Specifications

Performance with various diffraction gratings:

Outline Drawing

Some example / test spectra

Deuterium spectrum

Modes of Operation

The Seya-Namioka is ideal when experiments require more work space around the slits. The large included angle insures that exit or entrance-slits can 'reach' into source chambers or be postioned close by a sample. The Seya also holds up with direct detection array detectors or microchannel plates. For scanning monochromator or spectrograph detection applications the Model 235 delivers a good compromise of instrument size and spectral performance.

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Select Publications

Electron impact excitation of argon in the extreme vacuum ultraviolet

Abstract: Polarization-free excitation cross sections in the extreme vacuum ultraviolet have been measured for electron impact on Ar. Observed spectral features were those lines of ArI and ArII which lie between 700 and 1100 Å. Excitation functions were measured for the ArI resonance line at 1048 Å and the ArII resonance line at 920 Å. Peak cross sections for these two lines were found to be (39.4 ± 7.9) × 10−18 and (6.9 ± 1.4) × 10−18 cm2, respectively. At low energies, excitation of the ArII resonance line is dominated by an electron exchange transition.

James E. Mentall and H. D. Morgan

Determination of the Einstein A coefficient for the ?→? transition of ammonia‐d 3

Abstract: The fluorescence of ND3 has been observed for excitation into the ?←? system at 213.86 nm. The quantum yield for this transition is 8.3×10−5. With this quantum yield and the known rotational linewidth of the upper electronic state, an Einstein A coefficient is obtained that compares favorably with a value calculated from the emission intensity and absorption strength of the (ν1′,ν2′=0,0) ↔ (ν1 ″,ν2 ″ =0,2) vibronic bands. The average of these two values is A=3.6±0.3×107 sec−1. The underlying continuum of the ?←? absorption system, attributed to the predissociation of ND3, is invoked to explain most of the discrepancy between the above value for A and that predicted by the equation of Strickler and Berg. A weaker, more diffuse emission has also been observed from ND3 for excitation into the ?←? system at 206.24 nm with fluorescence quantum yield of 1.1×10−5.

T. A. Gregory and Sanford Lipsky

The optical properties of Kapton: Measurement and applications

Abstract: The optical properties of Kapton type H polyimide film, obtained from reflectance measurements, are presented for photon energies from 0.5 to 70 eV. Equations for the energy‐loss function, with parameters fixed by the optical data, are employed to calculate mean free paths and stopping powers for low‐energy electrons (100 eV to 10 keV) in Kapton. The values obtained show good agreement with those predicted by recently proposed analytical formulae for electron mean free paths and stopping powers in solid organic insulators.

E. T. Arakawa, M. W. Williams, J. C. Ashley and L. R. Painter

Intense Resonance Line Sources for Photochemical Work in the Vacuum Ultraviolet Region

Abstract: A simple, completely sealed, discharge resonance lamp operated by a 2450 Mc/sec microwave power is described which emits atomic lines of sufficient intensity to be useful as a photochemical light source. When a water impurity is present in the lamp, many emission lines appear in the region of wavelength from 1500 to 2000 Å. These impurity lines can be effectively removed by means of a getter or by a suitable cold trap. The pressures of pure Xe or Kr in the resonance lamp, required to give maximum intensity (approximately 5× 1014 quanta/sec), are 0.7 and 1.0 mm, respectively. The presence of a CO impurity does not affect the intensity of the resonance lines. After passing through a 1-mm LiF window, the intensity of the Xe resonance line at 1295 Å is about 2% of that at 1470 Å and the intensity of the Kr line at 1165 Å is about 28% of that at 1236Å . A mixture of the rare gas and He gives more intense light than the pure gas. The lifetime of the rare-gas resonance lamps is approximately 10 h. Lyman alpha (1216 Å) line from excited atomic hydrogen and a group of lines at 1743–45 Å from excited atomic nitrogen may be used as a photochemical light source.

HIDEO OKABE

Radiative lifetimes for excited states in doubly ionized elements (21 ≤ Z ≤ 30) of astrophysical interest

Abstract: Beam-foil technique has been applied to measurements of radiative lifetimes of 23 terms or levels, all belonging to the 3dn4p (n = 0 to 9) configurations, in Sc(III), Ti(III), V(III), Cr(III), Mn(III), Fe(III), Ni(III) and Zn(III). The experimental lifetimes are in good agreement with lifetimes derived from oscillator-strength calculations, based upon the scaled Thomas-Fermi method, for ultraviolet lines in the spectra of the doubly ionized transition elements.

T. Andersen, P. Petersen

Emission studies of 9-cyanoanthracene excimers generated in glassy and crystalline matrices

Abstract: Fluorescence spectra of 9-cyanoanthracene polycrystalline films and glasses of different viscosities and polarities are reported. The 490 nm emitting species is identified as the trans excimer. The blue-shift of 9-CNA crystal emission upon increasing temperature is explained in terms of a temperature-dependent competition between two crystal traps giving rise to cis or trans excimer position.

S.E. Morsi, D. Carr, M. Ashraf El-Bayoumi