Determination of the optical constants of amorphous carbon in the EUV spectral region 40-450 eV

Uspenskii, Yu. A.; Seely, John F.; Kjornrattanawanich, Benjawan; Windt, David L.; Bugayev, Ye.A.; Кондратенко, В. В.; Artyukov, I. A.; Titov, A. A.; Kulatov, E.; Виноградов, А. В.

doi:10.1117/12.683878

Cited by 6 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Optical constants measured from Windt et al [26] in the 46-120 nm spectral range, and taken from the CXRO database [27] for the 6-46 nm spectral range are also shown for comparison. Our data are in good agreement with those reported in the literature [28,29], with slightly larger values of n and k at long wavelengths. In particular, the optical constants calculated from the first session of measurements have a better agreement with the results of Ref.…”

Section: Resultssupporting

confidence: 95%

Optical properties of carbon coatings for extreme-ultraviolet high-order laser harmonics

et al. 2010

View full text Add to dashboard Cite

High-order laser harmonics (HHs) produced by the interaction between a very intense ultrashort laser pulse and a gas jet represent an extreme-ultraviolet (XUV) radiation source with high brightness, coherence and peak intensity. The characterization of processes involving the use of HHs deserves a particular attention in the design of the beamline that is demanded to manage the XUV radiation. From the instrumental point of view, the photon throughput depends mainly from the efficiency of the optical elements. Here we present the experimental study of the optical properties of thin carbon films to be used as grazing-incidence coatings for XUV HHs. Several carbon samples were deposited on plane glass substrates by electron beam evaporation technique. The sample reflectivity was measured at different incidence angles in the 6.7-120 nm (190-10 eV) region. The optical constants (real and imaginary part of the refraction index) have been calculated. The results are in good agreement with what is reported in the literature and confirm that carboncoated optics operated at grazing incidence have a remarkable gain over conventional metallic coatings in the XUV. Since XUV HHs co-propagate with the intense infrared laser generating beam, it is important to measure the damage threshold of the coating when exposed to ultrashort infrared laser pulses. The experimental results obtained on carbon samples will be presented.

show abstract

Section: Resultssupporting

confidence: 95%

Optical properties of carbon coatings for extreme-ultraviolet high-order laser harmonics

et al. 2010

View full text Add to dashboard Cite

show abstract

“…As these do not extend into the shorter-wavelength regions important for dust heating, we use the optical constants for astronomical silicates from Laor & Draine (1993) for 0.001 − 0.2 µm for all silicate species, interpolating between the two data sets to avoid discontinuities, and we extrapolate the experimental data up to 1000 µm. We also investigated carbon grains, using optical constants for the ACAR and BE samples from Zubko et al (1996), extended to 0.0003 µm with data from Uspenskii et al (2006), as described by Owen & Barlow (2015). We assume mass densities of 2.5 and 1.6 g cm −3 for silicate and carbon grains respectively, following De Looze et al (2017), and sublimation temperatures of 1500 and 2500 K, although our results are not sensitive to the choice of this parameter.…”

Section: Componentmentioning

confidence: 99%

The mass, location, and heating of the dust in the Cassiopeia A supernova remnant

Priestley

Barlow

2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We model the thermal dust emission from dust grains heated by synchrotron radiation and by particle collisions, under conditions appropriate for four different shocked and unshocked gas components of the Cassiopeia A (Cas A) supernova remnant (SNR). By fitting the resulting spectral energy distributions (SEDs) to the observed SNR dust fluxes, we determine the required mass of dust in each component. We find the observed SED can be reproduced by ∼ 0.6 M ⊙ of silicate grains, the majority of which is in the unshocked ejecta and heated by the synchrotron radiation field. Warmer dust, located in the X-ray emitting reverse shock and blastwave regions, contribute to the shorter wavelength infrared emission but make only a small fraction of the total dust mass. Carbon grains can at most make up ∼ 25% of the total dust mass. Combined with estimates for the gas masses, we obtain dust-to-gas mass ratios for each component, which suggest that the condensation efficiency in the ejecta is high, and that dust in the shocked ejecta clumps is well protected from destruction by sputtering in the reverse shock.

show abstract

“…Dust species and their adopted densities ρg, sublimation temperatures T sub and references for the optical constants. References: (1) Jäger et al (2003) (2) Laor & Draine (1993) (3) Zubko et al (1996) Uspenskii et al (2006).…”

Section: Methodsmentioning

confidence: 99%

Constraining early-time dust formation in core-collapse supernovae

Priestley

Bevan

Barlow

2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

There is currently a severe discrepancy between theoretical models of dust formation in core-collapse supernovae (CCSNe), which predict ≳ 0.01 M⊙ of ejecta dust forming within ∼ 1000 days, and observations at these epochs, which infer much lower masses. We demonstrate that, in the optically thin case, these low dust masses are robust despite significant observational and model uncertainties. For a sample of 11 well-observed CCSNe, no plausible model reaches carbon dust masses above 10−4M⊙, or silicate masses above ∼10−3M⊙. Optically thick models can accommodate larger dust masses, but the dust must be clumped and have a low (<0.1) covering fraction to avoid conflict with data at optical wavelengths. These values are insufficient to reproduce the observed infrared fluxes, and the required covering fraction varies not only between SNe but between epochs for the same object. The difficulty in reconciling large dust masses with early-time observations of CCSNe, combined with well-established detections of comparably large dust masses in supernova remnants, suggests that a mechanism for late-time dust formation is necessary.

show abstract

Determination of the optical constants of amorphous carbon in the EUV spectral region 40-450 eV

Cited by 6 publications

References 0 publications

Optical properties of carbon coatings for extreme-ultraviolet high-order laser harmonics

Optical properties of carbon coatings for extreme-ultraviolet high-order laser harmonics

The mass, location, and heating of the dust in the Cassiopeia A supernova remnant

Constraining early-time dust formation in core-collapse supernovae

Contact Info

Product

Resources

About