theory of emission spectra from metal films irradiated by low energy electrons near normal incidence

    International Nuclear Information System (INIS)

    Kretschmann, E.; Callcott, T.A.; Arakawa, E.T.

    1980-01-01

    The emission spectrum produced by low energy electrons incident on a rough metal surface has been calculated for a roughness auto-correlation function containing a prominent peak at a high wave vector. For low energy electrons near normal incidence, the high wavevector peak dominates the roughness coupled surface plasmon radiation (RCSPR) process. The calculation yields estimates of the ratio of RCSPR to transition radiation, the dependence of emission intensity on electron energy and the shape and position of the RCSPR peak. The most interesting result is that the high-wavevector roughness can split the RCSPR radiation into peaks lying above and below the asymptotic surface plasma frequency. The results are compared with data from Ag in the following paper. (orig.)

  20. VizieR Online Data Catalog: Spectra of 7 Hα emission line stars in MBM 18 (Brand+ 2012)

    Science.gov (United States)

    Brand, J.; Wouterloot, J. G. A.; Magnani, L.

    2012-10-01

    Data in tabular form (wavelength and flux) are presented of the spectra of seven candidate Hα emission line stars in the direction of translucent cloud MBM 18. The data were obtained on 5 different nights in 2009 and 2010 with the 3.58-m Telescopio Nazionale Galileo (TNG; La Palma, Canary Islands, Spain). The spectra are shown in the appendix of the paper, only visible in the on line version. The spectra were taken with the low-resolution spectrograph DOLORES on the TNG, using long-slit spectroscopy. We used grism VHR-R, which covers a wavelength range of 6240-7720 Angstrom with a dispersion of 0.80Å/pix. The scale of the CCD detector is 0.252 arcsec/pixel. The observations were carried out with a slit width of 1 or 1.5 arcsec, depending on the seeing, resulting in a spectral resolution of 3.2Å and 4.8Å, respectively. To avoid problems with cosmic rays, 2 to 4 separate spectra per star were obtained. Two of the stars (Ha4 and Ha6) were observed simultaneously with another target (Ha1 and Ha5, respectively) by positioning the slit at an appropriate angle. The integration time was based on the brighter star in the slit, thus the signal-to-noise ratio for the other target is smaller than for the primary one. To allow absolute flux calibration the standard star Feige24 or Feige34 (for Ha5-Ha6) was observed immediately before or after the target observations, using the same instrumental setup as for the target observations. Flat-fielding was performed using 10 (5 for Ha5-Ha6) frames, which were uniformly illuminated by a halogen lamp. Wavelength calibration was performed using an arc-spectrum of an Ar, Ne+Hg, and Kr lamp, or a Ne+Hg (for Ha7) comparison lamp. A bias frame, to be subtracted from the other frames before analysis, was constructed from ten individual bias frames. Flat-, arc-, and bias-frames were obtained on the same day as the science observations and with the same instrumental setup. Data were reduced with the IRAF package. From all science frames a

  1. Dominant role of dielectron satellites in emission spectra of laser plasma near target surface

    International Nuclear Information System (INIS)

    Rozmej, F.; Faenov, A.Ya.; Pikuz, T.A.

    1997-01-01

    It is shown that satellite structures of resonance lines may become more intensive than resonance lines themselves. The experimental and theoretical studies show that the conditions whereby the satellite structures become predominant in the plasma emission spectrum, are sufficiently easily realized in the experiment and moreover they obviously will present typical cases by studies on the plasma condensed areas in the experiments on inertial thermonuclear synthesis and by investigation of plasma, created through pico- and femtosecond laser pulses of high contrast

  2. New method for measuring time-resolved spectra of lanthanide emission using square-wave excitation

    International Nuclear Information System (INIS)

    Qin, Feng; Zhao, Hua; Cai, Wei; Duan, Qianqian; Zhang, Zhiguo; Cao, Wenwu

    2013-01-01

    A method using modulated continuous wave (CW) visible laser to measure time-resolved fluorescence spectra of trivalent rare-earth ions has been developed. Electro-optic modulator was used to modulate the CW pumping laser with a rise time of 2 μs. CW Nd 3+ lasers were used as examples to present the method. Upconversion dynamic process of Ho 3+ was studied utilizing a 532 nm CW laser. Quantum cutting dynamic process from Tb 3+ to Yb 3+ was analyzed by a 473 nm CW laser. This method can be applied to any CW laser such as He-Ne laser, Ar + laser, Kr + laser, Ti:sapphire laser, etc

  3. High resolution emission spectra of H2 and D2 near 80 nm

    International Nuclear Information System (INIS)

    Larzilliere, M.; Roncin, J.-Y.; Launay, F.

    1980-01-01

    A few lines have been observed in the far ultraviolet emission spectrum of molecular hydrogen and deuterium. They are assigned to transitions from levels of the 3pπD 1 PIsub(u)sup(-) state, lying above the dissociation limit into H(ls) + H(n=2), near 84.5 nm, and, for some of them, above the first ionization limit near 80.4 nm, the lower state being X 1 Σsub(g)sup(+) (v''=1). This is in fair agreement with measured predissociation and preionization yields. Accurate line position measurements lead to molecular constants in very good agreement with theoretical calculations

  4. A comparison of experiment, CEPXS/ONETRAN, TIGERP, and TIGER net electron emission coefficients for various bremsstrahlung spectra

    International Nuclear Information System (INIS)

    Ballard, W.P.; Lorence, L.J. Jr.; Snowden, D.P.; Van Lint, V.A.J.; Beale, E.S.

    1987-01-01

    This work compares a carefully designed experiment to measure photoemission with the predictions of three different codes (CEPXS/ONETRAN, TIGERP, and TIGER) for the complex bremsstrahlung spectra typical of very intense pulsed power x-ray generators. The Monte Carlo codes TIGER and TIGERP can calculate the net photon-induced electron emission but accurate results may require that statistical error be minimized. CEPXS/ONETRAN is a new deterministic coupled electron/photon transport code that is faster than Monte Carlo and is not subject to statistical error. The comparison of net yields is a sensitive test of the relative accuracy and efficiency of these various codes. The authors find that all of the codes substantially agree with the experiments for the forward net yields. However, for reverse net yields from high-Z materials, the codes overpredict relative to measurements

  5. Theoretical emission line ratios for [Fe III] and [Fe VII] applicable to the optical and infrared spectra of gaseous nebulae.

    Science.gov (United States)

    Keenan, F P; Aller, L H; Ryans, R S; Hyung, S

    2001-08-14

    Recent calculations of electron impact excitation rates and Einstein A-coefficients for transitions among the 3d(6) levels of Fe III and among the 3d(2) levels of Fe VII are used to derive theoretical emission line ratios applicable to the optical and infrared spectra of gaseous nebulae. Results for [Fe III] are generated for electron temperatures T(e) = 7,000-20,000 K and densities N(e) = 10(2)-10(8) cm(-3), whereas those for [Fe VII] are provided for T(e) = 10,000-30,000 K and N(e) = 10(2)-10(8) cm(-3). The theoretical line ratios are significantly different in some instances from earlier calculations and resolve discrepancies between theory and observation found for the planetary nebulae IC 4997 and NGC 7027.

  6. The x-ray emission spectra of multicharged xenon ions in a gas puff laser-produced plasma

    Energy Technology Data Exchange (ETDEWEB)

    Skobelev, I.Yu.; Dyakin, V.M.; Faenov, A.Ya. [Multicharged Ion Spectra Data Center, VNIIFTRI, Mendeleevo (Russian Federation); Bartnik, A.; Fiedorowicz, H.; Jarocki, R.; Kostecki, J.; Szczurek, M. [Institute of Optoelectronics, Military University of Technology, Warsaw (Poland); Biemont, E. [Institut de Physique Nucleaire Experimentale, Universite de Liege, Liege (Belgium); Astrophysique et Spectroscopie, Universite de Mons-Hainaut, Mons (Belgium); Quinet, P. [Astrophysique et Spectroscopie, Universite de Mons-Hainaut, Mons (Belgium); Nilsen, J. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Behar, E.; Doron, R.; Mandelbaum, P.; Schwob, J.L. [Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem (Israel)

    1999-01-14

    Emission spectra of multicharged xenon ions produced by a laser gas puff are observed with high spectral resolution in the 8.5-9.5 and 17-19 A wavelength ranges. Three different theoretical methods are employed to obtain 3l-n'l'(n' = 4 to 10) wavelengths and Einstein coefficients for Ni-like Xe{sup 26+}. For the 3d-4p transitions, very good agreement is found between the experimental wavelengths and the various theoretical wavelengths. These accurate energy level measurements can be useful for studying the Ni-like xenon x-ray laser scheme. On the other hand, several intense spectral lines could not be identified as 3l-n'l' lines of Ni-like xenon, despite the very good agreement between the wavelengths and Einstein coefficients calculated for these transitions using the three different methods. (author)

  7. Emission lines of [K V] in the optical spectra of gaseous nebulae.

    Science.gov (United States)

    Keenan, Francis P; Aller, Lawrence H; Espey, Brian R; Exter, Katrina M; Hyung, Siek; Keenan, Michael T C; Pollacco, Don L; Ryans, Robert S I

    2002-04-02

    Recent R-matrix calculations of electron impact excitation rates in K v are used to derive the nebular emission line ratio R = I(4122.6 A)/I(4163.3 A) as a function of electron density (N(e)). This ratio is found to be very sensitive to changes in N(e) over the density range 10(3) to 10(6) cm(-3), but does not vary significantly with electron temperature, and hence in principle should provide an excellent optical N(e) diagnostic for the high-excitation zones of nebulae. The observed value of R for the planetary nebula NGC 7027, measured from a spectrum obtained with the Hamilton Echelle spectrograph on the 3-m Shane Telescope, implies a density in excellent agreement with that derived from [Ne iv], formed in the same region of the nebula as [K v]. This observation provides observational support for the accuracy of the theoretical [K v] line ratios, and hence the atomic data on which they are based. However, the analysis of a high-resolution spectrum of the symbiotic star RR Telescopii, obtained with the University College London Echelle Spectrograph on the 3.9-m Anglo-Australian Telescope, reveals that the [K v] 4122.6 A line in this object is badly blended with Fe ii 4122.6 A. Hence, the [K v] diagnostic may not be used for astrophysical sources that show a strong Fe ii emission line spectrum.

  8. Position Dependent Spontaneous Emission Spectra of a Λ-Type Atomic System Embedded in a Defective Photonic Crystal

    International Nuclear Information System (INIS)

    Entezar, S. Roshan

    2012-01-01

    We investigate the position dependent spontaneous emission spectra of a Λ-type three-level atom with one transition coupled to the free vacuum reservoir and the other one coupled to a double-band photonic band gap reservoir with a defect mode in the band gap. It is shown that, for the atom at the defect location, we have a two-peak spectrum with a wide dark line due to the strong coupling between the atom and the defect mode. While, when the atom is far from the defect location (or in the absence of the defect mode), the spectrum has three peaks with two dark lines due to the coupling between the atom and the photonic band gap reservoir with the largest density of states near the band edges. On the other hand, we have a four-peak spectrum for the atom at the space in between. Moreover, the average spontaneous emission spectra of the atoms uniformly embedded in high dielectric or low dielectric regions are described. It is shown that the atoms embedded in high (low) dielectric regions far from the defect location, effectively couple to the modes of the lower (upper) photonic band. However, the atoms embedded in high dielectric or low dielectric regions at the defect location, are coupled mainly to the defect modes. While, the atoms uniformly embedded in high (low) dielectric regions with a normal distance from the defect location, are coupled to both of defect and lower (upper) photonic band modes. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  9. Using violet laser-induced chlorophyll fluorescence emission spectra for crop yield assessment of cowpea (Vigna unguiculata (L) Walp) varieties

    Science.gov (United States)

    Anderson, Benjamin; Buah-Bassuah, Paul K.; Tetteh, Jonathan P.

    2004-07-01

    The use of violet laser-induced chlorophyll fluorescence (LICF) emission spectra to monitor the growth of five varieties of cowpea in the University of Cape Coast Botanical Garden is presented. Radiation from a continuous-wave violet laser diode emitting at 396 nm through a fibre is closely incident on in vivo leaves of cowpea to excite chlorophyll fluorescence, which is detected by an integrated spectrometer with CCD readout. The chlorophyll fluorescence spectra with peaks at 683 and 731 nm were used for growth monitoring of the cowpea plants over three weeks and analysed using Gaussian spectral functions with curve fitted parameters to determine the peak positions, area under the spectral curve and the intensity ratio F683/F731. The variation in the intensity ratio of the chlorophyll bands showed sensitive changes indicating the photosynthetic activity of the cowpea varieties. A discussion of the fluorescence result as compared to conventional assessment is presented with regard to discrimination between the cowpea varieties in terms of crop yield performance.

  10. Anomaly in the P- and R- branches in the spectra of hydrogen Fulcher band emission

    International Nuclear Information System (INIS)

    Kado, Shinichiro; Yamasaki, Daisuke; Iida, Yohei; Xiao Bingjia

    2004-01-01

    Anomalies in the Fulcher-band (d 3 Π u -a 3 Σ g + ) spectra, which are widely used for the purpose of measuring ro-vibronic structure of the hydrogen molecule, are investigated using the hollow cathode glow discharge of 230 V-70 mA at 30 Pa. By making use of the recently developed analyzing scheme and experimentally determined life-time of the state involved, the historical data in the Ginsburg and Dieke's publication are reanalyzed and compared with our present data. Populations of the vibronic state v' ≥ 4 in the Q branch can be corrected to a considerable extend by taking into account the lifetime of the states, while those of any v' in the P and R branches cannot. However, the average values of the upper-Fulcher populations deduced from the P and R branches coincide with those from Q branch by taking into consideration the difference in the excitation from the ground electronic state. (author)

  11. Investigation of the neutron emission spectra of some deformed nuclei for (n, xn) reactions up to 26 MeV energy

    International Nuclear Information System (INIS)

    Kaplan, A.; Bueyuekuslu, H.; Tel, E.; Aydin, A.; Boeluekdemir, M.H.

    2011-01-01

    In this study, neutron-emission spectra produced by (n, xn) reactions up to 26 MeV for some deformed target nuclei as 165 Ho, 181 Ta, 184 W, 232 Th and 238 U have been investigated. Also, the mean free path parameter's effect for 9n, xn) neutron-emission spectra has been examined. In the calculations, pre-equilibrium neutron-emission spectra have been calculated by using new evaluated hybrid model and geometry dependent hybrid model, full exciton model and cascade exciton model. The reaction equilibrium component has been calculated by Weisskopf-Ewing model. The obtained results have been discussed and compared with the available experimental data and found agreement with each other. (author)

  12. Ion temperatures in HIP-1 and SUMMA from charge-exchange neutral optical emission spectra

    Science.gov (United States)

    Patch, R. W.; Lauver, M. R.

    1976-01-01

    Ion temperatures were obtained from observations of the H sub alpha, D sub alpha, and He 587.6 nm lines emitted from hydrogen, deuterium, and helium plasmas in the SUMMA and HIP-1 mirror devices at Lewis Research Center. Steady state discharges were formed by applying a radially inward dc electric field between cylindrical or annular anodes and hollow cathodes located at the peaks of the mirrors. The ion temperatures were found from the Doppler broadening of the charge-exchange components of spectral lines. A statistical method was developed for obtaining scaling relations of ion temperature as a function of current, voltage, and magnetic flux density. Derivations are given that take into account triangular monochromator slit functions, loss cones, and superimposed charge-exchange processes. In addition, the Doppler broadening was found to be sensitive to the influence of drift on charge-exchange cross section. The effects of finite ion-cyclotron radius, cascading, and delayed emission are reviewed.

  13. Optical emission spectra of a copper plasma produced by a metal vapour vacuum arc plasma source

    International Nuclear Information System (INIS)

    Yotsombat, B.; Poolcharuansin, P.; Vilaithong, T.; Davydov, S.; Brown, I.G.

    2001-01-01

    Optical emission spectroscopy in the range 200-800 nm was applied for investigation of the copper plasma produced by a metal vapour vacuum arc plasma source. The experiments were conducted for the cases when the plasma was guided by straight and Ω-shaped curved solenoids as well as without solenoids, and also for different vacuum conditions. It was found that, besides singly- and doubly-charged ions, a relatively high concentration of excited neutral copper atoms was present in the plasma. The relative fraction of excited atoms was much higher in the region close to the cathode surface than in the plasma column inside the solenoid. The concentration of excited neutral, singly- and doubly-ionized atoms increased proportionally when the arc current was increased to 400 A. Some weak lines were attributed to more highly ionized copper species and impurities in the cathode material. (author)

  14. THE LOCAL DUST FOREGROUNDS IN THE MICROWAVE SKY. I. THERMAL EMISSION SPECTRA

    International Nuclear Information System (INIS)

    Dikarev, Valeri; Preuss, Oliver; Solanki, Sami; Krueger, Harald; Krivov, Alexander

    2009-01-01

    Analyses of the cosmic microwave background (CMB) radiation maps made by the Wilkinson Microwave Anisotropy Probe (WMAP) have revealed anomalies not predicted by the standard inflationary cosmology. In particular, the power of the quadrupole moment of the CMB fluctuations is remarkably low, and the quadrupole and octopole moments are aligned mutually and with the geometry of the solar system. It has been suggested in the literature that microwave sky pollution by an unidentified dust cloud in the vicinity of the solar system may be the cause for these anomalies. In this paper, we simulate the thermal emission by clouds of spherical homogeneous particles of several materials. Spectral constraints from the WMAP multi-wavelength data and earlier infrared observations on the hypothetical dust cloud are used to determine the dust cloud's physical characteristics. In order for its emissivity to demonstrate a flat, CMB-like wavelength dependence over the WMAP wavelengths (3 through 14 mm), and to be invisible in the infrared light, its particles must be macroscopic. Silicate spheres of several millimeters in size and carbonaceous particles an order of magnitude smaller will suffice. According to our estimates of the abundance of such particles in the zodiacal cloud and trans-Neptunian belt, yielding the optical depths of the order of 10 -7 for each cloud, the solar system dust can well contribute 10 μK (within an order of magnitude) in the microwaves. This is not only intriguingly close to the magnitude of the anomalies (about 30 μK), but also alarmingly above the presently believed magnitude of systematic biases of the WMAP results (below 5 μK) and, to an even greater degree, of the future missions with higher sensitivities, e.g., Planck.

  15. Observation of soft X-ray spectra from a Seyfert 1 and a narrow emission-line galaxy

    International Nuclear Information System (INIS)

    Singh, K.P.; Garmire, G.P.; Nousek, J.

    1985-01-01

    The 0.2-40 keV X-ray spectra of the Seyfert 1 galaxy Mrk 509 and the narrow emission-line galaxy NGC 2992 are analyzed. The results suggest the presence of a steep soft X-ray component in Mrk 509 in addition to the well-known Gamma = 1.7 component found in other active galactic nuclei in the 2-40 keV energy range. The soft X-ray component is interpreted as due to thermal emission from a hot gas, probably associated with the highly ionized gas observed to be outflowing from the galaxy. The X-ray spectrum of NGC 2992 does not show any steepening in the soft X-ray band and is consistent with a single power law (Gamma = 1.78) with very low absorbing column density of 4 x 10 to the 21st/sq cm. A model with partial covering of the nuclear X-ray source is preferred, however, to a simple model with a single power law and absorption. 34 references

  16. X-ray emission spectra of the plasma produced by an ultrashort laser pulse in cluster targets

    International Nuclear Information System (INIS)

    Stenz, C; Bagnoud, V; Blasco, F; Roche, J R; Salin, F; Faenov, A Ya; Skobelev, I Yu; Magunov, A I; Pikuz, T A

    2000-01-01

    The first observation of x-ray emission spectra of multiply charged ions in the plasma produced by a 35-fs laser pulse with an intensity up to 10 17 W cm -2 in CO 2 and Kr gas jet targets is reported. The emission in the wavelength ranges of the 1snp-1s 2 (n=3-6) transitions of O VII ions and the Ly α line of O VIII ions, as well as of the (2s 1/2 2p 6 3p 3/2 ) 1 -2s 2 2p 6 1 S 0 and (2s 1/2 2p 6 3p 1/2 ) 1 -2s 2 2p 6 1 S 0 lines of Ne-like KrXXVII ions testifies that the highly ionised plasma is formed by collision processes in clusters. Modelling the shape of the spectral lines of oxygen ions by including the principal mechanisms of broadening and absorption in optically dense plasmas reveals that the main contribution to the time-integrated intensity is made by the plasma with the parameters N e =(2-20)x10 20 cm -3 and T e =100 - 115 eV. (interaction of laser radiation with matter. laser plasma)

  17. Energy levels of 4f3 in the Nd3+ free ion from emission spectra

    International Nuclear Information System (INIS)

    Wyart, Jean-Francois; Meftah, Ali; Bachelier, Annik; Sinzelle, Jocelyne; Tchang-Brillet, Wan-Ue Lydia; Champion, Norbert; Spector, Nissan; Sugar, Jack

    2006-01-01

    The emission spectrum of neodymium produced by vacuum spark sources was observed in the vacuum ultraviolet on two normal-incidence spectrographs. In an initial result, more than 550 lines have been identified as transitions from 85 4f 2 5d levels to 37 levels of the 4f 3 ground configuration in the free ion Nd 3+ . The levels 4f 34 F 3/2 and 4 I 11/2 , responsible for the well-known 1064 nm laser line, have respective positions of 11 698.57 ±0.1 cm -1 and 1897.07 ±0.1 cm -1 above the ground level 4 I 9/2 . The newly found levels of 4f 3 constitute the first isolated 4f N configuration (N > 2) and therefore enable checks of effective parameters that represent far configuration interaction. Slater parameters F k (4f, 4f) derived from Nd 3+ :LaCl 3 are 3% to 5% smaller than in the free ion. (letter to the editor)

  18. Local moments and electronic correlations in Fe-based Heusler alloys: Kα x-ray emission spectra measurements

    International Nuclear Information System (INIS)

    Svyazhin, Artem; Kurmaev, Ernst; Shreder, Elena; Shamin, Sergey; Sahle, Christoph J.

    2016-01-01

    Heusler alloys are a property-rich class of materials, intensively investigated today from both theoretical and real-world application points of view. In this paper, we attempt to shed light on the role of electronic correlations in the Fe_2MeAl group (where Me represents all 3d elements from Ti to Ni) of Heusler alloys. For this purpose, we have investigated the local moments of iron by means of the x-ray emission spectroscopy technique. To obtain numerical values of local moments, the Kα-FWHM method has been employed for the first time. In every compound of the group, the presence of a local moment on the Fe atom was detected. As has been revealed, the values of these moments are temperature-independent, pointing to an insufficiency of a pure itinerant approach to magnetism in these alloys. We also comprehensively compare the usage of Kβ main lines and Kα spectra as tools for the probing of local moments and point out the significant advantages of the latter. - Highlights: • Local spin moments of iron in Fe_2MeAl (Me = Ti … Ni) Heusler alloys were investigated by means of x-ray emission spectroscopy. • Independence of the local moments from temperature confirms their localized nature. • A local moment value of iron in Fe_2MeAl raises with the atomic number of element Me. • The applicability of the Kα x-ray emission line for extracting local moment values of 3d elements was established.

  19. Signature of intermittent behavior in the emission spectra of target associated particles from 84Kr-AgBr interactions at 0.95 GeV/A

    International Nuclear Information System (INIS)

    Bhattacharjee, B.; Sengupta, S.; Mukhopadhyay, A.; Singh, V.

    2004-01-01

    In this report an attempt has been made to study, by studying the fluctuation in spatial distribution in χ(cosθ) space, the intermittent behaviour and fractal properties of emission spectra of fast and slow target associated particles from 84 Kr-AgBr interactions at 0.95 GeV/A

  20. [Study on Square Super-Lattice Pattern with Surface Discharge in Dielectric Barrier Discharge by Optical Emission Spectra].

    Science.gov (United States)

    Niu, Xue-jiao; Dong, Li-fang; Liu, Ying; Wang, Qian; Feng, Jian-yu

    2016-02-01

    Square super-lattice pattern with surface discharge consisting of central spots and dim spots is firstly observed in the mixture of argon and air by using a dielectric barrier discharge device with water electrodes. By observing the image, it is found that the central spot is located at the centriod of its surrounding four dim spots. The short-exposure image recorded by a high speed video camera shows that the dim spot results from the surface discharges (SDs). The brightness of the central spot and is quite different from that of the dim spot, which indicates that the plasma states of the central spot and the dim spot may be differentiated. The optical emission spectrum method is used to further study the several plasma parameters of the central spot and the dim spot in different argon content. The emission spectra of the N₂ second positive band (C³IIu --> B³ IIg) are measured, from which the molecule vibration temperatures of the central spot and the dim spot are calculated respectively. The broadening of spectral line 696.57 nm (2P₂-->1S₅) is used to study the electron densities of the central spot and the dim spot. It is found that the molecule vibration temperature and electron density of the dim spot are higher than those of the central spot in the same argon content The molecule vibration temperature and electron density of the central spot and the dim spot increase with the argon content increasing from 90% to 99.9%. The surface discharge induced by the volume discharge (VD) has the determinative effect on the formation of the dim spot The experimental results above play an important role in studying the formation mechanism of surface discharg&of square super-lattice pattern with surface discharge. In addition, the studies exert an influence on the application of surface discharge and volume discharge in different fields.

  1. A comparison of experiment, CEPXS/ONETRAN, TIGERP, and QUICKE2 net electron emission coefficients for various bremsstrahlung spectra

    International Nuclear Information System (INIS)

    Ballard, W.P.; Lorence, L.J. Jr.; Snowden, D.P.; van Lint, V.A.J.; Beale, E.S.

    1987-01-01

    This work compares a carefully designed experiment with the predictions of four different codes (CEPXS/ONETRAN, TIGERP, TIGER and QUICKE2) for the complex bremsstrahlung spectra typical of very intense pulsed power x-ray generators. Accurate calculation of net photon-induced electron emission yields at material interfaces using Monte Carlo codes can be particularly difficult if the forward and reverse partial yields are of similar magnitudes. In such a circumstance, the statistical error in the Monte Carlo solution (TIGER or TIGERP) must be kept to a minimum to accurately resolve the difference. CEPXS/ONETRAN is a new deterministic coupled electron/photon transport code that is faster than Monte Carlo and is not subject to statistical error. QUICKE2 evaluates an analytical approximation and is also much less expensive to run than the Monte Carlo codes. The comparison of net yields is a sensitive test of the relative accuracy and efficiency of these various codes. We find that all of the codes except QUICKE2 substantially agree with the experiments for the forward net yields. Howver, for reverse net yields from high-Z materials, all the codes overpredict relative to measurements

  2. Absolute, time-resolved emission of non-LTE L-shell spectra from Ti-doped aerogels

    International Nuclear Information System (INIS)

    Back, C.A.; Feldman, U.; Weaver, J.L.; Seely, J.F.; Constantin, C.; Holland, G.; Lee, R.W.; Chung, H.-K.; Scott, H.A.

    2006-01-01

    Outstanding discrepancies between data and calculations of laser-produced plasmas in recombination have been observed since the 1980s. Although improvements in hydrodynamic modeling may reduce the discrepancies, there are indications that non-LTE atomic kinetics may be the dominant cause. Experiments to investigate non-LTE effects were recently performed at the NIKE KrF laser on low-density Ti-doped aerogels. The laser irradiated a 2mm diameter, cylindrical sample of various lengths with a 4-ns square pulse to create a volumetrically heated plasma. Ti L-shell spectra spanning a range of 0.47-3keV were obtained with a transmission grating coupled to Si photodiodes. The diagnostic can be configured to provide 1-dimensional spatial resolution at a single photon energy, or 18 discrete energies with a resolving power, λ/δλ of 3-20. The data are examined and compared to calculations to develop absolute emission measurements that can provide new tests of the non-LTE physics

  3. Absolute, time-resolved emission of non-LTE L-shell spectra from Ti-doped aerogels

    Energy Technology Data Exchange (ETDEWEB)

    Back, C.A. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States)]. E-mail: tinaback@llnl.gov; Feldman, U. [Artep Inc. 2922 Excelsior Ct., Ellicott City, MD 21042 (United States); Weaver, J.L. [Naval Research Laboratory, 4555 Overlook Drive, SW, Washington DC 20375 (United States); Seely, J.F. [Naval Research Laboratory, 4555 Overlook Drive, SW, Washington DC 20375 (United States); Constantin, C. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States); Holland, G. [Naval Research Laboratory, 4555 Overlook Drive, SW, Washington DC 20375 (United States); Lee, R.W. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States); Chung, H.-K. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States); Scott, H.A. [Lawrence Livermore National Laboratory, P.O. Box 808, L-21, Livermore, CA 94551 (United States)

    2006-05-15

    Outstanding discrepancies between data and calculations of laser-produced plasmas in recombination have been observed since the 1980s. Although improvements in hydrodynamic modeling may reduce the discrepancies, there are indications that non-LTE atomic kinetics may be the dominant cause. Experiments to investigate non-LTE effects were recently performed at the NIKE KrF laser on low-density Ti-doped aerogels. The laser irradiated a 2mm diameter, cylindrical sample of various lengths with a 4-ns square pulse to create a volumetrically heated plasma. Ti L-shell spectra spanning a range of 0.47-3keV were obtained with a transmission grating coupled to Si photodiodes. The diagnostic can be configured to provide 1-dimensional spatial resolution at a single photon energy, or 18 discrete energies with a resolving power, {lambda}/{delta}{lambda} of 3-20. The data are examined and compared to calculations to develop absolute emission measurements that can provide new tests of the non-LTE physics.

  4. Plasma parameter diagnosis using hydrogen emission spectra of a quartz-chamber 2.45 GHz ECRIS at Peking University

    Science.gov (United States)

    Wu, WenBin; Ren, HaiTao; Peng, ShiXiang; Xu, Yuan; Wen, JiaMei; Zhang, Tao; Zhang, JingFeng; Zhang, AiLin; Sun, Jiang; Guo, ZhiYu; Chen, JiaEr

    2018-04-01

    A quartz-chamber 2.45 GHz electron cyclotron resonance ion source (ECRIS) was designed for diagnostic purposes at Peking University [Patent Number: ZL 201110026605.4]. This ion source can produce a maximum 84 mA hydrogen ion beam at 50 kV with a duty factor of 10%. The root-mean-square (RMS) emittance of this beam is less than 0.12π mm mrad. In our initial work, the electron temperature and electron density inside the plasma chamber had been measured with the line intensity ratio of noble gases. Based on these results, the atomic and molecular emission spectra of hydrogen were applied to determine the dissociation degree of hydrogen and the vibrational temperature of hydrogen molecules in the ground state, respectively. Measurements were performed at gas pressures from 4×10-4 to 1×10-3 Pa and at input peak RF power ranging from 1000 to 1800 W. The dissociation degree of hydrogen in the range of 0.5%-10% and the vibrational temperature of hydrogen molecules in the ground state in the range of 3500-8500 K were obtained. The plasma processes inside this ECRIS chamber were discussed based on these results.

  5. Diagnosis of lubricating oil by evaluating cyanide and carbon molecular emission lines in laser induced breakdown spectra

    Science.gov (United States)

    Elnasharty, I. Y.; Kassem, A. K.; Sabsabi, M.; Harith, M. A.

    2011-08-01

    To prevent engine failure it is essential to change lubricating oil regularly before it loses its protective properties. It is also necessary to monitor the physical and chemical conditions of the oil to reliably determine the optimum oil-change intervals. The present work focuses on studying evolution of the cyanide (CN) and carbon (C 2) molecular spectral emission lines in the laser induced breakdown spectra of lubricating oil as a function of its consumption. The intensities of these molecular bands have been taken as indicator of engine oil degradation at certain mileage. Furthermore, the percentage of decay of CN and C 2 integral intensity values at the corresponding mileage was calculated in order to relate it to the degree of consumption of the motor oil. Such percentage decay of the CN and C 2 integral intensities have been found to increase gradually with increasing mileage which is accompanied with increasing depletion of engine oil. The results of using LIBS technique in the present measurements proved that it is possible to have a direct, straightforward and easy method for prediction of lubricating oil degree of consumption. This may facilitate scheduling the proper time and/or mileage intervals for changing the oil to avoid any possibility of engine failure.

  6. Diagnosis of lubricating oil by evaluating cyanide and carbon molecular emission lines in laser induced breakdown spectra

    Energy Technology Data Exchange (ETDEWEB)

    Elnasharty, I.Y.; Kassem, A.K. [National Institute of Laser Enhanced Science, Cairo University (Egypt); Sabsabi, M. [National Research Council, Industrial Material Institute, Quebec (Canada); Harith, M.A., E-mail: mharithm@niles.edu.eg [National Institute of Laser Enhanced Science, Cairo University (Egypt)

    2011-08-15

    To prevent engine failure it is essential to change lubricating oil regularly before it loses its protective properties. It is also necessary to monitor the physical and chemical conditions of the oil to reliably determine the optimum oil-change intervals. The present work focuses on studying evolution of the cyanide (CN) and carbon (C{sub 2}) molecular spectral emission lines in the laser induced breakdown spectra of lubricating oil as a function of its consumption. The intensities of these molecular bands have been taken as indicator of engine oil degradation at certain mileage. Furthermore, the percentage of decay of CN and C{sub 2} integral intensity values at the corresponding mileage was calculated in order to relate it to the degree of consumption of the motor oil. Such percentage decay of the CN and C{sub 2} integral intensities have been found to increase gradually with increasing mileage which is accompanied with increasing depletion of engine oil. The results of using LIBS technique in the present measurements proved that it is possible to have a direct, straightforward and easy method for prediction of lubricating oil degree of consumption. This may facilitate scheduling the proper time and/or mileage intervals for changing the oil to avoid any possibility of engine failure.

  7. Diagnosis of lubricating oil by evaluating cyanide and carbon molecular emission lines in laser induced breakdown spectra

    International Nuclear Information System (INIS)

    Elnasharty, I.Y.; Kassem, A.K.; Sabsabi, M.; Harith, M.A.

    2011-01-01

    To prevent engine failure it is essential to change lubricating oil regularly before it loses its protective properties. It is also necessary to monitor the physical and chemical conditions of the oil to reliably determine the optimum oil-change intervals. The present work focuses on studying evolution of the cyanide (CN) and carbon (C 2 ) molecular spectral emission lines in the laser induced breakdown spectra of lubricating oil as a function of its consumption. The intensities of these molecular bands have been taken as indicator of engine oil degradation at certain mileage. Furthermore, the percentage of decay of CN and C 2 integral intensity values at the corresponding mileage was calculated in order to relate it to the degree of consumption of the motor oil. Such percentage decay of the CN and C 2 integral intensities have been found to increase gradually with increasing mileage which is accompanied with increasing depletion of engine oil. The results of using LIBS technique in the present measurements proved that it is possible to have a direct, straightforward and easy method for prediction of lubricating oil degree of consumption. This may facilitate scheduling the proper time and/or mileage intervals for changing the oil to avoid any possibility of engine failure.

  8. Research as a guide for curriculum development: An example from introductory spectroscopy. II. Addressing student difficulties with atomic emission spectra

    Science.gov (United States)

    Ivanjek, L.; Shaffer, P. S.; McDermott, L. C.; Planinic, M.; Veza, D.

    2015-02-01

    This is the second of two closely related articles (Paper I and Paper II) that together illustrate how research in physics education has helped guide the design of instruction that has proved effective in improving student understanding of atomic spectroscopy. Most of the more than 1000 students who participated in this four-year investigation were science majors enrolled in the introductory calculus-based physics course at the University of Washington (UW) in Seattle, WA, USA. The others included graduate and undergraduate teaching assistants at UW and physics majors in introductory and advanced physics courses at the University of Zagreb, Zagreb, Croatia. About half of the latter group were preservice high school physics teachers. Paper I describes how several conceptual and reasoning difficulties were identified among university students as they tried to relate a discrete line spectrum to the energy levels of atoms in a light source. This second article (Paper II) illustrates how findings from this research informed the development of a tutorial that led to improvement in student understanding of atomic emission spectra.

  9. DETECTION OF BROAD Hα EMISSION LINES IN THE LATE-TIME SPECTRA OF A HYDROGEN-POOR SUPERLUMINOUS SUPERNOVA

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Lin; Masci, F. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Quimby, R. [Department of Astronomy, San Diego State University, San Diego, CA 92182 (United States); Ofek, E.; Gal-Yam, A.; Vreeswijk, P. M.; Leloudas, G.; Cia, A. de; Yaron, O. [Department of Particle Physics and Astrophysics, Faculty of Physics, The Weizmann Institute of Science, Rehovot 76100 (Israel); Mazzali, P. [Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Perley, D. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Cenko, S. B. [Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771 (United States); Cao, Y.; Kulkarni, S. R. [Astronomy Department, California Institute of Technology, Pasadena, CA 91125 (United States); Nugent, P. E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Rebbapragada, Umaa D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Woźniak, P. R., E-mail: lyan@ipac.caltech.edu [Space and Remote Sensing, ISR-2, MS-B244 Los Alamos National Laboratory Los Alamos, NM 87545 (United States)

    2015-12-01

    iPTF13ehe is a hydrogen-poor superluminous supernova (SLSN) at z = 0.3434, with a slow-evolving light curve and spectral features similar to SN2007bi. It rises in 83–148 days to reach a peak bolometric luminosity of ∼1.3 × 10{sup 44} erg s{sup −1}, then decays slowly at 0.015 mag day{sup −1}. The measured ejecta velocity is ∼ 13,000 km s{sup −1}. The inferred explosion characteristics, such as the ejecta mass (70–220 M{sub ⊙}), and the total radiative and kinetic energy (E{sub rad} ∼ 10{sup 51} erg, E{sub kin} ∼ 2 × 10{sup 53} erg), are typical of slow-evolving H-poor SLSN events. However, the late-time spectrum taken at +251 days (rest, post-peak) reveals a Balmer Hα emission feature with broad and narrow components, which has never been detected before among other H-poor SLSNe. The broad component has a velocity width of ∼4500 km s{sup −1} and a ∼300 km s{sup −1} blueward shift relative to the narrow component. We interpret this broad Hα emission with a luminosity of ∼2 × 10{sup 41} erg s{sup −1} as resulting from the interaction between the supernova ejecta and a discrete H-rich shell, located at a distance of ∼4 × 10{sup 16} cm from the explosion site. This interaction causes the rest-frame r-band LC to brighten at late times. The fact that the late-time spectra are not completely absorbed by the shock-ionized H-shell implies that its Thomson scattering optical depth is likely ≤1, thus setting upper limits on the shell mass ≤30 M{sub ⊙}. Of the existing models, a Pulsational Pair Instability supernova model can naturally explain the observed 30 M{sub ⊙} H-shell, ejected from a progenitor star with an initial mass of (95–150) M{sub ⊙} about 40 years ago. We estimate that at least ∼15% of all SLSNe-I may have late-time Balmer emission lines.

  10. State-of-the art comparability of corrected emission spectra. 2. Field laboratory assessment of calibration performance using spectral fluorescence standards.

    Science.gov (United States)

    Resch-Genger, Ute; Bremser, Wolfram; Pfeifer, Dietmar; Spieles, Monika; Hoffmann, Angelika; DeRose, Paul C; Zwinkels, Joanne C; Gauthier, François; Ebert, Bernd; Taubert, R Dieter; Voigt, Jan; Hollandt, Jörg; Macdonald, Rainer

    2012-05-01

    In the second part of this two-part series on the state-of-the-art comparability of corrected emission spectra, we have extended this assessment to the broader community of fluorescence spectroscopists by involving 12 field laboratories that were randomly selected on the basis of their fluorescence measuring equipment. These laboratories performed a reference material (RM)-based fluorometer calibration with commercially available spectral fluorescence standards following a standard operating procedure that involved routine measurement conditions and the data evaluation software LINKCORR developed and provided by the Federal Institute for Materials Research and Testing (BAM). This instrument-specific emission correction curve was subsequently used for the determination of the corrected emission spectra of three test dyes, X, QS, and Y, revealing an average accuracy of 6.8% for the corrected emission spectra. This compares well with the relative standard uncertainties of 4.2% for physical standard-based spectral corrections demonstrated in the first part of this study (previous paper in this issue) involving an international group of four expert laboratories. The excellent comparability of the measurements of the field laboratories also demonstrates the effectiveness of RM-based correction procedures.

  11. DISCOVERY OF RUBIDIUM, CADMIUM, AND GERMANIUM EMISSION LINES IN THE NEAR-INFRARED SPECTRA OF PLANETARY NEBULAE

    Energy Technology Data Exchange (ETDEWEB)

    Sterling, N. C. [Department of Physics, University of West Georgia, 1601 Maple Street, Carrollton, GA 30118 (United States); Dinerstein, Harriet L.; Kaplan, Kyle F. [Department of Astronomy, University of Texas, 2515 Speedway, C1400, Austin, TX 78712-1205 (United States); Bautista, Manuel A., E-mail: nsterlin@westga.edu, E-mail: harriet@astro.as.utexas.edu, E-mail: kfkaplan@astro.as.utexas.edu, E-mail: manuel.bautista@wmich.edu [Department of Physics, Western Michigan University, Kalamazoo, MI 49008 (United States)

    2016-03-01

    We identify [Rb iv] 1.5973 and [Cd iv] 1.7204 μm emission lines in high-resolution (R = 40,000) near-infrared spectra of the planetary nebulae (PNe) NGC 7027 and IC 5117, obtained with the Immersion GRating INfrared Spectrometer (IGRINS) on the 2.7 m telescope at McDonald Observatory. We also identify [Ge vi] 2.1930 μm in NGC 7027. Alternate identifications for these features are ruled out based on the absence of other multiplet members and/or transitions with the same upper levels. Ge, Rb, and Cd can be enriched in PNe by s-process nucleosynthesis during the asymptotic giant branch stage of evolution. To determine ionic abundances, we calculate [Rb iv] collision strengths and use approximations for those of [Cd iv] and [Ge vi]. Our identification of [Rb iv] 1.5973 μm is supported by the agreement between Rb{sup 3+}/H{sup +} abundances found from this line and the 5759.55 Å feature in NGC 7027. Elemental Rb, Cd, and Ge abundances are derived with ionization corrections based on similarities in ionization potential ranges between the detected ions and O and Ne ionization states. Our analysis indicates abundances 2–4 times solar for Rb and Cd in both nebulae. Ge is subsolar in NGC 7027, but its abundance is uncertain due to the large and uncertain ionization correction. The general consistency of the measured relative s-process enrichments with predictions from models appropriate for these PNe (2.0–2.5 M{sub ⊙}, [Fe/H] = −0.37) demonstrates the potential of using PN compositions to test s-process nucleosynthesis models.

  12. Non-intrusive measurement of emission indices. A new approach to the evaluation of infrared spectra emitted by aircraft engine exhaust gases

    Energy Technology Data Exchange (ETDEWEB)

    Lindermeir, E.; Haschberger, P.; Tank, V. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Optoelektronik

    1997-12-31

    A non-intrusive method is used to determine the emission indices of a research aircraft`s engine in-flight. The principle is based on the Fourier Transform Infrared Spectrometer MIROR which was specifically designed and built for operation aboard aircrafts. This device measures the spectrum of the infrared radiation emitted by the hot exhaust gas under cruise conditions. From these spectra mixing ratios and emission indices can be derived. An extension to previously applied evaluation schemes is proposed: Whereas formerly the plume was assumed a homogeneous layer of gas, temperature and concentration profiles are now introduced to the evaluation procedure. (author) 5 refs.

  13. Revealing discriminating power of the elements in edible sea salts: Line-intensity correlation analysis from laser-induced plasma emission spectra

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yonghoon, E-mail: yhlee@mokpo.ac.kr [Department of Chemistry, Mokpo National University, Jeonnam 534-729 (Korea, Republic of); Ham, Kyung-Sik [Department of Food Engineering, Mokpo National University, Jeonnam 534-729 (Korea, Republic of); Han, Song-Hee [Division of Maritime Transportation System, Mokpo National Maritime University, Jeonnam 530-729 (Korea, Republic of); Yoo, Jonghyun, E-mail: jyoo@appliedspectra.com [Applied Spectra, Inc., 46665 Fremont Boulevard, Fremont, CA 94538 (United States); Jeong, Sungho [School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

    2014-11-01

    We have investigated the discriminating power of the elements in edible sea salts using Laser-Induced Breakdown Spectroscopy (LIBS). For the ten different sea salts from South Korea, China, Japan, France, Mexico and New Zealand, LIBS spectra were recorded in the spectral range between 190 and 1040 nm, identifying the presence of Na, Cl, K, Ca, Mg, Li, Sr, Al, Si, Ti, Fe, C, O, N, and H. Intensity correlation analysis of the observed emission lines provided a valuable insight into the discriminating power of the different elements in the sea salts. The correlation analysis suggests that the elements with independent discrimination power can be categorized into three groups; those that represent dissolved ions in seawater (K, Li, and Mg), those that are associated with calcified particles (Ca and Sr), and those that are present in soils contained in the sea salts (Al, Si, Ti, and Fe). Classification models using a few emission lines selected based on the results from intensity correlation analysis and full broadband LIBS spectra were developed based on Principal Component Analysis (PCA) and Partial Least Squares-Discriminant Analysis (PLS-DA) and their performances were compared. Our results indicate that effective combination of a few emission lines can provide a dependable model for discriminating the edible sea salts and the performance is not much degraded from that based on the full broadband spectra. This can be rationalized by the intensity correlation results. - Highlights: • Broadband LIBS spectra of various edible sea salts were obtained. • Intensity correlation of emission lines of the elements in edible sea salts was analyzed. • The elements were categorized into three groups with independent discriminating power. • The effective combination of a few lines can provide dependable classification models.

  14. Signature of intermittent behavior in the emission spectra of target associated particles from 84Kr-AgBr interactions at 0.95 GeV/A

    International Nuclear Information System (INIS)

    Bhattacharjee, B.

    2005-01-01

    Intermittency and fractal behavior have been studied for emission spectra of target associated fast and slow particles from 84 Kr-AgBr interactions at 0.95 GeV/A. Intermittent behavior is observed for both knocked out and slow target fragments. In both the cases anomalous dimensions are seen to increase with the order of moments thereby indicating the association of multifractility with production mechanism of both fast and slow target associated particles

  15. Spectra of alkali atoms

    International Nuclear Information System (INIS)

    Santoso, Budi; Arumbinang, Haryono.

    1981-01-01

    Emission spectra of alkali atoms has been determined by using spectrometer at the ultraviolet to infra red waves range. The spectra emission can be obtained by absorption spectrophotometric analysis. Comparative evaluations between experimental data and data handbook obtained by spark method were also presented. (author tr.)

  16. DFT study of electron absorption and emission spectra of pyramidal LnPc(OAc) complexes of some lanthanide ions in the solid state

    Science.gov (United States)

    Hanuza, J.; Godlewska, P.; Lisiecki, R.; Ryba-Romanowski, W.; Kadłubański, P.; Lorenc, J.; Łukowiak, A.; Macalik, L.; Gerasymchuk, Yu.; Legendziewicz, J.

    2018-05-01

    The electron absorption and emission spectra were measured for the pyramidal LnPc(OAc) complexes in the solid state and co-doped in silica glass, where Ln = Er, Eu and Ho. The theoretical electron spectra were determined from the quantum chemical DFT calculation using four approximations CAM-B3LYP/LANL2DZ, CAM-B3LYP/CC-PVDZ, B3LYP/LANL2DZ and B3LYP/CC-PVDZ. It was shown that the best agreement between the calculated and experimental structural parameters and spectroscopic data was reached for the CAM-B3LYP/LANL2DZ model. The emission spectra were measured using the excitations both in the ligand and lanthanide absorption ranges. The possibility of energy transfer between the phthalocyanine ligand and excited states of lanthanide ions was discussed. It was shown that the back energy transfer from metal states to phthalocyanine state is responsible for the observed emission of the studied complexes both in the polycrystalline state and silica glass.

  17. Correcting for variable laser-target distances of laser-induced breakdown spectroscopy measurements with ChemCam using emission lines of Martian dust spectra

    Energy Technology Data Exchange (ETDEWEB)

    Melikechi, N.; Mezzacappa, A. [Optical Science Center for Applied Research, Delaware State University, Dover, DE (United States); Cousin, A.; Lanza, N.L. [Los Alamos National Laboratory, Los Alamos, NM (United States); Lasue, J. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Clegg, S.M. [Los Alamos National Laboratory, Los Alamos, NM (United States); Berger, G. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Wiens, R.C. [Los Alamos National Laboratory, Los Alamos, NM (United States); Maurice, S. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Tokar, R.L.; Bender, S. [Planetary Science Institute, Flagstaff, AZ (United States); Forni, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Breves, E.A.; Dyar, M.D. [Dept. of Astronomy, Mount Holyoke College, South Hadley, MA (United States); Frydenvang, J. [The Niels Bohr Institute, University of Copenhagen, Copenhagen (Denmark); Delapp, D. [Los Alamos National Laboratory, Los Alamos, NM (United States); Gasnault, O. [Institut de Recherche en Astophysique et Planetologie (IRAP), Universite' Paul Sabatier, Toulouse (France); Newsom, H.; Ollila, A.M. [Earth and Planetary Sciences, University of New Mexico, Alburquerque, NM (United States); Lewin, E. [Institut des Sciences de la Terre, Universite Grenoble l-CNRS, Grenoble (France); and others

    2014-06-01

    As part of the Mars Science Laboratory, the ChemCam instrument acquires remote laser induced breakdown spectra at distances that vary between 1.56 m and 7 m. This variation in distance affects the intensities of the measured LIBS emission lines in non-trivial ways. To determine the behavior of a LIBS emission line with distance, it is necessary to separate the effects of many parameters such as laser energy, laser spot size, target homogeneity, and optical collection efficiency. These parameters may be controlled in a laboratory on Earth but for field applications or in space this is a challenge. In this paper, we show that carefully selected ChemCam LIBS emission lines acquired from the Martian dust can be used to build an internal proxy spectroscopic standard. This in turn, allows for a direct measurement of the effects of the distance of various LIBS emission lines and hence can be used to correct ChemCam LIBS spectra for distance variations. When tested on pre-launch LIBS calibration data acquired under Martian-like conditions and with controlled and well-calibrated targets, this approach yields much improved agreement between targets observed at various distances. This work lays the foundation for future implementation of automated routines to correct ChemCam spectra for differences caused by variable distance. - Highlights: • Selected Martian dust emission lines are used to correct for variable laser-target distances. • The correction model yields improved agreement between targets observed at various distances. • The impact of the model reduces the bias between predicted and actual compositions by as much as 70%. • When implemented, the model will yield spectral corrections for various ChemCam measurements. • This work is a foundation to perform novel stand-off LIBS measurements on Earth and other planets.

  18. Extracting ion emission lines from femtosecond-laser plasma x-ray spectra heavily contaminated by spikes

    International Nuclear Information System (INIS)

    Gasilov, S. V.; Faenov, A. Ya.; Pikuz, T. A.; Villoresi, P.; Poletto, L.; Stagira, S.; Calegari, F.; Vozzi, C.; Nisoli, M.

    2007-01-01

    Nowadays charged-coupled device (CCD) detectors are widely used for the registration of multicharged ions x-ray spectra. These spectra are generated in a plasma during interaction of ultrashort, ultraintense laser pulses with solid targets. Strong parasitic radiation from the plasma affects CCD detectors and contaminates resulting spectra, so that spectral features can be completely covered by noise even during measurements with a very short accumulation time. In this work we propose a ''mean to median'' (M2M) algorithm for noise suppression in femtosecond laser plasma x-ray spectra. Series of spectra is necessary for the identification of corrupted data points by the developed method. The algorithm was tested with model spectra which reflect main features of experimental data. In practice we used it for extracting information about spectral lines of Ne-like Fe ions and He-like Al ions which allowed us to calculate plasma parameters. It is demonstrated that M2M method is able to clean spectra with more than 10% of corrupted pixels. Fluctuations in intensity of spectral lines induced by laser instability do not affect validity of the proposed method

  19. The characteristics of the IR emission features in the spectra of Herbig Ae stars : evidence for chemical evolution

    NARCIS (Netherlands)

    Boersma, C.; Bouwman, J.; Lahuis, F.; van Kerckhoven, C.; Tielens, A. G. G. M.; Waters, L. B. F. M.; Henning, T.

    Context. Infrared ( IR) spectra provide a prime tool to study the characteristics of polycyclic aromatic hydrocarbon ( PAH) molecules in regions of star formation. Herbig Ae/Be stars are a class of young pre-main sequence stellar objects of intermediate mass. They are known to have varying amounts

  20. Downwelling Far-Infrared Emission Spectra Measured By First at Cerro Toco, Chile and Table Mountain, California

    Science.gov (United States)

    Mast, J. C.; Mlynczak, M. G.; Cageao, R.; Kratz, D. P.; Johnson, D. G.; Mlawer, E. J.; Turner, D. D.

    2014-12-01

    The Far-Infrared Spectroscopy of the Troposphere (FIRST) instrument is a Fourier transform spectrometer developed to measure the important far-infrared spectrum between 100 and 650 cm-1. Presented here are measurements made by FIRST during two successful deployments in a ground-based configuration to measure downwelling longwave radiation at Earth's surface. The initial deployment was to Cerro Toco, Chile, where FIRST operated from August to October, 2009 as part of the Radiative Heating in Underexplored Bands Campaign (RHUBC-II) campaign. After recalibration, FIRST was deployed to the Table Mountain Facility from September through October, 2012. Spectra observed at each location are substantially different, due in large part to the order of magnitude difference in integrated precipitable water vapor (0.3 cm at Table Mountain, 0.03 cm at Cerro Toco). Dry days for both campaigns are chosen for analysis - 09/24/2009 and 10/19/2012. Also available during both deployments are coincident radiosonde temperature and water vapor vertical profiles which are used as inputs a line-by-line radiative transfer program. Comparisons between measured and modeled spectra are presented over the 200 to 800 cm-1 range. An extensive error analysis of both the measured and modeled spectra is presented. In general, the differences between the measured and modeled spectra are within their combined uncertainties.

  1. Observation of forbidden (E2) lines in the ultraviolet spectra of Ca II, Sr II, and Ba II by inductively coupled plasma emission spectroscopy

    International Nuclear Information System (INIS)

    Doidge, Peter S.

    2013-01-01

    Forbidden (electric quadrupole, E2) transitions of the type ns 2 S 1/2 –nd 2 D 3/2 and ns 2 S 1/2 –nd 2 D 5/2 in the ultraviolet spectra of singly ionized Ca, Sr, and Ba (with n = 4, 5 or 6 for Ca, Sr, and Ba, respectively) have been observed in the emission spectrum of an inductively coupled argon plasma. Wavelengths and wavenumbers of the six lines are reported and the values are in good agreement with those expected from literature data for the energy levels involved. - Highlights: • Wavelengths measured using commercially available ICP emission spectrometer • First wavelength and wavenumber measurements of some E2 lines of Ba +, Ca +, Sr + • Evidence for small plasma shifts in the wavenumbers of Ba + and Sr +

  2. The Equilibrium and Pre-equilibrium Triton Emission Spectra of Some Target Nuclei for ( n, xt) Reactions up to 45 MeV Energy

    Science.gov (United States)

    Tel, E.; Kaplan, A.; Aydın, A.; Özkorucuklu, S.; Büyükuslu, H.; Yıldırım, G.

    2010-08-01

    Although there have been significant research and development studies on the inertial and magnetic fusion reactor technology, there is still a long way to go to penetrate commercial fusion reactors to the energy market. Tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So, working out the systematics of ( n,t) reaction cross sections and triton emission differential data are important for the given reaction taking place on various nuclei at different energies. In this study, ( n,xt) reactions for some target nuclei as 16O, 27Al, 59Co and 209Bi have been investigated up to 45 MeV incident neutron energy. In the calculations of the triton emission spectra, the pre-equilibrium and equilibrium effects have been used. The calculated results have been compared with the experimental data taken from the literature.

  3. The influence of visible light and inorganic pigments on fluorescence excitation emission spectra of egg-, casein- and collagen-based painting media

    Science.gov (United States)

    Nevin, A.; Anglos, D.; Cather, S.; Burnstock, A.

    2008-07-01

    Spectrofluorimetric analysis of proteinaceous binding media is particularly promising because proteins employed in paintings are often fluorescent and media from different sources have significantly different fluorescence spectral profiles. Protein-based binding media derived from eggs, milk and animal tissue have been used for painting and for conservation, but their analysis using non-destructive techniques is complicated by interferences with pigments, their degradation and their low concentration. Changes in the fluorescence excitation emission spectra of films of binding media following artificial ageing to an equivalent of 50 and 100 years of museum lighting include the reduction of bands ascribed to tyrosine, tryptophan and Maillard reaction products and an increase in fluorescent photodegradation. Fluorescence of naturally aged paint is dependent on the nature of the pigment present and, with egg-based media, in comparison with un-pigmented films, emissions ascribed to amino acids are more pronounced.

  4. Gamma-Ray Emission Spectra as a Constraint on Calculations of 234,236,238U Neutron-Capture Cross Sections

    Energy Technology Data Exchange (ETDEWEB)

    Ullmann, John Leonard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kawano, Toshihiko [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bredeweg, Todd Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Baramsai, Bayarbadrakh [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Couture, Aaron Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Haight, Robert Cameron [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Jandel, Marian [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mosby, Shea Morgan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); O' Donnell, John M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rundberg, Robert S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Vieira, David J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wilhelmy, Jerry B. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Becker, John A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wu, Ching-Yen [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Krticka, Milan [Charles Univ., Prague (Czech Republic)

    2015-05-28

    Neutron capture cross sections in the “continuum” region (>≈1 keV) and gamma-emission spectra are of importance to basic science and many applied fields. Careful measurements have been made on most common stable nuclides, but physicists must rely on calculations (or “surrogate” reactions) for rare or unstable nuclides. Calculations must be benchmarked against measurements (cross sections, gamma-ray spectra, and <Γγ>). Gamma-ray spectrum measurements from resolved resonances were made with 1 - 2 mg/cm2 thick targets; cross sections at >1 keV were measured using thicker targets. The results show that the shape of capture cross section vs neutron energy is not sensitive to the form of the strength function (although the magnitude is); the generalized Lorentzian E1 strength function is not sufficient to describe the shape of observed gamma-ray spectra; MGLO + “Oslo M1” parameters produces quantitative agreement with the measured 238U(n,γ) cross section; additional strength at low energies (~ 3 MeV) -- likely M1-- is required; and careful study of complementary results on low-lying giant resonance strength is needed to consistently describe observations.

  5. Using Lava Tube Skylight Thermal Emission Spectra to Determine Lava Composition on Io: Quantitative Constraints for Observations by Future Missions to the Jovian System.

    Science.gov (United States)

    Davies, A. G.

    2008-12-01

    Deriving the composition of Io's dominant lavas (mafic or ultramafic?) is a major objective of the next missions to the jovian system. The best opportunities for making this determination are from observations of thermal emission from skylights, holes in the roof of a lava tube through which incandescent lava radiates, and Io thermal outbursts, where lava fountaining is taking place [1]. Allowing for lava cooling across the skylight, the expected thermal emission spectra from skylights of different sizes have been calculated for laminar and turbulent tube flow and for mafic and ultramafic composition lavas. The difference between the resulting mafic and ultramafic lava spectra has been quantified, as has the instrument sensitivity needed to acquire the necessary data to determine lava eruption temperature, both from Europa orbit and during an Io flyby. A skylight is an excellent target to observe lava that has cooled very little since eruption (California Institute of Technology, under contract to NASA. AGD is supported by a grant from the NASA OPR Program. References: [1] Davies, A. G., 1996, Icarus, 124, 45-61. [2] Keszthelyi, L., et al., 2006, JGS, 163, 253-264. [3] Davies, A. G., 2007, Volcanism on Io, Cambridge University Press. [4] Keszthelyi, L., et al., 2007, Icarus, 192, 491-502. [5] Davies, A. G., et al., 2006, Icarus, 184, 460-477.

  6. Detailed analysis of hollow ions spectra from dense matter pumped by X-ray emission of relativistic laser plasma

    International Nuclear Information System (INIS)

    Hansen, S. B.; Colgan, J.; Abdallah, J.; Faenov, A. Ya.; Pikuz, S. A.; Skobelev, I. Yu.; Wagenaars, E.; Culfa, O.; Dance, R. J.; Tallents, G. J.; Rossall, A. K.; Woolsey, N. C.; Booth, N.; Lancaster, K. L.; Evans, R. G.; Gray, R. J.; McKenna, P.; Kaempfer, T.; Schulze, K. S.; Uschmann, I.

    2014-01-01

    X-ray emission from hollow ions offers new diagnostic opportunities for dense, strongly coupled plasma. We present extended modeling of the x-ray emission spectrum reported by Colgan et al. [Phys. Rev. Lett. 110, 125001 (2013)] based on two collisional-radiative codes: the hybrid-structure Spectroscopic Collisional-Radiative Atomic Model (SCRAM) and the mixed-unresolved transition arrays (MUTA) ATOMIC model. We show that both accuracy and completeness in the modeled energy level structure are critical for reliable diagnostics, investigate how emission changes with different treatments of ionization potential depression, and discuss two approaches to handling the extensive structure required for hollow-ion models with many multiply excited configurations

  7. The 3D-HST Survey: Hubble Space Telescope WFC3/G141 Grism Spectra, Redshifts, and Emission Line Measurements for ~ 100,000 Galaxies

    Science.gov (United States)

    Momcheva, Ivelina G.; Brammer, Gabriel B.; van Dokkum, Pieter G.; Skelton, Rosalind E.; Whitaker, Katherine E.; Nelson, Erica J.; Fumagalli, Mattia; Maseda, Michael V.; Leja, Joel; Franx, Marijn; Rix, Hans-Walter; Bezanson, Rachel; Da Cunha, Elisabete; Dickey, Claire; Förster Schreiber, Natascha M.; Illingworth, Garth; Kriek, Mariska; Labbé, Ivo; Ulf Lange, Johannes; Lundgren, Britt F.; Magee, Daniel; Marchesini, Danilo; Oesch, Pascal; Pacifici, Camilla; Patel, Shannon G.; Price, Sedona; Tal, Tomer; Wake, David A.; van der Wel, Arjen; Wuyts, Stijn

    2016-08-01

    We present reduced data and data products from the 3D-HST survey, a 248-orbit HST Treasury program. The survey obtained WFC3 G141 grism spectroscopy in four of the five CANDELS fields: AEGIS, COSMOS, GOODS-S, and UDS, along with WFC3 H 140 imaging, parallel ACS G800L spectroscopy, and parallel I 814 imaging. In a previous paper, we presented photometric catalogs in these four fields and in GOODS-N, the fifth CANDELS field. Here we describe and present the WFC3 G141 spectroscopic data, again augmented with data from GO-1600 in GOODS-N (PI: B. Weiner). We developed software to automatically and optimally extract interlaced two-dimensional (2D) and one-dimensional (1D) spectra for all objects in the Skelton et al. (2014) photometric catalogs. The 2D spectra and the multi-band photometry were fit simultaneously to determine redshifts and emission line strengths, taking the morphology of the galaxies explicitly into account. The resulting catalog has redshifts and line strengths (where available) for 22,548 unique objects down to {{JH}}{IR}≤slant 24 (79,609 unique objects down to {{JH}}{IR}≤slant 26). Of these, 5459 galaxies are at z\\gt 1.5 and 9621 are at 0.7\\lt z\\lt 1.5, where Hα falls in the G141 wavelength coverage. The typical redshift error for {{JH}}{IR}≤slant 24 galaxies is {σ }z≈ 0.003× (1+z), I.e., one native WFC3 pixel. The 3σ limit for emission line fluxes of point sources is 2.1× {10}-17 erg s-1 cm-2. All 2D and 1D spectra, as well as redshifts, line fluxes, and other derived parameters, are publicly available.18

  8. Investigating the flow dynamics and chemistry of an expanding thermal plasma through CH(A-X) emission spectra

    NARCIS (Netherlands)

    Hansen, T. A. R.; Colsters, P. G. J.; M. C. M. van de Sanden,; Engeln, R.

    2011-01-01

    The gas flow in a linear plasma reactor and the plasma chemistry during hydrogenated amorphous carbon and graphite etching are investigated via time and spatially resolved measurements of the ion density and CH emission. A convolution of the ion and hydrocarbon density shows the importance of charge

  9. Analysis of energy transfer process based emission spectra of erbium doped germanate glasses for mid-infrared laser materials

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Muzhi; Wei, Tao; Zhou, Beier; Tian, Ying; Zhou, Jiajia; Xu, Shiqing, E-mail: shiqingxu@cjlu.edu.cn; Zhang, Junjie, E-mail: jjzhang@cjlu.edu.cn

    2015-03-25

    Highlights: • Er{sup 3+} doped germanate glass with good thermal stability were prepared. • Ionic boding nature was proved by bonding parameter calculation. • Mid-infrared fluorescent behaviors and energy transfer were investigated. • Rate equation and Dexter’s theory were utilized to elucidate 2.7 μm emission. - Abstract: Er{sup 3+} activated germanate glass with good thermal stability was prepared. Bonding parameters have been calculated and the nature of ionic bonding of the germanate glass has been determined. Mid-infrared fluorescence was observed and corresponding radiative properties were investigated. For Er{sup 3+}:{sup 4}I{sub 11/2}→{sup 4}I{sub 13/2} transition, high spontaneous radiative transition probability (30.09 s{sup −1}), large emission cross section ((14.84 ± 0.10) × 10{sup −21} cm{sup 2}) and superior gain performance were obtained from the prepared glass. Besides, energy transfer processes concerning the 2.7 μm emission were also discussed in detail. According to simplified rate equation and Dexter’s theory, energy transfer microscopic parameters were computed to elucidate observed 2.7 μm emissions. Results demonstrate that the prepared germanate glass possessing excellent spectroscopic properties might be an attractive candidate for mid-infrared laser or amplifier.

  10. Analysis of energy transfer process based emission spectra of erbium doped germanate glasses for mid-infrared laser materials

    International Nuclear Information System (INIS)

    Cai, Muzhi; Wei, Tao; Zhou, Beier; Tian, Ying; Zhou, Jiajia; Xu, Shiqing; Zhang, Junjie

    2015-01-01

    Highlights: • Er 3+ doped germanate glass with good thermal stability were prepared. • Ionic boding nature was proved by bonding parameter calculation. • Mid-infrared fluorescent behaviors and energy transfer were investigated. • Rate equation and Dexter’s theory were utilized to elucidate 2.7 μm emission. - Abstract: Er 3+ activated germanate glass with good thermal stability was prepared. Bonding parameters have been calculated and the nature of ionic bonding of the germanate glass has been determined. Mid-infrared fluorescence was observed and corresponding radiative properties were investigated. For Er 3+ : 4 I 11/2 → 4 I 13/2 transition, high spontaneous radiative transition probability (30.09 s −1 ), large emission cross section ((14.84 ± 0.10) × 10 −21 cm 2 ) and superior gain performance were obtained from the prepared glass. Besides, energy transfer processes concerning the 2.7 μm emission were also discussed in detail. According to simplified rate equation and Dexter’s theory, energy transfer microscopic parameters were computed to elucidate observed 2.7 μm emissions. Results demonstrate that the prepared germanate glass possessing excellent spectroscopic properties might be an attractive candidate for mid-infrared laser or amplifier

  11. Stable angular emission spectra in white organic light-emitting diodes using graphene/PEDOT:PSS composite electrode.

    Science.gov (United States)

    Cho, Hyunsu; Lee, Hyunkoo; Lee, Jonghee; Sung, Woo Jin; Kwon, Byoung-Hwa; Joo, Chul-Woong; Shin, Jin-Wook; Han, Jun-Han; Moon, Jaehyun; Lee, Jeong-Ik; Cho, Seungmin; Cho, Nam Sung

    2017-05-01

    In this work, we suggest a graphene/ poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) composite as a transparent electrode for stabilizing white emission of organic light-emitting diodes (OLEDs). Graphene/PEDOT:PSS composite electrodes have increased reflectance when compared to graphene itself, but their reflectance is still lower than that of ITO itself. Changes in the reflectance of the composite electrode have the advantage of suppressing the angular spectral distortion of white emission OLEDs and achieving an efficiency of 16.6% for white OLEDs, comparable to that achieved by graphene-only electrodes. By controlling the OLED structure to compensate for the two-beam interference effect, the CIE color coordinate change (Δxy) of OLEDs based on graphene/PEDOT:PSS composite electrodes is 0.018, less than that based on graphene-only electrode, i.e.,0.027.

  12. Emission spectra of a pulse needle-to-plane corona-like discharge in conductive aqueous solution

    Czech Academy of Sciences Publication Activity Database

    Šimek, Milan; Člupek, Martin; Babický, Václav; Lukeš, Petr; Šunka, Pavel

    2012-01-01

    Roč. 21, č. 5 (2012), 055031-055031 ISSN 0963-0252 R&D Projects: GA AV ČR IAAX00430802 Institutional research plan: CEZ:AV0Z20430508 Keywords : Water * pulsed electrical breakdown * point-plane geometry * streamer propagation * corona discharge * emission spectroscopy Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.515, year: 2012 http://iopscience.iop.org/0963-0252/21/5/055031/pdf/0963-0252_21_5_055031.pdf

  13. Förster resonance energy transfer, absorption and emission spectra in multichromophoric systems. II. Hybrid cumulant expansion.

    Science.gov (United States)

    Ma, Jian; Moix, Jeremy; Cao, Jianshu

    2015-03-07

    We develop a hybrid cumulant expansion method to account for the system-bath entanglement in the emission spectrum in the multi-chromophoric Förster transfer rate. In traditional perturbative treatments, the emission spectrum is usually expanded with respect to the system-bath coupling term in both real and imaginary time. This perturbative treatment gives a reliable absorption spectrum, where the bath is Gaussian and only the real-time expansion is involved. For the emission spectrum, the initial state is an entangled state of the system plus bath. Traditional perturbative methods are problematic when the excitations are delocalized and the energy gap is larger than the thermal energy, since the second-order expansion cannot predict the displacement of the bath. In the present method, the real-time dynamics is carried out by using the 2nd-order cumulant expansion method, while the displacement of the bath is treated more accurately by utilizing the exact reduced density matrix of the system. In a sense, the hybrid cumulant expansion is based on a generalized version of linear response theory with entangled initial states.

  14. Theoretical modeling and analysis of the emission spectra of a ChemCam standard: Basalt BIR-1A

    Energy Technology Data Exchange (ETDEWEB)

    Colgan, J. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Judge, E.J. [Chemical Diagnostics and Engineering, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Johns, H.M.; Kilcrease, D.P. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Barefield, J.E. [Chemical Diagnostics and Engineering, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); McInroy, R. [Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Hakel, P. [Computational Physics Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Wiens, R.C. [Space and Remote Sensing Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Clegg, S.M. [Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2015-08-01

    We report on efforts to perform theoretical modeling of the emission spectrum measured from a basalt sample. We compare our calculations with measurements that were made to provide standards for the ChemCam instrument on the Mars Science Laboratory. We find that to obtain good agreement between modeling and the measurement, it is necessary to determine atomic and ionic level populations via a multi-element approach in which the free electron density that is created influences all the species within the plasma. Calculations that consider each element separately are found to be in poorer agreement with the measured spectrum, indicating that the ‘matrix effect’ term often used to describe the influence of other species on the emission spectrum from a given element is due to the influence of the global electron density of the plasma. We explore the emission features in both the visible and near-infrared wavelength ranges, and also examine radiation transport effects for some of the most intense features found in the basalt spectrum. Finally, we also provide comparisons of the ChemCam measurement with new high-resolution spectral measurements. - Highlights: • LIBS basalt spectrum • Ab-initio theoretical modeling • Discussion of matrix effects • Discussion of radiation transport effects • High-resolution measurements of Basalt.

  15. A case study of HF radar spectra and 630.0 nm auroral emission in the pre-midnight sector

    Directory of Open Access Journals (Sweden)

    M. Lester

    2001-03-01

    Full Text Available A comparison of HF radar backscatter observed by the CUTLASS Finland radar, meridian scanning photometer data from Longyearbyen, magnetic field variations from IMAGE stations, and particle precipitation measured by the DMSP F12 spacecraft is presented. The interval under discussion occurred in the pre-midnight local time sector, during a period of weakly northward interplanetary magnetic field. A region of HF backscatter, typically 8 degrees wide, occurred in the field of view of the CUTLASS Finland radar. A well defined gradient in the spectral width parameter was present, with mainly low (< 200 m s - 1 spectral widths in the lower latitude part of the scatter and predominantly large (> 200 ms - 1 spectral widths in the higher latitude part. The relationship between the spectral width and the red line (630.0 nm emission measured by the meridian scanning photometer is considered. The poleward border of the red line emission, which has, in the past, been proposed as being representative of the polar cap boundary, was co-located to within 1° of magnetic latitude with the gradient in spectral width for part of the interval. Statistically, large spectral widths occurred poleward of the red line emission, while small spectral widths occurred within or equatorward of the red line emission. Near simultaneous DMSP particle observations in the 20 eV to 20 keV range indicate that the poleward border of the red line emission and the gradient in spectral width occurred at the same latitude as the transition from auroral oval to polar rain particle energies. We conclude that the large spectral widths were not caused by particle precipitation associated with the auroral oval. There were two periods of special interest when the relationship between the red line and the spectral width broke down. The first of these happened during enhanced red line and green line (557.7 nm emission, with a drop out of the radar scatter and an enhanced, narrow westward

  16. Emission spectra of the species ablated from a solid target submerged in liquid: vibrational temperature of C2 molecules in water-confined geometry

    International Nuclear Information System (INIS)

    Sakka, Tetsuo; Saito, Kotaro; Ogata, Yukio H.

    2002-01-01

    Emission spectra of C 2 molecules produced at the water-graphite interface by pulsed laser irradiation were obtained at various delay times from the irradiation. Vibrational temperature was determined by the Boltzmann plot based on the vibrational bands in Δν=-1 branch of the Swan system. The results show that it was ca. 5000 K and did not change significantly with the delay time. With increasing the delay time up to ca. 500 ns the signal from the Swan band disappeared before the decrease of the vibrational temperature. The results were explained by the formation of a gas cavity and its collapse at several hundreds of nanoseconds from the laser pulse

  17. Detection of organic compound signatures in infra-red, limb emission spectra observed by the MIPAS-B2 balloon instrument

    Directory of Open Access Journals (Sweden)

    J. J. Remedios

    2007-01-01

    Full Text Available Organic compounds play a central role in troposphere chemistry and increasingly are a viable target for remote sensing observations. In this paper, infra-red spectral features of three organic compounds are investigated in thermal emission spectra recorded on a flight on 8 May 1998 near Aire sur l'Adour by a balloon-borne instrument, MIPAS-B2, operating at high spectral resolution. It is demonstrated, for the first time, that PAN and acetone can be detected in infra-red remote sensing spectra of the upper troposphere; detection results are presented at tangent altitudes of 10.4 km and 7.5 km (not acetone. In addition, the results provide the first observation of spectral features of formic acid in thermal emission, as opposed to solar occultation, and confirm that concentrations of this gas are measurable in the mid-latitude upper troposphere, given accurate spectroscopic data. For PAN, two bands are observed centred at 794 cm−1 and 1163 cm−1. For acetone and formic acid, one band has been detected for each so far with band centres at 1218 cm−1 and 1105 cm−1 respectively. Mixing ratios inferred at 10.4 km tangent altitude are 180 pptv and 530 pptv for PAN and acetone respectively, and 200 pptv for formic acid with HITRAN 2000 spectroscopy. Accuracies are on the order of 15 to 40%. The detection technique applied here is verified by examining weak but known signatures of CFC-12 and HCFC-22 in the same spectral regions as those of the organic compounds, with results confirming the quality of both the instrument and the radiative transfer model. The results suggest the possibility of global sensing of the organic compounds studied here which would be a major step forward in verifying and interpreting global tropospheric model calculations.

  18. Effects of varying environmental conditions on emissivity spectra of bulk lunar soils: Application to Diviner thermal infrared observations of the Moon

    Science.gov (United States)

    Donaldson Hanna, K. L.; Greenhagen, B. T.; Patterson, W. R.; Pieters, C. M.; Mustard, J. F.; Bowles, N. E.; Paige, D. A.; Glotch, T. D.; Thompson, C.

    2017-02-01

    Currently, few thermal infrared measurements exist of fine particulate (samples (e.g. minerals, mineral mixtures, rocks, meteorites, and lunar soils) measured under simulated lunar conditions. Such measurements are fundamental for interpreting thermal infrared (TIR) observations by the Diviner Lunar Radiometer Experiment (Diviner) onboard NASA's Lunar Reconnaissance Orbiter as well as future TIR observations of the Moon and other airless bodies. In this work, we present thermal infrared emissivity measurements of a suite of well-characterized Apollo lunar soils and a fine particulate (sample as we systematically vary parameters that control the near-surface environment in our vacuum chamber (atmospheric pressure, incident solar-like radiation, and sample cup temperature). The atmospheric pressure is varied between ambient (1000 mbar) and vacuum (radiation is varied between 52 and 146 mW/cm2, and the sample cup temperature is varied between 325 and 405 K. Spectral changes are characterized as each parameter is varied, which highlight the sensitivity of thermal infrared emissivity spectra to the atmospheric pressure and the incident solar-like radiation. Finally spectral measurements of Apollo 15 and 16 bulk lunar soils are compared with Diviner thermal infrared observations of the Apollo 15 and 16 sampling sites. This comparison allows us to constrain the temperature and pressure conditions that best simulate the near-surface environment of the Moon for future laboratory measurements and to better interpret lunar surface compositions as observed by Diviner.

  19. Compressed shell conditions extracted from spectroscopic analysis of Ti K-shell absorption spectra with evaluation of line self-emission

    Energy Technology Data Exchange (ETDEWEB)

    Johns, H. M.; Mancini, R. C.; Hakel, P.; Nagayama, T. [Physics Department, University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557 (United States); Smalyuk, V. A.; Regan, S. P.; Delettrez, J. [Laboratory for Laser Energetics, University of Rochester, 250 E. River Road, Rochester, New York 14623 (United States)

    2014-08-15

    Ti-doped tracer layers embedded in the shell at varying distances from the fuel-shell interface serve as a spectroscopic diagnostic for direct-drive experiments conducted at OMEGA. Detailed modeling of Ti K-shell absorption spectra produced in the tracer layer considers n = 1–2 transitions in F- through Li-like Ti ions in the 4400–4800 eV range, both including and excluding line self-emission. Testing the model on synthetic spectra generated from 1-D LILAC hydrodynamic simulations reveals that the model including self-emission best reproduces the simulation, while the model excluding self-emission overestimates electron temperature T{sub e} and density N{sub e} to a higher degree for layers closer to the core. The prediction of the simulation that the magnitude of T{sub e} and duration of Ti absorption will be strongly tied to the distance of the layer from the core is consistent with the idea that regions of the shell close to the core are more significantly heated by thermal transport out of the hot dense core, but more distant regions are less affected by it. The simulation predicts more time variation in the observed T{sub e}, N{sub e} conditions in the compressed shell than is observed in the experiment, analysis of which reveals conditions remain in the range T{sub e} = 400–600 eV and N{sub e} = 3.0–10.0 × 10{sup 24} cm{sup −3} for all but the most distant Ti-doped layer, with error bars ∼5% T{sub e} value and ∼10% N{sub e} on average. The T{sub e}, N{sub e} conditions of the simulation lead to a greater degree of ionization for zones close to the core than occurs experimentally, and less ionization for zones far from the core.

  20. Chemical analysis of industrial scale deposits by combined use of correlation coefficients with emission line detection of laser induced breakdown spectroscopy spectra

    International Nuclear Information System (INIS)

    Siozos, P.; Philippidis, A.; Hadjistefanou, M.; Gounarakis, C.; Anglos, D.

    2013-01-01

    Laser-induced breakdown spectroscopy (LIBS) was used to determine the mineral composition of various industrial scale samples. The aim of the study has been to investigate the capacity of LIBS to provide a fast, reliable analytical tool for carrying out routine analysis of inorganic scales, potentially on site, as a means to facilitate decision making concerning scale removal procedures. LIBS spectra collected in the range of 200–660 nm conveyed information about the metal content of the minerals. Via a straightforward analysis based on linear correlation of LIBS spectra it was possible to successfully discriminate scale samples into three main groups, Fe-rich, Ca-rich and Ba-rich, on the basis of correlation coefficients. By combining correlation coefficients with spectral data collected in the NIR, 860–960 nm, where sulfur emissions are detected, it became further possible to discriminate sulfates from carbonates as confirmed by independent analysis based on Raman spectroscopy. It is emphasized that the proposed LIBS-based method successfully identifies the major mineral or minerals present in the samples classifying the scales into relevant groups hence enabling process engineers to select appropriate scale dissolution strategies. - Highlights: • LIBS was used to determine the mineral composition of industrial scale samples. • Three groups of inorganic scales were identified: Ca rich, Ba rich and Fe rich. • A method that combines correlation coefficients and line detection is proposed. • The method successfully identifies the main mineral, or minerals, in the samples. • The results were compared with results obtained by use of Raman analysis

  1. Predicting enteric methane emission of dairy cows with milk Fourier-transform infrared spectra and gas chromatography-based milk fatty acid profiles.

    Science.gov (United States)

    van Gastelen, S; Mollenhorst, H; Antunes-Fernandes, E C; Hettinga, K A; van Burgsteden, G G; Dijkstra, J; Rademaker, J L W

    2018-06-01

    FTIR-based models. The cross validation results indicate that all CH 4 prediction models (both GC-determined MFA-based and FTIR-based models) are robust; the difference between the coefficient of determination and the coefficient of determination of cross validation ranged from 0.01 to 0.07. The results indicate that GC-determined MFA have a greater potential than FTIR spectra to estimate CH 4 production, yield, and intensity. Both techniques hold potential but may not yet be ready to predict CH 4 emission of dairy cows in practice. Additional CH 4 measurements are needed to improve the accuracy and robustness of GC-determined MFA and FTIR spectra for CH 4 prediction. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  2. The Infrared Spectra of Polycyclic Aromatic Hydrocarbons with Excess Peripheral H Atoms (H(sub n)-PAHs) and their Relation to the 3.4 and 6.9 Micrometer PAH Emission Features

    Science.gov (United States)

    Sandford, Scott A.; Bernstein, Max P.; Materese, Christopher K.

    2013-01-01

    A population of polycyclic aromatic hydrocarbons (PAHs) and related materials are thought to be responsible for the family of infrared emission features that are seen towards a wide variety of astrophysical environments. A potentially important subclass of these materials are polycyclic aromatic hydrocarbons whose edges contain excess H atoms (H(sub n)-PAHs). While it has been suggested that this type of compound may be present in the interstellar population, it has been difficult to properly assess this possibility because of a lack of suitable infrared laboratory spectra to assist with analysis of the astronomical data. We present the 4000-500 cm(exp -1) (2.5-20 micrometers) infrared spectra of 23 H(sub n)-PAHs and related molecules isolated in argon matrices, under conditions suitable for use in the interpretation of astronomical data. The spectra of molecules with mixed aromatic and aliphatic domains show unique characteristics that distinguish them from their fully aromatic PAH equivalents. We discuss the changes to the spectra of these types of molecules as they transition from fully aromatic to fully aliphatic forms. The implications for the interpretation of astronomical spectra are discussed with specific emphasis on the 3.4 and 6.9 micrometer features. Laboratory data is compared with emission spectra from IRAS 21282+5050, an object with normal PAH emission features, in addition to IRAS 22272+5435 and IRAS 0496+3429, two protoplanetary nebulae with abnormally large 3.4 micrometer features. We show that 'normal' PAH emission objects contain relatively few H(sub n)-PAHs in their emitter populations, but less evolved protoplanetary nebulae may contain significant abundances of these molecules.

  3. Analysis on heavy quarkonia transitions with pion emission in terms of the QCD multipole expansion and determination of mass spectra of hybrids

    International Nuclear Information System (INIS)

    Ke, Hong-Wei; Tang, Jian; Hao, Xi-Qing; Li, Xue-Qian

    2007-01-01

    One of the most important tasks in high energy physics is the search for the exotic states, such as glueball, hybrid, and multiquark states. The transitions ψ(ns)→ψ(ms)+ππ and Υ(ns)→Υ(ms)+ππ attract great attention because they may reveal characteristics of hybrids. In this work, we analyze those transition modes in terms of the theoretical framework established by Yan and Kuang. It is interesting to notice that the intermediate states between the two gluon emissions are hybrids, therefore by fitting the data, we are able to determine the mass spectra of hybrids. The ground hybrid states are predicted as 4.23 GeV (for charmonium) and 10.79 GeV (for bottonium) which do not correspond to any states measured in recent experiments, thus it may imply that, very possibly, hybrids mix with regular quarkonia to constitute physical states. Comprehensive comparisons of the potentials for hybrids whose parameters are obtained in this scenario with the lattice results are presented

  4. Use of details in secondary emission spectra in order to take into account element composition in the radioisotopic, x-ray-fluorescence method

    Energy Technology Data Exchange (ETDEWEB)

    Ivanyukovich, G A; Meier, V A; Nakhabtsev, V S

    1974-01-01

    A study is made of secondary emission spectra applicable to the conditions of determining tin in complex iron ores. Use is made of recorders having an intermediate target of samarium oxide, which assure measurement under geometry of a direct field of vision. It is shown that the integral count rate with a definite selection of the initial condition of discrimination or the count rate in the 32 to 34 keV interval of energies characterizes mainly the composition of the filler. With the purpose of increasing the accuracy and decreasing the effect of equipment factors it is more suitable to estimate the filler composition from the integral count rate. Methods are considered for taking into account the effect of composition of the medium on the measurement results according to the method of spectral ratios by means of a nomogram and analytical expressions. With measurements on models the error of determining the tin content was +- 5 percent in effective atomic number range of 13 to 20, while the error was 50 percent without the introduction of corrections. 10 refs. (tr-auth)

  5. Detection of Copper (II) and Cadmium (II) binding to dissolved organic matter from macrophyte decomposition by fluorescence excitation-emission matrix spectra combined with parallel factor analysis

    International Nuclear Information System (INIS)

    Yuan, Dong-hai; Guo, Xu-jing; Wen, Li; He, Lian-sheng; Wang, Jing-gang; Li, Jun-qi

    2015-01-01

    Fluorescence excitation-emission matrix (EEM) spectra coupled with parallel factor analysis (PARAFAC) was used to characterize dissolved organic matter (DOM) derived from macrophyte decomposition, and to study its complexation with Cu (II) and Cd (II). Both the protein-like and the humic-like components showed a marked quenching effect by Cu (II). Negligible quenching effects were found for Cd (II) by components 1, 5 and 6. The stability constants and the fraction of the binding fluorophores for humic-like components and Cu (II) can be influenced by macrophyte decomposition of various weight gradients in aquatic plants. Macrophyte decomposition within the scope of the appropriate aquatic phytomass can maximize the stability constant of DOM-metal complexes. A large amount of organic matter was introduced into the aquatic environment by macrophyte decomposition, suggesting that the potential risk of DOM as a carrier of heavy metal contamination in macrophytic lakes should not be ignored. - Highlights: • Macrophyte decomposition increases fluorescent DOM components in the upper sediment. • Protein-like components are quenched or enhanced by adding Cu (II) and Cd (II). • Macrophyte decomposition DOM can impact the affinity of Cu (II) and Cd (II). • The log K M and f values showed a marked change due to macrophyte decomposition. • Macrophyte decomposition can maximize the stability constant of DOM-Cu (II) complexes. - Macrophyte decomposition DOM can influence on the binding affinity of metal ions in macrophytic lakes

  6. Thermoluminescence spectra of amethyst

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Q. [Suzhou Railway Teachers College (China). Dept. of Physics; Yang, B. [Beijing Normal University (China). Dept. of Physics; Wood, R.A.; White, D.R.R.; Townsend, P.D.; Luff, B.J. [Sussex Univ., Brighton (United Kingdom). School of Mathematical and Physical Sciences

    1994-04-01

    Thermoluminescence and cathodoluminescence data from natural and synthetic amethyst and synthetic quartz samples are compared. The spectra include features from the quartz host lattice and from impurity-generated recombination sites. Emission features exist throughout the wavelength range studied, 250-800 nm. The near infrared emission at 740-750 nm appears to be characteristic of the amethyst and is proposed to be due to Fe ion impurity. (Author).

  7. Interaction of 4p54dN+1 and 4p64dN-14f configurations and its influence on the photoexcitation and emission spectra in the isoelectronic and isonuclear sequences

    International Nuclear Information System (INIS)

    Kucas, S; Karazija, R; Jonauskas, V; Momkauskaite, A

    2009-01-01

    The strong interaction of 4p 5 4d N+1 + 4p 6 4d N-1 4f configurations and its influence on the photoexcitation and emission spectra corresponding to the excitations from the ground level of 4p 6 4d N have been considered. The results are presented for the isoelectronic sequences from the ionization degree q = 5 up to q = 29-37 as well as for the isonuclear sequences of Sn q+ and W q+ . It is shown that depending on the number of 4d electrons, the variation of spectra in the isoelectronic sequences corresponds to three different types. At N = 4 and N = 6-9, the strong concentration of lines takes place in the whole isoelectronic sequence, except for small ionization degrees. At N ≤ 3, the width of photoexcitation and emission spectra also obtains a relatively larger value at small ionization degrees, decreases with ionization degree rising, but tends to increase again at large ionization degrees. In the whole isoelectronic sequence, a very narrow group of a few intense lines is obtained for N = 5. The transitions from the excited levels mainly proceed to the lowest level of the ground configuration; it is the reason for the similarity of photoexcitation and emission spectra. The quenching of many lines and the concentration of line strengths in a few transitions indicate the existence of some wavefunction basis with strict selection rules for dipole transitions.

  8. Franck-Condon Simulations including Anharmonicity of the Ã(1)A''-X̃(1)A' Absorption and Single Vibronic Level Emission Spectra of HSiCl and DSiCl.

    Science.gov (United States)

    Mok, Daniel W K; Lee, Edmond P F; Chau, Foo-Tim; Dyke, John M

    2009-03-10

    RCCSD(T) and/or CASSCF/MRCI calculations have been carried out on the X̃(1)A' and Ã(1)A'' states of HSiCl employing basis sets of up to the aug-cc-pV5Z quality. Contributions from core correlation and extrapolation to the complete basis set limit were included in determining the computed equilibrium geometrical parameters and relative electronic energy of these two states of HSiCl. Franck-Condon factors which include allowance for anharmonicity and Duschinsky rotation between these two states of HSiCl and DSiCl were calculated employing RCCSD(T) and CASSCF/MRCI potential energy functions, and were used to simulate the Ã(1)A'' ← X̃(1)A' absorption and Ã(1)A'' → X̃(1)A' single vibronic level (SVL) emission spectra of HSiCl and DSiCl. Simulated absorption and experimental LIF spectra, and simulated and observed Ã(1)A''(0,0,0) → X̃(1)A' SVL emission spectra, of HSiCl and DSiCl are in very good agreement. However, agreement between simulated and observed Ã(1)A''(0,1,0) → X̃(1)A' and Ã(1)A''(0,2,1) → X̃(1)A' SVL emission spectra of DSiCl is not as good. Preliminary calculations on low-lying excited states of HSiCl suggest that vibronic interaction between low-lying vibrational levels of the Ã(1)A'' state and highly excited vibrational levels of the ã(3)A'' is possible. Such vibronic interaction may change the character of the low-lying vibrational levels of the Ã(1)A'' state, which would lead to perturbation in the SVL emission spectra from these vibrational levels.

  9. [Study on Hexagonal Super-Lattice Pattern with Light Spot and Dim Spot in Dielectric Barrier Discharge by Optical Emission Spectra].

    Science.gov (United States)

    Liu, Ying; Dong, Li-fang; Niu, Xue-jiao; Zhang, Chao

    2016-02-01

    The hexagonal super-lattice pattern composed of the light spot and the dim spot is firstly observed and investigated in the discharge of gas mixture of air and argon by using the dielectric barrier discharge device with double water electrodes. It is found that the dim spot is located at the center of its surrounding three light spots by observing the discharge image. Obviously, the brightness of the light spot and the dim spot are different, which indicates that the plasma states of the light spot and the dim spot may be different. The optical emission spectrum method is used to further study the several plasma parameters of the light spot and the dim spot in different argon content. The emission spectra of the N₂ second positive band (C³IIu --> B³IIg) are measured, from which the molecule vibration temperatures of the light spot and the dim spot are calculated. Based on the relative intensity ratio of the line at 391.4 nm and the N₂ line at 394.1 nm, the average electron energies of the light spot and the dim spot are investigated. The broadening of spectral line 696.57 nm (2P₂-1S₅) is used to study the electron densities of the light spot and the dim spot. The experiment shows that the molecule vibration temperature, average electron energy and the electron density of the dim spot are higher than those of the light spot in the same argon content. The molecule vibration temperature and electron density of the light spot and dim spot increase with the argon content increasing from 70% to 95%, while average electron energies of the light spot and dim spot decrease gradually. The short-exposure image recorded by a high speed video camera shows that the dim spot results from the surface discharges (SDs). The surface discharge induced by the volume discharge (VD) has the decisive effect on the formation of the dim spot. The experiment above plays an important role in studying the formation mechanism of the hexagonal super-lattice pattern with light spot and

  10. Double pulse laser induced breakdown spectroscopy of a solid in water: Effect of hydrostatic pressure on laser induced plasma, cavitation bubble and emission spectra

    Science.gov (United States)

    López-Claros, M.; Dell'Aglio, M.; Gaudiuso, R.; Santagata, A.; De Giacomo, A.; Fortes, F. J.; Laserna, J. J.

    2017-07-01

    There is a growing interest in the development of sensors use in exploration of the deep ocean. Techniques for the chemical analysis of submerged solids are of special interest, as they show promise for subsea mining applications where a rapid sorting of materials found in the sea bottom would improve efficiency. Laser-Induced Breakdown Spectroscopy (LIBS) has demonstrated potential for this application thanks to its unique capability of providing the atomic composition of submerged solids. Here we present a study on the parameters that affect the spectral response of metallic targets in an oceanic pressure environment. Following laser excitation of the solid, the plasma persistence and the cavitation bubble size are considerably reduced as the hydrostatic pressure increases. These effects are of particular concern in dual pulse excitation as reported here, where a careful choice of the interpulse timing is required. Shadowgraphic images of the plasma demonstrate that cavitation bubbles are formed early after the plasma onset and that the effect of hydrostatic pressure is negligible during the early stage of plasma expansion. Contrarily to what is observed at atmospheric pressure, emission spectra observed at high pressures are characterized by self-absorbed atomic lines on continuum radiation resulting from strong radiative recombination in the electron-rich confined environment. This effect is much less evident with ionic lines due to the much higher energy of the levels involved and ionization energy of ions, as well as to the lower extent of absorption effects occurring in the inner part of the plasma, where ionized species are more abundant. As a result of the smaller shorter-lived cavitation bubble, the LIBS intensity enhancement resulting from dual pulse excitation is reduced when the applied pressure increases.

  11. New investigation of the ν3 C-H stretching region of 12CH4 through the analysis of high temperature infrared emission spectra

    Science.gov (United States)

    Amyay, Badr; Gardez, Aline; Georges, Robert; Biennier, Ludovic; Vander Auwera, Jean; Richard, Cyril; Boudon, Vincent

    2018-04-01

    The ν3 C-H stretching region of methane was reinvestigated in this work using high temperature (620-1715 K) emission spectra recorded in Rennes at Doppler limited resolution. This work follows our recent global analysis of the Dyad system Δn = ±1 (1000-1500 cm-1), with n being the polyad number [B. Amyay et al., J. Chem. Phys. 144, 24312 (2016)]. Thanks to the high temperature, new assignments of vibration-rotation methane line positions have been achieved successfully in the Pentad system and some associated hot bands (Δn = ±2) observed in the spectral region 2600-3300 cm-1. In particular, rotational assignments in the cold band [Pentad-ground state (GS)] and in the first related hot band (Octad-Dyad) were extended up to J = 30 and 27, respectively. In addition, 1525 new transitions belonging to the Tetradecad-Pentad hot band system were assigned for the first time, up to J = 20. The effective global model used to deal with the new assignments was developed to the 6th order for the first three polyads (Monad, Dyad, and Pentad), and to the 5th order for both the Octad and the Tetradecad. 1306 effective parameters were fitted with a dimensionless standard deviation σ = 2.64. The root mean square deviations dRMS obtained are 4.18 × 10-3 cm-1 for the Pentad-GS cold band, 2.48 × 10-3 cm-1 for the Octad-Dyad, and 1.43 × 10-3 cm-1 for the Tetradecad-Pentad hot bands.

  12. Use of neural network based auto-associative memory as a data compressor for pre-processing optical emission spectra in gas thermometry with the help of neural network

    International Nuclear Information System (INIS)

    Dolenko, S.A.; Filippov, A.V.; Pal, A.F.; Persiantsev, I.G.; Serov, A.O.

    2003-01-01

    Determination of temperature from optical emission spectra is an inverse problem that is often very difficult to solve, especially when substantial noise is present. One of the means that can be used to solve such a problem is a neural network trained on the results of modeling of spectra at different temperatures (Dolenko, et al., in: I.C. Parmee (Ed.), Adaptive Computing in Design and Manufacture, Springer, London, 1998, p. 345). Reducing the dimensionality of the input data prior to application of neural network can increase the accuracy and stability of temperature determination. In this study, such pre-processing is performed with another neural network working as an auto-associative memory with a narrow bottleneck in the hidden layer. The improvement in the accuracy and stability of temperature determination in presence of noise is demonstrated on model spectra similar to those recorded in a DC-discharge CVD reactor

  13. BETA SPECTRA. I. Negatrons spectra

    International Nuclear Information System (INIS)

    Grau Malonda, A.; Garcia-Torano, E.

    1978-01-01

    Using the Fermi theory of beta decay, the beta spectra for 62 negatrons emitters have been computed introducing a correction factor for unique forbidden transitions. These spectra are plotted vs. energy, once normal i sed, and tabulated with the related Fermi functions. The average and median energies are calculated. (Author)

  14. Blue emission in photoluminescence spectra of the red phosphor CaAlSiN3:Eu2+ at low Eu2+ concentration

    Science.gov (United States)

    Suda, Yoriko; Kamigaki, Yoshiaki; Yamamoto, Hajime

    2018-04-01

    In red phosphor CaAlSiN3:Eu2+, unintentional blue emission occurs with increasing intensity at low Eu2+ concentrations and also at low measurement temperatures. Time-resolved photoluminescence measurements were used to confirm the decrease in red emission and increase in blue emission with the decreasing Eu2+ concentration. The peak timing of blue emission occurred faster than that of red emission, and long lasting luminescence of red emission was observed as well as that of blue emission. The Eu2+ concentration dependences of the red and blue emissions were similar to those of the g values 4.75 (Eu2+) and 2.0025 (nitrogen vacancies), respectively, which were observed from electron spin resonance (ESR) measurements. The origin of the blue emission is proposed to be nitrogen vacancy defects, which had about the same ESR signal intensity as that of Eu2+ ions in CaAlSiN3:Eu2+ containing 0.01 at. % Eu2+. The possibility of red emission also arising from excited electron tunneling or thermal pathways via nitrogen vacancies is discussed. Long lasting red emission was observed, which is proposed to involve trapped electrons remaining at nitrogen vacancies, yielding blue emission and inducing red emission from Eu2+ ions.

  15. Spectral intensities: The emission spectra for the Cs2NaScCl6: MoCl63- system in the Fm3m space group

    International Nuclear Information System (INIS)

    Acevedo, R.; Meruane, T.; Navarro, G.

    2000-01-01

    Taking advantage of the data reported by Flint and Paulusz, we have undertaken a theoretical investigation of the intensity mechanism for the various emissions; Γ 8 ( 2 T 2g ) → Γ 8 ( 4 A 2g ), Γ 8 ( 2 E g ), Γ 8 ( 2 T 1g ), Γ 6 ( 2 T 1g ) for the Cs 2 NaScCl 6 :MoCl 6 3- system in the Fm3m-space group. The experimental data reported by these authors, refer to the visible and near infrared luminescence spectra of MoCl 3- 6 complex ion in different host, such as Cs 2 NaMCl 6 (M = Sc, Y, In), measured between 15,000 cm -1 and 3,000 cm -1 at liquid helium temperatures. At least, five luminescence transitions have been identified and assigned and each of them show extensive vibronic structure, which was analyzed to yield the vibrational frequencies of the MoX 3- 6 (X -1 = Cl -1 Br -1 ) ion in each excitation. A careful analysis of the experimental data reported shows that for the various observed electronic transitions, the vibration frequencies do change only slightly, and therefore there is no indication that the system undergoes a Jahn-Teller distortion (along an active coordinate) of some importance to be taken into account in the current work. There is, though clear evidence that for the chloro-elpasolites, there is a strong resonance interaction between ν 3 (τ 1u : stretching) of the MoX 6 3- , complex ion and that of the host when M = In, Y. Thus for M = Sc, the slighter higher host ν 3 , wavenumber is likely to minimizes the effect of this coupling. This experimental evidence, will allow us for the Cs 2 NaScCl 6 3- system to neglect to first order approximation, the coupling among the internal and the external vibrations and to proceed using a both a molecular model and the independent system model (ISM)

  16. Pr:Ca1-xRxF2+x (R=Y or Gd) crystals: Modulated blue, orange and red emission spectra with the proportion of R3+ ions

    Science.gov (United States)

    Yu, Hao; Qian, Xiaobo; Guo, Linyang; Jiang, Dapeng; Wu, Qinghui; Tang, Fei; Su, Liangbi; Ju, Qiangwen; Wang, Jingya; Xu, Jun

    2018-04-01

    The spectroscopic properties of 0.6at.%:Pr:Ca1-xRxF2+x (R = Y, Gd; x = 0,0.006, 0.012, 0.03, 0.06) crystals were investigated and compared. The XRD tests were conducted and the cell dimensions of the crystals were calculated. Room temperature absorption spectra have been registered and analyzed. The emission spectra and decay curves of the crystals were obtained at room temperature. Increasing the proportion of the lattice regulators of Y3+ or Gd3+ ions could significantly enhance the luminescence intensity of all visible emission bands with different ratios. Particularly, the emission intensity ratio of orange to red increased from 0.15 to 1.9 in Pr:Ca1-xYxF2+x crystals and to 1.02 in Pr:Ca1-xGdxF2+x crystals, respectively. Furthermore, Pr:Ca1-xGdxF2+x crystals have substantially strong emission at orange and red region of 580-660 nm, comparable with blue light at 482 nm. The quantum efficiency of the crystals increased rapidly with the increment of R3+ concentration, and finally tend to be 100%.

  17. Large Charge-Transfer Energy in LiFePO4 Revealed by Full-Multiplet Calculation for the Fe L3 -edge Soft X-ray Emission Spectra.

    Science.gov (United States)

    Asakura, Daisuke; Nanba, Yusuke; Makinose, Yuki; Matsuda, Hirofumi; Glans, Per-Anders; Guo, Jinghua; Hosono, Eiji

    2018-04-17

    We analyzed the Fe 3d electronic structure in LiFePO 4 /FePO 4 (LFP/FP) nanowire with a high cyclability by using soft X-ray emission spectroscopy (XES) combined with configuration-interaction full-multiplet (CIFM) calculation. The ex situ Fe L 2,3 -edge resonant XES (RXES) spectra for LFP and FP are ascribed to oxidation states of Fe 2+ and Fe 3+ , respectively. CIFM calculations for Fe 2+ and Fe 3+ states reproduced the Fe L 3 RXES spectra for LFP and FP, respectively. In the calculations for both states, the charge-transfer energy was considerably larger than those for typical iron oxides, indicating very little electron transfer from the O 2p to Fe 3d orbitals and a weak hybridization on the Fe-O bond during the charge-discharge reactions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. DISSECTING THE POWER SOURCES OF LOW-LUMINOSITY EMISSION-LINE GALAXY NUCLEI VIA COMPARISON OF HST-STIS AND GROUND-BASED SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Constantin, Anca; Castillo, Christopher A. [Department of Physics and Astronomy, James Madison University, Harrisonburg, VA 22807 (United States); Shields, Joseph C. [Department of Physics and Astronomy, Ohio University, Athens, OH 45701 (United States); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Barth, Aaron J. [Department of Physics and Astronomy, University of California, Irvine, CA 92697-4575 (United States); Filippenko, Alexei V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)

    2015-12-01

    Using a sample of ∼100 nearby line-emitting galaxy nuclei, we have built the currently definitive atlas of spectroscopic measurements of Hα and neighboring emission lines at subarcsecond scales. We employ these data in a quantitative comparison of the nebular emission in Hubble Space Telescope (HST) and ground-based apertures, which offer an order-of-magnitude difference in contrast, and provide new statistical constraints on the degree to which transition objects and low-ionization nuclear emission-line regions (LINERs) are powered by an accreting black hole at ≲10 pc. We show that while the small-aperture observations clearly resolve the nebular emission, the aperture dependence in the line ratios is generally weak, and this can be explained by gradients in the density of the line-emitting gas: the higher densities in the more nuclear regions potentially flatten the excitation gradients, suppressing the forbidden emission. The transition objects show a threefold increase in the incidence of broad Hα emission in the high-resolution data, as well as the strongest density gradients, supporting the composite model for these systems as accreting sources surrounded by star-forming activity. The narrow-line LINERs appear to be the weaker counterparts of the Type 1 LINERs, where the low accretion rates cause the disappearance of the broad-line component. The enhanced sensitivity of the HST observations reveals a 30% increase in the incidence of accretion-powered systems at z ≈ 0. A comparison of the strength of the broad-line emission detected at different epochs implies potential broad-line variability on a decade-long timescale, with at least a factor of three in amplitude.

  19. GNASH: a preequilibrium, statistical nuclear-model code for calculation of cross sections and emission spectra. [In FORTRAN for CDC 7600

    Energy Technology Data Exchange (ETDEWEB)

    Young, P.G.; Arthur, E.D.

    1977-11-01

    A new multistep Hauser--Feshbach code that includes corrections for preequilibrium effects is described. The code can calculate up to 60 decay reactions (cross sections and energy spectra) in one computation, and thereby provide considerable flexibility for handling processes with complicated reaction chains. Input parameter setup, problem output, and subroutine descriptions are given along with a sample problem calculation. A brief theoretical description is also included. 8 figures, 3 tables.

  20. Angular Spectra of Polarized Galactic Foregrounds

    OpenAIRE

    Cho, Jung; Lazarian, A.

    2003-01-01

    It is believed that magnetic field lines are twisted and bend by turbulent motions in the Galaxy. Therefore, both Galactic synchrotron emission and thermal emission from dust reflects statistics of Galactic turbulence. Our simple model of Galactic turbulence, motivated by results of our simulations, predicts that Galactic disk and halo exhibit different angular power spectra. We show that observed angular spectra of synchrotron emission are compatible with our model. We also show that our mod...

  1. Measurements of neutron emission spectra and 7Be production in Li(d, n) and Be(d, n) reactions for 25 and 40 MeV deuterons

    International Nuclear Information System (INIS)

    Hagiwara, Masayuki; Baba, Mamoru; Aoki, Takao; Kawata, Naoki; Hirabayashi, Naoya; Itoga, Toshiro

    2003-01-01

    The neutron spectra in Li(d, n) and Be(d, n) reactions for Ed = 25, 40 MeV were measured from ∼1 MeV to highest energy of secondary neutrons at ten laboratory angles between 0- and 110-deg with the time-of-flight (TOF) method. In addition, the number of 7 Be accumulated in the targets was also measured by counting the γ-rays from 7 Be using a pure Ge detector to obtain 7 Be production cross-section and yields. (author)

  2. Photobleaching Response of Different Sources of Chromophoric Dissolved Organic Matter Exposed to Natural Solar Radiation Using Absorption and Excitation?Emission Matrix Spectra

    OpenAIRE

    Zhang, Yunlin; Liu, Xiaohan; Osburn, Christopher L.; Wang, Mingzhu; Qin, Boqiang; Zhou, Yongqiang

    2013-01-01

    CDOM biogeochemical cycle is driven by several physical and biological processes such as river input, biogeneration and photobleaching that act as primary sinks and sources of CDOM. Watershed-derived allochthonous (WDA) and phytoplankton-derived autochthonous (PDA) CDOM were exposed to 9 days of natural solar radiation to assess the photobleaching response of different CDOM sources, using absorption and fluorescence (excitation-emission matrix) spectroscopy. Our results showed a marked decrea...

  3. Fluorescence-excitation and emission spectra from LH2 antenna complexes of Rhodopseudomonas acidophila as a function of the sample preparation conditions.

    Science.gov (United States)

    Kunz, Ralf; Timpmann, Kõu; Southall, June; Cogdell, Richard J; Köhler, Jürgen; Freiberg, Arvi

    2013-10-10

    The high sensitivity of optical spectra of pigment-protein complexes to temperature and pressure is well known. In the present study, we have demonstrated the significant influence of the environments commonly used in bulk and single-molecule spectroscopic studies at low temperatures on the LH2 photosynthetic antenna complex from Rhodopseudomonas acidophila. A transfer of this LH2 complex from a bulk-buffer solution into a spin-coated polymer film results in a 189 cm(-1) blue shift of the B850 excitonic absorption band at 5 K. Within the molecular exciton model, the origin of this shift could be disentangled into three parts, namely to an increase of the local site energies, a contraction of the exciton band, and a decrease of the displacement energy.

  4. Analysis of energy transfer based emission spectra of (Sm{sup 3+}, Dy{sup 3+}): Li{sub 2}O–LiF–B{sub 2}O{sub 3}–CdO glasses

    Energy Technology Data Exchange (ETDEWEB)

    Naresh, V., E-mail: varna.naresh@gmail.com; Buddhudu, S., E-mail: profsb_svuniv@hotmail.com

    2014-03-15

    The present paper brings out the results concerning the preparation and optical properties of Sm{sup 3+} and Dy{sup 3+} each ion separately in four different concentrations (0.1, 0.5, 1.0 and 1.5 mol%) and also together doped (1 mol% Dy{sup 3+}+x mol% Sm{sup 3+}): Li{sub 2}O–LiF–B{sub 2}O{sub 3}–CdO (where x=0.1, 0.5, 1.0 and 1.5 mol%) glasses by a melt quenching method. Sm{sup 3+} doped base glasses have displayed an intense orange emission at 602 nm ({sup 4}G{sub 5/2}→{sup 6}H{sub 7/2}) with an excitation at 403 nm and Dy{sup 3+} doped glasses have shown two emissions located at 486 nm ({sup 4}F{sub 9/2}→{sup 6}H{sub 15/2}; blue) and 577 nm ({sup 4}F{sub 9/2}→{sup 6}H{sub 13/2}; yellow) with λ{sub exci}=387 nm. The co-doped (Dy{sup 3+}+Sm{sup 3+}) lithium fluoro-boro cadmium glasses have been excited with an excitation at 387 nm of Dy{sup 3+} which has resulted in with a significant reduction in Dy{sup 3+} emission, at the same time there exists an increase in the reddish-orange emission of Sm{sup 3+} due to an energy transfer from Dy{sup 3+} to Sm{sup 3+}. The non-radiative energy transfer from Dy{sup 3+} to Sm{sup 3+} is governed by dipole–quadrupole interactions as is explained in terms of their emission spectra, donor lifetime, energy level diagram and energy transfer characteristic factors. -- Highlights: • In co-doped (Dy{sup 3+}+Sm{sup 3+}): LFBCd glass, reddish-orange emission due to Sm{sup 3+} ({sup 4}F{sub 9/2}→{sup 6}H{sub J}) has been enhanced due to an energy transfer from Dy{sup 3+} ions in the glass. • This has been evidenced from a lowering trend in the emission transition lifetimes of donor (Dy{sup 3+}) ions with increasing acceptor (Sm{sup 3+}) concentration. • Energy transfer mechanism involved in Dy{sup 3+}→Sm{sup 3+} has been explained in terms of I–H luminescence decay curve analysis.

  5. Proton and electron impact on molecular and atomic oxygen: I. High resolution fluorescence spectra in the visible and VUV spectral range and emission cross-sections for dissociative ionisation and excitation of O2

    International Nuclear Information System (INIS)

    Wilhelmi, O.; Schartner, K.H.

    2000-01-01

    For pt.II see ibid., vol.11, p.45-58, 2000. Molecular oxygen O 2 was dissociated in collisions with protons and electrons in the intermediate velocity range (p + -energies: 17-800 keV, e - -energies: 0.2-2 keV). Fluorescence from excited atomic and singly ionised fragments and from singly ionised molecules was detected in the VUV and in the visible and near UV spectral range. Highly resolved spectra are presented for the VUV (46-131 nm) and the near UV/visible (340-605 nm) spectral range. Absolute emission cross-sections have been determined for dissociative ionisation and excitation leading to fluorescence in the VUV. Results are compared with published data. (orig.)

  6. Ab Initio Potential Energy Surfaces for Both the Ground (X̃1A′ and Excited (A∼1A′′ Electronic States of HSiBr and the Absorption and Emission Spectra of HSiBr/DSiBr

    Directory of Open Access Journals (Sweden)

    Anyang Li

    2012-01-01

    Full Text Available Ab initio potential energy surfaces for the ground (X̃1A′ and excited (A˜A′′1 electronic states of HSiBr were obtained by using the single and double excitation coupled-cluster theory with a noniterative perturbation treatment of triple excitations and the multireference configuration interaction with Davidson correction, respectively, employing an augmented correlation-consistent polarized valence quadruple zeta basis set. The calculated vibrational energy levels of HSiBr and DSiBr of the ground and excited electronic states are in excellent agreement with the available experimental band origins. In addition, the absorption and emission spectra of HSiBr and DSiBr were calculated using an efficient single Lanczos propagation method and are in good agreement with the available experimental observations.

  7. 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM)-doping density dependence of luminescence spectra and white emission in polymer light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Akinori; Hosokawa, Takeshi; Haishi, Motoki; Ohtani, Naoki [Department of Electronics, Doshisha University, Tatara-Miyakodani, Kyotanabe-shi, Kyoto (Japan)

    2009-01-15

    We fabricated white polymer light-emitting diodes (PLEDs), in which the active region is doped with a low-weight molecule. The host polymer material is Poly(9,9-didodecyl-fluorenyl-2,7-yleneethylnylene) (PFO), while the guest luminescent low-weight-molecule is 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM). The photoluminescence (PL) and electroluminescence (EL) spectra strongly depend on DCM-doping-density. However, the most suitable DCM-doping-densities for white emissions in PL and EL are slightly different. This discrepancy is caused by the difference in excitation efficiencies. The photo-excitation system for PL measurement is better than the current injection for generating carriers efficiently. Thus, the realization of the white EL signal requires the larger DCM-doping-density than that of the white PL signal. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Multidimensional Models of Type Ia Supernova Nebular Spectra: Strong Emission Lines from Stripped Companion Gas Rule Out Classic Single-degenerate Systems

    Science.gov (United States)

    Botyánszki, János; Kasen, Daniel; Plewa, Tomasz

    2018-01-01

    The classic single-degenerate model for the progenitors of Type Ia supernova (SN Ia) predicts that the supernova ejecta should be enriched with solar-like abundance material stripped from the companion star. Spectroscopic observations of normal SNe Ia at late times, however, have not resulted in definite detection of hydrogen. In this Letter, we study line formation in SNe Ia at nebular times using non-LTE spectral modeling. We present, for the first time, multidimensional radiative transfer calculations of SNe Ia with stripped material mixed in the ejecta core, based on hydrodynamical simulations of ejecta–companion interaction. We find that interaction models with main-sequence companions produce significant Hα emission at late times, ruling out these types of binaries being viable progenitors of SNe Ia. We also predict significant He I line emission at optical and near-infrared wavelengths for both hydrogen-rich or helium-rich material, providing an additional observational probe of stripped ejecta. We produce models with reduced stripped masses and find a more stringent mass limit of M st ≲ 1 × 10‑4 M ⊙ of stripped companion material for SN 2011fe.

  9. A study of radiative Auger emission, satellites and hypersatellites in photon-induced K x-ray spectra of some elements in the range 20≤Z≤32

    International Nuclear Information System (INIS)

    Verma, H.R.

    2000-01-01

    Photon-induced K x-ray spectra of Ca, Ti, Fe, Zn and Ge have been investigated. The measurements have been made using a crystal spectrometer combined with a thin scintillation detector. Excited by the collimated photon beam from an Rh-anode x-ray tube, the spectra of all these elements reveal the existence of radiative Auger emission (RAE) structure and the satellite and hypersatellite lines along with the diagram lines. The energies and intensities of the Kα 2 , Kα 1 , Kβ 1,3 and Kβ 5 diagram lines and the Kα satellites and hypersatellite transitions are presented. The intensity of the RAE structure corresponding to the Kβ 1,3 x-ray transition and the energy of the RAE edge for each element is also reported. The measured results have been compared with the values from other sources such as electron/heavy-ion excitation and theoretical values. From the intensities of the satellite lines of these elements, the average L-vacancy fraction P L has been deduced in each case. (author)

  10. Evaluation of secondary and prompt fission neutron spectra

    Energy Technology Data Exchange (ETDEWEB)

    Porodzinskij, Yu.V.; Sukhovitskij, E.Sh. [Radiation Physics and Chemistry Problems Inst., Minsk-Sosny (Belarus)

    1997-03-01

    A simple model allowing to split neutron emission spectra into reaction partials is suggested. Predicted spectra of (n,n`{gamma}), (n,n`f), etc appear to be much harder than usually evaluated. (author)

  11. Proton, deuteron, and triton emission at target rapidity in Au+Au collisions at 10.20A GeV: Spectra and directed flow

    International Nuclear Information System (INIS)

    Ashktorab, K.; Beavis, D.; Chasman, C.; Chen, Z.; Chu, Y.Y.; Cumming, J.B.; Debbe, R.; Gonin, M.; Gushue, S.; Levine, M.; Moskowitz, B.; Olness, J.; Remsberg, L.P.; Tannenbaum, M.J.; Videbaek, F.; Zhu, F.; Crawford, H.J.; Engelage, J.; Judd, E.; Chang, J.; Eldredge, W.; Fung, S.Y.; Seto, R.; Xu, G.; Zhu, Q.; Chi, C.; Cole, B.A.; Moulson, M.; Nagamiya, S.; Nayak, T.K.; Wang, F.Q.; Wang, Y.; Wu, Y.; Zajc, W.A.; Akiba, Y.; Hamagaki, H.; Homma, S.; Sako, H.; Kaneko, H.; Britt, H.C.; Cianciolo, V.; Luke, J.; Namboodiri, M.N.; Sangster, T.C.; Soltz, R.; Thomas, J.H.; Tonse, S.R.; Ahle, L.; Baker, M.D.; Heintzelman, G.; Ogilvie, C.A.; Steadman, S.G.; Stephans, G.S.; Sung, T.; Woodruff, D.S.; Zachary, D.; Hayano, R.S.; Shigaki, K.; Kumagai, A.; Kurita, K.; Miake, Y.; Ueno-Hayashi, S.; Yagi, K.; Kang, J.H.; Gaardhoje, J.J.; Hansen, A.G.; Hansen, L.

    1998-01-01

    Systematic results are presented on proton, deuteron, and triton emission from the target spectator region in collisions of 10.20A GeV gold projectiles with a gold target. A forward hodoscope utilizes detection of projectile spectator fragments to determine the orientation of the reaction plane, event by event. The directed flow left-angle p x right-angle is determined as a function of pseudorapidity. Projectile spectator energy is used to estimate impact parameters. Results are compared to current theoretical models ARC, ART, and RQMD. In all cases good agreement with theory is obtained for calculations utilizing a pure cascade without nuclear potential contributions. copyright 1998 The American Physical Society

  12. High resolution emission Fourier transform infrared spectra of the 4p-5s and 5p-6s bands of ArH.

    Science.gov (United States)

    Baskakov, O I; Civis, S; Kawaguchi, K

    2005-03-15

    In the 2500-8500 cm(-1) region several strong emission bands of (40)ArH were observed by Fourier transform spectroscopy through a dc glow discharge in a mixture of argon and hydrogen. Rotational-electronic transitions of the two previously unstudied 4p-5s and 5p-6s,v = 0-0, bands of (40)ArH were measured and assigned in the 6060 and 3770 cm(-1) regions, respectively. A simultaneous fit of the emission transitions of the 4p-5s and 5p-6s bands and an extended set of transitions of the 6s-4p band observed by Dabrowski, Tokaryk, and Watson [J. Mol. Spectrosc. 189, 95 (1998)] and remeasured in the present work yielded consistent values of the spectroscopic parameters of the electronic states under investigation. In the branch of the 4p-5s band with transitions of type (Q)Q(f(3)e) we observed a narrowing in the linewidths with increasing rotational quantum number N. The rotational dependence of the linewidth is caused by predissociation of the 5s state by the repulsive ground 4s state through homogeneous coupling and changes in overlap integrals of the vibrational wave functions with the rotational level. Analysis was based on the Fermi's golden rule approximation model. In the 4p-5s band region a vibrational sequence ofv(')-v(")=1-1, 2-2, and 3-3 were recorded and a number of transitions belonging to the strongest (Q)Q(f(3)e) form branch of the 1-1 band were analyzed.

  13. Experimental and theoretical studies of the VUV emission and absorption spectra of H{sub 2}, HD and D{sub 2} molecules; Etude experimentale et theorique des spectres d'emission et d'absorption VUV des molecules H{sub 2}, D{sub 2} et HD

    Energy Technology Data Exchange (ETDEWEB)

    Roudjane, M

    2007-12-15

    The aim of this thesis is to carry out an experimental study of the absorption and emission spectra of the D{sub 2} and HD isotopes, with high resolution, in the VUV domain and to supplement it by a theoretical study of the excited electronic states involved in the observed transitions. The emission spectra of HD and D{sub 2} are produced by Penning discharge source operating under low pressure and are recorded in the spectral range 78 - 170 nm. The recorded spectra contains more than 20.000 lines. The analysis of the spectrum consists in identifying and assigning the lines to the electronic transitions between energy levels of the molecule. The present analysis is based on our theoretical calculations of the ro-vibrational energy levels of the excited electronic states and the transition probabilities from these states towards the energy levels of the fundamental state. The theoretical results are obtained by resolving the coupled equations between the excited electronic states B{sup 1}{sigma}{sub u}{sup 1}, B'{sup 1}{sigma}{sub u}{sup 1}, C{sup 1}{pi}{sub u}{sup 1} and D{sup 1}{pi}{sub u}{sup 1}, taking into account the nonadiabatic couplings between these states, and they are obtained in the adiabatic approximation for the excited electronic states B''B-bar{sup 1}{sigma}{sub u}{sup +}, D'{sup 1}{pi}{sub u}{sup 1} and D''{sup 1}{pi}{sub u}{sup 1}. The equations are resolved using a modern method based on the discretization variables representation method. In addition, we have carried out a study of the absorption spectra of the HD and D{sub 2} molecules.

  14. Polarization dependence of resonant X-ray emission spectra in 3dn transition metal compounds with n=0, 1, 2, 3

    International Nuclear Information System (INIS)

    Matsubara, Masahiko; Kotani, Akio; Shin, Shik; Uozumi, Takayuki; Harada, Yoshihisa

    2002-01-01

    The polarization dependence of 2p → 3d → 2p resonant X-ray emission spectroscopy (RXES) in 3d 1 , 3d 2 and 3d 3 systems (TiF 3 , VF 3 and Cr 2 O 3 , respectively) is measured and analyzed by means of the MX 6 (M denotes a transition metal and X denotes a ligand, respectively) cluster model. The results are compared with a previous one for the 3d 0 system (TiO 2 ). Generally, with increasing 3d electron number, the spectral structure of RXES becomes more complicated by the influence of the crystal field and the multiplet coupling effect. Moreover, we point out that the selection rules on the polarization dependence of RXES change with the 3d electron number and that a drastic resonance enhancement corresponding to the excitation to an antibonding state in the 3d 0 system is almost absent for the 3d n systems with n=1, 2 and 3. (author)

  15. Photobleaching response of different sources of chromophoric dissolved organic matter exposed to natural solar radiation using absorption and excitation-emission matrix spectra.

    Science.gov (United States)

    Zhang, Yunlin; Liu, Xiaohan; Osburn, Christopher L; Wang, Mingzhu; Qin, Boqiang; Zhou, Yongqiang

    2013-01-01

    CDOM biogeochemical cycle is driven by several physical and biological processes such as river input, biogeneration and photobleaching that act as primary sinks and sources of CDOM. Watershed-derived allochthonous (WDA) and phytoplankton-derived autochthonous (PDA) CDOM were exposed to 9 days of natural solar radiation to assess the photobleaching response of different CDOM sources, using absorption and fluorescence (excitation-emission matrix) spectroscopy. Our results showed a marked decrease in total dissolved nitrogen (TDN) concentration under natural sunlight exposure for both WDA and PDA CDOM, indicating photoproduction of ammonium from TDN. In contrast, photobleaching caused a marked increase in total dissolved phosphorus (TDP) concentration for both WDA and PDA CDOM. Thus TDN:TDP ratios decreased significantly both for WDA and PDA CDOM, which partially explained the seasonal dynamic of TDN:TDP ratio in Lake Taihu. Photobleaching rate of CDOM absorption a(254), was 0.032 m/MJ for WDA CDOM and 0.051 m/MJ for PDA CDOM from days 0-9, indicating that phototransformations were initially more rapid for the newly produced CDOM from phytoplankton than for the river CDOM. Extrapolation of these values to the field indicated that 3.9%-5.1% CDOM at the water surface was photobleached and mineralized every day in summer in Lake Taihu. Photobleaching caused the increase of spectral slope, spectral slope ratio and molecular size, indicating the CDOM mean molecular weight decrease which was favorable to further microbial degradation of mineralization. Three fluorescent components were validated in parallel factor analysis models calculated separately for WDA and PDA CDOM. Our study suggests that the humic-like fluorescence materials could be rapidly and easily photobleached for WDA and PDA CDOM, but the protein-like fluorescence materials was not photobleached and even increased from the transformation of the humic-like fluorescence substance to the protein

  16. Photobleaching Response of Different Sources of Chromophoric Dissolved Organic Matter Exposed to Natural Solar Radiation Using Absorption and Excitation–Emission Matrix Spectra

    Science.gov (United States)

    Zhang, Yunlin; Liu, Xiaohan; Osburn, Christopher L.; Wang, Mingzhu; Qin, Boqiang; Zhou, Yongqiang

    2013-01-01

    CDOM biogeochemical cycle is driven by several physical and biological processes such as river input, biogeneration and photobleaching that act as primary sinks and sources of CDOM. Watershed-derived allochthonous (WDA) and phytoplankton-derived autochthonous (PDA) CDOM were exposed to 9 days of natural solar radiation to assess the photobleaching response of different CDOM sources, using absorption and fluorescence (excitation-emission matrix) spectroscopy. Our results showed a marked decrease in total dissolved nitrogen (TDN) concentration under natural sunlight exposure for both WDA and PDA CDOM, indicating photoproduction of ammonium from TDN. In contrast, photobleaching caused a marked increase in total dissolved phosphorus (TDP) concentration for both WDA and PDA CDOM. Thus TDN∶TDP ratios decreased significantly both for WDA and PDA CDOM, which partially explained the seasonal dynamic of TDN∶TDP ratio in Lake Taihu. Photobleaching rate of CDOM absorption a(254), was 0.032 m/MJ for WDA CDOM and 0.051 m/MJ for PDA CDOM from days 0–9, indicating that phototransformations were initially more rapid for the newly produced CDOM from phytoplankton than for the river CDOM. Extrapolation of these values to the field indicated that 3.9%–5.1% CDOM at the water surface was photobleached and mineralized every day in summer in Lake Taihu. Photobleaching caused the increase of spectral slope, spectral slope ratio and molecular size, indicating the CDOM mean molecular weight decrease which was favorable to further microbial degradation of mineralization. Three fluorescent components were validated in parallel factor analysis models calculated separately for WDA and PDA CDOM. Our study suggests that the humic-like fluorescence materials could be rapidly and easily photobleached for WDA and PDA CDOM, but the protein-like fluorescence materials was not photobleached and even increased from the transformation of the humic-like fluorescence substance to the protein

  17. Beta spectra. II-Positron spectra

    International Nuclear Information System (INIS)

    Grau, A.; Garcia-Torano, E.

    1981-01-01

    Using the Fermi theory of beta decay, the beta spectra for 30 positron emitters have been computed, introducing a correction factor for unique forbidden transitions. The spectra are ploted vs. energy, once normalised, and tabulated with the related Fermi functions. The average and median energies are calculated. (author)

  18. SOLAR-WIND ION-DRIVEN X-RAY EMISSION FROM COMETARY AND PLANETARY ATMOSPHERES: MEASUREMENTS AND THEORETICAL PREDICTIONS OF CHARGE-EXCHANGE CROSS-SECTIONS AND EMISSION SPECTRA FOR O{sup 6+} + H{sub 2}O, CO, CO{sub 2}, CH{sub 4}, N{sub 2}, NO, N{sub 2}O, AND Ar

    Energy Technology Data Exchange (ETDEWEB)

    Machacek, J. R. [Atomic and Molecular Physics Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra 2601 (Australia); Mahapatra, D. P. [Department of Physics, Utkal University, Bhubaneswar 751004 (India); Schultz, D. R. [Department of Physics, Univ. of North Texas, Denton, TX 76203 (United States); Ralchenko, Yu. [Atomic Spectroscopy Group, National Institute of Standards and Technology, Gaithersburg, MD 20899-8422 (United States); Moradmand, A.; El Ghazaly, M. O. A.; Chutjian, A. [Astrophysics and Space Sciences Section, Jet Propulsion Laboratory/Caltech, Pasadena, CA 91109 (United States)

    2015-08-10

    Relevant to modeling and understanding X-ray emission from cometary and planetary atmospheres, total cross-sections for 1.17 and 2.33 keV/u O{sup 6+} colliding with H{sub 2}O, CO, CO{sub 2}, CH{sub 4}, N{sub 2}, NO, N{sub 2}O, and Ar have been measured for the processes of single, double, and triple charge exchanges. Using these measurements as benchmarks, synthetic emission spectra spanning the X-ray, UV, and visible range have been calculated based on theoretical treatment of the transfer of between one and six electrons from the target neutrals to the projectile ion, followed by radiative and non-radiative decay of the highly excited states produced in these collisions. The results help add to the base of knowledge required to simulate ion-neutral processes in astrophysical environments; refine the present understanding of these fundamental atomic processes; and guide future observations, laboratory measurements, and theoretical predictions.

  19. IRAS low-resolution spectra of galaxies

    International Nuclear Information System (INIS)

    Cohen, M.; Volk, K.

    1989-01-01

    The spectra of external galaxies are selected and extracted from the IRAS LRS database. Twenty-one objects present viable spectra. One is a peculiar star-forming E-S0 galaxy. The remainder are all starburst or H II region galaxies. Their average spectrum demonstrates the importance of the PAH emission bands in the 8-23-micron region and reinforces the conclusion reached from ground-based spectra, that there is a strong correlation between the PAH bands and the starburst or H II region character of a galaxy. 32 refs

  20. Gamma-ray burst spectra

    International Nuclear Information System (INIS)

    Teegarden, B.J.

    1982-01-01

    A review of recent results in gamma-ray burst spectroscopy is given. Particular attention is paid to the recent discovery of emission and absorption features in the burst spectra. These lines represent the strongest evidence to date that gamma-ray bursts originate on or near neutron stars. Line parameters give information on the temperature, magnetic field and possibly the gravitational potential of the neutron star. The behavior of the continuum spectrum is also discussed. A remarkably good fit to nearly all bursts is obtained with a thermal-bremsstrahlung-like continuum. Significant evolution is observed of both the continuum and line features within most events

  1. Uranium spectra in the ICP

    Energy Technology Data Exchange (ETDEWEB)

    Ghazi, A.A.; Qamar, S.; Atta, M.A. (Khan (A.Q.) Research Labs., Rawalpindi (Pakistan))

    1994-05-01

    Uranium spectra have been studied by inductively coupled plasma atomic emission spectroscopy (ICP-AES). In total, 8361 uranium lines were observed in the wavelength range of 235-500 nm. This article is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta Part B (SAB). The hard copy text is accompanied by a disk with data files and test files for an IBM-compatible computer. The main article discusses the scientific aspects of the subject and explains the purpose of the data files. (Author).

  2. Uranium spectra in the ICP

    International Nuclear Information System (INIS)

    Ghazi, A.A.; Qamar, S.; Atta, M.A.

    1994-01-01

    Uranium spectra have been studied by inductively coupled plasma atomic emission spectroscopy (ICP-AES). In total, 8361 uranium lines were observed in the wavelength range of 235-500 nm. This article is an electronic publication in Spectrochimica Acta Electronica (SAE), the electronic section of Spectrochimica Acta Part B (SAB). The hard copy text is accompanied by a disk with data files and test files for an IBM-compatible computer. The main article discusses the scientific aspects of the subject and explains the purpose of the data files. (Author)

  3. Ultraviolet spectra of Mg in liquid helium

    International Nuclear Information System (INIS)

    Moriwaki, Y.; Morita, N.

    1999-01-01

    Emission and absorption spectra of Mg atoms implanted in liquid helium have been observed in the ultraviolet region. We have presented a model of exciplex formation of Mg-He 10 and found that this model is more suitable for understanding the dynamics in the 3s3p 1 P→3s 21 S transition than the bubble model. (orig.)

  4. Quantum synchrotron spectra from semirelativistic electrons in teragauss magnetic fields

    International Nuclear Information System (INIS)

    Brainerd, J.J.

    1987-01-01

    Synchrotron spectra are calculated from quantum electrodynamic transition rates for thermal and power-law electron distributions. It is shown that quantum effects appear in thermal spectra when the photon energy is greater than the electron temperature, and in power-law spectra when the electron energy in units of the electron rest mass times the magnetic field strength in units of the critical field strength is of order unity. These spectra are compared with spectra calculated from the ultrarelativistic approximation for synchrotron emission. It is found that the approximation for the power-law spectra is good, and the approximation for thermal spectra produces the shape of the spectrum accurately but fails to give the correct normalization. Single photon pair creation masks the quantum effects for power-law distributions, so only modifications to thermal spectra are important for gamma-ray bursts. 13 references

  5. Spectra of Graphs

    NARCIS (Netherlands)

    Brouwer, A.E.; Haemers, W.H.

    2012-01-01

    This book gives an elementary treatment of the basic material about graph spectra, both for ordinary, and Laplace and Seidel spectra. The text progresses systematically, by covering standard topics before presenting some new material on trees, strongly regular graphs, two-graphs, association

  6. Statistical properties of Fermi GBM GRBs' spectra

    Science.gov (United States)

    Rácz, István I.; Balázs, Lajos G.; Horvath, Istvan; Tóth, L. Viktor; Bagoly, Zsolt

    2018-03-01

    Statistical studies of gamma-ray burst (GRB) spectra may result in important information on the physics of GRBs. The Fermi GBM catalogue contains GRB parameters (peak energy, spectral indices, and intensity) estimated fitting the gamma-ray spectral energy distribution of the total emission (fluence, flnc), and during the time of the peak flux (pflx). Using contingency tables, we studied the relationship of the models best-fitting pflx and flnc time intervals. Our analysis revealed an ordering of the spectra into a power law - Comptonized - smoothly broken power law - Band series. This result was further supported by a correspondence analysis of the pflx and flnc spectra categorical variables. We performed a linear discriminant analysis (LDA) to find a relationship between categorical (spectral) and model independent physical data. LDA resulted in highly significant physical differences among the spectral types, that is more pronounced in the case of the pflx spectra, than for the flnc spectra. We interpreted this difference as caused by the temporal variation of the spectrum during the outburst. This spectral variability is confirmed by the differences in the low-energy spectral index and peak energy, between the pflx and flnc spectra. We found that the synchrotron radiation is significant in GBM spectra. The mean low-energy spectral index is close to the canonical value of α = -2/3 during the peak flux. However, α is ˜ -0.9 for the spectra of the fluences. We interpret this difference as showing that the effect of cooling is important only for the fluence spectra.

  7. Algorithms for classification of astronomical object spectra

    Science.gov (United States)

    Wasiewicz, P.; Szuppe, J.; Hryniewicz, K.

    2015-09-01

    Obtaining interesting celestial objects from tens of thousands or even millions of recorded optical-ultraviolet spectra depends not only on the data quality but also on the accuracy of spectra decomposition. Additionally rapidly growing data volumes demands higher computing power and/or more efficient algorithms implementations. In this paper we speed up the process of substracting iron transitions and fitting Gaussian functions to emission peaks utilising C++ and OpenCL methods together with the NOSQL database. In this paper we implemented typical astronomical methods of detecting peaks in comparison to our previous hybrid methods implemented with CUDA.

  8. High-level ab initio calculations on HGeCl and the equilibrium geometry of the A1A'' state derived from Franck-Condon analysis of the single-vibronic-level emission spectra of HGeCl and DGeCl.

    Science.gov (United States)

    Mok, Daniel K W; Chau, Foo-Tim; Lee, Edmond P F; Dyke, John M

    2010-02-01

    CCSD(T) and/or CASSCF/MRCI calculations have been carried out on the X(1)A' and A(1)A'' states of HGeCl. The fully relativistic effective core potential, ECP10MDF, and associated standard valence basis sets of up to the aug-cc-pV5Z quality were employed for Ge. Contributions from core correlation and extrapolation to the complete basis set limit were included in determining the computed equilibrium geometrical parameters and relative electronic energy of these two states of HGeCl. Based on the currently, most systematic CCSD(T) calculations performed in this study, the best theoretical geometrical parameters of the X(1)A' state are r(e)(HGe) = 1.580 +/- 0.001 A, theta(e) = 93.88 +/- 0.01 degrees and r(e)(GeCl) = 2.170 +/- 0.001 A. In addition, Franck-Condon factors including allowance for anharmonicity and Duschinsky rotation between these two states of HGeCl and DGeCl were calculated employing CCSD(T) and CASSCF/MRCI potential energy functions, and were used to simulate A(1)A'' --> X(1)A' SVL emission spectra of HGeCl and DGeCl. The iterative Franck-Condon analysis (IFCA) procedure was carried out to determine the equilibrium geometrical parameters of the A(1)A'' state of HGeCl by matching the simulated, and available experimental SVL emission spectra of HGeCl and DGeCl of Tackett et al., J Chem Phys 2006, 124, 124320, using the available, estimated experimental equilibrium (r(e)(z)) structure for the X(1)A' state, while varying the equilibrium geometrical parameters of the A(1)A'' state systematically. Employing the derived IFCA geometry of r(e)(HGe) = 1.590 A, r(e)(GeCl) = 2.155 A and theta(e)(HGeCl) = 112.7 degrees for the A(1)A'' state of HGeCl in the spectral simulation, the simulated absorption and SVL emission spectra of HGeCl and DGeCl agree very well with the available experimental LIF and SVL emission spectra, respectively. Copyright 2009 Wiley Periodicals, Inc.

  9. Flare stars of the Orion Nebula - spectra of an outburst

    International Nuclear Information System (INIS)

    Carter, B.D.; O'Mara, B.J.; Ross, J.E.

    1988-01-01

    For the first time, detailed, time-resolved spectra of a flare event of an Orion cluster flare star are presented. These spectra, covering ∼ λλ3600-4600, were obtained by using the Anglo-Australian Telescope with a fibre coupler to simultaneously monitor 23 flare stars in the region of the Orion Nebula. The flare spectra reveal continuous emission which filled in the photospheric Ca I 4226 A absorption, and hydrogen Balmer, Ca II H and K, He I 4026 A and He I 4471 A line emission. Overall, the spectral behaviour indicates similarities to strong outbursts of the classical dMe flare stars. (author)

  10. The characterization of the high-frequency vibronic contributions to the 77 K emission spectra of ruthenium-am(m)ine-bipyridyl complexes, their attenuation with decreasing energy gaps, and the implications of strong electronic coupling for inverted-region electron transfer.

    Science.gov (United States)

    Xie, Puhui; Chen, Yuan-Jang; Uddin, Md Jamal; Endicott, John F

    2005-06-02

    The 77 K emission spectra of a series of [Ru(Am)6-2n(bpy)n]2+ complexes (n = 1-3) have been determined in order to evaluate the effects of appreciable excited state (e)/ground state (g) configurational mixing on the properties of simple electron-transfer systems. The principal focus is on the vibronic contributions, and the correlated distortions of the bipyridine ligand in the emitting MLCT excited state. To address the issues that are involved, the emission band shape at 77 K is interpreted as the sum of a fundamental component, corresponding to the {e,0'} --> {g,0} transition, and progressions in the ground-state vibrational modes that correlate with the excited-state distortion. Literature values of the vibrational parameters determined from the resonance-Raman (rR) for [Ru(NH3)4bpy]2+ and [Ru(bpy)3]2+ are used to model the emission spectra and to evaluate the spectral analysis. The Gaussian fundamental component with an energy Ef and bandwidth Deltanu1/2 is deconvoluted from the observed emission spectrum. The first-, second-, and third-order terms in the progressions of the vibrational modes that contribute to the band shape are evaluated as the sums of Gaussian-shaped contributions of width Deltanu1/2. The fundamental and the rR parameters give an excellent fit of the observed emission spectrum of [Ru(NH3)4bpy]2+, but not as good for the [Ru(bpy)3]2+ emission spectrum probably because the Franck-Condon excited state probed by the rR is different in symmetry from the emitting MLCT excited state. Variations in vibronic contributions for the series of complexes are evaluated in terms of reorganizational energy profiles (emreps, Lambdax) derived from the observed spectra, and modeled using the rR parameters. This modeling demonstrates that most of the intensity of the vibronic envelopes obtained from the frozen solution emission spectra arises from the overlapping of first-order vibronic contributions of significant bandwidth with additional convoluted

  11. Two Dimensional Multiwavelength Fluorescence Spectra of Dipicolinic Acid and Calcium Dipicolinate

    National Research Council Canada - National Science Library

    Sarasanandarajah, Sivananthan

    2004-01-01

    .... In this paper we report in some detail on the room temperature fluorescence excitation and emission spectra of DPA and its calcium ion complex and comparison of the excitation-emission spectrum...

  12. Solar Energetic Particle Spectra

    Science.gov (United States)

    Ryan, J. M.; Boezio, M.; Bravar, U.; Bruno, A.; Christian, E. R.; de Nolfo, G. A.; Martucci, M.; Mergè, M.; Munini, R.; Ricci, M.; Sparvoli, R.; Stochaj, S.

    2017-12-01

    We report updated event-integrated spectra from several SEP events measured with PAMELA. The measurements were made from 2006 to 2014 in the energy range starting at 80 MeV and extending well above the neutron monitor threshold. The PAMELA instrument is in a high inclination, low Earth orbit and has access to SEPs when at high latitudes. Spectra have been assembled from these high-latitude measurements. The field of view of PAMELA is small and during the high-latitude passes it scans a wide range of asymptotic directions as the spacecraft orbits. Correcting for data gaps, solid angle effects and improved background corrections, we have compiled event-integrated intensity spectra for twenty-eight SEP events. Where statistics permit, the spectra exhibit power law shapes in energy with a high-energy exponential roll over. The events analyzed include two genuine ground level enhancements (GLE). In those cases the roll-over energy lies above the neutron monitor threshold ( 1 GV) while the others are lower. We see no qualitative difference between the spectra of GLE vs. non-GLE events, i.e., all roll over in an exponential fashion with rapidly decreasing intensity at high energies.

  13. [Experimental study on spectra of compressed air microwave plasma].

    Science.gov (United States)

    Liu, Yong-Xi; Zhang, Gui-Xin; Wang, Qiang; Hou, Ling-Yun

    2013-03-01

    Using a microwave plasma generator, compressed air microwave plasma was excited under 1 - 5 atm pressures. Under different pressures and different incident microwave power, the emission spectra of compressed air microwave plasma were studied with a spectra measuring system. The results show that continuum is significant at atmospheric pressure and the characteristic will be weakened as the pressure increases. The band spectra intensity will be reduced with the falling of the incident microwave power and the band spectra were still significant. The experimental results are valuable to studying the characteristics of compressed air microwave plasma and the generating conditions of NO active groups.

  14. Ultraviolet spectra of planetary nebulae

    International Nuclear Information System (INIS)

    Harrington, J.P.; Seaton, M.J.; Adams, S.; Lutz, J.H.

    1982-01-01

    A detailed study of NGC 7662 is based on UV results obtained from 15 IUE spectra and on observations of other workers at optical, IR and radio wavelengths. Improved techniques are used to extract IUE data for an extended source. Relative fluxes in the different apertures which have been used are obtained using the brightness contours of Coleman, Reay and Worswick. There is close agreement between the reddening deduced from the ratios He II (lambda 1640)/(lambda 4686) and (radio)/(Hβ) and the nebular continuum emission observed with the IUE large slots agrees closely with that predicted using absolute radio and Hβ fluxes. The fluxes in nebular emission lines observed with the small slots are smaller than expected from brightness distributions; it is concluded that, for an extended source, the small slots have aperture transmission factors of 0.85 for SWP and 0.46 for LWR. The central star is fainter than has been previously supposed (by more than two magnitudes). The blackbody He II Zanstra temperature of 113 000 K is consistent with the UV colour temperature. Previous work on colour temperatures of central stars is discussed critically. Two models are discussed. (author)

  15. Development of a photonuclear activation file and measurement of delayed neutron spectra; Creation d'une bibliotheque d'activation photonucleaire et mesures de spectres d'emission de neutrons retardes

    Energy Technology Data Exchange (ETDEWEB)

    Giacri-Mauborgne, M.L

    2005-11-15

    This thesis work consists in two parts. The first part is the description of the creation of a photonuclear activation file which will be used to calculated photonuclear activation. To build this file we have used different data sources: evaluations but also calculations done using several cross sections codes (HMS-ALICE, GNASH, ABLA). This file contains photonuclear activation cross sections for more than 600 nuclides and fission fragments distributions for 30 actinides at tree different Bremsstrahlung energies and the delay neutron spectrum associated. These spectra are not in good agreement with experimental data. That is why we decided to launch measurement of delayed neutrons spectra from photofission. The second part of this thesis consists in demonstrating the possibility to do such measurements at the ELSA accelerator facility. To that purpose, we have developed the detection, the acquisition system and the analysis method of such spectra. These were tested for the measurement of the delayed neutron spectrum of uranium-238 after irradiation in a 2 MeV neutron flux. Finally, we have measured the delayed neutron spectrum of uranium-238 after irradiation in a 15 MeV Bremsstrahlung flux. We compare our results with experimental data. The experiment has allowed us to improve the value of {nu}{sub p}-bar with an absolute uncertainty below 7%, we propose {nu}{sub p}-bar = (3.03 {+-} 0.02) n/100 fissions, and to correct the Nikotin's parameters for the six group representation. Particularly, we have improved the data concerning the sixth group by taking into account results from different irradiation times.

  16. Parameterization of rotational spectra

    International Nuclear Information System (INIS)

    Zhou Chunmei; Liu Tong

    1992-01-01

    The rotational spectra of the strongly deformed nuclei with low rotational frequencies and weak band mixture are analyzed. The strongly deformed nuclei are commonly encountered in the rare-earth region (e. g., 150 220). A lot of rotational band knowledge are presented

  17. Atomic Spectra Database (ASD)

    Science.gov (United States)

    SRD 78 NIST Atomic Spectra Database (ASD) (Web, free access)   This database provides access and search capability for NIST critically evaluated data on atomic energy levels, wavelengths, and transition probabilities that are reasonably up-to-date. The NIST Atomic Spectroscopy Data Center has carried out these critical compilations.

  18. Measurements of neutron emission spectra and {sup 7}Be production in Li(d, n) and Be(d, n) reactions for 25 and 40 MeV deuterons

    Energy Technology Data Exchange (ETDEWEB)

    Hagiwara, Masayuki; Baba, Mamoru; Aoki, Takao; Kawata, Naoki; Hirabayashi, Naoya; Itoga, Toshiro [Tohoku Univ., Cyclotron and Radioisotope Center, Sendai, Miyagi (Japan)

    2003-06-01

    The neutron spectra in Li(d, n) and Be(d, n) reactions for Ed = 25, 40 MeV were measured from {approx}1 MeV to highest energy of secondary neutrons at ten laboratory angles between 0- and 110-deg with the time-of-flight (TOF) method. In addition, the number of {sup 7}Be accumulated in the targets was also measured by counting the {gamma}-rays from {sup 7}Be using a pure Ge detector to obtain {sup 7}Be production cross-section and yields. (author)

  19. Laboratory-based grain-shape models for simulating dust infrared spectra

    NARCIS (Netherlands)

    Mutschke, H.; Min, M.; Tamanai, A.

    2009-01-01

    Context. Analysis of thermal dust emission spectra for dust mineralogy and physical grain properties depends on comparison spectra, which are either laboratory-measured infrared extinction spectra or calculated extinction cross sections based on certain grain models. Often, the agreement between

  20. Can blueshifted Agn spectra explain B L Lac objects

    International Nuclear Information System (INIS)

    Basu, D.

    2009-01-01

    B L Lac spectra are almost completely devoid of any emission line, and absorption features are often present based on which redshifts are estimated. Several models have been proposed to explain the spectra, including the unification scheme currently most popular among astronomers. However, there appear to be ambiguities, uncertainties and contradictory results in this model, and many questions remain unanswered. Also, it involves the process of artificially enhancing the continuum to be concentrated to a high level, by the relativistically beaming jet action, in order to submerge the emission lines, partly or completely, to make them appear weak or invisible. Additionally, the sample based on which B L Lac objects have been included in the unification scheme is rather small to be statistically viable. In this context, we present an alternative and much simpler interpretation of the observed spectra of B L Lac objects, both emission and absorption, as blueshifted lines in Agn. Original spectra of fifty six objects available in the current literature are re-analyzed. Nine of these show only a single weak emission line and no absorption feature, while thirty five exhibit no emission feature but several absorption lines, and another twelve show more than one emission line and, in some cases, several absorption lines. It is demonstrated that emission lines in most B L Lac objects are blueshifted out of the visible region, and, hence, not seen at all. Emission lines, when seen, and absorption lines, are blueshifted and are identified with search lines of longer wavelengths that are naturally weak. Blue shifts, in emission and absorption features, are determined for all objects. Various considerations lead to the conclusion that the blue shift interpretation of B L Lac spectra is superior to and more important than the redshift interpretation. A possible explanation of observed blue shifts is presented in the scenario of the ejection process, a well-recognized mechanism

  1. Lattice vibration spectra. 16

    International Nuclear Information System (INIS)

    Lutz, H.D.; Willich, P.

    1977-01-01

    The FIR absorption spectra of pyrite type compounds RuS 2 , RuSsub(2-x)Sesub(x), RuSe 2 , RuTe 2 , OsS 2 , OsSe 2 , and PtP 2 as well as loellingite type phosphides FeP 2 , RuP 2 , and OsP 2 are reported. For RuS 2 , RuSe 2 , RuTe 2 , OsS 2 , and PtP 2 all of the five infrared allowed modes (k = 0) are observed. As a first result of a numerical normal coordinate treatment vibration forms of pyrite structure are communicated. The spectra show that lattice forces of corresponding sulfides, tellurides, and phosphides are about the same strength, but increase strongly by substitution of iron by ruthenium and especially of ruthenium by osmium. The lattice constants of the RuSsub(2-x)Sesub(x) solid solution obey Vegard's rule. (author)

  2. Deconvoluting double Doppler spectra

    International Nuclear Information System (INIS)

    Ho, K.F.; Beling, C.D.; Fung, S.; Chan, K.L.; Tang, H.W.

    2001-01-01

    The successful deconvolution of data from double Doppler broadening of annihilation radiation (D-DBAR) spectroscopy is a promising area of endeavour aimed at producing momentum distributions of a quality comparable to those of the angular correlation technique. The deconvolution procedure we test in the present study is the constrained generalized least square method. Trials with computer simulated DDBAR spectra are generated and deconvoluted in order to find the best form of regularizer and the regularization parameter. For these trials the Neumann (reflective) boundary condition is used to give a single matrix operation in Fourier space. Experimental D-DBAR spectra are also subject to the same type of deconvolution after having carried out a background subtraction and using a symmetrize resolution function obtained from an 85 Sr source with wide coincidence windows. (orig.)

  3. Spectra, Winter 2014

    Science.gov (United States)

    2014-01-01

    additional copies or more information, please email spectra@nrl.navy.mil. LEADINGEDGE 1 Contents 30 Navy Launches UAV from Submerged Submarine 31... multitasking have become mainstream concerns. For example, the New York Times in 2005 and Time magazine in 2006 both reported stories about...interruptions and multitasking , and how they affect performance by increasing human er- ror. In 2005, the information technol- ogy research firm Basex

  4. Auger spectra of alkanes

    International Nuclear Information System (INIS)

    Rye, R.R.; Jennison, D.R.; Houston, J.E.

    1980-01-01

    The gas-phase Auger line shapes of the linear alkanes C 1 through C 6 and of neopentane are presented and analyzed. The general shape of the spectra are characteristic of carbon in a tetrahedral environment with the major feature in all cases occurring at approx.249 eV. The relatively large spectral changes found between methane and ethane results from the direct interaction of the terminal methyl groups in ethane, and the spectra of the higher alkanes are shown to be a composite of contributions from terminal methyl and interior methylene group carbon atoms. Theoretical analysis based on a one-electron approximation is shown to be capable of making a molecular orbital assignment by comparing calculated vertical transitions to features in the Auger spectra of ethane and propane, and, in the case of ethane, of differentiating between the 2 E/sub g/ and 2 A/sub 1g/ assignment of the ground state of (C 2 H 6 ) + . A one-electron based molecular orbital treatment, however, is shown to partially break down in propane and neopentane. Analysis of neopentane and the observed absence of any noticeable major peak energy shift with increasing molecular size (as predicted by the one-electron treatment) suggests that some Auger final states occur in which both valence holes are localized on the same subunit of the molecule

  5. Pattern recognition in spectra

    International Nuclear Information System (INIS)

    Gebran, M; Paletou, F

    2017-01-01

    We present a new automated procedure that simultaneously derives the effective temperature T eff , surface gravity log g , metallicity [ Fe/H ], and equatorial projected rotational velocity v e sin i for stars. The procedure is inspired by the well-known PCA-based inversion of spectropolarimetric full-Stokes solar data, which was used both for Zeeman and Hanle effects. The efficiency and accuracy of this procedure have been proven for FGK, A, and late type dwarf stars of K and M spectral types. Learning databases are generated from the Elodie stellar spectra library using observed spectra for which fundamental parameters were already evaluated or with synthetic data. The synthetic spectra are calculated using ATLAS9 model atmospheres. This technique helped us to detect many peculiar stars such as Am, Ap, HgMn, SiEuCr and binaries. This fast and efficient technique could be used every time a pattern recognition is needed. One important application is the understanding of the physical properties of planetary surfaces by comparing aboard instrument data to synthetic ones. (paper)

  6. Diversity of soft X-ray spectra in quasars

    International Nuclear Information System (INIS)

    Elvis, M.; Wilkes, B.J.; Tananbaum, H.

    1985-01-01

    Soft X-ray spectra for three quasars obtained with the Einstein Imaging Proportional Counter covering the 0.1-4.0 keV band are reported. Power-law fits to these spectra have best-fit energy indices of 1.2 +0.6 or -0.2, for the quasar NAB 0205 + 024, 0.6 +0.3 or -0.2 for the quasar B2 1028 + 313, and 2.2 + or -0.4 for the quasar PG 1211 + 143. None of the quasars shows any evidence for a column density of cold matter in excess of the galactic values. The derived spectra demonstrate that there is no single universal power law slope for quasar X-ray spectra. The implications of these results for the X-ray background, X-ray continuum emission mechanisms, and the production of the optical/UV emission lines are briefly discussed. 46 references

  7. Deconvolution of Positrons' Lifetime spectra

    International Nuclear Information System (INIS)

    Calderin Hidalgo, L.; Ortega Villafuerte, Y.

    1996-01-01

    In this paper, we explain the iterative method previously develop for the deconvolution of Doppler broadening spectra using the mathematical optimization theory. Also, we start the adaptation and application of this method to the deconvolution of positrons' lifetime annihilation spectra

  8. Vibrational spectra of aminoacetonitrile

    International Nuclear Information System (INIS)

    Bak, B.; Hansen, E.L.; Nicolaisen, F.M.; Nielsen, O.F.

    1975-01-01

    The preparation of pure, stable aminoacetonitrile(1-amino, 1'-cyanomethane)CH 2 NH 2 CN (1) is described. The Raman spectrum, now complete, and a novel infrared spectrum extending over the 50-3600 cm -1 region are reported. A tentative normal vibration analysis is presented and supported by Raman and infrared data from the spectra of CH 2 NHDCN (2) and CH 2 ND 2 CN (3). The predominance of the trans rotamer may be attributed to intramolecular hydrogen bonding but this is too unimportant to influence the vibrational frequencies of gaseous 1, 2, and 3. However, large gas/liquid frequency shifts occur. (author)

  9. Nuclear Neutrino Spectra in Late Stellar Evolution

    Science.gov (United States)

    Misch, G. Wendell; Sun, Yang; Fuller, George

    2018-05-01

    Neutrinos are the principle carriers of energy in massive stars, beginning from core carbon burning and continuing through core collapse and after the core bounce. In fact, it may be possible to detect neutrinos from nearby pre-supernova stars. Therefore, it is of great interest to understand the neutrino energy spectra from these stars. Leading up to core collapse, beginning around core silicon burning, nuclei become dominant producers of neutrinos, particularly at high neutrino energy, so a systematic study of nuclear neutrino spectra is desirable. We have done such a study, and we present our sd-shell model calculations of nuclear neutrino energy spectra for nuclei in the mass number range A = 21 - 35. Our study includes neutrinos produced by charged lepton capture, charged lepton emission, and neutral current nuclear deexcitation. Previous authors have tabulated the rates of charged current nuclear weak interactions in astrophysical conditions, but the present work expands on this not only by providing neutrino energy spectra, but also by including the heretofore untabulated neutral current de-excitation neutrino pairs.

  10. [Fluorescence spectra analysis of the scrophularia soup].

    Science.gov (United States)

    Yan, Li-hua; Song, Feng; Han, Juan; Su, Jing; Qu, Fei-fei; Song, Yi-zhan; Hu, Bo-lin; Tian, Jian-guo

    2008-08-01

    The cold-water and boiled-water soaked scrophularia soups have been prepared. The emission and excitation spectra of each scrophularia soup under different conditions have been measured at room temperature. The pH values of the different scrophularia soups have been also detected. There are obvious differences between the cold-water soaked scrophularia soup and the boiled-water soaked scrophularia. For both soups the emission wavelength increases with the wavelength of the excitation, but the peaks of the emission spectra for cold-water and boiled-water soaked scrophularia soup are different, which are 441 and 532 nm, respectively. Excitation spectrum has double peaks in the cold-water soaked scrophularia soup while only one peak with longer wavelength in the boiled-water soaked one. The pH value changes from 5.5 to 4.1. According to the organic admixture fluorescence mechanism we analyzed the reasons of the experimental results. Through heating, the interaction in different fluorescence molecular and the energy transfer process in the same fluorescence molecular become more active, and the conjugate structures and the generation of hydrogen bonds, increase. The fluorescence measurement is of value for the scrophularia pharmacology analysis and provides an analytical method for the quality identification of scrophularia soup.

  11. Catalogue of neutron spectra

    International Nuclear Information System (INIS)

    Buxerolle, M.; Massoutie, M.; Kurdjian, J.

    1987-09-01

    Neutron dosimetry problems have arisen as a result of developments in the applications of nuclear energy. The largest number of possible irradiation situations has been collected: they are presented in the form of a compilation of 44 neutron spectra. Diagrams show the variations of energy fluence and energy fluence weighted by the dose equivalent/fluence conversion factor, with the logarithm of the corresponding energy. The equivalent dose distributions are presented as percentages for the following energy bins: 0.01 eV/0.5 eV/50 keV/1 MeV/5 MeV/15 MeV. The dose equivalent, the mean energy and the effective energy for the dose equivalent for 1 neutron cm -2 are also given [fr

  12. Photographic infrared spectra of symbiotic stars

    International Nuclear Information System (INIS)

    Andrillat, Y.; Houziaux, L.

    1982-01-01

    The authors have observed six symbiotic stars during the period 1962-1977 with a grating spectrograph attached to the newtonian focus of the 120-cm telescope at Observatoire de Haute Provence. The reciprocal dispersion is 230 A.mm -1 and the region 5800 to 8800 A has been covered using hypersensitized IN plates. The minimum equivalent width for an emission line to be seen is about 0.5 A. The spectra are displayed and the main spectral characteristics are reviewed briefly. (Auth.)

  13. Monte Carlo simulation of x-ray spectra in mammography

    Energy Technology Data Exchange (ETDEWEB)

    Ng, K.P. [Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China). E-mail: benngkp at netvigator.com; Kwok, C.S.; Ng, K.P.; Tang, F.H. [Department of Optometry and Radiography, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

    2000-05-01

    A model for generating x-ray spectra in mammography is presented. This model used the ITS version 3 Monte Carlo code for simulating the radiation transport. Various target/filter combinations such as tungsten/aluminium, molybdenum/molybdenum, molybdenum/rhodium and rhodium/rhodium were used in the simulation. Both bremsstrahlung and characteristic x-ray production were included in the model. The simulated x-ray emission spectra were compared with two sets of spectra, those of Boone et al (1997 Med. Phys. 24 1863-74) and IPEM report 78. The {chi}{sup 2} test was used for the overall goodness of fit of the spectral data. There is good agreement between the simulated x-ray spectra and the comparison spectra as the test yielded a probability value of nearly 1. When the transmitted x-ray spectra for specific target/filter combinations were generated and compared with a measured molybdenum/rhodium spectrum and spectra generated in IPEM report 78, close agreement is also observed. This was demonstrated by the probability value for the {chi}{sup 2} test being almost 1 for all the cases. However, minor differences between the simulated spectra and the 'standard' ones are observed. (author)

  14. Monte Carlo simulation of x-ray spectra in mammography

    International Nuclear Information System (INIS)

    Ng, K.P.

    2000-01-01

    A model for generating x-ray spectra in mammography is presented. This model used the ITS version 3 Monte Carlo code for simulating the radiation transport. Various target/filter combinations such as tungsten/aluminium, molybdenum/molybdenum, molybdenum/rhodium and rhodium/rhodium were used in the simulation. Both bremsstrahlung and characteristic x-ray production were included in the model. The simulated x-ray emission spectra were compared with two sets of spectra, those of Boone et al (1997 Med. Phys. 24 1863-74) and IPEM report 78. The χ 2 test was used for the overall goodness of fit of the spectral data. There is good agreement between the simulated x-ray spectra and the comparison spectra as the test yielded a probability value of nearly 1. When the transmitted x-ray spectra for specific target/filter combinations were generated and compared with a measured molybdenum/rhodium spectrum and spectra generated in IPEM report 78, close agreement is also observed. This was demonstrated by the probability value for the χ 2 test being almost 1 for all the cases. However, minor differences between the simulated spectra and the 'standard' ones are observed. (author)

  15. Observed Barium Emission Rates

    Science.gov (United States)

    Stenbaek-Nielsen, H. C.; Wescott, E. M.; Hallinan, T. J.

    1993-01-01

    The barium releases from the CRRES satellite have provided an opportunity for verifying theoretically calculated barium ion and neutral emission rates. Spectra of the five Caribbean releases in the summer of 1991 were taken with a spectrograph on board a U.S. Air Force jet aircraft. Because the line of sight release densities are not known, only relative rates could be obtained. The observed relative rates agree well with the theoretically calculated rates and, together with other observations, confirm the earlier detailed theoretical emission rates. The calculated emission rates can thus with good accuracy be used with photometric observations. It has been postulated that charge exchange between neutral barium and oxygen ions represents a significant source for ionization. If so. it should be associated with emissions at 4957.15 A and 5013.00 A, but these emissions were not detected.

  16. Design energy spectra for Turkey

    OpenAIRE

    López Almansa, Francisco; Yazgan, Ahmet Utku; Benavent Climent, Amadeo

    2012-01-01

    This work proposes design energy spectra in terms of velocity, derived through linear dynamic analyses on Turkish registers and intended for regions with design peak acceleration 0.3 g or higher. In the long and mid period ranges the analyses are linear, taking profit of the rather insensitivity of the spectra to the structural parameters other than the fundamental period; in the short period range, the spectra are more sensitive to the structural parameters and nonlinear analyses would be re...

  17. Spectra of chemical trees

    International Nuclear Information System (INIS)

    Balasubramanian, K.

    1982-01-01

    A method is developed for obtaining the spectra of trees of NMR and chemical interests. The characteristic polynomials of branched trees can be obtained in terms of the characteristic polynomials of unbranched trees and branches by pruning the tree at the joints. The unbranched trees can also be broken down further until a tree containing just two vertices is obtained. The effectively reduces the order of the secular determinant of the tree used at the beginning to determinants of orders atmost equal to the number of vertices in the branch containing the largest number of vertices. An illustrative example of a NMR graph is given for which the 22 x 22 secular determinant is reduced to determinants of orders atmost 4 x 4 in just the second step of the algorithm. The tree pruning algorithm can be applied even to trees with no symmetry elements and such a factoring can be achieved. Methods developed here can be elegantly used to find if two trees are cospectral and to construct cospectral trees

  18. Sequencing BPS spectra

    Energy Technology Data Exchange (ETDEWEB)

    Gukov, Sergei [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Max-Planck-Institut für Mathematik,Vivatsgasse 7, D-53111 Bonn (Germany); Nawata, Satoshi [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Centre for Quantum Geometry of Moduli Spaces, University of Aarhus,Nordre Ringgade 1, DK-8000 (Denmark); Saberi, Ingmar [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Stošić, Marko [CAMGSD, Departamento de Matemática, Instituto Superior Técnico,Av. Rovisco Pais, 1049-001 Lisbon (Portugal); Mathematical Institute SANU,Knez Mihajlova 36, 11000 Belgrade (Serbia); Sułkowski, Piotr [Walter Burke Institute for Theoretical Physics, California Institute of Technology,1200 E California Blvd, Pasadena, CA 91125 (United States); Faculty of Physics, University of Warsaw,ul. Pasteura 5, 02-093 Warsaw (Poland)

    2016-03-02

    This paper provides both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explain from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincaré polynomials in numerous examples. Among these structural properties is a novel “sliding” property, which can be explained by using (refined) modular S-matrix. This leads to the identification of modular transformations in Chern-Simons theory and 3d N=2 theory via the 3d/3d correspondence. Lastly, we introduce the notion of associated varieties as classical limits of recursion relations of colored superpolynomials of links, and study their properties.

  19. Sequencing BPS spectra

    International Nuclear Information System (INIS)

    Gukov, Sergei; Nawata, Satoshi; Saberi, Ingmar; Stošić, Marko; Sułkowski, Piotr

    2016-01-01

    This paper provides both a detailed study of color-dependence of link homologies, as realized in physics as certain spaces of BPS states, and a broad study of the behavior of BPS states in general. We consider how the spectrum of BPS states varies as continuous parameters of a theory are perturbed. This question can be posed in a wide variety of physical contexts, and we answer it by proposing that the relationship between unperturbed and perturbed BPS spectra is described by a spectral sequence. These general considerations unify previous applications of spectral sequence techniques to physics, and explain from a physical standpoint the appearance of many spectral sequences relating various link homology theories to one another. We also study structural properties of colored HOMFLY homology for links and evaluate Poincaré polynomials in numerous examples. Among these structural properties is a novel “sliding” property, which can be explained by using (refined) modular S-matrix. This leads to the identification of modular transformations in Chern-Simons theory and 3d N=2 theory via the 3d/3d correspondence. Lastly, we introduce the notion of associated varieties as classical limits of recursion relations of colored superpolynomials of links, and study their properties.

  20. Near infrared spectra of Wolf-Rayet stars

    International Nuclear Information System (INIS)

    Bappu, M.K.V.; Ganesh, K.S.; Scaria, K.K.

    1977-01-01

    The near-infrared spectra of three Wolf-Rayet stars of the carbon sequence and five of the nitrogen sequence have been studied. Wavelength identifications and intensity scans are presented to show the emission line characteristics of these objects in the 6800 A to 8200 A domain of the spectrum. (author)

  1. Bioluminescence emissions of the firefly Luciola praeusta ...

    Indian Academy of Sciences (India)

    Prakash

    The emission of light by fireflies has been of considerable ... vivo emission spectrum of a firefly Luciola praeusta, where the full width at ... In vivo emission spectra of fifty specimens, both male .... oxidation in a liquid phase; Biofizika 9 306–311.

  2. An analysis of scattered light in low dispersion IUE spectra

    Science.gov (United States)

    Basri, G.; Clarke, J. T.; Haisch, B. M.

    1985-01-01

    A detailed numerical simulation of light scattering from the low-resolution grating in the short wavelength spectrograph of the IUE Observatory was developed, in order to quantitatively analyze the effects of scattering on both continuum and line emission spectra. It is found that: (1) the redistribution of light by grating scattering did not appreciably alter either the shape or the absolute flux level of continuum spectra for A-F stars; (2) late-type stellar continua showed a tendency to flatten when observed in scattered light toward the shorter wavelengths; and (3) the effect of grating scattering on emission lines is to decrease measured line intensities by an increasing percentage toward the shorter wavelengths. The spectra obtained from scattering experiments for solar-type and late type stars are reproduced in graphic form.

  3. The Rovibronic Spectra of the Cyclopentadienyl Radical

    Science.gov (United States)

    Sharma, Ketan; Miller, Terry A.; Stanton, John F.; Nesbitt, David

    2017-06-01

    Cyclopentadienyl (Cp) radical has been subject to numerous studies for the greater part of half a century. Experimental work has involved photo-electron spectroscopy, laser induced fluorescence excitation and emission, infrared absorption spectroscopy, and recently rotationally resolved spectra in the CH stretch region taken at JILA. Even more theoretical works appear in the literature, but substantial advances in computation have occurred since their completion. Cp's highly symmetric (D_{5h}) structure and doubly degenerate electronic ground (˜{X}^2E_1^{''}), which is subject to linear Jahn-Teller distortion, have been a great motivation for work on it. We have commenced new computational work to obtain a broad understanding of the electronic, vibrational, and rotational, i.e. rovibronic, structure of the Cp radical as revealed by its spectra, with particular emphasis on the new infrared spectra. The goal is to guide experiments and their analyses and reconcile results from spectroscopy and quantum chemistry calculations. T. Ichino, et al. J. Chem. Phys. 129, 084310 (2008) L. Yu, S. C. Foster, J. M. Williamson, M. C. Heaven and T. A. Miller J. Phys. Chem. 92, 4263 (1988) B. E. Applegate, A. J. Bezant and T. A. Miller J. Chem. Phys 114, 4869 (2001) D. Leicht, M. Kaufmann, G. Schwaab, and M. Havenith J. Chem. Phys. 145, 7 (2016), 074304.

  4. Transient Infrared Emission Spectroscopy

    Science.gov (United States)

    Jones, Roger W.; McClelland, John F.

    1989-12-01

    Transient Infrared Emission Spectroscopy (TIRES) is a new technique that reduces the occurrence of self-absorption in optically thick solid samples so that analytically useful emission spectra may be observed. Conventional emission spectroscopy, in which the sample is held at an elevated, uniform temperature, is practical only for optically thin samples. In thick samples the emission from deep layers of the material is partially absorbed by overlying layers.1 This self-absorption results in emission spectra from most optically thick samples that closely resemble black-body spectra. The characteristic discrete emission bands are severely truncated and altered in shape. TIRES bypasses this difficulty by using a laser to heat only an optically thin surface layer. The increased temperature of the layer is transient since the layer will rapidly cool and thicken by thermal diffusion; hence the emission collection must be correlated with the laser heating. TIRES may be done with both pulsed and cw lasers.2,3 When a pulsed laser is used, the spectrometer sampling must be synchronized with the laser pulsing so that only emission during and immediately after each laser pulse is observed.3 If a cw laser is used, the sample must move rapidly through the beam. The hot, transient layer is then in the beam track on the sample at and immediately behind the beam position, so the spectrometer field of view must be limited to this region near the beam position.2 How much self-absorption the observed emission suffers depends on how thick the heated layer has grown by thermal diffusion when the spectrometer samples the emission. Use of a pulsed laser synchronized with the spectrometer sampling readily permits reduction of the time available for heat diffusion to about 100 acs .3 When a cw laser is used, the heat-diffusion time is controlled by how small the spectrometer field of view is and by how rapidly the sample moves past within this field. Both a very small field of view and a

  5. Pre-equilibrium gamma emissions

    International Nuclear Information System (INIS)

    Ghosh, Sudip

    1993-01-01

    Together with the direct reaction and the compound nuclear emissions the pre-equilibrium (PEQ) or pre-compound processes give a fairly complete picture of nuclear reactions induced by light ions at energies of some tens of MeV. PEQ particle emissions covering the higher energy continuum spectra have been investigated in detail both experimentally and theoretically. In contrast, very little work has been done on PEQ γ- emissions. The reason is that in spite of extensive work done on PEQ particle emissions, the mechanism is not yet fully understood. Also, the PEQ γ-emission cross-sections (∼ micro barns) are very small compared to the PEQ particle emission cross-sections (∼ milli barns). Yet apart from the academic interest the understanding of PEQ γ-emissions is important for applied fusion research etc. In this paper the PEQ γ-emissions is discussed and the work done in this field is reviewed. (author). 14 refs

  6. EFFECTS OF FORSTERITE GRAIN SHAPE ON INFRARED SPECTRA

    International Nuclear Information System (INIS)

    Koike, C.; Imai, Y.; Chihara, H.; Murata, K.; Tsuchiyama, A.; Suto, H.; Tachibana, S.; Ohara, S.

    2010-01-01

    The Infrared Space Observatory (ISO) detected several sharp infrared features around young stars, comets, and evolved stars. These sharp features were identified as Mg-rich crystalline silicates of forsterite and enstatite by comparison with spectra from laboratory data. However, certain infrared emission bands in the observed spectra cannot be identified because they appear at slightly shorter wavelengths than the peaks in forsterite laboratory spectra, where the shapes of forsterite particles are irregular. To solve this problem, we measured infrared spectra of forsterite grains of various shapes (irregular, plate-like with no sharp edges, elliptical, cauliflower, and spherical) in the infrared spectral region between 5 and 100 μm. The spectra depend on particle shape. The spectra of the 11, 19, 23, and 33 μm bands, in particular, are extremely sensitive to particle shape, whereas some peaks such as the 11.9, 49, and 69 μm bands remained almost unchanged despite different particle shapes. This becomes most evident from the spectra of near-spherical particles produced by annealing an originally amorphous silicate sample at temperature from 600 to 1150 deg. C. The spectra of these samples differ strongly from those of other ones, showing peaks at much shorter wavelengths. At a higher annealing temperature of 1200 deg. C, the particle shapes changed drastically from spherical to irregular and the spectra became similar to those of forsterite particles with irregular shapes. Based on ISO data and other observational data, the spectra of outflow sources and disk sources may correspond to differences in forsterite shape, and further some unidentified peaks, such as those at 32.8 or 32.5 μm, may be due to spherical or spherical-like forsterite.

  7. Observational and theoretical spectra of supernovae

    Science.gov (United States)

    Wheeler, J. Craig; Swartz, Douglas A.; Harkness, Robert P.

    1993-05-01

    Progress in nuclear astrophysics by means of quantitative supernova spectroscopy is discussed with special concentration on type Ia, Ib and Ic and on SN 1987A. Spectral calculations continue to support an exploding C/O white dwarf as the best model of a SN Ia. Deflagration model W7 produces good maximum light spectra of SN Ia and seems to have a better composition distribution compared to delayed detonation models, but proper treatment of opacity remains a problem and the physical basis of SN Ia explosions is still not completely understood. All models for SN Ia predict large quantities of 56Co in the ejecta, but it is not clear that observations confirm this. Although the evolutionary origin of SN Ia remains uncertain, there is recent evidence that transfer of hydrogen in a binary system may be involved, as long suspected. There has been progress in comparing dynamical models with the optical/IR spectra of SN 1987A. The evolution of the [OI] λλ6300, 6364 feature and the presence of strong persistent HeI λ10 830 indicate that both the envelope and core material contribute substantially to the formation of emission lines in the nebular phase and that neither the core nor the envelope can be neglected. Blending with nearby hydrogen lines may affect both of these spectral features, thereby complicating the analysis of the lines. The effects of continuum transfer and photoionization have been included and are under study. The discrepancies between theoretical and observed spectra are due primarily to the one-dimensional hydrodynamic models. The spectral data are not consistent with the high density ``spike'' (in radial coordinate) of the core material that is predicted by all such models. Analysis of the light curves of SN Ib and SN Ic supernovae implies that there are significant differences in their physical properties. Some SN Ib have considerably more ejecta mass than SN Ic events. SN Ib require He-rich atmospheres to produce the observed strong optical lines of

  8. Effect of surfactants on the fluorescence spectra of water-soluble ...

    Indian Academy of Sciences (India)

    TECS

    Effect of surfactants on the fluorescence spectra of water-soluble. MEHPPV ... polyacrylic acid (PAA) chains grafted onto their backbone were found to be water soluble, and they exhi- ..... in other words the variation of emission intensity.

  9. Raman spectra of lithium compounds

    Science.gov (United States)

    Gorelik, V. S.; Bi, Dongxue; Voinov, Y. P.; Vodchits, A. I.; Gorshunov, B. P.; Yurasov, N. I.; Yurasova, I. I.

    2017-11-01

    The paper is devoted to the results of investigating the spontaneous Raman scattering spectra in the lithium compounds crystals in a wide spectral range by the fibre-optic spectroscopy method. We also present the stimulated Raman scattering spectra in the lithium hydroxide and lithium deuteride crystals obtained with the use of powerful laser source. The symmetry properties of the lithium hydroxide, lithium hydroxide monohydrate and lithium deuteride crystals optical modes were analyzed by means of the irreducible representations of the point symmetry groups. We have established the selection rules in the Raman and infrared absorption spectra of LiOH, LiOH·H2O and LiD crystals.

  10. FSFE: Fake Spectra Flux Extractor

    Science.gov (United States)

    Bird, Simeon

    2017-10-01

    The fake spectra flux extractor generates simulated quasar absorption spectra from a particle or adaptive mesh-based hydrodynamic simulation. It is implemented as a python module. It can produce both hydrogen and metal line spectra, if the simulation includes metals. The cloudy table for metal ionization fractions is included. Unlike earlier spectral generation codes, it produces absorption from each particle close to the sight-line individually, rather than first producing an average density in each spectral pixel, thus substantially preserving more of the small-scale velocity structure of the gas. The code supports both Gadget (ascl:0003.001) and AREPO.

  11. Behavior of lambda 2800 Mg II in stellar spectra

    International Nuclear Information System (INIS)

    Gurzadyan, G.A.

    1975-01-01

    The results of measurements of the equivalent widths of the resonance doublet of ionized magnesium lambda 2800 Mg II in the spectra of 51 relatively faint stars, up to 10/sup m/, of the spectral classes B1-K5 are presented. The observed material has been obtained by means of the space observatory ''Orion-2''. Some regularities in the behavior of lambda 2800 Mg II in stellar spectra have been revealed: wide and deep depression of the continuous spectra at 2800 A in F-G type stars; the presence of the doublet lambda 2800 Mg II in the form of weak emission in the spectra of cold stars (K2-K5); the presence both of the multiplet lambda 3080 Ti II and the doublet lambda 2800 Mg II simultaneously either in emission--in the late-type stars--or in absorption in earlier types; the existence of combined profiles of lambda 2800 Mg II, i.e., a wide absorption line with a weak emission in the center, in stars of the transitional class (G5-K0), etc. A well-defined empirical relationship between the equivalent width of lambda 2800 Mg II and the spectral class of the star has been established (Fig. 8). (U.S.)

  12. Infrared spectra of mineral species

    CERN Document Server

    Chukanov, Nikita V

    2014-01-01

    This book details more than 3,000 IR spectra of more than 2,000 mineral species collected during last 30 years. It features full descriptions and analytical data of each sample for which IR spectrum was obtained.

  13. Correlation Functions and Power Spectra

    DEFF Research Database (Denmark)

    Larsen, Jan

    2006-01-01

    The present lecture note is a supplement to the textbook Digital Signal Processing by J. Proakis and D.G. Manolakis used in the IMM/DTU course 02451 Digital Signal Processing and provides an extended discussion of correlation functions and power spectra. The definitions of correlation functions...... and spectra for discrete-time and continuous-time (analog) signals are pretty similar. Consequently, we confine the discussion mainly to real discrete-time signals. The Appendix contains detailed definitions and properties of correlation functions and spectra for analog as well as discrete-time signals....... It is possible to define correlation functions and associated spectra for aperiodic, periodic and random signals although the interpretation is different. Moreover, we will discuss correlation functions when mixing these basic signal types. In addition, the note include several examples for the purpose...

  14. Correlation between optical emission spectra and the process ...

    Indian Academy of Sciences (India)

    and disadvantages, but, good quality diamond can be deposited mainly using ... increase in the CH4 concentration up to 0.8% of the total gas mixture, and then ... the effect of microwave reactor parameters on thermal management of silicon.

  15. Multifractal spectra in shear flows

    Science.gov (United States)

    Keefe, L. R.; Deane, Anil E.

    1989-01-01

    Numerical simulations of three-dimensional homogeneous shear flow and fully developed channel flow, are used to calculate the associated multifractal spectra of the energy dissipation field. Only weak parameterization of the results with the nondimensional shear is found, and this only if the flow has reached its asymptotic development state. Multifractal spectra of these flows coincide with those from experiments only at the range alpha less than 1.

  16. Sequential Analysis of Gamma Spectra

    International Nuclear Information System (INIS)

    Fayez-Hassan, M.; Hella, Kh.M.

    2009-01-01

    This work shows how easy one can deal with a huge number of gamma spectra. The method can be used for radiation monitoring. It is based on the macro feature of the windows XP connected to QBASIC software. The routine was used usefully in generating accurate results free from human errors. One hundred measured gamma spectra were fully analyzed in 10 minutes using our fast and automated method controlling the Genie 2000 gamma acquisition analysis software.

  17. Temperature dependent analysis of three classes of fluorescence spectra from p-6P nanofiber films

    DEFF Research Database (Denmark)

    Balzer, F.; Pogantsch, Alexander; Rubahn, Horst-Günter

    2009-01-01

    devices, given that the spectra are reproducible for varying surface temperatures. A detailed investigation as a function of surface temperature variation from 300 to 30 K reveals three classes of spectra: (a) spectra with well resolved excitonic peaks, which shift 35meV to the blue with decreasing...... temperature, (b) similar spectra with an additional intermediate broadening around 150 K, and (c) excitonic spectra similar to (b), but with a green defect emission band. Quantitative fitting of type (a) spectra results in an  exciton–phonon coupling factor of 80 ± 10meV and an average phonon temperature of Θ...... = 670 ± 70 K. The Huang–Rhys factor decreases linearly from 1.2 at 300 K to 1.0 at 30 K. Fitting of type (b) spectra reveals that the apparent intermediate temperature broadening is due to additional fluorescence peaks, the relative importance of which increasing with decreasing temperature....

  18. FHILs in Seyferts and Liners in the optical spectra

    Science.gov (United States)

    Vera, R. J. C.; Rodriguez, A. M.; Portilla, J. G.

    2014-10-01

    We present the main results from a selection of optical spectra of Seyfert and LINER galaxies taken from the 9^{th} release of the SDSS with detectable emission of forbidden high ionization lines (FHILs), better known as coronal lines. A catalog of 345 Seyfert 1 (Sy1) and Seyfert 2 (Sy2) galaxies with FHILs emission is presented. By analyzing their spectra and utilizing data from the literature we found the following results: (1) The flux ratios between FHILs suggests anisotropy of emission between Sy1 and Sy2 galaxies, which agrees with the results found by Nagao et al. (2002) and Portilla (2012). Sy1 seems to emit more FHILs than Sy2. (2) This anisotropy suggests the idea that an important, but not the majority, of the emission of FHILs comes from the inner part of the obscuring torus. (3) We present diagnostic diagrams between FHILs lines which indicate clear correlations between the flux ratios. (4) It is observed that the ratio of Ne V/Fe VII is of the order of 3 to 10, while the ratios between iron lines (i.e., Fe VII, Fe X, Fe XI) are roughly around the unity. (5) At least in the optical spectra, the present study continues to support the general idea that LINERs are not energetic enough to present FHILs. A complete version of this study including the catalog with the objects of study, and diagnosis diagrams using only this kind of lines can be found in Vera & Portilla (in prep).

  19. Mid-Infrared Silicate Dust Features in Seyfert 1 Spectra

    Science.gov (United States)

    Thompson, Grant D.; Levenson, N. A.; Sirocky, M. M.; Uddin, S.

    2007-12-01

    Silicate dust emission dominates the mid-infrared spectra of galaxies, and the dust produces two spectral features, at 10 and 18 μm. These features' strengths (in emission or absorption) and peak wavelengths reveal the geometry of the dust distribution, and they are sensitive to the dust composition. We examine mid-infrared spectra of 32 Seyfert 1 active galactic nuclei (AGN), observed with the Infrared Spectrograph aboard the Spitzer Space Telescope. In the spectra, we typically find the shorter-wavelength feature in emission, at an average peak wavelength of 10.0 μm, although it is known historically as the "9.7 μm" feature. In addition, peak wavelength increases with feature strength. The 10 and 18 μm feature strengths together are sensitive to the dust geometry surrounding the central heating engine. Numerical calculations of radiative transfer distinguish between clumpy and smooth distributions, and we find that the surroundings of these AGN (the obscuring "tori" of unified AGN schemes) are clumpy. Polycyclic aromatic hydrocarbon (PAH) features are associated with star formation, and we find strong PAH emission (luminosity ≥ 1042 erg/s) in only four sources, three of which show independent evidence for starbursts. We will explore the effects of luminosity on dust geometry and chemistry in a comparison sample of quasars. We acknowledge work supported by the NSF under grant number 0237291.

  20. Response spectra in alluvial soils

    International Nuclear Information System (INIS)

    Chandrasekharan, A.R.; Paul, D.K.

    1975-01-01

    For aseismic design of structures, the ground motion data is assumed either in the form of ground acceleration as a function of time or indirectly in the form of response spectra. Though the response spectra approach has limitations like not being applicable for nonlinear problems, it is usually used for structures like nuclear power plants. Fifty accelerograms recorded at alluvial sites have been processed. Since different empirical formulas relating acceleration with magnitude and distance give a wide scatter of values, peak ground acceleration alone cannot be the parameter as is assumed by a number of authors. The spectra corresponding to 5% damping have been normalised with respect to three parameters, namely, peak ground acceleration, peak ground velocity and a nondimensional quantity ad/v 2 . Envelopee of maxima and minima as well as average response spectra has been obtained. A comparison with the USAEC spectra has been made. A relation between ground acceleration, ground velocity and ad/v 2 has been obtained which would nearly give the same magnification of the response. A design response spectra for alluvial soils has been recommended. (author)

  1. Acoustic emission

    International Nuclear Information System (INIS)

    Nichols, R.W.

    1976-01-01

    The volume contains six papers which together provide an overall review of the inspection technique known as acoustic emission or stress wave emission. The titles are: a welder's introduction to acoustic emission technology; use of acoustic emission for detection of defects as they arise during fabrication; examples of laboratory application and assessment of acoustic emission in the United Kingdom; (Part I: acoustic emission behaviour of low alloy steels; Part II: fatigue crack assessment from proof testing and continuous monitoring); inspection of selected areas of engineering structures by acoustic emission; Japanese experience in laboratory and practical applications of acoustic emission to welded structures; and ASME acoustic emission code status. (U.K.)

  2. Characterizing Sky Spectra Using SDSS BOSS Data

    Science.gov (United States)

    Florez, Lina Maria; Strauss, Michael A.

    2018-01-01

    In the optical/near-infrared spectra gathered by a ground-based telescope observing very faint sources, the strengths of the emission lines due to the Earth’s atmosphere can be many times larger than the fluxes of the sources we are interested in. Thus the limiting factor in faint-object spectroscopy is the degree to which systematics in the sky subtraction can be minimized. Longwards of 6000 Angstroms, the night-sky spectrum is dominated by multiple vibrational/rotational transitions of the OH radical from our upper atmosphere. While the wavelengths of these lines are the same in each sky spectrum, their relative strengths vary considerably as a function of time and position on the sky. The better we can model their strengths, the better we can hope to subtract them off. We expect that the strength of lines from common upper energy levels will be correlated with one another. We used flux-calibrated sky spectra from the Sloan Digital Sky Survey Baryon Oscillation Spectroscopic Survey (SDSS BOSS) to explore these correlations. Our aim is to use these correlations for creating improved sky subtraction algorithms for the Prime Focus Spectrograph (PFS) on the 8.2-meter Subaru Telescope. When PFS starts gathering data in 2019, it will be the most powerful multi-object spectrograph in the world. Since PFS will be gathering data on sources as faint as 24th magnitude and fainter, it's of upmost importance to be able to accurately measure and subtract sky spectra from the data that we receive.

  3. Interstellar dehydrogenated PAH anions: vibrational spectra

    Science.gov (United States)

    Buragohain, Mridusmita; Pathak, Amit; Sarre, Peter; Gour, Nand Kishor

    2018-03-01

    Interstellar polycyclic aromatic hydrocarbon (PAH) molecules exist in diverse forms depending on the local physical environment. Formation of ionized PAHs (anions and cations) is favourable in the extreme conditions of the interstellar medium (ISM). Besides in their pure form, PAHs are also likely to exist in substituted forms; for example, PAHs with functional groups, dehydrogenated PAHs etc. A dehydrogenated PAH molecule might subsequently form fullerenes in the ISM as a result of ongoing chemical processes. This work presents a density functional theory (DFT) calculation on dehydrogenated PAH anions to explore the infrared emission spectra of these molecules and discuss any possible contribution towards observed IR features in the ISM. The results suggest that dehydrogenated PAH anions might be significantly contributing to the 3.3 μm region. Spectroscopic features unique to dehydrogenated PAH anions are highlighted that may be used for their possible identification in the ISM. A comparison has also been made to see the size effect on spectra of these PAHs.

  4. Fourier transform spectra of quantum dots

    Science.gov (United States)

    Damian, V.; Ardelean, I.; Armăşelu, Anca; Apostol, D.

    2010-05-01

    Semiconductor quantum dots are nanometer-sized crystals with unique photochemical and photophysical properties that are not available from either isolated molecules or bulk solids. These nanocrystals absorb light over a very broad spectral range as compared to molecular fluorophores which have very narrow excitation spectra. High-quality QDs are proper to be use in different biological and medical applications (as fluorescent labels, the cancer treatment and the drug delivery). In this article, we discuss Fourier transform visible spectroscopy of commercial quantum dots. We reveal that QDs produced by Evident Technologies when are enlightened by laser or luminescent diode light provides a spectral shift of their fluorescence spectra correlated to exciting emission wavelengths, as shown by the ARCspectroNIR Fourier Transform Spectrometer. In the final part of this paper we show an important biological application of CdSe/ZnS core-shell ODs as microbial labeling both for pure cultures of cyanobacteria (Synechocystis PCC 6803) and for mixed cultures of phototrophic and heterotrophic microorganisms.

  5. Laser-induced fluorescence spectra of Ba+*-He exciplexes produced in cold He gas

    International Nuclear Information System (INIS)

    Fukuyama, Yoshimitsu; Matsuo, Yukari; Moriwaki, Yoshiki

    2004-01-01

    We report the observation of laser-induced fluorescence spectra of Ba +* -He exciplexes. The experiment is carried out in an environment of cold gaseous helium at a temperature range of 3-30 K. We have observed the emission spectra of exciplexes by means of excitation of the 6p 2 P 32 2 S 12 transition of Ba + ions. It is found that these spectra are redshifted from the D2 emission line in the free space and are composed of several peaks. The experimental results are reproduced well by theoretical calculation of the emission spectra for vibrational levels of Ba +* -He. We also investigate the vibrational dynamics of the 6p 2 Π 32 state of Ba + *-He, and we have determined the collision-induced vibrational relaxation cross sections of the 6p 2 Π 32 state to be 9.7±1.1 A 2 at 15 K

  6. Spectra of matrix isolated metal atoms and clusters

    International Nuclear Information System (INIS)

    Meyer, B.

    1977-01-01

    The matrix isolation spectra of all of the 40 presently known atomic metal species show strong matrix effects. The transition energies are increased, and the bands are broad and exhibit splitting of sublevels which are degenerate in the gas phase. Several models have been proposed for splitting of levels, but basic effects are not yet understood, and spectra cannot be predicted, yet it is possible to correlate gas phase and matrix in many of the systems. Selective production of diatomics and clusters via thermal and optical annealing of atomic species can be monitored by optical spectra, but yields spectroscopically complex systems which, however, especially in the case of transition metals, can be used as precursors in novel chemical reactions. A combination of absorption, emission, ir, Raman, ESR, and other methods is now quickly yielding data which will help correlate the increasing wealth of existing data. 55 references, 6 figures

  7. Photoinduced Effects in the ZnO Luminescence Spectra

    Science.gov (United States)

    Akopyan, I. Kh.; Labzovskaya, M. E.; Novikov, B. V.; Lisachenko, A. A.; Serov, A. Yu.; Filosofov, N. G.

    2018-02-01

    The effect of intense UV irradiation on the photoluminescence (PL) spectra of ZnO powders and nanocrystalline films obtained by atomic layer deposition (ALD) was investigated. At room temperature, the behavior of the spectra under continuous UV irradiation in multiple vacuum-atmosphere cycles was studied. The changes in the intensities of exciton radiation and radiation in the "green" band region, associated with the phenomena of oxygen photodesorption and photoadsorption, are discussed. In the temperature range of 5-300 K, the effect of strong UV irradiation on the near-edge luminescence spectrum of ZnO films was studied. The nature of a new line arising in the photoluminescence spectra of an irradiated film in the region of emission of bound excitons is discussed.

  8. X ray spectra of X Per. [oso-8 observations

    Science.gov (United States)

    Becker, R. H.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Robinson-Saba, J.; Serlemitsos, P. J.; Swank, J. H.

    1978-01-01

    The cosmic X-ray spectroscopy experiment on OSO-8 observed X Per for twenty days during two observations in Feb. 1976 and Feb. 1977. The spectrum of X Per varies in phase with its 13.9 min period, hardening significantly at X-ray minimum. Unlike other X-ray binary pulsar spectra, X Per's spectra do not exhibit iron line emission or strong absorption features. The data show no evidence for a 22 hour periodicity in the X-ray intensity of X Per. These results indicate that the X-ray emission from X Per may be originating from a neutron star in a low density region far from the optically identified Be star.

  9. Ni-doped zinc oxide nanocombs and phonon spectra properties

    International Nuclear Information System (INIS)

    Zhang Bin; Zhang Xingtang; Gong Hechun; Wu Zhishen; Zhou Shaomin; Du Zuliang

    2008-01-01

    Ni-doped comb-like zinc oxide (ZnO) semiconductor nanostructures have been synthesized by a simple chemical vapor-deposition method (CVD) at relatively low temperature. The as-synthesized ZnO nanocombs consist of an array of very uniform, perfectly aligned, evenly spaced and long single-crystalline nanobelts (nanowires) with periods of about several tens of nanometers. X-ray diffraction and Raman spectra results provide the evidence that Ni is incorporated into the ZnO lattice at Zn site. Photoluminescence spectra of the as-obtained samples have been detected, in which the incorporation of donor Ni leads to the increases of the ultraviolet emission intensity and a blueshift of emission peak. This technique can be used to prepare other semiconductors and morphology-controlled doping nanocombs

  10. Research into spectra transformation of cooling tower droplet drift

    International Nuclear Information System (INIS)

    Mandrykin, G.P.

    1990-01-01

    Empirical droplet-diameter distributions in a cooling tower and outside are well approximated by the Rosin-Rammler-Bennet two-parameter function. Fractional efficiency of eliminators is also approximated by the above function fairly well. The design formulas proposed are universal and allow evaluation of droplet spectra transformation as well as the efficiency of measures for preventing droplet emissions from cooling towers both at the design and operation stages. Estimates of cooling tower droplet emissions calculated by the formulas suggested may be recommended as input data applied to the solution of environmental pollution problems and their assessment

  11. Biological Action Spectra (invited paper)

    International Nuclear Information System (INIS)

    Gruijl, F.R. de

    2000-01-01

    Ultraviolet (UV) radiation induces a wide variety of biological responses: ranging in humans from well-known short-term effects like sunburn to long-term effects like skin cancer. The wavelength dependencies ('action spectra') of the responses can differ significantly, depending on the UV-targeted molecules (their absorption spectra), their localisation (transmission to the target depth) and the photochemical reactions involved (e.g. quantum yields, competing reaction). An action spectrum (e.g. of sunburn) is usually determined in a wavelength by wavelength analysis of the response. This is not always possible (e.g. in case of skin cancer), and an action spectrum may then be extracted mathematically from differences in responses to broadband UV sources of various spectral compositions (yielding 'biological spectral weights'). However, relative spectral weights may shift with exposure levels and contributions from different wavelengths may not always add up. Under these circumstances conventional analyses will yield different action spectra for different experimental conditions. (author)

  12. Double photoionisation spectra of molecules

    CERN Document Server

    Eland, John

    2017-01-01

    This book contains spectra of the doubly charged positive ions (dications) of some 75 molecules, including the major constituents of terrestrial and planetary atmospheres and prototypes of major chemical groups. It is intended to be a new resource for research in all areas of molecular spectroscopy involving high energy environments, both terrestrial and extra-terrestrial. All the spectra have been produced by photoionisation using laboratory lamps or synchrotron radiation and have been measured using the magnetic bottle time-of-flight technique by coincidence detection of correlated electron pairs. Full references to published work on the same species are given, though for several molecules these are the first published spectra. Double ionisation energies are listed and discussed in relation to the molecular electronic structure of the molecules. A full introduction to the field of molecular double ionisation is included and the mechanisms by which double photoionisation can occur are examined in detail. A p...

  13. QUALITATIVE INTERPRETATION OF GALAXY SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Almeida, J.; Morales-Luis, A. B. [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain); Terlevich, R.; Terlevich, E. [Instituto Nacional de Astrofisica, Optica y Electronica, Tonantzintla, Puebla (Mexico); Cid Fernandes, R., E-mail: jos@iac.es, E-mail: abml@iac.es, E-mail: rjt@ast.cam.ac.uk, E-mail: eterlevi@inaoep.mx, E-mail: cid@astro.ufsc.br [Departamento de Fisica-CFM, Universidade Federal de Santa Catarina, P.O. Box 476, 88040-900 Florianopolis, SC (Brazil)

    2012-09-10

    We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis and for gaining physical insight when interpreting the outputs provided by automated tools. Though the recipe is for general application, it was developed for understanding the nature of the Automatic Spectroscopic K-means-based (ASK) template spectra. They resulted from the classification of all the galaxy spectra in the Sloan Digital Sky Survey data release 7, thus being a comprehensive representation of the galaxy spectra in the local universe. Using the recipe, we give a description of the properties of the gas and the stars that characterize the ASK classes, from those corresponding to passively evolving galaxies, to H II galaxies undergoing a galaxy-wide starburst. The qualitative analysis is found to be in excellent agreement with quantitative analyses of the same spectra. We compare the mean ages of the stellar populations with those inferred using the code STARLIGHT. We also examine the estimated gas-phase metallicity with the metallicities obtained using electron-temperature-based methods. A number of byproducts follow from the analysis. There is a tight correlation between the age of the stellar population and the metallicity of the gas, which is stronger than the correlations between galaxy mass and stellar age, and galaxy mass and gas metallicity. The galaxy spectra are known to follow a one-dimensional sequence, and we identify the luminosity-weighted mean stellar age as the affine parameter that describes the sequence. All ASK classes happen to have a significant fraction of old stars, although spectrum-wise they are outshined by the youngest populations. Old stars are metal-rich or metal-poor depending on whether they reside in passive galaxies or in star-forming galaxies.

  14. The structure of BPS spectra

    Science.gov (United States)

    Longhi, Pietro

    In this thesis we develop and apply novel techniques for analyzing BPS spectra of supersymmetric quantum field theories of class S. By a combination of wall-crossing, spectral networks and quiver methods we explore the BPS spectra of higher rank four-dimensional N = 2 super Yang-Mills, uncovering surprising new phenomena. Focusing on the SU(3) case, we prove the existence of wild BPS spectra in field theory, featuring BPS states of higher spin whose degeneracies grow exponentially with the energy. The occurrence of wild BPS states is surprising because it appears to be in tension with physical expectations on the behavior of the entropy as a function of the energy scale. The solution to this puzzle comes from realizing that the size of wild BPS states grows rapidly with their mass, and carefully analyzing the volume-dependence of the entropy of BPS states. We also find some interesting structures underlying wild BPS spectra, such as a Regge-like relation between the maximal spin of a BPS multiplet and the square of its mass, and the existence of a universal asymptotic distribution of spin-j irreps within a multiplet of given charge. We also extend the spectral networks construction by introducing a refinement in the topological classification of 2d-4d BPS states, and identifying their spin with a topological invariant known as the "writhe of soliton paths". A careful analysis of the 2d-4d wall-crossing behavior of this refined data reveals that it is described by motivic Kontsevich-Soibelman transformations, controlled by the Protected Spin Character, a protected deformation of the BPS index encoding the spin of BPS states. Our construction opens the way for the systematic study of refined BPS spectra in class S theories. We apply it to several examples, including ones featuring wild BPS spectra, where we find an interesting relation between spectral networks and certain functional equations. For class S theories of A 1 type, we derive an alternative technique for

  15. Automatic identification of mass spectra

    International Nuclear Information System (INIS)

    Drabloes, F.

    1992-01-01

    Several approaches to preprocessing and comparison of low resolution mass spectra have been evaluated by various test methods related to library search. It is shown that there is a clear correlation between the nature of any contamination of a spectrum, the basic principle of the transformation or distance measure, and the performance of the identification system. The identification of functionality from low resolution spectra has also been evaluated using several classification methods. It is shown that there is an upper limit to the success of this approach, but also that this can be improved significantly by using a very limited amount of additional information. 10 refs

  16. Investigation of gamma spectra analysis

    International Nuclear Information System (INIS)

    Wu Huailong; Liu Suping; Hao Fanhua; Gong Jian; Liu Xiaoya

    2006-01-01

    In the investigation of radiation fingerprint comparison, it is found out that some of the popular gamma spectra analysis software have shortcomings, which decrease the radiation fingerprint comparison precision. So a new analysis software is developed for solving the problems. In order to display the advantage of developed program, some typical simulative warhead gamma spectra are analyzed respectively by present software and GAMMAVISION and GENNIE2000. Present software can be applied not only in nuclear warheads deep-cuts verification, but also in any radiation measurement field. (authors)

  17. Ultraviolet spectra of planetary nebulae

    International Nuclear Information System (INIS)

    Adams, S.; Seaton, M.J.

    1982-01-01

    Features observed in infrared spectra suggest that certain very low excitation (VLE) nebulae have low C/O abundance ratios (Cohen and Barlow 1980; Aitken and Roche 1982). Fluxes in the multiplets [O II] lambda 2470 and C II] lambda 2326 have been measured for the VLE nebula He He 2-131 = HD 138403 using IUE high-dispersion spectra. An analysis similar to that of Harrington et al. (1980) for IC 418 gives C/O = 0.3 for He 2-131, compared with C/O = 1.3 for IC 418 and 0.6 for the Sun. (author)

  18. Investigation of gamma spectra analysis

    International Nuclear Information System (INIS)

    Wu Huailong; Liu Suping; Hao Fanhua

    2006-12-01

    During the investigation of radiation fingerprint comparison, it is found out that the popular gamma spectra analysis softwares are faultful, which decrease the precision of radiation fingerprint comparison. So a new analysis software is development for solving the problems. In order to display the advantage of new program, some typical simulative gamma spectra of radiation source are analyzed respectively by our software and GAMMAVISION and GENNIE2000. The software can be applied not only in nuclear warheads deep-cuts verification, but also in any radiation measurement field. (authors)

  19. Raman spectra studies of dipeptides

    International Nuclear Information System (INIS)

    Blanchard, Simone.

    1977-10-01

    This work deals with the homogenous and heterogeneous dipeptides derived from alanine and glycine, in the solid state or in aqueous solutions, in the zwitterions or chlorhydrates form. The Raman spectra comparative study of these various forms of hydrogenated or deuterated compounds allows to specify some of the attributions which are necessary in the conformational study of the like tripeptides. These compounds contain only one peptidic group; therefore there is no possibility of intramolecular hydrogen bond which caracterise vibrations of non bonded peptidic groups and end groups. Infrared spectra of solid dipeptides will be presented and discussed in the near future [fr

  20. Implication of the detection of very hard spectra from the TeV blazar Mrk 501

    Energy Technology Data Exchange (ETDEWEB)

    Shukla, Amit; Hughes, Gareth; Biland, Adrian [ETH Zurich, Institute for Particle Physics (Switzerland); Mannheim, Karl; Dorner, Daniela [Institute for Theoretical Physics and Astrophysics, Universitaet Wuerzburg (Germany); Chitnis, Varsha R. [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai (India); Roy, Jayashree; Acharya, Bannanje Sripathi [Center for Excellence in Basic Sciences, UM-DAE Mumbai (India)

    2016-07-01

    The emission from active galactic nuclei ranges from radio to TeV energies and shows high variability. The origin of the high energy emission is highly debated. The observed emission could be due to a complex superposition of emission from multiple zones. New evidence of the detection of very hard intrinsic gamma-ray spectra obtained from Fermi-LAT observations have challenged the theories about origin of VHE gamma-rays. We have used the 7 years of Fermi-LAT data to search for time intervals with unusually hard spectra from the nearby TeV blazar Mrk 501. In the presentation, we discuss a few possible explanations for the origin of these hard spectra within a leptonic scenario.

  1. Channeling effect in electronic spectra produced by grazing impact of fast protons on insulator surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Archubi, C D; Gravielle, M S, E-mail: archubi@iafe.uba.a, E-mail: msilvia@iafe.uba.a [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428, Buenos Aires (Argentina)

    2009-11-01

    Electron emission due to grazing scattering of fast protons from LiF and KCl surfaces is studied under axial incidence conditions. The differential emission probability is calculated within a distorted-wave formalism, taking into account axial channeled trajectories. For different emission angles, electronic spectra for proton incidence along the two principal crystal axes ([100] and [110]) are compared with those corresponding to an impact velocity in a random direction, finding effects associated with the channeling conditions.

  2. Classical Trajectories and Quantum Spectra

    Science.gov (United States)

    Mielnik, Bogdan; Reyes, Marco A.

    1996-01-01

    A classical model of the Schrodinger's wave packet is considered. The problem of finding the energy levels corresponds to a classical manipulation game. It leads to an approximate but non-perturbative method of finding the eigenvalues, exploring the bifurcations of classical trajectories. The role of squeezing turns out decisive in the generation of the discrete spectra.

  3. Vibrational spectra of ordered perovskites

    NARCIS (Netherlands)

    Corsmit, A.F.; Hoefdraad, H.E.; Blasse, G.

    1972-01-01

    The vibrational spectra of the molecular M6+O6 (M = Mo, Te, W) group in ordered perovskites of the type Ba2M2+M6+O6 are reported. These groups have symmetry Oh, whereas their site symmetry is also Oh. An assignment of the internal vibrations is presented.

  4. Raman spectra of graphene ribbons

    International Nuclear Information System (INIS)

    Saito, R; Furukawa, M; Dresselhaus, G; Dresselhaus, M S

    2010-01-01

    Raman spectra of graphene nanoribbons with zigzag and armchair edges are calculated within non-resonant Raman theory. Depending on the edge structure and polarization direction of the incident and scattered photon beam relative to the edge direction, a symmetry selection rule for the phonon type appears. These Raman selection rules will be useful for the identification of the edge structure of graphene nanoribbons.

  5. Explanation of earthquake response spectra

    OpenAIRE

    Douglas, John

    2017-01-01

    This is a set of five slides explaining how earthquake response spectra are derived from strong-motion records and simple models of structures and their purpose within seismic design and assessment. It dates from about 2002 and I have used it in various introductory lectures on engineering seismology.

  6. Spectral analysis of K-shell X-ray emission of magnesium plasma ...

    Indian Academy of Sciences (India)

    2014-02-06

    Feb 6, 2014 ... the experimental spectra with the synthetic spectra generated using .... user to specify the time duration over which the ionic populations ... ied the dependence of X-ray emission spectrum as a function of laser intensity in the.

  7. Analytic and numerical calculations of quantum synchrotron spectra from relativistic electron distributions

    International Nuclear Information System (INIS)

    Brainerd, J.J.; Petrosian, V.

    1987-01-01

    Calculations are performed numerically and analytically of synchrotron spectra for thermal and power-law electron distributions using the single-particle synchrotron power spectrum derived from quantum electrodynamics. It is found that the photon energy at which quantum effects appear is proportional to temperature and independent of field strength for thermal spectra; quantum effects introduce an exponential roll-off away from the classical spectra. For power law spectra, the photon energy at which quantum effects appear is inversely proportional to the magnetic field strength; quantum effects produce a steeper power law than is found classically. The results are compared with spectra derived from the classical power spectrum with an energy cutoff ensuring conservation of energy. It is found that an energy cutoff is generally an inadequate approximation of quantum effects for low photon energies and for thermal spectra, but gives reasonable results for high-energy emission from power-law electron distributions. 17 references

  8. Skyshine spectra of gamma rays

    International Nuclear Information System (INIS)

    Swarup, Janardan

    1980-01-01

    A study of the spectra of gamma photons back-scattered in vertical direction by infinite air above ground (skyshine) is presented. The source for these measurements is a 650 Ci Cobalt-60 point-source and the skyshine spectra are reported for distances from 150 m to 325 m from the source, measured with a 5 cm x 5 cm NaI(Tl) detector collimated with collimators of 12 mm and 20 mm diameter and 5 cm length. These continuous spectra are unfolded with Gold's iterative technique. The photon-spectra so obtained have a distinct line at 72 keV due to multiply-scattered photons. This is an energy where photoelectric and Compton cross-sections for multiply-scattered photons balance each other. The intensity of the line(I) decreases exponentially with distance (d) from the source obeying a relation of the type I = Isub(o)esup(-μd) where μ is called as ''Multiply-Scatter Coefficient'', a constant of the medium which is air in these measurements. This relationship is explained in terms of a halo around the source comprising of multiply-scattered gamma photons, Isub(0) being the intensity of these scattered photons at the location of cobalt-source. A fraction called as ''Back-scattered Fraction'', the ratio of Isub(0) to the number of original photons from the cobalt-source entering the infinite air, is also calculated. It is shown that with a properly calibrated detector system, this fraction can be used to determine the strength of a large gamma source, viz. a nuclear explosion in air, and for mineral prospecting. These conclusions are general and can be applied to any other infinite medium. Some forward-scatter (transmission) spectra of cobalt-60 source through 10 cm of Pb and 2.5 cm of Al are also reported. (auth.)

  9. Gigahertz-peaked spectra pulsars in Pulsar Wind Nebulae

    Science.gov (United States)

    Basu, R.; RoŻko, K.; Kijak, J.; Lewandowski, W.

    2018-04-01

    We have carried out a detailed study of the spectral nature of six pulsars surrounded by pulsar wind nebulae (PWNe). The pulsar flux density was estimated using the interferometric imaging technique of the Giant Metrewave Radio Telescope at three frequencies 325, 610, and 1280 MHz. The spectra showed a turnover around gigahertz frequency in four out of six pulsars. It has been suggested that the gigahertz-peaked spectrum (GPS) in pulsars arises due to thermal absorption of the pulsar emission in surrounding medium like PWNe, H II regions, supernova remnants, etc. The relatively high incidence of GPS behaviour in pulsars surrounded by PWNe imparts further credence to this view. The pulsar J1747-2958 associated with the well-known Mouse nebula was also observed in our sample and exhibited GPS behaviour. The pulsar was detected as a point source in the high-resolution images. However, the pulsed emission was not seen in the phased-array mode. It is possible that the pulsed emission was affected by extreme scattering causing considerable smearing of the emission at low radio frequencies. The GPS spectra were modelled using the thermal free-free absorption and the estimated absorber properties were largely consistent with PWNe. The spatial resolution of the images made it unlikely that the point source associated with J1747-2958 was the compact head of the PWNe, but the synchrotron self-absorption seen in such sources was a better fit to the estimated spectral shape.

  10. A climatology of visible surface reflectance spectra

    International Nuclear Information System (INIS)

    Zoogman, Peter; Liu, Xiong; Chance, Kelly; Sun, Qingsong; Schaaf, Crystal; Mahr, Tobias; Wagner, Thomas

    2016-01-01

    We present a high spectral resolution climatology of visible surface reflectance as a function of wavelength for use in satellite measurements of ozone and other atmospheric species. The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is planned to measure backscattered solar radiation in the 290–740 nm range, including the ultraviolet and visible Chappuis ozone bands. Observation in the weak Chappuis band takes advantage of the relative transparency of the atmosphere in the visible to achieve sensitivity to near-surface ozone. However, due to the weakness of the ozone absorption features this measurement is more sensitive to errors in visible surface reflectance, which is highly variable. We utilize reflectance measurements of individual plant, man-made, and other surface types to calculate the primary modes of variability of visible surface reflectance at a high spectral resolution, comparable to that of TEMPO (0.6 nm). Using the Moderate-resolution Imaging Spectroradiometer (MODIS) Bidirection Reflectance Distribution Function (BRDF)/albedo product and our derived primary modes we construct a high spatial resolution climatology of wavelength-dependent surface reflectance over all viewing scenes and geometries. The Global Ozone Monitoring Experiment–2 (GOME-2) Lambertian Equivalent Reflectance (LER) product provides complementary information over water and snow scenes. Preliminary results using this approach in multispectral ultraviolet+visible ozone retrievals from the GOME-2 instrument show significant improvement to the fitting residuals over vegetated scenes. - Highlights: • Our goals was visible surface reflectance for satellite trace gas measurements. • Captured the range of surface reflectance spectra through EOF analysis. • Used satellite surface reflectance products for each given scene to anchor EOFs. • Generated a climatology of time/geometry dependent surface reflectance spectra. • Demonstrated potential to

  11. Spectroscopic modeling for tungsten EUV spectra

    International Nuclear Information System (INIS)

    Murakami, Izumi; Kato, Daiji; Sakaue, Hiroyuki A.; Suzuki, Chihiro; Morita, Shigeru; Goto, Motoshi; Sasaki, Akira; Nakamura, Nobuyuki; Yamamoto, Norimasa; Koike, Fumihiro

    2014-01-01

    We have constructed an atomic model for tungsten extreme ultraviolet (EUV) spectra to reconstruct characteristic spectral feature of unresolved transition array (UTA) observed at 4-7 nm for tungsten ions. In the tungsten atomic modeling, we considered fine-structure levels with the quantum principal number n up to 6 as the atomic structure and calculated the electron-impact collision cross sections by relativistic distorted-wave method, using HULLAC atomic code. We measured tungsten EUV spectra in Large Helical Device (LHD) and Compact Electron Beam Ion Trap device (CoBIT) and compared them with the model calculation. The model successfully explain series of emission peaks at 1.5-3.5 nm as n=5-4 and 6-4 transitions of W"2"4"+ - W"3"2"+ measured in CoBIT and LHD and the charge state distributions were estimated for LHD plasma. The UTA feature observed at 4-7 nm was also successfully reconstructed with our model. The peak at ∼5 nm is produced mainly by many 4f-4d transition of W"2"2"+ - W"3"5"+ ions, and the second peak at ∼6 nm is produced by 4f-4d transition of W"2"5"+ - W"2"8"+ ions, and 4d-4p inner-shell transitions, 4p"54d"n"+"1 - 4p"64d"n, of W"2"9"+ - W"3"5"+ ions. These 4d-4p inner-shell transitions become strong since we included higher excited states such as 4p"54d"n4f state, which ADAS atomic data set does not include for spectroscopic modeling with fine structure levels. (author)

  12. Curved Radio Spectra of Weak Cluster Shocks

    Science.gov (United States)

    Kang, Hyesung; Ryu, Dongsu

    2015-08-01

    In order to understand certain observed features of arc-like giant radio relics such as the rareness, uniform surface brightness, and curved integrated spectra, we explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud containing fossil relativistic electrons. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. Three types of fossil electron populations are considered: a delta-function like population with the shock injection momentum, a power-law distribution, and a power law with an exponential cutoff. The surface brightness profile of the radio-emitting postshock region and the volume-integrated radio spectrum are calculated and compared with observations. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed {u}{{s}}˜ 3× {10}3 {km} {{{s}}}-1 and sonic Mach number {M}{{s}}˜ 3. These shocks produce curved radio spectra that steepen gradually over (0.1-10){ν }{br} with a break frequency {ν }{br}˜ 1 GHz if the duration of electron acceleration is ˜60-80 Myr. However, the abrupt increase in the spectral index above ˜1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with {γ }{{e}}≳ {10}4.

  13. Resonant Inverse Compton Scattering Spectra from Highly Magnetized Neutron Stars

    Science.gov (United States)

    Wadiasingh, Zorawar; Baring, Matthew G.; Gonthier, Peter L.; Harding, Alice K.

    2018-02-01

    Hard, nonthermal, persistent pulsed X-ray emission extending between 10 and ∼150 keV has been observed in nearly 10 magnetars. For inner-magnetospheric models of such emission, resonant inverse Compton scattering of soft thermal photons by ultrarelativistic charges is the most efficient production mechanism. We present angle-dependent upscattering spectra and pulsed intensity maps for uncooled, relativistic electrons injected in inner regions of magnetar magnetospheres, calculated using collisional integrals over field loops. Our computations employ a new formulation of the QED Compton scattering cross section in strong magnetic fields that is physically correct for treating important spin-dependent effects in the cyclotron resonance, thereby producing correct photon spectra. The spectral cutoff energies are sensitive to the choices of observer viewing geometry, electron Lorentz factor, and scattering kinematics. We find that electrons with energies ≲15 MeV will emit most of their radiation below 250 keV, consistent with inferred turnovers for magnetar hard X-ray tails. More energetic electrons still emit mostly below 1 MeV, except for viewing perspectives sampling field-line tangents. Pulse profiles may be singly or doubly peaked dependent on viewing geometry, emission locale, and observed energy band. Magnetic pair production and photon splitting will attenuate spectra to hard X-ray energies, suppressing signals in the Fermi-LAT band. The resonant Compton spectra are strongly polarized, suggesting that hard X-ray polarimetry instruments such as X-Calibur, or a future Compton telescope, can prove central to constraining model geometry and physics.

  14. Analysis of photoluminescence spectra of lead-tungstate single crystals

    International Nuclear Information System (INIS)

    Kim, Do Hyung; Lee, Sang Yun; Lee, Myoung Bok

    2003-01-01

    In addition to the intrinsic blue emission band near 430 nm for an ideal PbWO 4 scheelite structure, the presence of three extra emission bands peaking near blue-green and green-red colors was clearly identified for thermally synthesized bulk crystals with the help of a reliable fitting process applicable for microscopic analysis of recorded PL spectra. The origin, nature, and electro-optical behaviors of the extra emission bands are strongly related to the structural change from an ideal scheelite to modified ones, so now we can more closely track down the nature and the relevant behaviors, which are still in dispute, of the apparent colors of the PbWO 4 scintillating medium by constructing structural models and by considering the energy transfer mechanism between the color centers

  15. ACCELERATED FITTING OF STELLAR SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Ting, Yuan-Sen; Conroy, Charlie [Harvard–Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Rix, Hans-Walter [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)

    2016-07-20

    Stellar spectra are often modeled and fitted by interpolating within a rectilinear grid of synthetic spectra to derive the stars’ labels: stellar parameters and elemental abundances. However, the number of synthetic spectra needed for a rectilinear grid grows exponentially with the label space dimensions, precluding the simultaneous and self-consistent fitting of more than a few elemental abundances. Shortcuts such as fitting subsets of labels separately can introduce unknown systematics and do not produce correct error covariances in the derived labels. In this paper we present a new approach—Convex Hull Adaptive Tessellation (chat)—which includes several new ideas for inexpensively generating a sufficient stellar synthetic library, using linear algebra and the concept of an adaptive, data-driven grid. A convex hull approximates the region where the data lie in the label space. A variety of tests with mock data sets demonstrate that chat can reduce the number of required synthetic model calculations by three orders of magnitude in an eight-dimensional label space. The reduction will be even larger for higher dimensional label spaces. In chat the computational effort increases only linearly with the number of labels that are fit simultaneously. Around each of these grid points in the label space an approximate synthetic spectrum can be generated through linear expansion using a set of “gradient spectra” that represent flux derivatives at every wavelength point with respect to all labels. These techniques provide new opportunities to fit the full stellar spectra from large surveys with 15–30 labels simultaneously.

  16. Reconstruction of neutron spectra through neural networks

    International Nuclear Information System (INIS)

    Vega C, H.R.; Hernandez D, V.M.; Manzanares A, E.

    2003-01-01

    A neural network has been used to reconstruct the neutron spectra starting from the counting rates of the detectors of the Bonner sphere spectrophotometric system. A group of 56 neutron spectra was selected to calculate the counting rates that would produce in a Bonner sphere system, with these data and the spectra it was trained the neural network. To prove the performance of the net, 12 spectra were used, 6 were taken of the group used for the training, 3 were obtained of mathematical functions and those other 3 correspond to real spectra. When comparing the original spectra of those reconstructed by the net we find that our net has a poor performance when reconstructing monoenergetic spectra, this attributes it to those characteristic of the spectra used for the training of the neural network, however for the other groups of spectra the results of the net are appropriate with the prospective ones. (Author)

  17. Biological Action Spectra (invited paper)

    Energy Technology Data Exchange (ETDEWEB)

    Gruijl, F.R. de

    2000-07-01

    Ultraviolet (UV) radiation induces a wide variety of biological responses: ranging in humans from well-known short-term effects like sunburn to long-term effects like skin cancer. The wavelength dependencies ('action spectra') of the responses can differ significantly, depending on the UV-targeted molecules (their absorption spectra), their localisation (transmission to the target depth) and the photochemical reactions involved (e.g. quantum yields, competing reaction). An action spectrum (e.g. of sunburn) is usually determined in a wavelength by wavelength analysis of the response. This is not always possible (e.g. in case of skin cancer), and an action spectrum may then be extracted mathematically from differences in responses to broadband UV sources of various spectral compositions (yielding 'biological spectral weights'). However, relative spectral weights may shift with exposure levels and contributions from different wavelengths may not always add up. Under these circumstances conventional analyses will yield different action spectra for different experimental conditions. (author)

  18. Systematic evaluation of prompt neutron spectra in fission

    International Nuclear Information System (INIS)

    Osawa, Takaaki

    1995-01-01

    To create the nuclear data fail JEND-32, the prompt fission neutron spectra X(E) of 233 U, 235 U, 238 U and 239 Pu were reevaluated and some improvement were added to the calculation models. We tried to extend the calculation method of fission spectra of nuclides with poor measurement data in consideration of increasing the importance of nuclear data of minor actinoids. We improved and extended the following five points. (1) On JENDL-3.1, the fission spectra of principal fissible materials had been calculated by the Modland-Nix model which the neutron emissions of fragments were calculated under the approximation of the constant inverse process cross section. In the paper, the spectra were calculated by the use of the inverse process cross section depend on the energy obtained by the calculation of the optical model. The result showed the increase of low energy components and the softening effect of spectra (2) On JENDL-3.1, the all fission processes were assumed to undergo (n,f) reaction. In the paper, they were calculated by the multi-chance fission such as (n, n'f), (n, 2nf) and (n, 3nf) etc. Softening of the spectra (En > 6 MeV) was obtained by this method. (3) The level density parameter (LDP) has been assumed as a = A/C in either case of light fragment (LF) and heavy fragment (HF) in the original Madland-Nix model. But we used LDP based on the Ignatyuk model under consideration of the shell effects of nuclear fragments, hence the neutron spectra of heavy fragments were hardening. (4) Nuclear temperature of both fragments had been assumed to be the same at original model, but now R T = Tm/TmH was derived to calculate them. The ratio of middle/both side components of spectra was changed. (5) Unknown neutron fission spectra of minor actinide were able to the assumed on the basis of Moriyama-Ohnishi model. (S.Y.)

  19. Emissions Trading

    NARCIS (Netherlands)

    Woerdman, Edwin; Backhaus, Juergen

    2014-01-01

    Emissions trading is a market-based instrument to achieve environmental targets in a cost-effective way by allowing legal entities to buy and sell emission rights. The current international dissemination and intended linking of emissions trading schemes underlines the growing relevance of this

  20. Understanding reconstructed Dante spectra using high resolution spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    May, M. J., E-mail: may13@llnl.gov; Widmann, K.; Kemp, G. E.; Thorn, D.; Colvin, J. D.; Schneider, M. B.; Moore, A.; Blue, B. E. [L-170 Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94551 (United States); Weaver, J. [Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, DC 20375 (United States)

    2016-11-15

    The Dante is an 18 channel filtered diode array used at the National Ignition Facility (NIF) to measure the spectrally and temporally resolved radiation flux between 50 eV and 20 keV from various targets. The absolute flux is determined from the radiometric calibration of the x-ray diodes, filters, and mirrors and a reconstruction algorithm applied to the recorded voltages from each channel. The reconstructed spectra are very low resolution with features consistent with the instrument response and are not necessarily consistent with the spectral emission features from the plasma. Errors may exist between the reconstructed spectra and the actual emission features due to assumptions in the algorithm. Recently, a high resolution convex crystal spectrometer, VIRGIL, has been installed at NIF with the same line of sight as the Dante. Spectra from L-shell Ag and Xe have been recorded by both VIRGIL and Dante. Comparisons of these two spectroscopic measurements yield insights into the accuracy of the Dante reconstructions.

  1. Simultaneous in-bore rail and insulator spectra from a railgun plasma armature

    International Nuclear Information System (INIS)

    Keefer, D.; Sedghinasah, A.; Crawford, R.

    1991-01-01

    This paper reports on absolute spectral radiance measurements obtained simultaneously at the rail and insulator surface of the UTSI 1 cm square-bore railgun. The emission spectra were obtained through the use of quartz optical fibers which penetrated both the rail and the insulator walls. The spectral characteristics of the rail and insulator emission are quite similar but differ significantly in magnitude. A detailed plasma radiation model was used to analyze these spectra. In order to obtain reasonable agreement between the model predictions and the experimental spectra, it was necessary to assume that these existed a broadband absorbing layer at the insulator surface. This result suggests a new physical model of the plasma armature in which insulator ablation leads to significant 3-dimensional flow and affects the shape of the current emission pattern on the rail surfaces

  2. Photoluminescence and absorption spectra of various common TL phosphors - interpretation of TL mechanisms

    International Nuclear Information System (INIS)

    Nagpal, J.S.

    1980-01-01

    Photoluminescence and absorption spectra of TL phosphors TLD-100, CaF 2 :Dy, CaSO 4 :Dy(0.05%wt), CaSO 4 :Tm(0.05%wt) and Mg 2 SiO 4 :Tb have been measured. The absorption spectra are typical of RE 2+ in rare earth doped irradiated phosphors. On heating RE 2+ yields RE 3+ and emission from the excited states of RE 3+ is observed. (author)

  3. MCNP modelling of scintillation-detector gamma-ray spectra from natural radionuclides.

    Science.gov (United States)

    Hendriks, P H G M; Maucec, M; de Meijer, R J

    2002-09-01

    gamma-ray spectra of natural radionuclides are simulated for a BGO detector in a borehole geometry using the Monte Carlo code MCNP. All gamma-ray emissions of the decay of 40K and the series of 232Th and 238U are used to describe the source. A procedure is proposed which excludes the time-consuming electron tracking in less relevant areas of the geometry. The simulated gamma-ray spectra are benchmarked against laboratory data.

  4. COLORED DISSOLVED ORGANIC MATTER (CDOM) CHARACTERIZATION BY ABSORPTION AND FLUORESCENCE SPECTRA

    OpenAIRE

    Goncalves Araujo, Rafael; Ramirez-Perez, Marta; Kraberg, Alexandra; Piera, Jaume; Bracher, Astrid

    2014-01-01

    Colored dissolved organic matter (CDOM) absorption and fluorescence spectra were analyzed from samples collected in the Lena River Delta region (Siberia, Russia; summer-2013) and in the Alfacs Bay (Ebro River Delta, Spain; summer-2013/winter-2014) in order to use optical measurements to infer loading and origin of CDOM. Absorbance spectra and Excitation-Emission matrices (EEMs) were obtained with a HORIBA Aqualog® spectrofluorometer. CDOM absorption at 443nm (a443) and terrestrial absorption ...

  5. THE CBS SPECTRA INVESTIGATION AS METHOD OF THE PN CHEMICAL COMPOSITION ANALYSIS

    OpenAIRE

    Shimanskaya, N. N.; Shimansky, V. V.; Bikmaev, I. F.; Sakhibullin, N. A.; Zhuchkov, R. Ya.

    2007-01-01

    We report the results of the investigations of chemical composition of close binaries which had gone through the stage of common envelope and which are the remnants of planetary nebular cores. High resolution spectra for different phases of orbital period of V471 Tau were taken by RTT-150 telescope and were investigated by the modified SYNTH-K program. It was found that the spectra show noticeable variability with appearance of emission components depended on the orbital period phase. For che...

  6. Design spectra development considering short time histories

    International Nuclear Information System (INIS)

    Weiner, E.O.

    1983-01-01

    The need for generation of seismic acceleration histories to prescribed response spectra arises several ways in structural dynamics. For example, one way of obtaining floor spectra is to generate a history from a foundation spectra and then solve for the floor motion from which a floor spectrum can be obtained. Two separate programs, MODQKE and MDOF, were written to provide a capability of obtaining equipment spectra from design spectra. MODQKE generates or modifies acceleration histories to conform with design spectra pertaining to, say, a foundation. MDOF is a simple linear modal superposition program that solves for equipment support histories using the design spectra conforming histories as input. Equipment spectra, then, are obtained from the support histories using MODQKE

  7. The Of emission lines near 4650 A

    International Nuclear Information System (INIS)

    Underhill, A.B.; Gilroy, K.K.; Hill, G.M.

    1989-01-01

    Rectified, normalized, high S/N intensity tracings of nine Of stars were obtained from Reticon spectra in the 4550-4800-A region. The well-known relatively sharp Of emission lines are seen to stand on pedestals of broad weak emission somewhat like the broad emission lines from WR stars. It is suggested that cascades following dielectronic recombination may be an important process driving some lines of N III, C III, and C IV into the emission of Of stars, and that the sharp Of lines come from plasma that is stationary with respect to the star. The broad emission features show an extensive low-density wind from each star. The results imply that the detection of two, more or less equal, broad jumps in the rest spectra of galaxies at about 4640 and 4686 A is more indicative of Of stars than of WR stars. 32 refs

  8. Emission Facilities - Air Emission Plants

    Data.gov (United States)

    NSGIC Education | GIS Inventory — Represents the Primary Facility type Air Emission Plant (AEP) point features. Air Emissions Plant is a DEP primary facility type related to the Air Quality Program....

  9. Theory of optical spectra of solvated electrons

    International Nuclear Information System (INIS)

    Kestner, N.R.

    1975-01-01

    During the last few years better theoretical models of solvated electron have been developed. These models allow one to calculate a priori the observable properties of the trapped electron. One of the most important and most widely determined properties is the optical spectrum. In this paper we consider the predictions of the theories not only as to the band maximum but line shape and width. In addition we will review how the theories predict these will depend on the solvent, pressure, temperature, and solvent density. In all cases extensive comparisons will be made with experimental work. In addition four new areas will be explored and recent results will be presented. These concern electrons in dense polar gases, the time development of the solvated electron spectrum, solvated electrons in mixed solvents, and photoelectron emission spectra (PEE) as it relates to higher excited states. This paper will review all recent theoretical calculations and present a critical review of the present status and future developments which are anticipated. The best theories are quite successful in predicting trends, and qualitative agreement concerning band maximum. The theory is still weak in predicting line shape and line width

  10. Wavelet spectra of JACEE events

    International Nuclear Information System (INIS)

    Suzuki, Naomichi; Biyajima, Minoru; Ohsawa, Akinori.

    1995-01-01

    Pseudo-rapidity distributions of two high multiplicity events Ca-C and Si-AgBr observed by the JACEE are analyzed by a wavelet transform. Wavelet spectra of those events are calculated and compared with the simulation calculations. The wavelet spectrum of the Ca-C event somewhat resembles that simulated with the uniform random numbers. That of Si-AgBr event, however, is not reproduced by simulation calculations with Poisson random numbers, uniform random numbers, or a p-model. (author)

  11. Identified hadron spectra from PHOBOS

    Science.gov (United States)

    Veres, Gábor I.; the PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wysłouch, B.; Zhang, J.

    2004-08-01

    Transverse momentum spectra of pions, kaons and protons, as well as antiparticle to particle ratios near mid-rapidity from d+Au collisions at \\sqrt{sNN} = 200 GeV have been measured by the PHOBOS experiment at RHIC. The transverse momentum range of particle identification was extended to beyond 3 GeV/c using the TOF detector and a new trigger system. The pseudorapidity dependence of the nuclear modification factor for charged hadrons in d+Au collisions is presented.

  12. Theoretical studies on core-level spectra of solids

    International Nuclear Information System (INIS)

    Kotani, Akio

    1995-01-01

    I present a review on theoretical studies of core-level spectra (CLS) in solids. In CLS, the dynamical response of outer electrons to a core hole is reflected through the screening of core hole potential. Impurity Anderson model (IAM) or cluster model is successfully applied to the analysis of X-ray photoemission spectra (XPS) and X-ray absorption spectra (XAS) in f and d electron systems, where the f and d electron states are hybridized with the other valence or conduction electron states. The effect of the core-hole potential in the final state of XPS and XAS plays an important role, as well as the solid state hybridization and intra-atomic multiplet coupling effects. As typical examples, the calculated results for XPS of rare-earth compounds and transition metal compounds are shown, and some discussions are given. As a subject of remarkable progress with high brightness synchrotron radiation sources, I discuss some theoretical aspects of X-ray emission spectra (XES) and their resonant enhancement at the X-ray absorption threshold. Some experimental data and their theoretical analysis are also given. (author)

  13. Neutron spectra due 13N production in a PET cyclotron

    International Nuclear Information System (INIS)

    Benavente, J.A.; Vega-Carrillo, H.R.; Lacerda, M.A.S.; Fonseca, T.C.F.; Faria, F.P.; Silva, T.A. da

    2015-01-01

    Monte Carlo and experimental methods have been used to characterize the neutron radiation field around PET (Positron Emission Tomography) cyclotrons. In this work, the Monte Carlo code MCNPX was used to estimate the neutron spectra, the neutron fluence rates and the ambient dose equivalent (H*(10)) in seven locations around a PET cyclotron during 13 N production. In order to validate these calculations, H*(10) was measured in three sites and were compared with the calculated doses. All the spectra have two peaks, one above 0.1 MeV due to the evaporation neutrons and another in the thermal region due to the room-return effects. Despite the relatively large difference between the measured and calculated H*(10) for one point, the agreement was considered good, compared with that obtained for 18 F production in a previous work. - Highlights: • MCNPX code was used to estimate the neutron spectra in a PET cyclotron. • Neutrons were estimated when 13 N is produced. • Neutron spectra show evaporation and room-return neutrons. • Calculated H*(10) were compared with measured H*(10)

  14. Operator functions and localization of spectra

    CERN Document Server

    Gil’, Michael I

    2003-01-01

    "Operator Functions and Localization of Spectra" is the first book that presents a systematic exposition of bounds for the spectra of various linear nonself-adjoint operators in a Hilbert space, having discrete and continuous spectra. In particular bounds for the spectra of integral, differential and integro-differential operators, as well as finite and infinite matrices are established. The volume also presents a systematic exposition of estimates for norms of operator-valued functions and their applications.

  15. Efficient light emitting devices based on phosphorescent partially doped emissive layers

    KAUST Repository

    Yang, Xiaohui; Jabbour, Ghassan E.

    2013-01-01

    We report efficient organic light emitting devices employing an ultrathin phosphor emissive layer. The electroluminescent spectra of these devices can be tuned by introducing a low-energy emitting phosphor layer into the emission zone. Devices

  16. Emission inventory; Inventaire des emissions

    Energy Technology Data Exchange (ETDEWEB)

    Fontelle, J.P. [CITEPA, Centre Interprofessionnel Technique d`Etudes de la Pollution Atmospherique, 75 - Paris (France)

    1997-12-31

    Statistics on air pollutant (sulfur dioxide, nitrogen oxides and ammonium) emissions, acid equivalent emissions and their evolution since 1990 in the various countries of Europe and the USA, are presented. Emission data from the industrial, agricultural, transportation and power sectors are given, and comparisons are carried out between countries based on Gnp and population, pollution import/export fluxes and compliance to the previous emission reduction objectives

  17. SpectraPLOT, Visualization Package with a User-Friendly Graphical Interface

    Science.gov (United States)

    Sebald, James; Macfarlane, Joseph; Golovkin, Igor

    2017-10-01

    SPECT3D is a collisional-radiative spectral analysis package designed to compute detailed emission, absorption, or x-ray scattering spectra, filtered images, XRD signals, and other synthetic diagnostics. The spectra and images are computed for virtual detectors by post-processing the results of hydrodynamics simulations in 1D, 2D, and 3D geometries. SPECT3D can account for a variety of instrumental response effects so that direct comparisons between simulations and experimental measurements can be made. SpectraPLOT is a user-friendly graphical interface for viewing a wide variety of results from SPECT3D simulations, and applying various instrumental effects to the simulated images and spectra. We will present SpectraPLOT's ability to display a variety of data, including spectra, images, light curves, streaked spectra, space-resolved spectra, and drilldown plasma property plots, for an argon-doped capsule implosion experiment example. Future SpectraPLOT features and enhancements will also be discussed.

  18. Measurements of impurity spectra using UV/visible spectroscopic system in a GAMMA 10 plasma

    International Nuclear Information System (INIS)

    Matama, K.; Yoshikawa, M.; Kobayashi, T.; Kubota, Y.; Cho, T.

    2006-01-01

    Impurity spectra have been measured and identified using a newly designed ultraviolet and visible (UV/visible) spectroscopic system in the tandem mirror GAMMA 10. It is constructed using two spectrometers to obtain an entire wavelength range of UV/visible impurity spectra with a high wavelength resolution in one plasma shot. We successfully obtained the emission intensities of the radiation spectra in detail and information on the time-varying population densities of the impurities. We evaluate radiation loss from the GAMMA 10 plasma in the UV/visible range; further we estimate the electron density and temperature after applying the measured spectral intensity to a collisional-radiative model

  19. Statistical theory for calculating energy spectra of β-delayed neutrons

    International Nuclear Information System (INIS)

    Kawano, Toshihiko; Moeller, Peter; Wilson, William B.

    2008-01-01

    Theoretical β-delayed neutron spectra are calculated based on the Quasi-particle Random Phase Approximation (QRPA) and the Hauser-Feshbach statistical model. Neutron emissions from an excited daughter nucleus after β-decay to the granddaughter residual are more accurately calculated than previous evaluations, including all the microscopic nuclear structure information, such as a Gamow-Teller strength distribution and discrete states in the granddaughter. The calculated delayed-neutron spectra reasonably agree with those evaluations in the ENDF decay library, which are based on experimental data. The model was adopted to generate the delayed-neutron spectra for all 271 precursors. (authors)

  20. Calculation of Spectra of Neutrons and Charged Particles Produced in a Target of a Neutron Generator

    Science.gov (United States)

    Gaganov, V. V.

    2017-12-01

    An algorithm for calculating the spectra of neutrons and associated charged particles produced in the target of a neutron generator is detailed. The products of four nuclear reactions 3H( d, n)4He, 2H( d, n)3He, 2H( d, p)3H, and 3He( d, p)4He are analyzed. The results of calculations are presented in the form of neutron spectra for several emission angles and spectra of associated charged particles emitted at an angle of 180° for a deuteron initial energy of 0.13 MeV.

  1. The X-ray electronic spectra of TiC-NbC solid solution

    International Nuclear Information System (INIS)

    Cherkashenko, V.M.; Ezhov, A.V.; Nazarova, S.Z.; Kurmaev, Eh.Z.; Nojmann, M.

    2001-01-01

    X-ray photoelectronic spectra of inner levels and valency lands in TiC-NbC solid solutions were studied. Results of combining TiL α -, NbL β2.15 -, CK α - X-ray emission spectra and photoelectronic spectra of valency bands in one energy scale in reference to the Fermi level were analyzed. It is shown that a change in crystal lattice parameters, as well as charge redistribution between titanium and niobium atoms, produce a strong effect on electronic structure formation in the mixed carbides mentioned [ru

  2. The eclipse of CI Cygni in 1980 on the objective prism spectra

    International Nuclear Information System (INIS)

    Mikolajewska, J.; Mikolajewski, M.

    1982-01-01

    The observations of CI Cyg were carried out with the Torun 60/90 cm Schmidt telescope with the objective prism giving a dispersion of 250 A/mm at H-gamma. Intensity traces of 20 selected spectra, made on the Kodak IIa-O plates, were made. The results were corrected for all instrumental effects and the interstellar extinction. The relative emission lines intensities have been obtained from the tracings after normalization to H-beta = 100. The spectra were typical for the quiet symbiotic star. So, all changes in the spectrum were caused by geometrical effects (eclipse). A preliminary analysis of the obtained spectra is presented. (Auth.)

  3. Integral characteristics of spectra of ions important for EUV lithography

    International Nuclear Information System (INIS)

    Karazija, R; Kucas, S; Momkauskaite, A

    2006-01-01

    The emission spectrum corresponding to the 4p 5 4d N+1 + 4p 6 4d N-1 4f → 4p 6 4d N transition array is concentrated in a narrow interval of wavelengths. That is due to the existence of an approximate selection rule and quenching of some lines by configuration mixing. Thus such emission of elements near Z = 50 is considered to be the main candidate for the EUV lithography source at λ = 13.5 nm. In the present work the regularities of these transition arrays are considered using their integral characteristics: average energy, total line strength, variance and interval of array containing some part of the total transition probability. Calculations for various ions of elements In, Sn, Sb, Te, I and Xe have been performed in a two-configuration pseudorelativistic approximation, which describes fairly well the main features of the spectra. The variation in the values of the main integral characteristics of the spectra with atomic number and ionization degree gives the possibility of comparing quantitatively the suitability of the emission of various ions for EUV lithography

  4. Raman spectra of SDW superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Rout, G.C. [Condensed Matter Physics Group, Department of Physics, Government Science College, Chatrapur, Orissa 761 020 (India)]. E-mail: gcr@iopb.res.in; Bishoyi, K.C. [P.G. Department of Physics, F.M. College (Autonomous), Balasore, Orissa 756 001 (India); Behera, S.N. [Institute of Physics, Bhubaneswar 751 005 (India)

    2005-03-15

    We report the calculation of the phonon response of the coexistent spin density wave (SDW) and superconducting (SC) state and predict the observation of SC gap in the Raman spectra of rare-earth nickel borocarbide superconductors. The SDW state normally does not couple to the lattice and hence, the phonons in the system are not expected to be affected by the SDW state. But there is a possibility of observing SC gap mode in the Raman spectra of a SDW superconductor due to the coupling of the SC gap excitation to the Raman active phonons in the system via the electron-phonon (e-p) interaction. A theoretical model is used for the coexistent phase and electron-phonon interaction. Phonon Green's function is calculated by Zubarev's technique and the phonon self-energy due to e-p interaction which is given by electron density response function in the coexistent state corresponding to the SDW wave vector q = Q is evaluated. The results so obtained exhibit agreement with the experimental observations.

  5. Raman spectra of SDW superconductors

    International Nuclear Information System (INIS)

    Rout, G.C.; Bishoyi, K.C.; Behera, S.N.

    2005-01-01

    We report the calculation of the phonon response of the coexistent spin density wave (SDW) and superconducting (SC) state and predict the observation of SC gap in the Raman spectra of rare-earth nickel borocarbide superconductors. The SDW state normally does not couple to the lattice and hence, the phonons in the system are not expected to be affected by the SDW state. But there is a possibility of observing SC gap mode in the Raman spectra of a SDW superconductor due to the coupling of the SC gap excitation to the Raman active phonons in the system via the electron-phonon (e-p) interaction. A theoretical model is used for the coexistent phase and electron-phonon interaction. Phonon Green's function is calculated by Zubarev's technique and the phonon self-energy due to e-p interaction which is given by electron density response function in the coexistent state corresponding to the SDW wave vector q = Q is evaluated. The results so obtained exhibit agreement with the experimental observations

  6. Global characteristics of atomic spectra and their use for the analysis of spectra. IV. Configuration interaction effects

    International Nuclear Information System (INIS)

    Kucas, S.; Jonauskas, V.; Karazija, R.

    1997-01-01

    For pt.III see ibid., vol.52, p.639, 1995. Changes of the moments of atomic spectrum due to configuration interaction (CI), the CI strength, the average shift of the energy of a level due to its interaction with all levels of distant configuration and other global characteristics of CI effects in atoms are systematised and their expressions presented. The results of the calculation of those characteristics for the energy level spectra of the 3s3p 3 + 3s 2 3p3d configurations in Si isoelectronic series, 3p 5 3d N + 3p 6 3d N-2 4p + 3p 6 3d N-2 4f (N = 5, 6, 7, 8) in Cr, Mn, Fe and Co isoelectronic series, ns 2 np N + np N+2 at n = 2 - 5 and N = 2 - 4 in neutral atoms as well as for the characteristic emission spectra corresponding to the 3p 5 3d 9 + 3d 7 4p → 3d 8 transitions as well as for the Auger M 4.3 N 1 N 2.3 spectra in Kr and N 4.5 O 1 O 2.3 in Xe are given and compared with the same characteristics of the more complete experimental spectra. (orig.)

  7. Multiscale climate emulator of multimodal wave spectra: MUSCLE-spectra

    Science.gov (United States)

    Rueda, Ana; Hegermiller, Christie A.; Antolinez, Jose A. A.; Camus, Paula; Vitousek, Sean; Ruggiero, Peter; Barnard, Patrick L.; Erikson, Li H.; Tomás, Antonio; Mendez, Fernando J.

    2017-02-01

    Characterization of multimodal directional wave spectra is important for many offshore and coastal applications, such as marine forecasting, coastal hazard assessment, and design of offshore wave energy farms and coastal structures. However, the multivariate and multiscale nature of wave climate variability makes this complex problem tractable using computationally expensive numerical models. So far, the skill of statistical-downscaling model-based parametric (unimodal) wave conditions is limited in large ocean basins such as the Pacific. The recent availability of long-term directional spectral data from buoys and wave hindcast models allows for development of stochastic models that include multimodal sea-state parameters. This work introduces a statistical downscaling framework based on weather types to predict multimodal wave spectra (e.g., significant wave height, mean wave period, and mean wave direction from different storm systems, including sea and swells) from large-scale atmospheric pressure fields. For each weather type, variables of interest are modeled using the categorical distribution for the sea-state type, the Generalized Extreme Value (GEV) distribution for wave height and wave period, a multivariate Gaussian copula for the interdependence between variables, and a Markov chain model for the chronology of daily weather types. We apply the model to the southern California coast, where local seas and swells from both the Northern and Southern Hemispheres contribute to the multimodal wave spectrum. This work allows attribution of particular extreme multimodal wave events to specific atmospheric conditions, expanding knowledge of time-dependent, climate-driven offshore and coastal sea-state conditions that have a significant influence on local nearshore processes, coastal morphology, and flood hazards.

  8. Analysis of extreme ultraviolet spectra from laser produced rhenium plasmas

    Science.gov (United States)

    Wu, Tao; Higashiguchi, Takeshi; Li, Bowen; Suzuki, Yuhei; Arai, Goki; Dinh, Thanh-Hung; Dunne, Padraig; O'Reilly, Fergal; Sokell, Emma; Liu, Luning; O'Sullivan, Gerry

    2015-08-01

    Extreme ultraviolet spectra of highly-charged rhenium ions were observed in the 1-7 nm region using two Nd:YAG lasers with pulse lengths of 150 ps and 10 ns, respectively, operating at a number of laser power densities. The maximum focused peak power density was 2.6 × 1014 W cm-2 for the former and 5.5 × 1012 W cm-2 for the latter. The Cowan suite of atomic structure codes and unresolved transition array (UTA) approach were used to calculate and interpret the emission properties of the different spectra obtained. The results show that n = 4-n = 4 and n = 4-n = 5 UTAs lead to two intense quasi-continuous emission bands in the 4.3-6.3 nm and 1.5-4.3 nm spectral regions. As a result of the different ion stage distributions in the plasmas induced by ps and ns laser irradiation the 1.5-4.3 nm UTA peak moves to shorter wavelength in the ps laser produced plasma spectra. For the ns spectrum, the most populated ion stage during the lifetime of this plasma that could be identified from the n = 4-n = 5 transitions was Re23+ while for the ps plasma the presence of significantly higher stages was demonstrated. For the n = 4-n = 4 4p64dN-4p54dN+1 + 4p64dN-14f transitions, the 4d-4f transitions contribute mainly in the most intense 4.7-5.5 nm region while the 4p-4d subgroup gives rise to a weaker feature in the 4.3-4.7 nm region. A number of previously unidentified spectral features produced by n = 4-n = 5 transitions in the spectra of Re XVI to Re XXXIX are identified.

  9. Scikit-spectra: Explorative Spectroscopy in Python

    Directory of Open Access Journals (Sweden)

    Adam Hughes

    2015-06-01

    Full Text Available Scikit-spectra is an intuitive framework for explorative spectroscopy in Python. Scikit-spectra leverages the Pandas library for powerful data processing to provide datastructures and an API designed for spectroscopy. Utilizing the new IPython Notebook widget system, scikit-spectra is headed towards a GUI when you want it, API when you need it approach to spectral analysis. As an application, analysis is presented of the surface-plasmon resonance shift in a solution of gold nanoparticles induced by proteins binding to the gold’s surface. Please refer to the scikit-spectra website for full documentation and support: http://hugadams.github.io/scikit-spectra/

  10. An RGB approach to extraordinary spectra

    Science.gov (United States)

    Grusche, Sascha; Theilmann, Florian

    2015-09-01

    After Newton had explained a series of ordinary spectra and Goethe had pointed out its complementary counterpart, Nussbaumer discovered a series of extraordinary spectra which are geometrically identical and colourwise analogous to Newton’s and Goethe’s spectra. To understand the geometry and colours of extraordinary spectra, the wavelength composition is explored with filters and spectroscopic setups. Visualized in a dispersion diagram, the wavelength composition is interpreted in terms of additive colour mixing. Finally, all spectra are simulated as the superposition of red, green, and blue images that are shifted apart. This RGB approach makes it easy to understand the complex relationship between wavelengths and colours.

  11. Electroplex emission from bi-layer blue emitting organic materials

    Science.gov (United States)

    Zhang, Fujun; Zhao, Suling; Zhao, Dewei; Jiang, Weiwei; Li, Yuan; Yuan, Guangcai; Zhu, Haina; Xu, Zheng

    2007-04-01

    Electroluminescence (EL) and photoluminescence (PL) spectra of an electron donor, an (poly(N-vinylcarbazole) (PVK))/electron acceptor, and a (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD)) bi-layer solid film are analysed. The EL emission peak has an apparent red-shift with the increase of driving voltage. There maybe exist an electroplex emission between the PVK and PBD interface under high electric field strength. According to their energy level, the electroplex emission peak should locate at 460 nm. There are great spectra overlapping between PVK emission and electroplex emission, and the ratio of electroplex emission intensity to exciton emission intensity (Ielectroplex/Iexciton) increases from 0.38 at 10 to 0.81 at 16 V. Therefore the measured emission peaks continuously shift from 410 nm at 10 V to 445 nm at 16 V.

  12. Electroplex emission from bi-layer blue emitting organic materials

    International Nuclear Information System (INIS)

    Zhang Fujun; Zhao Suling; Zhao Dewei; Jiang Weiwei; Li Yuan; Yuan Guangcai; Zhu Haina; Xu Zheng

    2007-01-01

    Electroluminescence (EL) and photoluminescence (PL) spectra of an electron donor, an (poly(N-vinylcarbazole) (PVK))/electron acceptor, and a (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD)) bi-layer solid film are analysed. The EL emission peak has an apparent red-shift with the increase of driving voltage. There maybe exist an electroplex emission between the PVK and PBD interface under high electric field strength. According to their energy level, the electroplex emission peak should locate at 460 nm. There are great spectra overlapping between PVK emission and electroplex emission, and the ratio of electroplex emission intensity to exciton emission intensity (I electroplex /I exciton ) increases from 0.38 at 10 to 0.81 at 16 V. Therefore the measured emission peaks continuously shift from 410 nm at 10 V to 445 nm at 16 V

  13. Electroplex emission from bi-layer blue emitting organic materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Fujun; Zhao Suling; Zhao Dewei; Jiang Weiwei; Li Yuan; Yuan Guangcai; Zhu Haina; Xu Zheng [Key Laboratory for Information Storage, Display and Materials, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044 (China)

    2007-04-15

    Electroluminescence (EL) and photoluminescence (PL) spectra of an electron donor, an (poly(N-vinylcarbazole) (PVK))/electron acceptor, and a (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD)) bi-layer solid film are analysed. The EL emission peak has an apparent red-shift with the increase of driving voltage. There maybe exist an electroplex emission between the PVK and PBD interface under high electric field strength. According to their energy level, the electroplex emission peak should locate at 460 nm. There are great spectra overlapping between PVK emission and electroplex emission, and the ratio of electroplex emission intensity to exciton emission intensity (I{sub electroplex}/I{sub exciton}) increases from 0.38 at 10 to 0.81 at 16 V. Therefore the measured emission peaks continuously shift from 410 nm at 10 V to 445 nm at 16 V.

  14. Different spectra with the same neutron source

    International Nuclear Information System (INIS)

    Vega C, H. R.; Ortiz R, J. M.; Hernandez D, V. M.; Martinez B, M. R.; Hernandez A, B.; Ortiz H, A. A.; Mercado, G. A.

    2010-01-01

    Using as source term the spectrum of a 239 Pu-Be source several neutron spectra have been calculated using Monte Carlo methods. The source term was located in the centre of spherical moderators made of light water, heavy water and polyethylene of different diameters. Also a 239 Pu-Be source was used to measure its neutron spectrum, bare and moderated by water. The neutron spectra were measured at 100 cm with a Bonner spheres spectrometer. Monte Carlo calculations were used to calculate the neutron spectra of bare and water-moderated spectra that were compared with those measured with the spectrometer. Resulting spectra are similar to those found in power plants with PWR, BWR and Candu nuclear reactors. Beside the spectra the dosimetric features were determined. Using moderators and a single neutron source can be produced neutron spectra alike those found in workplaces, this neutron fields can be utilized to calibrate neutron dosimeters and area monitors. (Author)

  15. Schottky spectra and crystalline beams

    International Nuclear Information System (INIS)

    Pestrikov, D.V.

    1996-01-01

    In this paper we revise the current dependence of the Schottky noise power of a cooled proton beam previously measured at NAP-M. More careful study of experimental data indicates a linear decrease in the inverse Schottky noise power with an increase in the beam intensity (N). The root of this function determines a threshold current which occurs at N = N th ≅1.2 x 10 8 particles. The inspection of measured Schottky spectra shows that this threshold does not correspond to some collective instability of the measured harmonic of the linear beam density. The found value of N th does not depend on the longitudinal beam temperature. For the case of NAP-M lattice, the study of the spectral properties of the Schottky noise in the crystalline string predicts the current dependence of the equilibrium momentum spread of the beam, which qualitatively agrees with that, recalculated from the NAP-M data. (orig.)

  16. Fractal analysis of power spectra

    International Nuclear Information System (INIS)

    Johnston, S.

    1982-01-01

    A general argument is presented concerning the Hausdorff dimension D of the power spectrum curve for a system of N weakly-coupled oscillators. Explicit upper and lower bounds for D are derived in terms of the number N of interacting modes. The mathematical reasoning relies upon the celebrated KAM theorem concerning the perturbation of Hamiltonian systems and the finite measure of the set of destroyed tori in phase space; this set can be related to Hausdorff dimension by certain mathematical theorems. An important consequence of these results is a simple empirical test for the applicability of Hamiltonian perturbation theory in the analysis of an experimentally observed spectrum. As an illustration, the theory is applied to the interpretation of a recent numerical analysis of both the power spectrum of the Sun and certain laboratory spectra of hydrodynamic turbulence. (Auth.)

  17. Spectra processing with computer graphics

    International Nuclear Information System (INIS)

    Kruse, H.

    1979-01-01

    A program of processng gamma-ray spectra in rock analysis is described. The peak search was performed by applying a cross-correlation function. The experimental data were approximated by an analytical function represented by the sum of a polynomial and a multiple peak function. The latter is Gaussian, joined with the low-energy side by an exponential. A modified Gauss-Newton algorithm is applied for the purpose of fitting the data to the function. The processing of the values derived from a lunar sample demonstrates the effect of different choices of polynomial orders for approximating the background for various fitting intervals. Observations on applications of interactive graphics are presented. 3 figures, 1 table

  18. Configuration interaction in LTE spectra of heavy elements

    International Nuclear Information System (INIS)

    Bar-Shalom, A.; Oreg, J.; Goldstein, W.

    1992-11-01

    We present a method for including the effects of configuration interaction (CI) between relativistic subconfigurations of an electron configuration in the calculation of emission and absorption spectra of plasmas in local thermodynamic equilibrium (LTE). Analytical expressions for the correction to the intensities, owing to Cl, of an unresolved transition array (UTA) and of a supertransition array (STA) are obtained when the correction is small compared to the spin-orbit splitting, bypassing the need to diagonalize energy matrices. These expressions serve as working formulas in the STA model and, in addition, reveal a priori the conditions under which CI effects are significant. Examples of the effect are presented

  19. Luminiscent emission of molecular levels excited by ionizant radiations

    International Nuclear Information System (INIS)

    Ortiz Ramis, M.

    1977-01-01

    The emission spectra and the time dependence of scintillations produced by alpha particles, gamma rays and ultraviolet light in some organic compounds crystals and liquids solutions normally used as radiation detectors has been studied. (author) [es

  20. Radio synchrotron spectra of star-forming galaxies

    Science.gov (United States)

    Klein, U.; Lisenfeld, U.; Verley, S.

    2018-03-01

    We investigated the radio continuum spectra of 14 star-forming galaxies by fitting nonthermal (synchrotron) and thermal (free-free) radiation laws. The underlying radio continuum measurements cover a frequency range of 325 MHz to 24.5 GHz (32 GHz in case of M 82). It turns out that most of these synchrotron spectra are not simple power-laws, but are best represented by a low-frequency spectrum with a mean slope αnth = 0.59 ± 0.20 (Sν ∝ ν-α), and by a break or an exponential decline in the frequency range of 1-12 GHz. Simple power-laws or mildly curved synchrotron spectra lead to unrealistically low thermal flux densities, and/or to strong deviations from the expected optically thin free-free spectra with slope αth = 0.10 in the fits. The break or cutoff energies are in the range of 1.5-7 GeV. We briefly discuss the possible origin of such a cutoff or break. If the low-frequency spectra obtained here reflect the injection spectrum of cosmic-ray electrons, they comply with the mean spectral index of Galactic supernova remnants. A comparison of the fitted thermal flux densities with the (foreground-corrected) Hα fluxes yields the extinction, which increases with metallicity. The fraction of thermal emission is higher than believed hitherto, especially at high frequencies, and is highest in the dwarf galaxies of our sample, which we interpret in terms of a lack of containment in these low-mass systems, or a time effect caused by a very young starburst.

  1. UV line emission of symbiotic stars

    International Nuclear Information System (INIS)

    Nussbaumer, H.

    1982-01-01

    General characteristics of emission line spectra from symbiotic stars are outlined. Data from some special line ratios in the 1000 A - 3000 A range, and others connecting the visual and the far UV lines are presented, and their application to symbiotic stars is discussed. Integrated fractional abundances for ions easily observed in the far UV are given to facilitate abundance determinations for nebular conditions. It is found that the physical conditions of the regions emitting the emission line spectra differ considerably among different symbiotic stars. (Auth.)

  2. High-energy emission from gamma-ray bursts

    International Nuclear Information System (INIS)

    Nolan, P.L.; Share, G.H.; Matz, S.; Chupp, E.L.; Forrest, D.J.; Rieger, E.

    1984-01-01

    We discuss broad-band continuum spectroscopy of 17 gamma-ray bursts above 0.3 MeV. The spectra were fitted by 3 trial functions, none of which provided an adequate fit to all the spectra. Most were too hard for a thermal bremsstarhlung function. Harder functional forms, such as thermal synchrotron or power-law, provide better fits for most of the spectra. The strong emission observed above 1 MeV raises some interesting theoretical questions

  3. Vibration and Fluorescence Spectra of Porphyrin- CoredBis(methylol-propionic Acid Dendrimers

    Directory of Open Access Journals (Sweden)

    Boris Minaev

    2009-03-01

    Full Text Available Bis-MPA dendron-coated free-base tetraphenylporphyrin and zinc-tetraphenyl-porphyrin (TPPH2 and TPPZn were studied in comparison with simple porphyrins (H2P, ZnP by theoretical simulation of their infrared, Raman and electronic absorption spectra, as well as fluorescense emission. Infrared and fluorescence spectra of the dendrimers were measured and interpreted along with time-resolved measurements of the fluorescence. The 0-1 emission band of the dendron substituted TPPZn was found to experience a "heavy substitution"-effect. The 0-1 vibronic emission signal is associated with a longer decay time (approx. 7 - 8 ns than the 0-0 emission (approx. 1 - 1.5 ns. The former contributed with more relative emission yield for larger dendron substituents, in agreement with the appearance of steady-state emission spectra showing increased contribution from the 0-1 vibronic fluorescence band at 650 nm. No such substitution effect was observed in the electronic or vibrational spectra of the substituted free-base variant, TPPH2. Vibration spectra of the parent porphyrins (H2P, ZnP, TPPH2 and TPPZn were calculated by density functional theory (DFT using the B3LYP/6-31G** approximation and a detailed analysis of the most active vibration modes was made based on both literature and our own experimental data. Based on the results of theoretical calculations the wide vibronic bands in the visible region were assigned. The vibronic structure also gave a qualitative interpretation of bands in the electronic absorption spectra as well as in fluorescence emission depending on the size of dendrimer substitution. From the results of time-dependent DFT calculations it is suggested that the TPPZn-cored dendrimers indicate strong vibronic interaction and increased Jahn-Teller distortion of the prophyrin core for larger dendrimer generations. Specifically, this leads to the entirely different behaviour of the emission spectra upon substitution of the TPPH2 and TPPZn

  4. Superposition of the luminescence spectra of free and bound excitons in ZnP2-D48

    International Nuclear Information System (INIS)

    Stamov, Ion; Nemerenco, Lucretia; Ivanenco, Iurii; Syrbu, Nicolae

    2011-01-01

    The luminescence spectra of ZnP 2 tetragonal crystals doped Mn, Sn, Cd, Sb at 10 K emission lines of bound excitons is detected. In the spectra non-phonon emission lines of bound and free excitons and their phonon replicas is isolated. The emission lines by the levels of the axial center are described. The composition of the luminescence of free and bound excitons at the axial center is investigated. In the region of phonon replicas of free excitons observed enhancement of lines due to forbidden transitions involving the recombination of excitons. A model of optic recombination transitions of the axial centre is proposed

  5. Galactic water vapor emission: further observations of variability.

    Science.gov (United States)

    Knowles, S H; Mayer, C H; Sullivan, W T; Cheung, A C

    1969-10-10

    Recent observations of the 1.35-centimeter line emission of water vapor from galactic sources show short-term variability in the spectra of several sources. Two additional sources, Cygnus 1 and NGC 6334N, have been observed, and the spectra of W49 and VY Canis Majoris were measured over a wider range of radial velocity.

  6. CORRELATIONS OF QUASAR OPTICAL SPECTRA WITH RADIO MORPHOLOGY

    International Nuclear Information System (INIS)

    Kimball, Amy E.; Ivezic, Zeljko; Wiita, Paul J.; Schneider, Donald P.

    2011-01-01

    Using the largest homogeneous quasar sample with high-quality optical spectra and robust radio morphology classifications assembled to date, we investigate relationships between radio and optical properties with unprecedented statistical power. The sample consists of 4714 radio quasars from FIRST with S 20 ≥ 2 mJy and with spectra from the Sloan Digital Sky Survey (SDSS). Radio morphology classes include core-only (core), core-lobe (lobe), core-jet (jet), lobe-core-lobe (triple), and double-lobe. Electronic tables of the quasar samples, along with spectral composites for individual morphology classes, are made available. We examine the optical colors of these subsamples and find that radio quasars with core emission unresolved by FIRST (on ∼5'' scale) have a redder color distribution than radio-quiet quasars (S 20 ∼ I ) are correlated, which supports the hypothesis that both parameters are indicative of line-of-sight orientation. We investigate spectral line equivalent widths (EWs) as a function of R and R I , including the O [III] narrow line doublet and the C IV λ1549 and Mg II λ2799 broad lines. We find that the rest EWs of the broad lines correlate positively with R I at the 4σ-8σ level. However, we find no strong dependence of EW on R, in contrast to previously published results. A possible interpretation of these results is that EWs of quasar emission lines increase as the line-of-sight angle to the radio-jet axis decreases. These results are in stark contrast to commonly accepted orientation-based theories, which suggest that continuum emission should increase as the angle to the radio-jet axis decreases, resulting in smaller EWs of emission lines (assumed isotropic). Finally, we observe the Baldwin effect in our sample and find that it does not depend strongly on quasar radio morphology.

  7. HERSCHEL/SPIRE SUBMILLIMETER SPECTRA OF LOCAL ACTIVE GALAXIES {sup ,}

    Energy Technology Data Exchange (ETDEWEB)

    Pereira-Santaella, Miguel; Spinoglio, Luigi; Busquet, Gemma [Istituto di Astrofisica e Planetologia Spaziali, INAF, Via Fosso del Cavaliere 100, I-00133 Roma (Italy); Wilson, Christine D.; Schirm, Maximilien R. P. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada); Glenn, Jason; Kamenetzky, Julia; Rangwala, Naseem [Center for Astrophysics and Space Astronomy, 389-UCB, University of Colorado, Boulder, CO 80303 (United States); Isaak, Kate G. [ESA Astrophysics Missions Division, ESTEC, P.O. Box 299, 2200 AG Noordwijk (Netherlands); Baes, Maarten [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Barlow, Michael J. [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Boselli, Alessandro [Laboratoire d' Astrophysique de Marseille (LAM), Universite d' Aix-Marseille and CNRS, UMR7326, 38 rue F. Joliot-Curie, F-13388 Marseille Cedex 13 (France); Cooray, Asantha [Center for Cosmology, Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Cormier, Diane, E-mail: miguel.pereira@ifsi-roma.inaf.it [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d' Astrophysique, CEA Saclay, F-91191 Gif-sur-Yvette (France)

    2013-05-01

    We present the submillimeter spectra from 450 to 1550 GHz of 11 nearby active galaxies observed with the SPIRE Fourier Transform Spectrometer (SPIRE/FTS) on board Herschel. We detect CO transitions from J{sub up} = 4 to 12, as well as the two [C I] fine structure lines at 492 and 809 GHz and the [N II]1461 GHz line. We used radiative transfer models to analyze the observed CO spectral line energy distributions. The FTS CO data were complemented with ground-based observations of the low-J CO lines. We found that the warm molecular gas traced by the mid-J CO transitions has similar physical conditions (n{sub H{sub 2}}{approx} 10{sup 3.2}-10{sup 3.9} cm{sup -3} and T{sub kin} {approx} 300-800 K) in most of our galaxies. Furthermore, we found that this warm gas is likely producing the mid-IR rotational H{sub 2} emission. We could not determine the specific heating mechanism of the warm gas, however, it is possibly related to the star formation activity in these galaxies. Our modeling of the [C I] emission suggests that it is produced in cold (T{sub kin} < 30 K) and dense (n{sub H{sub 2}}>10{sup 3} cm{sup -3}) molecular gas. Transitions of other molecules are often detected in our SPIRE/FTS spectra. The HF J = 1-0 transition at 1232 GHz is detected in absorption in UGC 05101 and in emission in NGC 7130. In the latter, near-infrared pumping, chemical pumping, or collisional excitation with electrons are plausible excitation mechanisms likely related to the active galactic nucleus of this galaxy. In some galaxies, few H{sub 2}O emission lines are present. Additionally, three OH{sup +} lines at 909, 971, and 1033 GHz are identified in NGC 7130.

  8. X-ray-emission studies of chemical bonding in transition-metal silicides

    NARCIS (Netherlands)

    Weijs, P.J.W.; Leuken, H. van; Groot, R.A. de; Fuggle, J.C.; Reiter, S.; Wiech, G.; Buschow, K.H.J.

    1991-01-01

    We present Si L2,3 emission-band spectra of a series of 3d and 4d transition-metal (TM) silicides, together wtih Si K emission-band spectra of four 3d TM disilicides. The data are compared with augmented-spherical-wave density-of-states (DOS) calculations, and good agreement is found. The trends we

  9. Determination of the optical absorption spectra of thin layers from their photoacoustic spectra

    Science.gov (United States)

    Bychto, Leszek; Maliński, Mirosław; Patryn, Aleksy; Tivanov, Mikhail; Gremenok, Valery

    2018-05-01

    This paper presents a new method for computations of the optical absorption coefficient spectra from the normalized photoacoustic amplitude spectra of thin semiconductor samples deposited on the optically transparent and thermally thick substrates. This method was tested on CuIn(Te0.7Se0.3)2 thin films. From the normalized photoacoustic amplitude spectra, the optical absorption coefficient spectra were computed with the new formula as also with the numerical iterative method. From these spectra, the value of the energy gap of the thin film material and the type of the optical transitions were determined. From the experimental optical transmission spectra, the optical absorption coefficient spectra were computed too, and compared with the optical absorption coefficient spectra obtained from photoacoustic spectra.

  10. Structure of high-resolution NMR spectra

    CERN Document Server

    Corio, PL

    2012-01-01

    Structure of High-Resolution NMR Spectra provides the principles, theories, and mathematical and physical concepts of high-resolution nuclear magnetic resonance spectra.The book presents the elementary theory of magnetic resonance; the quantum mechanical theory of angular momentum; the general theory of steady state spectra; and multiple quantum transitions, double resonance and spin echo experiments.Physicists, chemists, and researchers will find the book a valuable reference text.

  11. Measurement and calculation of characteristic prompt gamma ray spectra emitted during proton irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Polf, J C; Peterson, S; Beddar, S [M D Anderson Cancer Center, Univeristy of Texas, Houston, TX 77030 (United States); McCleskey, M; Roeder, B T; Spiridon, A; Trache, L [Cyclotron Institute, Texas A and M University, College Station, TX 77843 (United States)], E-mail: jcpolf@mdanderson.org

    2009-11-21

    In this paper, we present results of initial measurements and calculations of prompt gamma ray spectra (produced by proton-nucleus interactions) emitted from tissue equivalent phantoms during irradiations with proton beams. Measurements of prompt gamma ray spectra were made using a high-purity germanium detector shielded either with lead (passive shielding), or a Compton suppression system (active shielding). Calculations of the spectra were performed using a model of both the passive and active shielding experimental setups developed using the Geant4 Monte Carlo toolkit. From the measured spectra it was shown that it is possible to distinguish the characteristic emission lines from the major elemental constituent atoms (C, O, Ca) in the irradiated phantoms during delivery of proton doses similar to those delivered during patient treatment. Also, the Monte Carlo spectra were found to be in very good agreement with the measured spectra providing an initial validation of our model for use in further studies of prompt gamma ray emission during proton therapy. (note)

  12. Reflectance spectra of subarctic lichens

    International Nuclear Information System (INIS)

    Petzold, D.E.; Goward, S.N.

    1988-01-01

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the mid latitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 μm, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future. (author)

  13. Energy spectra of quantum rings.

    Science.gov (United States)

    Fuhrer, A; Lüscher, S; Ihn, T; Heinzel, T; Ensslin, K; Wegscheider, W; Bichler, M

    2001-10-25

    Quantum mechanical experiments in ring geometries have long fascinated physicists. Open rings connected to leads, for example, allow the observation of the Aharonov-Bohm effect, one of the best examples of quantum mechanical phase coherence. The phase coherence of electrons travelling through a quantum dot embedded in one arm of an open ring has also been demonstrated. The energy spectra of closed rings have only recently been studied by optical spectroscopy. The prediction that they allow persistent current has been explored in various experiments. Here we report magnetotransport experiments on closed rings in the Coulomb blockade regime. Our experiments show that a microscopic understanding of energy levels, so far limited to few-electron quantum dots, can be extended to a many-electron system. A semiclassical interpretation of our results indicates that electron motion in the rings is governed by regular rather than chaotic motion, an unexplored regime in many-electron quantum dots. This opens a way to experiments where even more complex structures can be investigated at a quantum mechanical level.

  14. Reflectance spectra of subarctic lichens

    Science.gov (United States)

    Petzold, Donald E.; Goward, Samuel N.

    1988-01-01

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the midlatitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 microns, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future.

  15. Methodology for analyzing weak spectra

    International Nuclear Information System (INIS)

    Yankovich, T.L.; Swainson, I.P.

    2000-02-01

    There is considerable interest in quantifying radionuclide transfer between environmental compartments. However, in many cases, it can be a challenge to detect concentrations of gamma-emitting radionuclides due to their low levels in environmental samples. As a result, it is valuable to develop analytical protocols to ensure consistent analysis of the areas under weak peaks. The current study has focused on testing how reproducibly peak areas and baselines can be determined using two analytical approaches. The first approach, which can be carried out using Maestro software, involves extracting net counts under a curve without fitting a functional form to the peak, whereas the second approach, which is used by most other peak fitting programs, determines net counts from spectra by fitting a Gaussian form to the data. It was found that the second approach produces more consistent peak area and baseline measurements, with the ability to de-convolute multiple, overlapping peaks. In addition, programs, such as Peak Fit, which can be used to fit a form to spectral data, often provide goodness of fit analyses, since the Gaussian form can be described using a characteristic equation against which peak data can be tested for their statistical significance. (author)

  16. Spectra of short-period pulsars according to the hypothesis of the two types of pulsars

    International Nuclear Information System (INIS)

    Malov, I.F.

    1985-01-01

    The lack of low-frequency turnovers in the spectra of PSR 0531+21 and 1937+21 may be expl ned if the generation of radio emission in these pulsars occurs near the light cylinder. Differences of high frequency cut-offs and spectral inoices for long-period pulsars and short-period ones are discussed

  17. Kα X-ray satellite spectra of Ti, V, Cr and Mn induced by photons

    Indian Academy of Sciences (India)

    K X-ray emission spectra of Ti, V, Cr and Mn generated by photon excitation have been studied with a crystal spectrometer. The measured energy shifts of K satellite relative to the diagram line are compared with values obtained by electron excitation and with different theoretical estimates. The present experimental ...

  18. MCNP modelling of scintillation-detector gamma-ray spectra from natural radionuclides

    NARCIS (Netherlands)

    Hendriks, Peter; Maucec, M; de Meijer, RJ

    gamma-ray spectra of natural radionuclides are simulated for a BGO detector in a borehole geometry using the Monte Carlo code MCNP. All gamma-ray emissions of the decay of K-40 and the series of Th-232 and U-238 are used to describe the source. A procedure is proposed which excludes the

  19. Survey of neutron spectra generated by the fission of heavy nuclei induced by fast neutrons

    International Nuclear Information System (INIS)

    Lovchikova, G.N.; Trufanov, A.M.

    1997-01-01

    A review of neutron fission spectra measurements is presented. This review and the results of this analysis was performed with the participation of the authors. It is shown that there is a need for additional measurements of the energy and angular distributions of secondary neutrons in order to improve the understanding of the neutron emission mechanism in fission. (author). 21 refs, 6 figs

  20. The NASA Ames Polycyclic Aromatic Hydrocarbon Infrared Spectroscopic Database : The Computed Spectra

    NARCIS (Netherlands)

    Bauschlicher, C. W.; Boersma, C.; Ricca, A.; Mattioda, A. L.; Cami, J.; Peeters, E.; de Armas, F. Sanchez; Saborido, G. Puerta; Hudgins, D. M.; Allamandola, L. J.

    The astronomical emission features, formerly known as the unidentified infrared bands, are now commonly ascribed to polycyclic aromatic hydrocarbons (PAHs). The laboratory experiments and computational modeling done at the NASA Ames Research Center to create a collection of PAH IR spectra relevant

  1. Soft X-Ray Spectra from High Current Nitrogen Z-Pinch Discharge

    Czech Academy of Sciences Publication Activity Database

    Vrba, Pavel; Vrbová, M.; Nevrkla, M.; Jančárek, A.

    2016-01-01

    Roč. 3, č. 1 (2016), s. 48 ISSN 2336-2626. [SPPT 2016 - 27th Symposium on Plasma Physics and Technology/27./. Prague, 20.06.2016-23.06.2016] Institutional support: RVO:61389021 Keywords : Capillary discharge * recombination pumping * pinch dynamics * evolution of spectra emission * computer modelling Subject RIV: BH - Optics, Masers, Lasers www.plasmaconference.cz

  2. General and efficient method for calculating modulation ressponses and noise spectra of active semiconductor waveguides

    DEFF Research Database (Denmark)

    Blaaberg, Søren; Öhman, Filip; Mørk, Jesper

    2008-01-01

    We present a theoretical method for obtaining small-signal responses in a spatially resolved active semiconductor waveguide including finite end-facet reflectivities and amplified spontaneous emission. RF-modulation responses and output noise spectra of an SOA are shown....

  3. X-ray emission from hot plasma

    International Nuclear Information System (INIS)

    Hayakawa, Satio; Kato, Takako.

    1979-01-01

    X-ray emission from hot plasmas is discussed with a critical review of different theories. The results given in the present paper are complementary to those given by Kato in the sense that the present paper is introductory to the paper by Kato. The contents of the present paper are; 1. Introduction 2. Ionization and Recombination Rate Coefficients 3. Relative Abundances of Ions 4. Intensity and Spectra of Radiation 5. Comparison with Earlier Results 6. Emission and Absorption Lines (author)

  4. Neutron and photon spectra in LINACs

    International Nuclear Information System (INIS)

    Vega-Carrillo, H.R.; Martínez-Ovalle, S.A.; Lallena, A.M.; Mercado, G.A.; Benites-Rengifo, J.L.

    2012-01-01

    A Monte Carlo calculation, using the MCNPX code, was carried out in order to estimate the photon and neutron spectra in two locations of two linacs operating at 15 and 18 MV. Detailed models of both linac heads were used in the calculations. Spectra were estimated below the flattening filter and at the isocenter. Neutron spectra show two components due to evaporation and knock-on neutrons. Lethargy spectra under the filter were compared to the spectra calculated from the function quoted by Tosi et al. that describes reasonably well neutron spectra beyond 1 MeV, though tends to underestimate the energy region between 10 –6 and 1 MeV. Neutron and the Bremsstrahlung spectra show the same features regardless of the linac voltage. - Highlights: ► With MCNPX code realistic models of two LINACs were built. ► Photon and neutron spectra below the flattening filter and at the isocenter were calculated. ► Neutron spectrum at the flattening filter was compared against the Tosi et al. source-term model. ► Tosi et al. model underestimates the neutron contribution below 1 MeV. ► Photon spectra look alike to those published in literature.

  5. Optical absorption spectra of Ag-11 isomers

    DEFF Research Database (Denmark)

    Martinez, Jose Ignacio; Fernandez, E. M.

    2009-01-01

    The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground-stale confi......The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground...

  6. Electroplex emission of the blend film of PVK and DPVBi

    Science.gov (United States)

    Li, Junming; Xu, Zheng; Zhang, Fujun; Zhao, Suling; Song, Dandan; Zhu, Haina; Song, Jinglu; Wang, Yongsheng; Xu, Xurong

    2010-04-01

    Influences of electric fields on the emission from organic light-emitting diodes (OLEDs) based on poly(N-vinylcarbazole) (PVK) and 4‧-bis(2-2diphenylvinyl)-1,1‧-biphenyl (DPVBi) as the active emission layer are studied. Electroluminescence (EL) spectra of PVK:DPVBi (1:1 w/w) films show one new emission peak locating at 640 nm compared with its photoluminescence (PL) spectra. There may be exists an electroplex emission between the PVK and DPVBi under high electric field strength. The emission intensity of peaking at 640 nm strongly depends on the driving voltage, and the ratio of electroplex emission intensity to exciton emission intensity (Ielectroplex/Iexciton) increases with the increase of driving voltage.

  7. Mid-IR Spectra of Refractory Minerals Relevant to Comets

    Science.gov (United States)

    Jauhari, Shekeab

    2008-09-01

    On 4 July 2005 the Spitzer Space Telescope obtained mid-IR ( 5-40 µm) spectra of the ejecta from the hypervelocity impact of the Deep Impact projectile with comet 9P/Tempel 1. Spectral modeling demonstrates that there are abundant minerals present in the ejecta including Ca/Fe/Mg-rich silicates, carbonates, phyllosilicates, water ice, amorphous carbon, and sulfides [1]. However, precise mineralogical identifications are hampered by the lack of comprehensive 5 - 40 µm spectral measurements of the emissivity for a broad compositional range of these materials. Here, we present our initial results for 2 - 50 µm transmission spectra and absorption constants for materials relevant to comets, including pyrrhotite, pyrite, and several phyllosilicate (clay) minerals. Measuring the transmission of materials over the full spectral range sensitive by Spitzer requires grinding the minerals into submicron powders and then mixing them with KBr (for the 1-25 um region) and polyethylene (16-50 um region) to form pellets. Transmission measurements of sub-micron sulfides are particularly difficult to obtain because the minerals oxidize rapidly upon grinding and subsequent handling unless special care is taken. A detailed description of our sample preparation and measurement technique will be provided to assist other researchers in their attempts to acquire similar spectra. References: [1] Lisse, C.M. et al., Science 313, 635 - 640 (2006)

  8. Fluorescence spectra of benign and malignant prostate tissues

    International Nuclear Information System (INIS)

    AlSalhi, M S; Masilamani, V; Atif, M; Farhat, K; Rabah, D; Al Turki, M R

    2012-01-01

    In this study, fluorescence emission spectrum (FES), Stokes' shift spectrum (SSS), and reflectance spectrum (RS) of benign (N = 12) and malignant prostate tissues (N = 8) were investigated to discriminate the two types of tissues. The FES was done with the excitation at 325 nm only; SSS with Δλ = 70 and Δλ = 0, the latter being equivalent to reflectance spectra. Of the three modes of spectra, SSS with Δλ = 70 nm showed the best discrimination. There were four important bands, one at 280 nm (due to tryptophan); 320 nm (due to elastin and tryptophan); 355 and 385 (due to NADH) and 440 nm (due to flavin). From the relative intensities of these bands, three ratios were evaluated. Similarly another two ratios were obtained from reflectance spectra and one more from FES. Thus, there are 6 ratio parameters which represent the relative concentration of tryptophan, elastin, nicotinamide adenine dinucleotide (NADH), and flavin. A statistical analysis showed that benign and malignant tissues could be classified with accuracy greater than 90%. This report is only for in vitro analysis; but employing optical fiber, this can be extended to in vivo analysis too, so that benign tumor could be distinguished without surgery

  9. Multivariate calibration applied to the quantitative analysis of infrared spectra

    Energy Technology Data Exchange (ETDEWEB)

    Haaland, D.M.

    1991-01-01

    Multivariate calibration methods are very useful for improving the precision, accuracy, and reliability of quantitative spectral analyses. Spectroscopists can more effectively use these sophisticated statistical tools if they have a qualitative understanding of the techniques involved. A qualitative picture of the factor analysis multivariate calibration methods of partial least squares (PLS) and principal component regression (PCR) is presented using infrared calibrations based upon spectra of phosphosilicate glass thin films on silicon wafers. Comparisons of the relative prediction abilities of four different multivariate calibration methods are given based on Monte Carlo simulations of spectral calibration and prediction data. The success of multivariate spectral calibrations is demonstrated for several quantitative infrared studies. The infrared absorption and emission spectra of thin-film dielectrics used in the manufacture of microelectronic devices demonstrate rapid, nondestructive at-line and in-situ analyses using PLS calibrations. Finally, the application of multivariate spectral calibrations to reagentless analysis of blood is presented. We have found that the determination of glucose in whole blood taken from diabetics can be precisely monitored from the PLS calibration of either mind- or near-infrared spectra of the blood. Progress toward the non-invasive determination of glucose levels in diabetics is an ultimate goal of this research. 13 refs., 4 figs.

  10. The impact of molecular emission in compositional depth profiling using Glow Discharge-Optical Emission Spectroscopy

    International Nuclear Information System (INIS)

    Bengtson, Arne

    2008-01-01

    The scope of this paper is to investigate and discuss how molecular emission can affect elemental analysis in glow discharge optical emission (GD-OES), particularly in compositional depth profiling (CDP) applications. Older work on molecular emission in glow discharges is briefly reviewed, and the nature of molecular emission spectra described. Work on the influence of hydrogen in the plasma, in particular elevated background due to a continuum spectrum, is discussed. More recent work from sputtering of polymers and other materials with a large content of light elements in a Grimm type source is reviewed, where substantial emission has been observed from several light diatomic molecules (CO, CH, OH, NH, C 2 ). It is discussed how the elevated backgrounds from such molecular emission can lead to significant analytical errors in the form of 'false' depth profile signals of several atomic analytical lines. Results from a recent investigation of molecular emission spectra from mixed gases in a Grimm type glow discharge are presented. An important observation is that dissociation and subsequent recombination processes occur, leading to formation of molecular species not present in the original plasma gas. Experimental work on depth profiling of a polymer coating and a thin silicate film, using a spectrometer equipped with channels for molecular emission lines, is presented. The results confirm that molecular emission gives rise to apparent depth profiles of elements not present in the sample. The possibilities to make adequate corrections for such molecular emission in CDP of organic coatings and very thin films are discussed

  11. Thermal Infrared Spectra of a Suite of Forsterite Samples and Ab-initio Modelling of theirs Spectra

    Science.gov (United States)

    Maturilli, A.; Stangarone, C.; Helbert, J.; Tribaudino, M.; Prencipe, M.

    2017-12-01

    Forsterite is the dominating component in olivine, a major constituent in ultrafemic rocks, as well as planetary bodies. Messenger X-ray spectrometer has shown that Mg-rich silicate minerals, such as enstatite and forsterite, dominate Mercury's surface (Weider et al 2012). A careful and detailed acquaintance with the forsterite spectral features and their dependence wrt environmental conditions on Mercury is needed to interpret the remote sensing data from previous and forthcoming missions. We propose an experimental vs calculation approach to reproduce and describe the spectral features of forsterite. TIR emissivity measurements are performed by the Planetary Spectroscopy Laboratory (PSL) of DLR. PSL offers the unique capability to measure the emissivity of samples at temperature up to 1000K under vacuum conditions. TIR emissivity and reflectance measurements are performed on 11 olivine samples having a different composition within the forsterite-fayalite series. When available, the sample has been measured in 2 different grain sizes (chameleon-like effects of Mercury surface already observed (Helbert et al. 2013), this study wants to point out the main spectral features due to the composition and temperature. Our results are used to create a theoretical background to interpret the high temperature infrared emissivity spectra from MERTIS onboard the ESA BepiColombo mission to Mercury (Helbert et al. 2010).

  12. Modeling Formaldehyde Emission in Comets

    Science.gov (United States)

    Disanti, M. A.; Reuter, D. C.; Bonev, B. P.; Mumma, M. J.; Villanueva, G. L.

    Modeling fluorescent emission from monomeric formaldehyde (H2CO) forms an integral part of our overall comprehensive program of measuring the volatile composition of comets through high-resolution (RP ~ 25,000) infrared spectroscopy using CSHELL at the IRTF and NIRSPEC at Keck II. The H2CO spectra contain lines from both the nu1 (symmetric CH2 stretch) and nu5 (asymmetric CH2 stretch) bands near 3.6 microns. We have acquired high-quality spectra of twelve Oort cloud comets, and at least six of these show clear emission from H2CO. We also detected H2CO with NIRSPEC in one Jupiter Family comet, 9P/Tempel 1, during Deep Impact observations. Our H2CO model, originally developed to interpret low-resolution spectra of comets Halley and Wilson (Reuter et al. 1989 Ap J 341:1045), predicts individual line intensities (g-factors) as a function of rotational temperature for approximately 1300 lines having energies up to approximately 400 cm^-1 above the ground state. Recently, it was validated through comparison with CSHELL spectra of C/2002 T7 (LINEAR), where newly developed analyses were applied to obtain robust determinations of both the rotational temperature and abundance of H2CO (DiSanti et al. 2006 Ap J 650:470). We are currently in the process of extending the model to higher rotational energy (i.e., higher rotational quantum number) in an attempt to improve the fit to high-J lines in our spectra of C/T7 and other comets. Results will be presented, and implications discussed.Modeling fluorescent emission from monomeric formaldehyde (H2CO) forms an integral part of our overall comprehensive program of measuring the volatile composition of comets through high-resolution (RP ~ 25,000) infrared spectroscopy using CSHELL at the IRTF and NIRSPEC at Keck II. The H2CO spectra contain lines from both the nu1 (symmetric CH2 stretch) and nu5 (asymmetric CH2 stretch) bands near 3.6 microns. We have acquired high-quality spectra of twelve Oort cloud comets, and at least six of

  13. Fluctuation analysis of rotational spectra

    International Nuclear Information System (INIS)

    Doessing, T.; Bracco, A.; Broglia, R.A.; Matsuo, M.

    1996-01-01

    The compound state rotational degree of freedom is ''damped'' in the sense that the electric quadrupole decay of a single quantum state with angular momentum I exhibits a spectrum of final states all having spin I-2. In actual experiments, the cascade of γ-rays associated with each of the members of the ensemble of compound nuclei uses each of the ''discrete'' transitions many more times than the ''continuum'' transitions. Relatively large and small fluctuations in the recorded coincidence spectrum ensue, respectively. The analysis of the fluctuations will be shown to be instrumental to gain insight into the phenomenon of rotational damping. For this purpose, two- and higher-fold coincidence spectra emitted from rotating nuclei are analyzed with respect to the count fluctuations. The coincidences from consecutive γ-rays emitted from discrete rotational bands generate ridges in the E γ1 .E γ2 spectrum, and the fluctuation analysis of the ridges is based upon the ansatz of a random selection of transition energies from band to band. This ansatz is supported by a cranked mean-field calculation for the nucleus 168 Yb, as well as by analyzing resolved bands in 168 Yb and its neighbors. The fluctuation analysis of the central valley (E γ1 =E γ2 ) is based upon the ansatz of fluctuations in the intensity of the transitions of Porter-Thomas type superposed on a smooth spectrum of transition energies. This ansatz is again supported by a mixed-band calculation. The mathematical treatment of count fluctuations is formulated in general (orig.)

  14. THE NASA AMES POLYCYCLIC AROMATIC HYDROCARBON INFRARED SPECTROSCOPIC DATABASE: THE COMPUTED SPECTRA

    International Nuclear Information System (INIS)

    Bauschlicher, C. W.; Ricca, A.; Boersma, C.; Mattioda, A. L.; Cami, J.; Peeters, E.; Allamandola, L. J.; Sanchez de Armas, F.; Puerta Saborido, G.; Hudgins, D. M.

    2010-01-01

    The astronomical emission features, formerly known as the unidentified infrared bands, are now commonly ascribed to polycyclic aromatic hydrocarbons (PAHs). The laboratory experiments and computational modeling done at the NASA Ames Research Center to create a collection of PAH IR spectra relevant to test and refine the PAH hypothesis have been assembled into a spectroscopic database. This database now contains over 800 PAH spectra spanning 2-2000 μm (5000-5 cm -1 ). These data are now available on the World Wide Web at www.astrochem.org/pahdb. This paper presents an overview of the computational spectra in the database and the tools developed to analyze and interpret astronomical spectra using the database. A description of the online and offline user tools available on the Web site is also presented.

  15. Optical spectra of phthalocyanines and related compounds a guide for beginners

    CERN Document Server

    Isago, Hiroaki

    2015-01-01

    This book displays how optical (absorption, emission, and magnetic circular dichroism) spectra of phthalocyanines and related macrocyclic dyes can be varied from their prototypical ones depending on conditions. As these compounds can be involved in colorful chemistry (which might be driven by impurities in solvents), their spectra behave like the sea-god Proteus in their mutability. Therefore, those who have been engaged with phthalocyanines for the first time, including even educated professional researchers and engineers, may have been embarrassed by the deceptive behavior of their compounds and could have, in the worst cases, given up their projects. This book is aimed not merely at reviewing the optical spectra, but also at helping such people, particularly beginners, to figure them out by showing some examples of their prototypical spectra and their variations in several situations. For the purpose of better understanding, the book also provides an introduction to their theoretical backgrounds as graphic...

  16. Molecular absorption spectra of beryllium, cerium, lanthanum, iron, and platinum salts

    International Nuclear Information System (INIS)

    Daidoji, Hidehiro

    1980-01-01

    The absorption spectra of some salts of beryllium, cerium, lanthanum, iron and platinum in air-acetylene flame were measured in the wavelength range from 200 to 400 nm. A Hitachi 207 type atomic absorption spectrophotometer was used. A deuterium lamp, a home-made continuous radiation lamp and some hollow cathode lamps were used as light sources. The new molecular absorption spectra of cerium, lanthanum and platinum and the absorption spectra due to Be(OH) 2 , LaO, PtH, FeO and FeCl in 200-400 nm region were obtained. Emission spectra of CeO, LaO and FeOH were also obtained. These molecular absorption bands were estimated as absorption errors of maximum 15 times to the sensitivity of each elements in atomic absorption spectrometry. In addition, spectral line interferences of iron were observed in atomic absorption spectrometry of Zn, Cd, Ni, Cu and Cr. (author)

  17. Area spectra of near extremal black holes

    International Nuclear Information System (INIS)

    Chen, Deyou; Yang, Haitang; Zu, Xiaotao

    2010-01-01

    Motivated by Maggiore's new interpretation of quasinormal modes, we investigate area spectra of a near extremal Schwarzschild-de Sitter black hole and a higher-dimensional near extremal Reissner-Nordstrom-de Sitter black hole. The result shows that the area spectra are equally spaced and irrelevant to the parameters of the black holes. (orig.)

  18. Composite Spectra Paper 1: HR 6902

    Indian Academy of Sciences (India)

    tribpo

    spectra; in many cases we have used the maximum width permitted by the optics of ... 10 mЕ, corresponding to 1 µm the plate, are the norm. ..... an inequality ..... on the spectra of HR 6902, we have thought it appropriate to weight the four ...

  19. Thermoluminescence spectra measured with a Michelson interferometer

    International Nuclear Information System (INIS)

    Haschberger, P.

    1991-01-01

    A Michelson interferometer was redesigned to prove its capabilities in the measurement of short-lived, low-intensity thermoluminescence spectra. Interferograms are collected during heating up the thermoluminescent probe in a heater plate. A personal computer controls the data acquisition and processes the Fourier transform. As the results show, even a comparatively simple and limited setup leads to relevant and reproducible spectra. (author)

  20. Near IR spectra of symbiotic stars

    International Nuclear Information System (INIS)

    Andrillat, Y.

    1982-01-01

    The author reports on recent observations from the near IR spectra of symbiotic stars. The helium and oxygen lines useful for the construction of theoretical models are identified. Observations for cool stars and novae (nebular phase) are outlined and the spectra of specific symbiotic stars between lambdalambda 8000-11000 are presented and discussed. (Auth./C.F.)

  1. Aircraft Measurements of Atmospheric Kinetic Energy Spectra

    DEFF Research Database (Denmark)

    Lundtang Petersen, Erik; Lilly, D. K.

    1983-01-01

    Wind velocity data obtained from a jet airliner are used to construct kinetic energy spectra over the range of wavelengths from 2.5 to 2500 km. The spectra exhibit an approximate -5/3 slope for wavelengths of less than about 150 km, steepening to about -2.2 at larger scales. These results support...

  2. Observing the Spectra of MEarth and TRAPPIST Planets with JWST

    Science.gov (United States)

    Morley, Caroline; Kreidberg, Laura; Rustamkulov, Zafar; Robinson, Tyler D.; Fortney, Jonathan J.

    2017-10-01

    During the past two years, nine planets close to Earth in radius have been discovered around nearby M dwarfs cooler than 3300 K. These planets include the 7 planets in the TRAPPIST-1 system and two planets discovered by the MEarth survey, GJ 1132b and LHS 1140b (Dittmann et al. 2017; Berta-Thompson et al. 2015; Gillon et al. 2017). These planets are the smallest planets discovered to date that will be amenable to atmospheric characterization with JWST. They span equilibrium temperatures from ˜130 K to >500 K, and radii from 0.7 to 1.43 Earth radii. Some of these planets orbit as distances potentially amenable to surface liquid water, though the actual surface temperatures will depend strongly on the albedo of the planet and the thickness and composition of its atmosphere. The stars they orbit also vary in activity levels, from the quiet LHS 1140b host star to the more active TRAPPIST-1 host star. This set of planets will form the testbed for our first chance to study the diversity of atmospheres around Earth-sized planets. Here, we will present model spectra of these 9 planets, varying the composition and the surface pressure of the atmosphere. We base our elemental compositions on three outcomes of planetary atmosphere evolution in our own solar system: Earth, Titan, and Venus. We calculate the molecular compositions in chemical equilibrium. We present both thermal emission spectra and transmission spectra for each of these objects, and make predictions for the observability of these spectra with different instrument modes with JWST.

  3. Comparison of (alpha, n) thick-target neutron yields and spectra from ORIGEN-S and SOURCES

    International Nuclear Information System (INIS)

    Brown, T.H.; Wilson, W.B.; Perry, R.T.; Charlton, W.S.

    1998-01-01

    Both ORIGEN-S and SOURCES generate thick-target neutron yields and energy spectra from (α,n) reactions in homogeneous materials. SOURCES calculates yield and spectra for any material containing α-emitting and (α,n) target elements by simulating reaction physics, using α-emission energy spectra, elemental stopping cross sections, (α,n) cross sections for target nuclei, and branching fractions to produce-nuclide energy levels. This methodology results in accurate yield and spectra. ORIGEN-S has two options for calculating yields and spectra. The UO 2 option (default) estimates yields and spectra assuming the input α-emitters to be infinitely dilute in UO 2 . The borosilicate-glass option estimates yields from the total input material composition and generates spectra purportedly representative of spectra generated by 238 Pu, 241 Am, 242 Cm, and 244 Cm infinitely dilute in borosilicate glass, even if none of these four α-emitters are present in the input material composition. Because yields from the borosilicate-glass option in ORIGEN-S are based on entire input material composition and are reasonably accurate, the same is often assumed to be true for spectra. The input/output functionality of the borosilicate-glass option, along with ambiguity in ORIGEN-S documentation, gives the incorrect impression that spectra representative of input compositions are generated. This impression is reinforced by wide usage of the SCALE code system and its ORIGEN-S module and their sponsorship by the US Nuclear Regulatory Commission

  4. PCA: Principal Component Analysis for spectra modeling

    Science.gov (United States)

    Hurley, Peter D.; Oliver, Seb; Farrah, Duncan; Wang, Lingyu; Efstathiou, Andreas

    2012-07-01

    The mid-infrared spectra of ultraluminous infrared galaxies (ULIRGs) contain a variety of spectral features that can be used as diagnostics to characterize the spectra. However, such diagnostics are biased by our prior prejudices on the origin of the features. Moreover, by using only part of the spectrum they do not utilize the full information content of the spectra. Blind statistical techniques such as principal component analysis (PCA) consider the whole spectrum, find correlated features and separate them out into distinct components. This code, written in IDL, classifies principal components of IRS spectra to define a new classification scheme using 5D Gaussian mixtures modelling. The five PCs and average spectra for the four classifications to classify objects are made available with the code.

  5. General Notes on Processes and Their Spectra

    Directory of Open Access Journals (Sweden)

    Gustav Cepciansky

    2012-01-01

    Full Text Available The frequency spectrum performs one of the main characteristics of a process. The aim of the paper is to show the coherence between the process and its own spectrum and how the behaviour and properties of a process itself can be deduced from its spectrum. Processes are categorized and general principles of their spectra calculation and recognition are given. The main stress is put on power spectra of electric and optic signals, as they also perform a kind of processes. These spectra can be directly measured, observed and examined by means of spectral analyzers and they are very important characteristics which can not be omitted at transmission techniques in telecommunication technologies. Further, the paper also deals with non electric processes, mainly with processes and spectra at mass servicing and how these spectra can be utilised in praxis.

  6. ELEMENTAL ABUNDANCES IN THE EJECTA OF OLD CLASSICAL NOVAE FROM LATE-EPOCH SPITZER SPECTRA

    International Nuclear Information System (INIS)

    Helton, L. Andrew; Vacca, William D.; Gehrz, Robert D.; Woodward, Charles E.; Shenoy, Dinesh P.; Wagner, R. Mark; Evans, Aneurin; Krautter, Joachim; Schwarz, Greg J.; Starrfield, Sumner

    2012-01-01

    We present Spitzer Space Telescope mid-infrared IRS spectra, supplemented by ground-based optical observations, of the classical novae V1974 Cyg, V382 Vel, and V1494 Aql more than 11, 8, and 4 years after outburst, respectively. The spectra are dominated by forbidden emission from neon and oxygen, though in some cases, there are weak signatures of magnesium, sulfur, and argon. We investigate the geometry and distribution of the late time ejecta by examination of the emission line profiles. Using nebular analysis in the low-density regime, we estimate lower limits on the abundances in these novae. In V1974 Cyg and V382 Vel, our observations confirm the abundance estimates presented by other authors and support the claims that these eruptions occurred on ONe white dwarfs (WDs). We report the first detection of neon emission in V1494 Aql and show that the system most likely contains a CO WD.

  7. ELEMENTAL ABUNDANCES IN THE EJECTA OF OLD CLASSICAL NOVAE FROM LATE-EPOCH SPITZER SPECTRA

    Energy Technology Data Exchange (ETDEWEB)

    Helton, L. Andrew; Vacca, William D. [SOFIA Science Center, USRA, NASA Ames Research Center, M.S. N232-11, Moffett Field, CA 94035 (United States); Gehrz, Robert D.; Woodward, Charles E.; Shenoy, Dinesh P. [Minnesota Institute for Astrophysics, School of Physics and Astronomy, 116 Church Street S.E., University of Minnesota, Minneapolis, MN 55455 (United States); Wagner, R. Mark [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Evans, Aneurin [Astrophysics Group, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom); Krautter, Joachim [Landessternwarte-Zentrum fuer Astronomie der Universitaet, Koenigstuhl, D-69117 Heidelberg (Germany); Schwarz, Greg J. [American Astronomical Society, 2000 Florida Avenue, NW, Suite 400, Washington, DC 20009 (United States); Starrfield, Sumner, E-mail: ahelton@sofia.usra.edu [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287 (United States)

    2012-08-10

    We present Spitzer Space Telescope mid-infrared IRS spectra, supplemented by ground-based optical observations, of the classical novae V1974 Cyg, V382 Vel, and V1494 Aql more than 11, 8, and 4 years after outburst, respectively. The spectra are dominated by forbidden emission from neon and oxygen, though in some cases, there are weak signatures of magnesium, sulfur, and argon. We investigate the geometry and distribution of the late time ejecta by examination of the emission line profiles. Using nebular analysis in the low-density regime, we estimate lower limits on the abundances in these novae. In V1974 Cyg and V382 Vel, our observations confirm the abundance estimates presented by other authors and support the claims that these eruptions occurred on ONe white dwarfs (WDs). We report the first detection of neon emission in V1494 Aql and show that the system most likely contains a CO WD.

  8. Prompt fission neutron spectra of n + 235U above the (n, nf) fission threshold

    International Nuclear Information System (INIS)

    Shu Nengchuan; Chen Yongjing; Liu Tingjin; Jia Min

    2015-01-01

    Calculations of prompt fission neutron spectra (PFNS) from the 235 U(n, f) reaction were performed with a semi-empirical method for En = 7.0 and 14.7 MeV neutron energies. The total PFNS were obtained as a superposition of (n, xnf) pre-fission neutron spectra and post-fission spectra of neutrons which were evaporated from fission fragments, and these two kinds of spectra were taken as an expression of the evaporation spectrum. The contributions of (n, xnf) fission neutron spectra on the calculated PFNS were discussed. The results show that emission of one or two neutrons in the (n, nf) or (n, 2nf) reactions influences the PFNS shape, and the neutron spectra of the (n, xnf) fission-channel are soft compared with the neutron spectra of the (n, f) fission channel. In addition, analysis of the multiple-chance fission component showed that second-chance fission dominates the PFNS with an incident neutron energy of 14.7 MeV whereas first-chance fission dominates the 7 MeV case. (authors)

  9. On the mechanism of fission neutron emission

    International Nuclear Information System (INIS)

    Maerten, H.; Richter, D.; Seeliger, D.

    1986-01-01

    This review represents the present knowledge of the mechanism of prompt fission neutron emission. Starting with a brief fission process characterization related with neutron emission, possible emission mechanisms are discussed. It is emphasized that the experimental study of special mechanisms, i.e. scission neutron emission processes, requires a sufficiently correct description of emission probabilities on the base of the main mechanism, i.e. the evaporation from fully accelerated fragments. Adequate statistical-model approaches have to account for the complexity of nuclear fission reflected by an intricate fragment distribution. The present picture of scission neutron emission is not clarified neither experimentally nor theoretically. Deduced data are contradictory and depend on the used analysis procedures often involving rough discriptions of evaporated-neutron distributions. The contribution of two secondary mechanisms of fission neutron emission, i.e. the neutron evaporation during fragment acceleration and neutron emission due to the decay of 5 He after ternary fission, is estimated. We summarize the recent progress of the theoretical description of fission neutron spectra in the framework of statistical models considering the standard spectrum of 252 Cf(sf) neutrons especially. The main experimental basis for the study of fission neutron emission is the accurate measurement of emission probabilities as a function of emission energy and angle (at least) as well as fragment parameters (mass number ratio and kinetic energy). The present status is evaluated. (author)

  10. Design spectra development considering short time histories

    International Nuclear Information System (INIS)

    Weiner, E.O.

    1983-01-01

    Two separate programs, MODQKE and MDOF, were written to provide a capability of obtaining equipment spectra from design spectra. MODQKE generates or modifies acceleration histories to conform with design spectra pertaining to, say, a foundation. MDOF is a simple linear modal superposition program that solves for equipment support histories using the design spectra conforming histories as input. Equipment spectra, then, are obtained from the support histories using MODQKE. MODQKE was written to modify or provide new histories with special attention paid to short seismic records. A technique from the open literature was borrowed to generate an initial history that approximates a given response spectrum. Further refinement is done with smoothing cycles in which several correction signals are added to the history in a way that produces a least squares fit between actual and prescribed spectra. Provision is made for history shaping, a baseline correction, and final scaling. MODQKE performance has been demonstrated with seven examples having zero to ten percent damping ratios, and 2.5 seconds to 20 seconds durations and a variety of target spectra. The examples show the program is inexpensive to use. MDOF is a simple modal superposition program. It has no eigensolver, and the user supplies mode shapes, frequencies, and participation factors as input. Floor spectra can be generated from design spectra by using a history from MODQKE that conforms to the design spectrum as input to MDOF. Floor motions from MDOF can be fed back to MODQKE without modification to obtain the floor spectra. A simple example is given to show how equipment mass effects can be incorporated into the MDOF solution. Any transient solution capability can be used to replace MDOF. For example, a direct transient approach may be desirable if both the equipment and floor structures are to be included in the model with different damping fractions. (orig./HP)

  11. Spectra of atoms and molecules

    CERN Document Server

    Bernath, Peter F

    2005-01-01

    1. Introduction. 1.1. Waves, Particles, and Units. 1.2. The Electromagnetic Spectrum. 1.3. Interaction of Radiation with Matter. 1.3a. Blackbody Radiation. 1.3b. Einstein A and B Coefficients. 1.3c. Absorption and Emission of Radiation. 1.3d. Beer''s Law. 1.3e. Lineshape Functions. 1.3f. Natural Lifetime Broadening. 1.3g. Pressure Broadening. 1.3h. Doppler Broadening. 1.3i. Transit-Time Broadening. 1.3j. Power Broadening. 2. Molecular Symmetry. 2.1. Symmetry Operations. 2.1a. Operator Algebra. 2.1b. Symmetry Operator Algebra. 2.2. Groups. 2.2a. Point Groups. 2.2b. Classes. 2.2c. Subgroups. 2.3. Notation for Point Groups. 3. Matrix Representation of Groups. 3.1. Vectors and Matrices. 3.1a. Matrix Eigenvalue Problem. 3.1b. Similarity Transformations. 3.2. Symmetry Operations and Position Vectors. 3.2a. Reflection. 3.2b. Rotation. 3.2c. Rotation-Reflection. 3.2d. Inversion. 3.2e. Identity. 3.3. Symmetry Operators and Basic Vectors. 3.4. Symmetry Operators and Basic Functions. 3.4a. Function Spaces. 3.4b. Gram-Sc...

  12. ZnO nanorod based low turn-on voltage LEDs with wide electroluminescence spectra

    International Nuclear Information System (INIS)

    Jha, S.K.; Kutsay, O.; Bello, I.; Lee, S.T.

    2013-01-01

    Light emitting diodes (LEDs) based on arrays of n-type ZnO Nanorods were fabricated on p-GaN films using a hydrothermal method. The LEDs emit mainly in blue and UV range of the light. Their current–Voltage (I–V) characteristics typically show a low leakage current (7.2 μA) and a high rectification ratio (3 5 5). Devices operate at a low turn-on voltage of ∼4.5 V. Photoluminescence (PL) and electroluminescence (EL) measurements suggest low density of ZnO defects; however, in some aspects density of interfacial defects still might be considerable in the studied devices. The PL emission is deconvoluted to three peaks that are located at wavelengths of 361, 381, and 397 nm, while the wide EL spectra are deconvoluted to five peaks appearing at 368, 385, 427, 474, and 515 nm. Near-band-edge (NBE) emission of p-GaN and n-ZnO was observed in both the PL and EL spectra. Deconvoluted EL spectra consist of a very wide green band with the peak at 515 nm and extending up to 650 nm (red), and a rarely reported EL emission at 474 nm. Origin of these emissions is discussed, herein. The electrical characteristics together with EL characteristics indicate potential to develop and study p-GaN/n-ZnO nanorod LEDs for white emitting applications. - Highlights: ► A low turn-on voltage (4–4.5 V) and low threshold (5 V) electroluminescence from ZnO/GaN heterostructure. ► A wide spectrum EL emission (360–700 nm) suitable for white LED application. ► EL spectra consist of a rarely reported emission band with peak at 474 nm. ► Low-temperature and solution based fabrication, which is scalable and of low cost.

  13. Spectra of conformal sigma models

    International Nuclear Information System (INIS)

    Tlapak, Vaclav

    2015-04-01

    In this thesis the spectra of conformal sigma models defined on (generalized) symmetric spaces are analysed. The spaces where sigma models are conformal without the addition of a Wess-Zumino term are supermanifolds, in other words spaces that include fermionic directions. After a brief review of the general construction of vertex operators and the background field expansion, we compute the diagonal terms of the one-loop anomalous dimensions of sigma models on semi-symmetric spaces. We find that the results are formally identical to the symmetric case. However, unlike for sigma models on symmetric spaces, off diagonal terms that lead to operator mixing are also present. These are not computed here. We then present a detailed analysis of the one-loop spectrum of the supersphere S 3 vertical stroke 2 sigma model as one of the simplest examples. The analysis illustrates the power and simplicity of the construction. We use this data to revisit a duality with the OSP(4 vertical stroke 2) Gross-Neveu model that was proposed by Candu and Saleur. With the help of a recent all-loop result for the anomalous dimension of (1)/(2)BPS operators of Gross-Neveu models, we are able to recover the entire zero-mode spectrum of the supersphere model. We also argue that the sigma model constraints and its equations of motion are implemented correctly in the Gross-Neveu model, including the one-loop data. The duality is further supported by a new all-loop result for the anomalous dimension of the ground states of the sigma model. However, higher-gradient operators cannot be completely recovered. It is possible that this discrepancy is related to a known instability of the sigma model. The instability of sigma models is due to symmetry preserving high-gradient operators that become relevant at arbitrarily small values of the coupling. This feature has been observed long ago in one-loop calculations of the O(N)-vector model and soon been realized to be a generic property of sigma models

  14. Infrared spectra of interstellar deuteronated PAHs

    Science.gov (United States)

    Buragohain, Mridusmita; Pathak, Amit; Sarre, Peter

    2015-08-01

    Polycyclic Aromatic Hydrocarbon (PAH) molecules have emerged as a potential constituent of the ISM that emit strong features at 3.3, 6.2, 7.7, 8.6, 11.2 and 12.7 μm with weaker and blended features in the 3-20μm region. These features are proposed to arise from the vibrational relaxation of PAH molecules on absorption of background UV photons (Tielens 2008). These IR features have been observed towards almost all types of astronomical objects; say H II regions, photodissociation regions, reflection nebulae, planetary nebulae, young star forming regions, external galaxies, etc. A recent observation has proposed that interstellar PAHs are major reservoir for interstellar deuterium (D) (Peeters et al. 2004). According to the `deuterium depletion model' as suggested by Draine (2006), some of the Ds formed in the big bang are depleted in PAHs, which can account for the present value of D/H in the ISM. Hence, study of deuterated PAHs (PADs) is essential in order to measure D/H in the ISM.In this work, we consider another probable category of the large PAH family, i.e. Deuteronated PAHs (DPAH+). Onaka et al. have proposed a D/H ratio which is an order of magnitude smaller than the proposed value of D/H by Draine suggesting that if Ds are depleted in PAHs, they might be accommodated in large PAHs (Onaka et al. 2014). This work reports a `Density Functional Theory' calculation of large deuteronated PAHs (coronene, ovalene, circumcoronene and circumcircumcoronene) to determine the expected region of emission features and to find a D/H ratio that is comparable to the observational results. We present a detailed analysis of the IR spectra of these molecules and discuss the possible astrophysical implications.ReferencesDraine B. T. 2006, in ASP Conf. Ser. 348, Proc. Astrophysics in the Far Ultraviolet: Five Years of Discovery with FUSE, ed. G. Sonneborn, H. Moos, B-G Andersson (San Francisco, CA:ASP) 58Onaka T., Mori T. I., Sakon I., Ohsawa R., Kaneda H., Okada Y., Tanaka M

  15. Time-resolved emission from laser-ablated uranium

    International Nuclear Information System (INIS)

    Stoffels, E.; Mullen, J. van der; Weijer, P. van de

    1991-01-01

    Time-resolved emission spectra from the plasma, induced by laser ablation of uranium samples have been studied. The dependence of the emission intensity on time is strongly affected by the nature and pressure of the buffer gas. Air and argon have been used in the pressure range 0.002 to 5 mbar. The emission intensity as a function of time displays three maxima, indicating that three different processes within the expanding plasma plume are involved. On basis of the time-resolved spectra we propose a model that explains qualitatively the phenomena that are responsible for this time behaviour. (author)

  16. Scaling properties of the transverse mass spectra

    International Nuclear Information System (INIS)

    Schaffner-Bielich, J.

    2002-01-01

    Motivated from the formation of an initial state of gluon-saturated matter, we discuss scaling relations for the transverse mass spectra at BNL's relativistic heavy-ion collider (RHIC). We show on linear plots, that the transverse mass spectra for various hadrons can be described by an universal function in m t . The transverse mass spectra for different centralities can be rescaled into each other. Finally, we demonstrate that m t -scaling is also present in proton-antiproton collider data and compare it to m t -scaling at RHIC. (orig.)

  17. Parametrization relating the fermionic mass spectra

    International Nuclear Information System (INIS)

    Kleppe, A.

    1993-01-01

    When parametrizing the fermionic mass spectra in terms of the unit matrix and a recursive matrix scrR 0 , which corresponds to an underlying scaling pattern in the mass spectra, each fermionic sector is characterized by three parameters: k, α, and R. Using the set of relations displayed by the parameters of the different sectors, it is possible to formulate a ''family Lagrangian'' which for each sector encompasses all the families. Relations between quark masses are furthermore deduced from these ''family Lagrangians.'' Using the relations between the parameters of the different charge sectors, it is also possible to ''derive'' the quark mass spectra from the (charged) leptonic mass spectrum

  18. Analysis of extreme ultraviolet spectra from laser produced rhenium plasmas

    International Nuclear Information System (INIS)

    Wu, Tao; Dunne, Padraig; O’Reilly, Fergal; Sokell, Emma; Liu, Luning; O’Sullivan, Gerry; Higashiguchi, Takeshi; Suzuki, Yuhei; Arai, Goki; Dinh, Thanh-Hung; Li, Bowen

    2015-01-01

    Extreme ultraviolet spectra of highly-charged rhenium ions were observed in the 1–7 nm region using two Nd:YAG lasers with pulse lengths of 150 ps and 10 ns, respectively, operating at a number of laser power densities. The maximum focused peak power density was 2.6 × 10 14 W cm −2 for the former and 5.5 × 10 12 W cm −2 for the latter. The Cowan suite of atomic structure codes and unresolved transition array (UTA) approach were used to calculate and interpret the emission properties of the different spectra obtained. The results show that n = 4-n = 4 and n = 4-n = 5 UTAs lead to two intense quasi-continuous emission bands in the 4.3–6.3 nm and 1.5–4.3 nm spectral regions. As a result of the different ion stage distributions in the plasmas induced by ps and ns laser irradiation the 1.5–4.3 nm UTA peak moves to shorter wavelength in the ps laser produced plasma spectra. For the ns spectrum, the most populated ion stage during the lifetime of this plasma that could be identified from the n = 4-n = 5 transitions was Re 23+ while for the ps plasma the presence of significantly higher stages was demonstrated. For the n = 4-n = 4 4p 6 4d N -4p 5 4d N+1  + 4p 6 4d N−1 4f transitions, the 4d-4f transitions contribute mainly in the most intense 4.7–5.5 nm region while the 4p-4d subgroup gives rise to a weaker feature in the 4.3–4.7 nm region. A number of previously unidentified spectral features produced by n = 4-n = 5 transitions in the spectra of Re XVI to Re XXXIX are identified. (paper)

  19. Dynamical and Radiative Properties of X-Ray Pulsar Accretion Columns: Phase-averaged Spectra

    Energy Technology Data Exchange (ETDEWEB)

    West, Brent F. [Department of Electrical and Computer Engineering, United States Naval Academy, Annapolis, MD (United States); Wolfram, Kenneth D. [Naval Research Laboratory (retired), Washington, DC (United States); Becker, Peter A., E-mail: bwest@usna.edu, E-mail: kswolfram@gmail.com, E-mail: pbecker@gmu.edu [Department of Physics and Astronomy, George Mason University, Fairfax, VA (United States)

    2017-02-01

    The availability of the unprecedented spectral resolution provided by modern X-ray observatories is opening up new areas for study involving the coupled formation of the continuum emission and the cyclotron absorption features in accretion-powered X-ray pulsar spectra. Previous research focusing on the dynamics and the associated formation of the observed spectra has largely been confined to the single-fluid model, in which the super-Eddington luminosity inside the column decelerates the flow to rest at the stellar surface, while the dynamical effect of gas pressure is ignored. In a companion paper, we have presented a detailed analysis of the hydrodynamic and thermodynamic structure of the accretion column obtained using a new self-consistent model that includes the effects of both gas and radiation pressures. In this paper, we explore the formation of the associated X-ray spectra using a rigorous photon transport equation that is consistent with the hydrodynamic and thermodynamic structure of the column. We use the new model to obtain phase-averaged spectra and partially occulted spectra for Her X-1, Cen X-3, and LMC X-4. We also use the new model to constrain the emission geometry, and compare the resulting parameters with those obtained using previously published models. Our model sheds new light on the structure of the column, the relationship between the ionized gas and the photons, the competition between diffusive and advective transport, and the magnitude of the energy-averaged cyclotron scattering cross-section.

  20. Acoustic emission

    International Nuclear Information System (INIS)

    Straus, A.; Lopez Pumarega, M.I.; Di Gaetano, J.O.; D'Atellis, C.E.; Ruzzante, J.E.

    1990-01-01

    This paper is related to our activities on acoustic emission (A.E.). The work is made with different materials: metals and fibre reinforced plastics. At present, acoustic emission transducers are being developed for low and high temperature. A test to detect electrical discharges in electrical transformers was performed. Our experience in industrial tests to detect cracks or failures in tanks or tubes is also described. The use of A.E. for leak detection is considered. Works on pattern recognition of A.E. signals are also being performed. (Author)

  1. Power spectra of currents off Bombay

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    Current measurements were carried out using a recording current meter across the continental shelf off Bombay, Maharashtra, India at 4 stations from an anchored ship. Power spectra were computed for selected lengths of records. Spectral energy...

  2. Contribution to the study of turbulence spectra

    Science.gov (United States)

    Dumas, R.

    1979-01-01

    An apparatus suitable for turbulence measurement between ranges of 1 to 5000 cps and from 6 to 16,000 cps was developed and is described. Turbulence spectra downstream of the grills were examined with reference to their general characteristics, their LF qualities, and the effects of periodic turbulence. Medium and HF are discussed. Turbulence spectra in the boundary layers are similarly examined, with reference to their fluctuations at right angles to the wall, and to lateral fluctuations. Turbulence spectra in a boundary layer with suction to the wall is discussed. Induced turbulence, and turbulence spectra at high Reynolds numbers. Calculations are presented relating to the effect of filtering on the value of the correlations in time and space.

  3. Experimental phase diagram for random laser spectra

    International Nuclear Information System (INIS)

    El-Dardiry, Ramy G S; Mooiweer, Ronald; Lagendijk, Ad

    2012-01-01

    We systematically study the presence of narrow spectral features in a wide variety of random laser samples. Less gain or stronger scattering are shown to lead to a crossover from spiky to smooth spectra. A decomposition of random laser spectra into a set of Lorentzians provides unprecedented detail in the analysis of random laser spectra. We suggest an interpretation in terms of mode competition that enables an understanding of the observed experimental trends. In this interpretation, smooth random laser spectra are a consequence of competing modes for which the loss and gain are proportional. Spectral spikes are associated with modes that are uncoupled from the mode competition in the bulk of the sample. (paper)

  4. On two-spectra inverse problems

    OpenAIRE

    Guliyev, Namig J.

    2018-01-01

    We consider a two-spectra inverse problem for the one-dimensional Schr\\"{o}dinger equation with boundary conditions containing rational Herglotz--Nevanlinna functions of the eigenvalue parameter and provide a complete solution of this problem.

  5. DMSO-Water Clustering in Solution Observed in Soft X-ray Spectra.

    Science.gov (United States)

    Engel, Nicholas; Atak, Kaan; Lange, Kathrin M; Gotz, Malte; Soldatov, Mikhail; Golnak, Ronny; Suljoti, Edlira; Rubensson, Jan-Erik; Aziz, Emad F

    2012-12-20

    The significant deviation from the ideality of dimethyl sulfoxide (DMSO)/water mixtures can be addressed based on the change of the local molecular orbitals of each solvent upon mixing. Oxygen K-edge absorption and emission spectra of DMSO/water solutions were measured using the liquid microjet technique. The spectra demonstrate that the hydrogen bond network in liquid water is already influenced at small DMSO concentrations, and at the molar fraction xDMSO = 0.43 we find strong evidence of DMSO-water clustering reflected by the influence on the occupied molecular orbitals.

  6. Correlated relativistic dynamics and nuclear effects in dielectronic and visible spectra of highly charged ions

    International Nuclear Information System (INIS)

    Harman, Z.; Artemyev, A.N.; Crespo Lopez-Urrutia, J.R.

    2008-01-01

    Dielectronic recombination and visible emission spectra are investigated theoretically and experimentally. Spectra of x-rays emitted from electron beam ion trap plasmas allow the study of correlation and quantum electrodynamic effects in relativistic few-body systems. In the visible range, exploring the forbidden M1 transitions in Be- and B-like argon ions provides one new insights into the relativistic modelling of isotope shift effects and extend the scope of bound-electron g factor measurements to few-electron ions. (author)

  7. Attempt to separate the fluorescence spectra of adrenaline and noradrenaline using chemometrics

    DEFF Research Database (Denmark)

    Nikolajsen, Rikke P; Hansen, Åse Marie; Bro, R

    2000-01-01

    An investigation was conducted on whether the fluorescence spectra of the very similar catecholamines adrenaline and noradrenaline could be separated using chemometric methods. The fluorescence landscapes (several excitation and emission spectra were measured) of two data sets with respectively 16...... regression (Unfold-PLSR) on the larger data set and parallel factor analysis (PARAFAC) of the six samples of the smaller set showed that there was no difference between the fluorescence landscapes of adrenaline and noradrenaline. It can be concluded that chemometric separation of adrenaline and noradrenaline...

  8. Dual fluorescence excitation spectra of methyl salicylate in a free jet

    Science.gov (United States)

    Heimbrook, Lou Ann; Kenny, Jonathan E.; Kohler, Bryan E.; Scott, Gary W.

    1981-11-01

    Separate fluorescence excitation spectra of the blue- and UV-emitting forms of methyl salicylate cooled in a free-jet expansion are reported. This study represents the first observation of the detailed vibrational structure of these transitions. The two excitation spectra have no features in common, and their intensity patterns are very different. Many individual lines are ˜2 cm-1 wide (nearly laser limited), although in the excitation spectrum of the UV emission, spectral congestion persists at high energies despite the high degree of cooling. (AIP)

  9. Auroral nitric oxide concentration and infrared emission

    Science.gov (United States)

    Reidy, W. P.; Degges, T. C.; Hurd, A. G.; Stair, A. T., Jr.; Ulwick, J. C.

    1982-05-01

    Rocket-borne measurements of infrared auroral emission by nitric oxide are analyzed. Four rocket flights provided opportunities to measure 5.3- and 2.7-micron NO emission by means of infrared fixed band radiometers and CVF spectrometers, narrow band photometers, and incident energy spectra on various occasions. Analysis of infrared emission profiles and electron flux data indicates the NO density to be significantly enhanced with respect to midlatitude values. NO emission in the fundamental 5.3-micron band is attributed to resonance excitation by warm earth radiation, collisional excitation primarily by O atoms and chemiluminescence from the reaction of N with O2; with an energy efficiency of 0.015. The overtone band emission at 2.7 microns is accounted for by chemiluminescence produced with an energy efficiency of 0.0054. Total photon yield for the chemiluminescence reaction is estimated to range from 1.2 to 2.4 vibrational quanta per NO molecule.

  10. Spectral wave analysis at the mesopause from SCIAMACHY airglow data compared to SABER temperature spectra

    Directory of Open Access Journals (Sweden)

    M. Ern

    2009-01-01

    Full Text Available Space-time spectral analysis of satellite data is an important method to derive a synoptic picture of the atmosphere from measurements sampled asynoptically by satellite instruments. In addition, it serves as a powerful tool to identify and separate different wave modes in the atmospheric data. In our work we present space-time spectral analyses of chemical heating rates derived from Scanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY hydroxyl nightglow emission measurements onboard Envisat for the years 2002–2006 at mesopause heights. Since SCIAMACHY nightglow hydroxyl emission measurements are restricted to the ascending (nighttime part of the satellite orbit, our analysis also includes temperature spectra derived from 15 μm CO2 emissions measured by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER instrument. SABER offers better temporal and spatial coverage (daytime and night-time values of temperature and a more regular sampling grid. Therefore SABER spectra also contain information about higher frequency waves. Comparison of SCIAMACHY and SABER results shows that SCIAMACHY, in spite of its observational restrictions, provides valuable information on most of the wave modes present in the mesopause region. The main differences between wave spectra obtained from these sensors can be attributed to the differences in their sampling patterns.

  11. Spectral wave analysis at the mesopause from SCIAMACHY airglow data compared to SABER temperature spectra

    Directory of Open Access Journals (Sweden)

    M. Ern

    2009-01-01

    Full Text Available Space-time spectral analysis of satellite data is an important method to derive a synoptic picture of the atmosphere from measurements sampled asynoptically by satellite instruments. In addition, it serves as a powerful tool to identify and separate different wave modes in the atmospheric data. In our work we present space-time spectral analyses of chemical heating rates derived from Scanning Imaging Absorption SpectroMeter for Atmospheric CHartographY (SCIAMACHY hydroxyl nightglow emission measurements onboard Envisat for the years 2002–2006 at mesopause heights.

    Since SCIAMACHY nightglow hydroxyl emission measurements are restricted to the ascending (nighttime part of the satellite orbit, our analysis also includes temperature spectra derived from 15 μm CO2 emissions measured by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER instrument. SABER offers better temporal and spatial coverage (daytime and night-time values of temperature and a more regular sampling grid. Therefore SABER spectra also contain information about higher frequency waves.

    Comparison of SCIAMACHY and SABER results shows that SCIAMACHY, in spite of its observational restrictions, provides valuable information on most of the wave modes present in the mesopause region. The main differences between wave spectra obtained from these sensors can be attributed to the differences in their sampling patterns.

  12. Analysis of neon soft x-ray spectra from short-pulse laser-produced plasmas

    International Nuclear Information System (INIS)

    Abare, A.C.; Keane, C.J.; Crane, J.K.; DaSilva, L.B.; Lee, R.W.; Perry, M.D.; Falcone, R.W.

    1993-04-01

    We report preliminary results from the analysis of streaked soft x-ray neon spectra a gas jet target. In obtained from the interaction of a picosecond Nd:glass laser with these experiments streaked spectra show prompt harmonic emission followed by longer time duration soft x-ray line emission. The majority of the line emission observed was found to originate from Li- and Be-like Ne and the major transitions in the observed spectra have been identified. Li-like emission lines were observed to decay faster in time than Be-like transitions, suggesting that recombination is taking place. Line ratios of n=4-2 and n=3-2 transitions supported the view that these lines were optically thin and thick, respectively. The time history of Li-like Ne 2p-4d and 2p-3d lines is in good agreement with a simple adiabatic expansion model coupled to a time dependent collisional-radiative code. Further x-ray spectroscopic analysis is underway which is aimed at diagnosing plasma conditions and assessing the potential of this recombining neon plasma as a quasi-steady-state recombination x-ray laser medium

  13. Generation of synthetic gamma spectra with MATLAB

    International Nuclear Information System (INIS)

    Palmerio, Julian J.; Coppo, Anibal D.

    2009-01-01

    Objectives: The aim of this work is the simulation of gamma spectra using the MATLAB program to generate the calibration curves in efficiency, which will be used to measure radioactive waste in drums. They are necessary for the proper characterization of these drums. A Monte Carlo simulation was basically developed with the random number generator Mersenne Twister and nuclear data obtained from NIST. This paper shows the results obtained and difficulties encountered until today. The physical correction of the simulated spectra has been the only aspect we have been working, up to this moment. Procedures: A simplified representation of the 'Laboratorio de Verificacion y Control de la Calidad' was chosen. Drums with cemented liquid waste are routinely measured in this laboratory. The commercial program MCNP was also used to get a valid reference in the field of simulation of spectra. We analyzed the spectra obtained by MATLAB in the light of classical literature photon detection and the spectrum obtained by MCNP. Conclusions: Currently the program developed seems adequate to simulate a measurement in the 'Laboratorio de Verificacion y Control de la Calidad'. The spectra obtained by MATLAB seem to physically represent what is observed in real spectra. However, it is a slow program. The current development efforts are directed to improve the speed of simulation. An alternative is to use the CUDA language for NVIDIA video cards to parallelized the simulation. An adequate simulation of the electronic measuring chain is also needed to obtain better representations of the shapes of the peaks. (author)

  14. Identifying Broadband Rotational Spectra with Neural Networks

    Science.gov (United States)

    Zaleski, Daniel P.; Prozument, Kirill

    2017-06-01

    A typical broadband rotational spectrum may contain several thousand observable transitions, spanning many species. Identifying the individual spectra, particularly when the dynamic range reaches 1,000:1 or even 10,000:1, can be challenging. One approach is to apply automated fitting routines. In this approach, combinations of 3 transitions can be created to form a "triple", which allows fitting of the A, B, and C rotational constants in a Watson-type Hamiltonian. On a standard desktop computer, with a target molecule of interest, a typical AUTOFIT routine takes 2-12 hours depending on the spectral density. A new approach is to utilize machine learning to train a computer to recognize the patterns (frequency spacing and relative intensities) inherit in rotational spectra and to identify the individual spectra in a raw broadband rotational spectrum. Here, recurrent neural networks have been trained to identify different types of rotational spectra and classify them accordingly. Furthermore, early results in applying convolutional neural networks for spectral object recognition in broadband rotational spectra appear promising. Perez et al. "Broadband Fourier transform rotational spectroscopy for structure determination: The water heptamer." Chem. Phys. Lett., 2013, 571, 1-15. Seifert et al. "AUTOFIT, an Automated Fitting Tool for Broadband Rotational Spectra, and Applications to 1-Hexanal." J. Mol. Spectrosc., 2015, 312, 13-21. Bishop. "Neural networks for pattern recognition." Oxford university press, 1995.

  15. Flaw identification using acoustic emission

    International Nuclear Information System (INIS)

    Woodward, B.; McDonald, N.R.

    1975-01-01

    In order to realise the full inspection potential of acoustic emission monitoring, data obtained from zirconium and steel testpieces have been correlated with metallurgical condition and mechanical behaviour, since the nature of emission signatures is strongly affected by the physical characteristics and internal structure of the material. During experiments, signals were tape recorded and the surface of each testpiece was recorded on movie film or videotape so that acoustic and visual information could be correlated. Large numbers of tape-recorded bursts have been analysed with a real time spectrum analyser, and statistical parameters (such as mean energy density, mean frequency and variance) derived from the spectra were calculated by an IBM 360/50 computer and selectively displayed on a line plotter. In the case of zirconium, observed differences in these parameters were an indication that the emission signals were generated by three different metallurgical mechanisms. A movie film of testpiece surface deformation revealed the occurrence of twin initiation, twin broadening and slip. Fracture events either in the zirconium matrix or in second phase particles are also possible although not observed directly. A direct correlation was confirmed between twin initiations and emission signals. Work is proceeding on establishing a different correlation between emission signals and stress corrosion cracks

  16. The ir emission features: Emission from PAH (Polycyclic Aromatic Hydrocarbons) molecules and amorphous carbon particles

    Energy Technology Data Exchange (ETDEWEB)

    Allamandola, L.J.; Tielens, A.G.G.M.; Barker, J.R.

    1986-01-01

    PAHs can have several forms in the interstellar medium. To assess the importance of each requires the availability of a collection of high quality, complete mid-ir interstellar emission spectra, a collection of laboratory spectra of PAH samples prepared under realistic conditions and a firm understanding of the microscopic emission mechanism. Given what we currently know about PAHs, the spectroscopic data suggests that there are at least two components which contribute to the interstellar emission spectrum: free molecule sized PAHs producing the narrow features and amorphous carbon particles (which are primarily made up of an irregular ''lattice'' of PAHs) contributing to the broad underlying components. An exact treatment of the ir fluorescence from highly vibrationally excited large molecules shows that species containing between 20 and 30 carbon atoms are responsible for the narrow features, although the spectra match more closely with the spectra of amorphous carbon particles. Since little is known about the spectroscopic properties of free PAHs and PAH clusters, much laboratory work is called for in conjunction with an observational program which focuses on the spatial characteristics of the spectra. In this way the distribution and evolution of carbon from molecule to particle can be traced. 38 refs., 9 figs.

  17. The ir emission features: Emission from PAH [Polycyclic Aromatic Hydrocarbons] molecules and amorphous carbon particles

    International Nuclear Information System (INIS)

    Allamandola, L.J.; Tielens, A.G.G.M.; Barker, J.R.

    1986-01-01

    PAHs can have several forms in the interstellar medium. To assess the importance of each requires the availability of a collection of high quality, complete mid-ir interstellar emission spectra, a collection of laboratory spectra of PAH samples prepared under realistic conditions and a firm understanding of the microscopic emission mechanism. Given what we currently know about PAHs, the spectroscopic data suggests that there are at least two components which contribute to the interstellar emission spectrum: free molecule sized PAHs producing the narrow features and amorphous carbon particles (which are primarily made up of an irregular ''lattice'' of PAHs) contributing to the broad underlying components. An exact treatment of the ir fluorescence from highly vibrationally excited large molecules shows that species containing between 20 and 30 carbon atoms are responsible for the narrow features, although the spectra match more closely with the spectra of amorphous carbon particles. Since little is known about the spectroscopic properties of free PAHs and PAH clusters, much laboratory work is called for in conjunction with an observational program which focuses on the spatial characteristics of the spectra. In this way the distribution and evolution of carbon from molecule to particle can be traced. 38 refs., 9 figs

  18. Measurement of thermal neutron spectra using LINAC in Japan Atomic Energy Research Institute (JAERI)

    International Nuclear Information System (INIS)

    Akino, Fujiyoshi

    1982-01-01

    The exact grasp of thermal neutron spectra in a core region is very important for obtaining accurate thermal neutron group constants in the calculation for the nuclear design of a reactor core. For the accurate grasp of thermal neutron spectra, the capability of thermal neutron spectra to describe the moderator cross-sections for thermal neutron scattering is a key factor. Accordingly, 0 deg angular thermal neutron spectra were measured by the time of flight (TOF) method using the JAERI LINAC as a pulsed neutron source, for light water system added with Cd and In, high temperature graphite system added with boron, and light water-natural uranium heterogeneous multiplication system among the reactor moderators of light water or graphite systems. First, the equations to give the time of flight and neutron flux by TOF method were analyzed, and several corrections were investigated, such as those for detector efficiency, background, the transmission coefficient of air and the Al window of a flight tube, mean emission time of neutrons, and the distortion effect of re-entrant hole on thermal neutron spectra. Then, the experimental system, results and calculation were reported for the experiments on the above three moderator systems. Finally, the measurement of fast neutron spectra in natural uranium system and that of the efficiency of a 6 Li glass scintillator detector are described. (Wakatsuki, Y.)

  19. Prediction of flyover jet noise spectra from static tests

    Science.gov (United States)

    Michel, U.; Michalke, A.

    A scaling law for predicting the overall flyover noise of a single stream shock-free circular jet from static experiments is outlined. It is valid for isothermal and hot jets. It assumes that the jet flow and turbulence field are axially stretched in flight. Effects of the boundary layer within the nozzle and along the engine nacelle are neglected. The scaling laws for the power spectral density and spectra with constant relative bandwidth can be derived. In order to compare static and inflight directivities, the far field point relative to the source position must be denoted by the emission angle and the wave normal distance. From the solution of the convective Lighthill equation in a coordinate system fixed to the jet nozzle (wind tunnel case), the power spectral density of sound pressure at a given frequency is found. Predictions for Aerotrain compare well with measured values.

  20. Learning the Relationship between Galaxy Spectra and Star Formation Histories

    Science.gov (United States)

    Lovell, Christopher; Acquaviva, Viviana; Iyer, Kartheik; Gawiser, Eric

    2018-01-01

    We explore novel approaches to the problem of predicting a galaxy’s star formation history (SFH) from its Spectral Energy Distribution (SED). Traditional approaches to SED template fitting use constant or exponentially declining SFHs, and are known to incur significant bias in the inferred SFHs, which are typically skewed toward younger stellar populations. Machine learning approaches, including tree ensemble methods and convolutional neural networks, would not be affected by the same bias, and may work well in recovering unbiased and multi-episodic star formation histories. We use a supervised approach whereby models are trained using synthetic spectra, generated from three state of the art hydrodynamical simulations, including nebular emission. We explore how SED feature maps can be used to highlight areas of the spectrum with the highest predictive power and discuss the limitations of the approach when applied to real data.

  1. Fluorescence Spectra Studies on the Interaction between Lanthanides and Calmodulin

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The conformation of Calmodulin(CaM) induced by lanthanides has been examined using fluorescence methods.With the addition of lanthanide (Ln3+), the intrinsic fluorescence intensity of CaM without calcium ions (Apo-CaM) first increases and then decreases.Ln3+ causes the decrease of intrinsic fluorescence intensity of calcium saturated CaM (Ca2+4-CaM) only at high concentrations.At low concentrations, Ln3+ results not only in the enhancement of fluorescence intensity of Apo-CaM, but also in a blue shift of the maximum emission wavelengh of dansyl labeled calmodulin(Apo-D-CaM).The molecular mechanism of the interaction between Ln3+ and CaM has been discussed in the light of the fluorescence spectra.

  2. Shaping the GeV-spectra of bright blazars

    Science.gov (United States)

    Hunger, L.; Reimer, A.

    2016-05-01

    Aims: The non-thermal spectra of jetted active galactic nuclei (AGN) show a variety of shapes and degrees of curvature in their low- and high energy components. From some of the brightest Fermi-LAT blazars, prominent spectral breaks at a few GeV have been regularly detected, which is inconsistent with conventional cooling effects. We study the effects of continuous time-dependent injection of electrons into the jet with differing rates, durations, locations, and power-law spectral indices, and evaluate its impact on the ambient emitting particle spectrum that is observed at a given snapshot time in the framework of a leptonic blazar emission model. With this study, we provide a basis for analyzing ambient electron spectra in terms of injection requirements, with implications for particle acceleration modes. Methods: The emitting electron spectrum is calculated by Compton cooling the continuously injected electrons, where target photons are assumed to be provided by the accretion disk and broad line region (BLR). From this setup, we calculate the non-thermal photon spectra produced by inverse Compton scattering of these external target radiation fields using the full Compton cross-section in the head-on approximation. Results: By means of a comprehensive parameter study we present the resulting ambient electron and photon spectra, and discuss the influence of each injection parameter individually. We found that varying the injection parameters has a notable influence on the spectral shapes, which in turn can be used to set interesting constraints on the particle injection scenarios. By applying our model to the flare state spectral energy distribution (SED) of 3C 454.3, we confirm a previous suggestion that explained the observed spectral changes at a few GeV by a combination of the Compton-scattered disk and BLR radiation. We determine the required injection parameters for this scenario. We also show that this spectral turn-over can also be understood as Compton

  3. Two-proton energy spectra of 12O nucleus

    International Nuclear Information System (INIS)

    Teruya, N.

    2010-01-01

    Full text: The two-proton radioactivity has attracted stimulating discussion concerning the competing mechanisms for the decay process. Some nuclei (like 45 Fe, 41 Ni and 54 Zn are considered as genuine ground-state two-proton emitter because the only possibility is the simultaneous channel, but others nuclei (as 12 O) can also have the sequential decay, in this case, the energy levels of the intermediary one-proton emitter nuclei plays an important role to the competition with the simultaneous decay mode. In this work we have calculated the energy spectra of 12 O, including ground state and excited states up to 5 MeV of energy, and the two-proton energy difference spectrum for the ground state decay. Our preliminary results estimates the energy peak and width of resonant excited states and contributions of simultaneous and sequential channels for ground state decay. The calculation method is based on the statistical analysis for two-proton decaying modes presented in previous work. For events generated by sequential channels, the energy levels of intermediary 11 N nucleus can dominate the first proton emission, depending on the proximity between the ground states of both nuclei, 11 N and 12 O , in particular, if the ground state of 11 N is broad and its energy is far away from that of 12 O, the sequential decay occurs via the tail of the ground state of 11 O. The decay of 12 O resonant ground state and higher energy excited resonances are investigated through the analysis of the experimental data for the two-proton emission process. The two proton decay spectra have been considered in a statistical calculation framework, by using the decay energy distribution and taken into account the intermediate states of 11 N resonant structures for the sequential channels. For simultaneous decay channel we construct a symmetric distribution similarly to Goldansky's proposition in Nucl. Phys. A19, 482 (1960). (author)

  4. The CaO orange system in meteor spectra

    Science.gov (United States)

    Berezhnoy, A. A.; Borovička, J.; Santos, J.; Rivas-Silva, J. F.; Sandoval, L.; Stolyarov, A. V.; Palma, A.

    2018-02-01

    The CaO orange band system was simulated in the region 5900-6300 Å and compared with the experimentally observed spectra of Benešov bolide wake. The required vibronic Einstein emission coefficients were estimated by means of the experimental radiative lifetimes under the simplest Franck-Condon approximation. A moderate agreement was achieved, and the largest uncertainties come from modeling shape of FeO orange bands. Using a simple model the CaO column density in the wake of the Benešov bolide at the height of 29 km was estimated as (5 ± 2) × 1014 cm-2 by a comparison of the present CaO spectra with the AlO bands nicely observed at 4600-5200 Å in the same spectrum. The obtained CaO content is in a good agreement with the quenching model developed for the impact-produced cloud, although future theoretical and experimental studies of both CaO and FeO orange systems contribution would be needed to confirm these results.

  5. Synoptic Mid-IR Spectra ToO Novae

    Science.gov (United States)

    Helton, L. Andrew; Woodward, Chick; Evans, Nye; Geballe, Tom; Spitzer Nova Team

    2007-02-01

    Stars are the engines of energy production and chemical evolution in our Universe, depositing radiative and mechanical energy into their environments and enriching the ambient ISM with elements synthesized in their interiors and dust grains condensed in their atmospheres. Classical novae (CN) contribute to this cycle of chemical enrichment through explosive nucleosynthesis and the violent ejection of material dredged from the white dwarf progenitor and mixed with the accreted surface layers. We propose to obtain mid-IR spectra of a new galactic CN in outburst to investigate aspects of the CN phenomenon including the in situ formation and mineralogy of nova dust and the elemental abundances resulting from thermonuclear runaway. Synoptic, high S/N Michelle spectra permit: 1) determination of the grain size distribution and mineral composition of nova dust; 2) estimation of chemical abundances of nova ejecta from coronal and other emission line spectroscopy; and 3) measurement of the density and masses of the ejecta. This Gemini `Target of Opportunity' initiative (trigger K=5- 8 mag, assuming adequate PWFS guide stars exist) complements our extensive Spitzer, Chandra, Swift, XMM-Newton CN DDT/ToO programs.

  6. Analysis of JET charge exchange spectra using neural networks

    International Nuclear Information System (INIS)

    Svensson, J.; Hellermann, M. von; Koenig, R.W.T.

    1999-01-01

    Active charge exchange spectra representing the local interaction of injected neutral beams and fully stripped impurity ions are hard to analyse due to strong blending with passive emission from the plasma edge. As a result, the deduced plasma parameters (e.g. ion temperature, rotation velocity, impurity density) cannot always be determined unambiguously. Also, the speed of the analysis is limited by the time consuming nonlinear least-squares minimization procedure. In practice, semi-manual analysis is necessary and fast, automatic analysis, based on currently used techniques, does not seem feasible. In this paper the development of a robust and accurate analysis procedure based on multi-layer perceptron (MLP) neural networks is described. This procedure is fully automatic and fast, thus enabling a real-time analysis of charge exchange spectra. Accuracy has been increased in several ways as compared to earlier straightforward neural network implementations and is comparable to a standard least-squares based analysis. Robustness is achieved by using a combination of different confidence measures. A novel technique for the creation of training data, suitable for high-dimensional inverse problems has been developed and used extensively. A new method for fast calculation of error bars directly from the hidden neurons in a MLP network is also described, and used as part of the confidence calculations. For demonstration purposes, a real-time ion temperature profile diagnostic based on this work has been implemented. (author)

  7. Fission neutron spectra measurements at LANSCE - Status and plans

    International Nuclear Information System (INIS)

    Haight, R. C.; Noda, S.; Nelson, R. O.; O'Donnell, J. M.; Devlin, M.; Chatillon, A.; Granier, T.; Taiebb, J.; Laurent, B.; Belier, G.; Becker, J. A.; Wu, C. Y.

    2010-01-01

    A program to measure fission neutron spectra from neutron-induced fission of actinides is underway at the Los Alamos Neutron Science Center (LANSCE) in a collaboration among the CEA laboratory at Bruyeres-le-Chatel, Lawrence Livermore National Laboratory and Los Alamos National Laboratory. The spallation source of fast neutrons at LANSCE is used to provide incident neutron energies from less than 1 MeV to 100 MeV or higher. The fission events take place in a gas-ionization fission chamber, and the time of flight from the neutron source to that chamber gives the energy of the incident neutron. Outgoing neutrons are detected by an array of organic liquid scintillator neutron detectors, and their energies are deduced from the time of flight from the fission chamber to the neutron detector. Measurements have been made of the fission neutrons from fission of 235 U, 238 U, 237 Np and 239 Pu. The range of outgoing energies measured so far is from 0.7 MeV to approximately 8 MeV. These partial spectra and average fission neutron energies are compared with evaluated data and with models of fission neutron emission. Results to date are summarized in this presentation. Future plans are to make significant improvements in the fission chambers, neutron detectors, signal processing, data acquisition and the experimental environment to provide high fidelity data including measurements of fission neutrons below 0.7 MeV and improvements in the data above 8 MeV. (authors)

  8. Good abundances from bad spectra - I. Techniques

    Science.gov (United States)

    Jones, J. Bryn; Gilmore, Gerard; Wyse, Rosemary F. G.

    1996-01-01

    Stellar spectra derived from multiple-object fibre-fed spectroscopic radial-velocity surveys, of the type feasible with, among other examples, AUTOFIB, 2dF, HYDRA, NESSIE, and the Sloan survey, differ significantly from those traditionally used for determination of stellar abundances. The spectra tend to be of moderate resolution (around 1A) and signal-to-noise ratio (around 10-20 per resolution element), and cannot usually have reliable continuum shapes determined over wavelength ranges in excess of a few tens of Angstroms. None the less, with care and a calibration of stellar effective temperature from photometry, independent of the spectroscopy, reliable iron abundances can be derived. We have developed techniques to extract true iron abundances and surface gravities from low-signal-to-noise ratio, intermediate-resolution spectra of G-type stars in the 4000-5000A wavelength region. Spectroscopic indices sensitive to iron abundance and gravity are defined from a set of narrow (few-several A wide) wavelength intervals. The indices are calibrated theoretically using synthetic spectra. Given adequate data and a photometrically determined effective temperature, one can derive estimates of the stellar iron abundance and surface gravity. We have also defined a single abundance indicator for the analysis of very low-signal-to-noise ratio spectra; with the further assumption of a value for the stellar surface gravity, this is able to provide useful iron abundance information from spectra having signal-to-noise ratios as low as 10 (1-A elements). The theoretical basis and calibration using synthetic spectra are described in this paper. The empirical calibration of these techniques by application to observational data is described in a separate paper (Jones, Wyse & Gilmore). The technique provides precise iron abundances, with zero-point correct to ~0.1 dex, and is reliable, with typical uncertainties being <~0.2 dex. A derivation of the in situ thick disc metallicity

  9. Magnetic emission ranking of electrical appliances. A comprehensive market survey

    International Nuclear Information System (INIS)

    Leitgeb, N.; Cech, R.; Schroettner, J.; Lehofer, P.; Schmidpeter, U.; Rampetsreiter, M.

    2008-01-01

    Over the last decades emissions of magnetic fields from electric appliances have considerably changed. Based on a comprehensive market survey it could be shown that today magnetic emissions are usually characterised by complex frequency spectra while single-frequency emissions have become rare. Therefore, spectral assessment procedures play a critical role. Compared to frequency-weighted equivalent magnetic induction, rms values may underestimate emissions up to two orders of magnitudes. Therefore, rms measurements are not suitable and emission-ranking lists of devices need revision. Surface hot-spot measurements at nominal load conditions and 230 V/50 Hz supply involved 1146 new electrical devices of 166 different categories. High emissions were not rare. Magnetic emissions of devices of 73 different categories exceeded reference levels up to almost two orders of magnitudes above reference levels. Maximum values were higher than reported so far. Magnetic emissions were high enough to make even conformity with existing basic restrictions not self-evident. (authors)

  10. Anomalous optical emission in hot dense oxygen

    Science.gov (United States)

    Santoro, Mario; Gregoryanz, Eugene; Mao, Ho-kwang; Hemley, Russell J.

    2007-11-01

    We report the observation of unusually strong, broad-band optical emission peaked between 590 and 650 nm when solid and fluid oxygen are heated by a near infrared laser at pressures from 3 to 46 GPa. In situ Raman spectra of oxygen were collected and corresponding temperatures were measured from the Stokes/anti-Stokes intensity ratios of vibrational transitions. The intense optical emission overwhelmed the Raman spectrum at temperatures exceeding 750 K. The spectrum was found to be much narrower than Planck-type thermal emission, and the intensity increase with input power was much steeper than expected for the thermal emission. The result places an important general caveat on calculating temperatures based on optical emission spectra in high-pressure laser-heating experiments. The intense emission in oxygen is photo-induced rather than being purely thermal, through multiphoton or multi-step single photon absorption processes related to the interaction with infrared radiation. The results suggest that short lived ionic species are induced by this laser-matter interaction.

  11. Optical properties of ion-implanted InP and GaAs: Selectivity-excited photoluminescence spectra

    International Nuclear Information System (INIS)

    Makita, Yunosuke; Yamada, Akimasa; Kimura, Shinji; Niki, Shigeru; Yoshinaga, Hiroshi; Matsumori, Tokue; Iida, Tsutomu; Uekusa, Ichiro

    1993-01-01

    Implantation of Mg+ ions was carried out into high purity InP grown by liquid encapsulated Czochralski method. Mg+ ion-implanted InP presented the formation of plural novel emissions with increasing Mg concentration, [Mg] in the low temperature photoluminescence spectra. Selectively-excited photoluminescence (SPL) measurements were made to examine the features of two-hole replicas pertinent to the emissions of excitons bound to neutral Mg and residual Zn acceptors. Systematic variation of the emission intensities from the two types of two-hole replicas was found to be utilized for the evaluation of ion-implanted materials. The significant discrepancy of emission spectra between PL and SPL was attributed to the difference of the depth examined by using the excitation light with high and low absorption coefficient. The results revealed that the diffusion of ion-implanted Mg is extremely enhanced when [Mg] exceeds 1x10 17 cm -3

  12. Differential dpa calculations with SPECTRA-PKA

    Science.gov (United States)

    Gilbert, M. R.; Sublet, J.-Ch.

    2018-06-01

    The processing code SPECTRA-PKA produces energy spectra of primary atomic recoil events (or primary knock-on atoms, PKAs) for any material composition exposed to an irradiation spectrum. Such evaluations are vital inputs for simulations aimed at understanding the evolution of damage in irradiated material, which is generated in cascade displacement events initiated by PKAs. These PKA spectra present the full complexity of the input (to SPECTRA-PKA) nuclear data-library evaluations of recoil events. However, the commonly used displacements per atom (dpa) measure, which is an integral measure over all possible recoil events of the displacement damage dose, is still widely used and has many useful applications - as both a comparative and correlative quantity. This paper describes the methodology employed that allows the SPECTRA-PKA code to evaluate dpa rates using the energy-dependent recoil (PKA) cross section data used for the PKA distributions. This avoids the need for integral displacement kerma cross sections and also provides new insight into the relative importance of different reaction channels (and associated different daughter residual and emitted particles) to the total integrated dpa damage dose. Results are presented for Fe, Ni, W, and SS316. Fusion dpa rates are compared to those in fission, highlighting the increased contribution to damage creation in the former from high-energy threshold reactions.

  13. Climatology of tropospheric vertical velocity spectra

    Science.gov (United States)

    Ecklund, W. L.; Gage, K. S.; Balsley, B. B.; Carter, D. A.

    1986-01-01

    Vertical velocity power spectra obtained from Poker Flat, Alaska; Platteville, Colorado; Rhone Delta, France; and Ponape, East Caroline Islands using 50-MHz clear-air radars with vertical beams are given. The spectra were obtained by analyzing the quietest periods from the one-minute-resolution time series for each site. The lengths of available vertical records ranged from as long as 6 months at Poker Flat to about 1 month at Platteville. The quiet-time vertical velocity spectra are shown. Spectral period ranging from 2 minutes to 4 hours is shown on the abscissa and power spectral density is given on the ordinate. The Brunt-Vaisala (B-V) periods (determined from nearby sounding balloons) are indicated. All spectra (except the one from Platteville) exhibit a peak at periods slightly longer than the B-V period, are flat at longer periods, and fall rapidly at periods less than the B-V period. This behavior is expected for a spectrum of internal waves and is very similar to what is observed in the ocean (Eriksen, 1978). The spectral amplitudes vary by only a factor of 2 or 3 about the mean, and show that under quiet conditions vertical velocity spectra from the troposphere are very similar at widely different locations.

  14. Artificial intelligence analysis of paraspinal power spectra.

    Science.gov (United States)

    Oliver, C W; Atsma, W J

    1996-10-01

    OBJECTIVE: As an aid to discrimination of sufferers with back pain an artificial intelligence neural network was constructed to differentiate paraspinal power spectra. DESIGN: Clinical investigation using surface electromyography. METHOD: The surface electromyogram power spectra from 60 subjects, 33 non-back-pain sufferers and 27 chronic back pain sufferers were used to construct a back propagation neural network that was then tested. Subjects were placed on a test frame in 30 degrees of lumbar forward flexion. An isometric load of two-thirds maximum voluntary contraction was held constant for 30 s whilst surface electromyograms were recorded at the level of the L(4-5). Paraspinal power spectra were calculated and loaded into the input layer of a three-layer back propagation network. The neural network classified the spectra into normal or back pain type. RESULTS: The back propagation neural was shown to have satisfactory convergence with a specificity of 79% and a sensitivity of 80%. CONCLUSIONS: Artificial intelligence neural networks appear to be a useful method of differentiating paraspinal power spectra in back-pain sufferers.

  15. Background noise spectra of global seismic stations

    Energy Technology Data Exchange (ETDEWEB)

    Wada, M.M.; Claassen, J.P.

    1996-08-01

    Over an extended period of time station noise spectra were collected from various sources for use in estimating the detection and location performance of global networks of seismic stations. As the database of noise spectra enlarged and duplicate entries became available, an effort was mounted to more carefully select station noise spectra while discarding others. This report discusses the methodology and criteria by which the noise spectra were selected. It also identifies and illustrates the station noise spectra which survived the selection process and which currently contribute to the modeling efforts. The resulting catalog of noise statistics not only benefits those who model network performance but also those who wish to select stations on the basis of their noise level as may occur in designing networks or in selecting seismological data for analysis on the basis of station noise level. In view of the various ways by which station noise were estimated by the different contributors, it is advisable that future efforts which predict network performance have available station noise data and spectral estimation methods which are compatible with the statistics underlying seismic noise. This appropriately requires (1) averaging noise over seasonal and/or diurnal cycles, (2) averaging noise over time intervals comparable to those employed by actual detectors, and (3) using logarithmic measures of the noise.

  16. Seismic spectra of events at regional distances

    International Nuclear Information System (INIS)

    Springer, D.L.; Denny, M.D.

    1976-01-01

    About 40 underground nuclear explosions detonated at the Nevada Test Site (NTS) were chosen for analysis of their spectra and any relationships they might have to source parameters such as yield, depth of burial, etc. The sample covered a large yield range (less than 20 kt to greater than 1 Mt). Broadband (0.05 to 20 Hz) data recorded by the four-station seismic network operated by Lawrence Livermore Laboratory were analyzed in a search for unusual explosion signatures in their spectra. Long time windows (total wave train) as well as shorter windows (for instance, P/sub n/) were used as input to calculate the spectra. Much variation in the spectra of the long windows is typical although some gross features are similar, such as a dominant peak in the microseismic window. The variation is such that selection of corner frequencies is impractical and yield scaling could not be determined. Spectra for one NTS earthquake showed more energy in the short periods (less than 1 sec) as well as in the long periods (greater than 8 sec) compared to those for NTS explosions

  17. Nuclear data for neutron emission in the fission process

    International Nuclear Information System (INIS)

    Ganesan, S.

    1991-11-01

    This document contains the proceedings of the IAEA Consultants' Meeting on Nuclear Data for Neutron Emission in the Fission Process, Vienna, 22 - 24 October 1990. Included are the conclusions and recommendations reached at the meeting and the papers presented by the meeting participants. These papers provide a review of the status of experimental and theoretical data on neutron emission in spontaneous and neutron induced fission with reference to the data needs for reactor applications oriented towards actinide burner studies. The specific topics covered are the following: experimental measurements and theoretical predictions and evaluations of fission neutron energy spectra, average prompt fission neutron multiplicity, correlation in neutron emission from complementary fragments, neutron emission during acceleration of fission fragments, statistical properties of neutron rich nuclei by study of emission spectra of neutrons from the excited fission fragments, integral qualification of nu-bar for the major fissile isotopes, nu-bar total of 239 Pu and 235 U, and related problems. Refs figs and tabs

  18. E2, E4, and E6 statistical decay spectra in 208Pb

    International Nuclear Information System (INIS)

    Teruya, N.; Wolynec, E.; Dias, H.

    1989-01-01

    Statistical decay spectra for the decay of giant resonances in 208 Pb by one neutron emission are calculated using the Hauser-Feshbach formalism and the experimental levels of the residual nucleus. The predicted decay spectra are compared with available experimental results. It is shown that the decay spectra are sensitive to multipole ad-mixtures of the excited state and can be used to study such admixtures. The available experimental data for the decay of the E2 resonances in 208 Pb contain spurious peaks that do not belong to the spectrum of 207 Pb. Theuuncertainty of the experimental data make it impossible to decide whether the decay is purely E2 or a mixture of 80% E2 plus 20% E6. (author) [pt

  19. {sup 235}U(n,F) prompt fission neutron spectra

    Energy Technology Data Exchange (ETDEWEB)

    Maslov, M.V.; Tetereva, N.A. [Joint Institute of Nuclear and Energy Research, Minsk-Sosny (Belarus); Pronyaev, V.P.; Kagalenko, A.B. [Institute of Physics and Power Engineering, Obninsk (Russian Federation); Capote, R. [International Atomic Energy Agency, Vienna (Austria); Granier, T.; Morillon, B. [CEA, Centre DAM-IIe de France, 91 - Arpajon (France); Hambsch, F.J. [EC-JRC Institute for Reference Materials and Measurements, Geel (Belgium); Sublet, J.C. [CEA Cadarache, 13 - Saint Paul lez Durance (France)

    2009-07-01

    The longstanding problem of inconsistency of integral thermal data testing and differential prompt fission neutron spectra data (PFNS) is mostly due to rather poor fits of differential PFNS data in major data libraries. The measured database is updated by using modern standards including Manhart's evaluation of the spontaneous fission neutron spectra of {sup 252}Cf(sf). That largely removes the inconsistency of older thermal neutron-induced PFNS measurements with newest data of JRC IRMM by Hambsch et al. (2009). A phenomenological approach, developed by Kornilov et al. (1999), for the first-chance fission and extended for the emissive fission domain by Maslov et al. (2005) is calibrated at E{sub th} to predict both the PFNS average energy and PFNS shape up to 20 MeV. The latter is extremely important, since rather close values in fact correspond to quite discrepant spectra shapes, which influences reactor neutronics strongly. The proposed phenomenological representation of the PFNS reproduces both soft and hard energy tails of {sup 235}U(n{sub th},F) PFNS at thermal incident neutron energy E{sub th}. In the first-chance and emissive fission domain evaluated PFNS are consistent with the data by Ethvignot et al. (2005). A compiled MF=5 Endf/B-formatted file of the {sup 235}U(n,F) PFNS largely removes the inconsistencies of the evaluated differential PFNS with integral data benchmarks. Almost perfect fits are attained for available differential PFNS data from E{sub th} up to E{sub n}=14.7 MeV, with few exceptions at E{sub n}=2.9 and E{sub n}=5 MeV. Fast integral critical experiment like GODIVA or Flattop benchmarks might be reproduced almost with the same accuracy as with the PFNS of the major data libraries. That reveals a rather delicate compensation effect, since present and previous PFNS shapes are drastically different from each other. Thermal assemblies benchmarking reveals positive biases in k(eff), which might be attributed to the influence of

  20. Three-dimensional thermoluminescence spectra of different origin quartz from Altay Orogenic belt, Xinjiang, China

    International Nuclear Information System (INIS)

    Tan Kaixuan; Liu Zehua; Zeng Sheng; Liu Yan; Xie Yanshi; Rieser, Uwe

    2009-01-01

    Three-dimensional thermoluminescence spectra are measured for different types of geological origin quartz from the Altay orogenic belt, northern Xinjiang, China. The results show striking differences which appear to be characteristic of their geological origin. Granitic quartz is dominated by emission bands at 420-430 nm, 550-560 nm, at a temperature of 170 deg. C. Pegmatite quartz is characterized by an intense 480 nm emission band at 170 deg. C. Volcanic quartz has exclusive UV (340-360 nm) and violet (410-430 nm) emission bands. Hydrothermal quartz exhibits very different TL spectral characteristics because of different hydrothermal activity and mineralization. Only one TL peaks at 485 nm/170 deg. C was observed in sedimentary quartz. An intense 730 nm emission band observed at 170 deg. C considered generally to be characteristics of feldspar was observed in quartz from granite and hydrothermal Au-bearing quartz. This TL peak is probably related to the centre of [FeO 4 ] 0 on an Si site. All samples show an intense 990-1000 nm emission band at 330 deg. C. Identical types of quartz formed in different regions or different geological and tectonic settings can also exhibit striking differences in TL spectra.

  1. Effective temperatures and radiation spectra for a higher-dimensional Schwarzschild-de Sitter black hole

    Science.gov (United States)

    Kanti, P.; Pappas, T.

    2017-07-01

    The absence of a true thermodynamical equilibrium for an observer located in the causal area of a Schwarzschild-de Sitter spacetime has repeatedly raised the question of the correct definition of its temperature. In this work, we consider five different temperatures for a higher-dimensional Schwarzschild-de Sitter black hole: the bare T0, the normalized TBH, and three effective ones given in terms of both the black-hole and cosmological horizon temperatures. We find that these five temperatures exhibit similarities but also significant differences in their behavior as the number of extra dimensions and the value of the cosmological constant are varied. We then investigate their effect on the energy emission spectra of Hawking radiation. We demonstrate that the radiation spectra for the normalized temperature TBH—proposed by Bousso and Hawking over twenty years ago—leads to the dominant emission curve, while the other temperatures either support a significant emission rate only in a specific Λ regime or have their emission rates globally suppressed. Finally, we compute the bulk-over-brane emissivity ratio and show that the use of different temperatures may lead to different conclusions regarding the brane or bulk dominance.

  2. Simulations of the Fe K α Energy Spectra from Gravitationally Microlensed Quasars

    Energy Technology Data Exchange (ETDEWEB)

    Krawczynski, H. [Physics Department and McDonnell Center for the Space Sciences, Washington University in St. Louis, 1 Brookings Drive, CB 1105, St. Louis, MO 63130 (United States); Chartas, G., E-mail: krawcz@wustl.edu [Department of Physics and Astronomy, College of Charleston, Charleston, SC 29424 (United States)

    2017-07-10

    The analysis of the Chandra X-ray observations of the gravitationally lensed quasar RX J1131−1231 revealed the detection of multiple and energy-variable spectral peaks. The spectral variability is thought to result from the microlensing of the Fe K α emission, selectively amplifying the emission from certain regions of the accretion disk with certain effective frequency shifts of the Fe K α line emission. In this paper, we combine detailed simulations of the emission of Fe K α photons from the accretion disk of a Kerr black hole with calculations of the effect of gravitational microlensing on the observed energy spectra. The simulations show that microlensing can indeed produce multiply peaked energy spectra. We explore the dependence of the spectral characteristics on black hole spin, accretion disk inclination, corona height, and microlensing amplification factor and show that the measurements can be used to constrain these parameters. We find that the range of observed spectral peak energies of QSO RX J1131−1231 can only be reproduced for black hole inclinations exceeding 70° and for lamppost corona heights of less than 30 gravitational radii above the black hole. We conclude by emphasizing the scientific potential of studies of the microlensed Fe K α quasar emission and the need for more detailed modeling that explores how the results change for more realistic accretion disk and corona geometries and microlensing magnification patterns. A full analysis should furthermore model the signal-to-noise ratio of the observations and the resulting detection biases.

  3. FIER: Software for analytical modeling of delayed gamma-ray spectra

    Science.gov (United States)

    Matthews, E. F.; Goldblum, B. L.; Bernstein, L. A.; Quiter, B. J.; Brown, J. A.; Younes, W.; Burke, J. T.; Padgett, S. W.; Ressler, J. J.; Tonchev, A. P.

    2018-05-01

    A new software package, the Fission Induced Electromagnetic Response (FIER) code, has been developed to analytically predict delayed γ-ray spectra following fission. FIER uses evaluated nuclear data and solutions to the Bateman equations to calculate the time-dependent populations of fission products and their decay daughters resulting from irradiation of a fissionable isotope. These populations are then used in the calculation of γ-ray emission rates to obtain the corresponding delayed γ-ray spectra. FIER output was compared to experimental data obtained by irradiation of a 235U sample in the Godiva critical assembly. This investigation illuminated discrepancies in the input nuclear data libraries, showcasing the usefulness of FIER as a tool to address nuclear data deficiencies through comparison with experimental data. FIER provides traceability between γ-ray emissions and their contributing nuclear species, decay chains, and parent fission fragments, yielding a new capability for the nuclear science community.

  4. Time-resolved soft x-ray spectra from laser-produced Cu plasma

    International Nuclear Information System (INIS)

    Cone, K.V.; Dunn, J.; Baldis, H.A.; May, M.J.; Purvis, M.A.; Scott, H.A.; Schneider, M.B.

    2012-01-01

    The volumetric heating of a thin copper target has been studied with time resolved x-ray spectroscopy. The copper target was heated from a plasma produced using the Lawrence Livermore National Laboratory's Compact Multipulse Terrawatt (COMET) laser. A variable spaced grating spectrometer coupled to an x-ray streak camera measured soft x-ray emission (800-1550 eV) from the back of the copper target to characterize the bulk heating of the target. Radiation hydrodynamic simulations were modeled in 2-dimensions using the HYDRA code. The target conditions calculated by HYDRA were post-processed with the atomic kinetics code CRETIN to generate synthetic emission spectra. A comparison between the experimental and simulated spectra indicates the presence of specific ionization states of copper and the corresponding electron temperatures and ion densities throughout the laser-heated copper target.

  5. The Radio-optical Spectra of BL Lacs and Possible Relatives

    Science.gov (United States)

    Dennett-Thorpe, J.

    I consider the suggestion that, in a complete sample of flat-spectrum radio sources with available optical spectra (Marcha et al 1996), the strong emission line objects, or those with passive elliptical spectra are close relatives of the BL Lacs. New observations at four frequencies from 8 to 43GHz are presented, together with evidence for radio variability. Combined with other radio and optical data from the literature, we are able to construct the non-thermal SEDs and use these to address the questions: are the optically passive objects potentially `unrecognised' BL Lacs (either intrinsically weak and/or hidden by starlight)? What is the relationship between the surprising number of strong emission-line objects and the BL Lacs?

  6. Time-resolved x-ray spectra of laser irradiated high-Z targets

    International Nuclear Information System (INIS)

    Lee, P.H.Y.; Attwood, D.T.; Boyle, M.J.; Campbell, E.M.; Coleman, L.C.; Kornblum, H.N.

    1977-01-01

    Recent results obtained by using the Livermore 15 psec x-ray streak camera to record x-ray emission from laser-irradiated high-z targets in the 1-20 keV range are reported. Nine to eleven K-edge filter channels were used for the measurements. In the lower energy channels, a dynamic range of x-ray emission intensity of better than three orders of magnitude have been recorded. Data will be presented which describe temporally and spectrally resolved x-ray spectra of gold disk targets irradiated by laser pulses from the Argus facility, including the temporal evolution of the superthermal x-ray tail

  7. FAST INVERSION OF SOLAR Ca II SPECTRA

    International Nuclear Information System (INIS)

    Beck, C.; Choudhary, D. P.; Rezaei, R.; Louis, R. E.

    2015-01-01

    We present a fast (<<1 s per profile) inversion code for solar Ca II lines. The code uses an archive of spectra that are synthesized prior to the inversion under the assumption of local thermodynamic equilibrium (LTE). We show that it can be successfully applied to spectrograph data or more sparsely sampled spectra from two-dimensional spectrometers. From a comparison to a non-LTE inversion of the same set of spectra, we derive a first-order non-LTE correction to the temperature stratifications derived in the LTE approach. The correction factor is close to unity up to log τ ∼ –3 and increases to values of 2.5 and 4 at log τ = –6 in the quiet Sun and the umbra, respectively

  8. Tunneling spectra of graphene on copper unraveled

    DEFF Research Database (Denmark)

    Zhang, Xin; Stradi, Daniele; Liu, Lei

    2016-01-01

    mechanisms, etc. The interpretation of the spectra can be complicated, however. Specifically for graphene grown on copper, there have been conflicting reports of tunneling spectra. A clear understanding of the mechanisms behind the variability is desired. In this work, we have revealed that the root cause...... of the variability in tunneling spectra is the variation in graphene-substrate coupling under various experimental conditions, providing a salutary perspective on the important role of 2D material-substrate interactions. The conclusions are drawn from measured data and theoretical calculations for monolayer, AB......-stacked bilayer, and twisted bilayer graphene coexisting on the same substrates in areas with and without intercalated oxygen, demonstrating a high degree of consistency. The Van Hove singularities of the twisted graphene unambiguously indicate the Dirac energy between them, lending strong evidence to our...

  9. Rotational structure in molecular infrared spectra

    CERN Document Server

    di Lauro, Carlo

    2013-01-01

    Recent advances in infrared molecular spectroscopy have resulted in sophisticated theoretical and laboratory methods that are difficult to grasp without a solid understanding of the basic principles and underlying theory of vibration-rotation absorption spectroscopy. Rotational Structure in Molecular Infrared Spectra fills the gap between these recent, complex topics and the most elementary methods in the field of rotational structure in the infrared spectra of gaseous molecules. There is an increasing need for people with the skills and knowledge to interpret vibration-rotation spectra in many scientific disciplines, including applications in atmospheric and planetary research. Consequently, the basic principles of vibration-rotation absorption spectroscopy are addressed for contemporary applications. In addition to covering operational quantum mechanical methods, spherical tensor algebra, and group theoretical methods applied to molecular symmetry, attention is also given to phase conventions and their effe...

  10. Observed and theoretical spectra in the 10-100 A interval. [of solar spectra

    Science.gov (United States)

    Brown, W. A.; Bruner, M. E.; Acton, L. W.

    1988-01-01

    The soft X-ray spectra recorded in two sounding-rocket flights in 1982 and 1985 are compared with predicted spectra. The processed densitometer trace of the full spectrum is presented, together with the new spectrum from the 1985 experiment. The intensities of the lines are then compared with predictions.

  11. BETA SPECTRA. I. Negatrons spectra; ESPECTROS BETA. I. Espectros simples de negatrones

    Energy Technology Data Exchange (ETDEWEB)

    Grau Malonda, A; Garcia-Torano, E

    1978-07-01

    Using the Fermi theory of beta decay, the beta spectra for 62 negatrons emitters have been computed introducing a correction factor for unique forbidden transitions. These spectra are plotted vs. energy, once normal i sed, and tabulated with the related Fermi functions. The average and median energies are calculated. (Author)

  12. ON THE VIABILITY OF THE PAH MODEL AS AN EXPLANATION OF THE UNIDENTIFIED INFRARED EMISSION FEATURES

    International Nuclear Information System (INIS)

    Zhang, Yong; Kwok, Sun

    2015-01-01

    Polycyclic aromatic hydrocarbon (PAH) molecules are widely considered the preferred candidate for the carrier of the unidentified infrared emission bands observed in the interstellar medium and circumstellar envelopes. In this paper, we report the results of fitting a variety of non-PAH spectra (silicates, hydrogenated amorphous carbon, coal, and even artificial spectra) using the theoretical infrared spectra of PAHs from the NASA Ames PAH IR Spectroscopic Database. We show that these non-PAH spectra can be well fitted by PAH mixtures. This suggests that a general match between astronomical spectra and those of PAH mixtures does not necessarily provide definitive support for the PAH hypothesis

  13. Effects of peripheral physical phenomena on ECE spectra

    International Nuclear Information System (INIS)

    Airoldi, A.; Ramponi, G.

    1993-01-01

    In large fusion Tokamaks the measurement of the Electron Cyclotron Emission (ECE) from the low field side, perpendicularly viewing chord, is by now a standard way of obtaining the radial electron temperature profile. In high temperature plasmas the condition of large optical thickness for the second harmonic X-mode may be easily satisfied even for frequencies corresponding to the edge plasma region, allowing the temperature profile to be inferred. Recent experimental observations of enhanced emission at frequencies associated with the extreme edge of the profile in H-mode JET plasmas have been interpreted as the effect of a small fraction of suprathermal electrons. It is well known that the ECE spectra are very sensitive to the presence of non-thermal electron components, thus it is important to interpret the ECE signals as an indication of the possible deviation of the electron distribution function from a 'pure' Maxwellian and to discern under which conditions they are a good measure of the plasma thermal energy. (author) 3 refs., 6 figs

  14. Contrasting light spectra constrain the macro and microstructures of scleractinian corals.

    Directory of Open Access Journals (Sweden)

    Rui J M Rocha

    Full Text Available The morphological plasticity of scleractinian corals can be influenced by numerous factors in their natural environment. However, it is difficult to identify in situ the relative influence of a single biotic or abiotic factor, due to potential interactions between them. Light is considered as a major factor affecting coral skeleton morphology, due to their symbiotic relation with photosynthetic zooxanthellae. Nonetheless, most studies addressing the importance of light on coral morphological plasticity have focused on photosynthetically active radiation (PAR intensity, with the effect of light spectra remaining largely unknown. The present study evaluated how different light spectra affect the skeleton macro- and microstructures in two coral species (Acropora formosa sensu Veron (2000 and Stylophora pistillata maintained under controlled laboratory conditions. We tested the effect of three light treatments with the same PAR but with a distinct spectral emission: 1 T5 fluorescent lamps with blue emission; 2 Light Emitting Diodes (LED with predominantly blue emission; and 3 Light Emitting Plasma (LEP with full spectra emission. To exclude potential bias generated by genetic variability, the experiment was performed with clonal fragments for both species. After 6 months of experiment, it was possible to detect in coral fragments of both species exposed to different light spectra significant differences in morphometry (e.g., distance among corallites, corallite diameter, and theca thickness, as well as in the organization of their skeleton microstructure. The variability found in the skeleton macro- and microstructures of clonal organisms points to the potential pitfalls associated with the exclusive use of morphometry on coral taxonomy. Moreover, the identification of a single factor influencing the morphology of coral skeletons is relevant for coral aquaculture and can allow the optimization of reef restoration efforts.

  15. Probing symmetry and symmetry breaking in resonant soft-x-ray fluorescence spectra of molecules

    Energy Technology Data Exchange (ETDEWEB)

    Glans, P.; Gunnelin, K.; Guo, J. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    Conventional non-resonant soft X-ray emission brings about information about electronic structure through its symmetry and polarization selectivity, the character of which is governed by simple dipole rules. For centro-symmetric molecules with the emitting atom at the inversion center these rules lead to selective emission through the required parity change. For the more common classes of molecules which have lower symmetry or for systems with degenerate core orbitals (delocalized over identical sites), it is merely the local symmetry selectivity that provides a probe of the local atomic orbital contribution to the molecular orbital. For instance, in X-ray spectra of first row species the intensities essentially map the p-density at each particular atomic site, and, in a molecular orbital picture, the contribution of the local p-type atomic orbitals in the LCAO description of the molecular orbitals. The situation is different for resonant X-ray fluorescence spectra. Here strict parity and symmetry selectivity gives rise to a strong frequency dependence for all molecules with an element of symmetry. In addition to symmetry selectivity the strong frequency dependence of resonant X-ray emission is caused by the interplay between the shape of a narrow X-ray excitation energy function and the lifetime and vibrational broadenings of the resonantly excited core states. This interplay leads to various observable effects, such as linear dispersion, resonance narrowing and emission line (Stokes) doubling. Also from the point of view of polarization selectivity, the resonantly excited X-ray spectra are much more informative than the corresponding non-resonant spectra. Examples are presented for nitrogen, oxygen, and carbon dioxide molecules.

  16. Publicly Released Prompt Radiation Spectra Suitable for Nuclear Detonation Simulations, Revision 1

    Science.gov (United States)

    2017-12-01

    dominates the photon emission. During the Hiroshima and Nagasaki bombings , the prompt radiation contributed from 40% to 70% of the free-in-air dose...spectra for high-, intermediate- and low-yield thermonuclear weapons for initial radiation shielding calculations No Gritzner, et al. 1976 ( EM -1...Glasstone (Fission) Neutron Glasstone & Dolan 1977 7.760 x 1022 Terrell Neutron Glasstone & Dolan 1977 7.760 x 1022 DNA 4267F ( EM -1 Fission

  17. Spectra of luminescence due to microdischarges on an aluminum valve anode

    International Nuclear Information System (INIS)

    Sizikov, A.M.; Vol'f, V.G.; Bugaenko, L.T.

    1995-01-01

    The spectrum of visible and near-UV luminescence due to a microdischarge on an AMg-6 aluminum alloy was studied under conditions of valve anodization in solutions of sodium carbonate and other electrolytes. It was shown that emission spectra exhibit lines that characterize anodic (aluminum and magnesium) and electrolytic (sodium) components. The dependence of the temperature of the microdischarge on the electrolyte concentration and composition is discussed

  18. Modeling of X-ray images and energy spectra produced by stepping lightning leaders

    OpenAIRE

    Xu , Wei; Marshall , Robert A.; Celestin , Sébastien; Pasko , Victor P.

    2017-01-01

    International audience; Recent ground-based measurements at the International Center for Lightning Research and Testing (ICLRT) have greatly improved our knowledge of the energetics, fluence, and evolution of X-ray emissions during natural cloud-to-ground (CG) and rocket-triggered lightning flashes. In this paper, using Monte Carlo simulations and the response matrix of unshielded detectors in the Thunderstorm Energetic Radiation Array (TERA), we calculate the energy spectra of X-rays as woul...

  19. Nebular Phase Spectra of SNe Ia from the CSP2 Sample

    Science.gov (United States)

    Diamond, Tiara; Carnegie Supernova Project II

    2018-06-01

    We present a comparison of late-time spectra in the near-infrared for some of the Type Ia supernovae from the Carnegie Supernova Project II. Particular attention is paid to the shape and evolution of several emission features, including the [Fe II] line at 1.6440 μm. We put our findings in context of several explosion scenarios and progenitor systems.

  20. Contrasting light spectra constrain the macro and microstructures of scleractinian corals.

    Science.gov (United States)

    Rocha, Rui J M; Silva, Ana M B; Fernandes, M Helena Vaz; Cruz, Igor C S; Rosa, Rui; Calado, Ricardo

    2014-01-01

    The morphological plasticity of scleractinian corals can be influenced by numerous factors in their natural environment. However, it is difficult to identify in situ the relative influence of a single biotic or abiotic factor, due to potential interactions between them. Light is considered as a major factor affecting coral skeleton morphology, due to their symbiotic relation with photosynthetic zooxanthellae. Nonetheless, most studies addressing the importance of light on coral morphological plasticity have focused on photosynthetically active radiation (PAR) intensity, with the effect of light spectra remaining largely unknown. The present study evaluated how different light spectra affect the skeleton macro- and microstructures in two coral species (Acropora formosa sensu Veron (2000) and Stylophora pistillata) maintained under controlled laboratory conditions. We tested the effect of three light treatments with the same PAR but with a distinct spectral emission: 1) T5 fluorescent lamps with blue emission; 2) Light Emitting Diodes (LED) with predominantly blue emission; and 3) Light Emitting Plasma (LEP) with full spectra emission. To exclude potential bias generated by genetic variability, the experiment was performed with clonal fragments for both species. After 6 months of experiment, it was possible to detect in coral fragments of both species exposed to different light spectra significant differences in morphometry (e.g., distance among corallites, corallite diameter, and theca thickness), as well as in the organization of their skeleton microstructure. The variability found in the skeleton macro- and microstructures of clonal organisms points to the potential pitfalls associated with the exclusive use of morphometry on coral taxonomy. Moreover, the identification of a single factor influencing the morphology of coral skeletons is relevant for coral aquaculture and can allow the optimization of reef restoration efforts.