E. Burattini

Optical performances of SINBAD, the Synchrotron INfrared Beamline At DAΦNE

SINBAD (Synchrotron Infrared Beamline At DAphiNE) is the first Italian synchrotron radiation beamline operating in the infrared range. It collects the radiation emitted by DANE, an electron-positron collider designed to work at 0.51 GeV with a beam current I> 1 A. The actual performances of the beamline, in terms of brilliance gain with respect to blackbodies and polarization properties, are presented and discussed. Finally, the stability of the SINBAD source, a critical issue for Fourier-transform infrared spectroscopy, is discussed.

The DAΦNE‐Light Facility

The new Synchrotron Radiation facility at Frascati exploits the intense photon emission from DAΦNE, the 0,51 GeV storage ring circulating over 1 A of electrons. Among the three beamlines commissioned, the Synchrotron INfrared Beamline At Daφne (SINBAD) is fully operational by a brilliant SR beam spanning the entire IR. Recently, the soft X‐ray beamline has been characterized and, once implemented the double‐crystal monocromator, X‐ray Absorption Spectroscopy is applied on material standards in the distinguishing energy region below 4 keV. An UltraViolet line, presently dedicated to photobiology dosimetry, has also given first results on cell irradiation in the UVB band.

SINBAD: the new powerful infrared source from the DAΦNE storage ring

We report on the status of the first Italian Infrared Synchrotron Radiation Beamline SINBAD (Synchrotron INfrared Beamline At DA(Phi) NE), that has been designed to work at wavelengths greater than 10 micrometers . SINBAD is being installed on DA(Phi) NE, the new collider of the Laboratori Nazionali di Frascati designed to work at 0.51 GeV with a beam current of 2 to 5 A. The infrared radiation extracted from a bending magnet under an angle of 50 X 50 mrad will be two orders of magnitude more brilliant than that of a black body at 2000 K at a wavelength of 100 micrometers . The beamline layout, which consists of two planar mirrors, two toroidal mirrors and one aspherical mirror, has been designed by ray tracing simulation. In this layout one ellipsoid focuses the radiation on a wedged CVD diamond-film window, the beam is then re-focused again on the entrance of an interferometer. With a calculated transmittance of the optics between 60% and 80% at 50 micrometers , this beamline will allow experiments which require a very high brilliance in the far infrared.

Evidence of double K-photoionization in P, Cl, and K

Abstract Measurements of the Kα-line from pure samples of phosphorus (Z=15), chlorine (Z=17), and potassium (Z=19) were carried out. The samples were excitated using monochromatized synchrotron radiation of different energies. Experimental evidence of the presence of double K-holes and their effects on X-ray-fluorescent spectra is reported.

Infrared beamline SINBAD at DAFNE: expected performance at the sample site

SINBAD, the infrared beamline which extracts radiation from the DA(Phi) NE collider of the Laboratori Nazionali di Frascati, will be operating in the fall of 1999. The optical layout of SINBAD, fully designed by ray tracing simulation, includes six mirrors which transfer and focus the radiation to an interferometer placed more than 20 m from the source. The actual brilliance gain at the entrance of the interferometer has been accurately evaluated by simulating the expected aberrations, the mirror roughness, and diffraction effects.

Electron beam lithography on LiF films for integrated active optical waveguides

Low energy electron beam irradiation of LiF single crystals and polycrystalline films induces efficient formation of stable laser active defects emitting in the visible spectral range at room temperature, together with a consistent increase of the real part of the refractive index in the same wavelength interval. The use of electron lithography techniques look promising for the realization of active channel waveguides.

Amplified spontaneous emission in e-beam induced LiF:F2 waveguides

Electron-beam lithography techniques allow realizing channel waveguides based on laser-active color centers in lithium fluoride (LiF) emitting in the visible. Amplified spontaneous emission (ASE) of red light from F2 defects has been observed in these confining structures: the appreciable values of the gain coefficient, several cm-1, with an exciting power density of few mW/cm2, makes LiF a good candidate for the realization of active integrated optical devices.

Effect of band inversion on the phonon spectra of the Hg{sub 1-x}Zn{sub x}Te alloys

The narrow-gap II-VI and IV-VI alloys are convenient objects for studying the electron-phonon interaction. However, the concentration of free carriers in the IV-VI alloys is rather high (∼1018 cm−3), which complicates studying this effect, by the optical reflection method. The concentration of free carriers in the narrow-gap Hg1-xZnxTe alloys is considerably lower (∼1016 cm−3). Therefore, the plasma component exerts less effect on the lattice reflection spectrum. The reflection spectra of Hg1-xZnxTe crystals with x = 0.1–1 were studied in the far-IR region in the range of 30–700 cm−1 at 40–300 K. Using the dispersion analysis and the Kramers-Kronig method, the frequencies of the TO phonons of the HgTe-like and ZnTe-like modes were determined depending on the composition. It is shown that the reconstructed phonon spectrum involves two modes. The temperature dependences of the frequencies of the TO phonons and the damping parameter were measured for the narrow-gap alloy with x = 0.1 in the range of 80–200 K. A decrease in the frequency of the TO phonon of the soft mode in the vicinity of the inversion point of the bands at T = 110 K was for the first time found by optical methods. The damping parameter slightly increases in the vicinity of this temperature. The result obtained qualitatively agreed with the theoretical model of Kawamura et al., which makes allowance for the effect of the electron-phonon interaction on the frequency of the soft mode in the IV-VI compounds.

XRF analysis of volcanic ash using synchrotron radiation

Abstract XRF quantitative analyses of volcanic ash were carried out in the Microanalysis Station of the PWA Group of the Frascati National Laboratories. Very accurate results were obtained using a conventional XRF arrangement. These results were compared with the ones obtained by means of chemical analysis, in a different laboratory, showing a good agreement. Qualitative analyses using a total-reflection setup were performed, obtaining optimal spectra and detecting new elements not observed in previous measurements.