Radiometric calibration of the telescope and ultraviolet spectrometer SUMER on SOHO.

The prelaunch spectral-sensitivity calibration of the solar spectrometer SUMER (Solar Ultraviolet Measurements of Emitted Radiation) is described. SUMER is part of the payload of the Solar and Heliospheric Observatory (SOHO), which begins its scientific mission in 1996. The instrument consists of a telescope and a spectrometer capable of taking spatially and spectrally highly resolved images of the Sun in a spectral range from 50 to 161 nm. The pointing capabilities, the dynamic range, and the sensitivity of the instrument allow measurements both on the solar disk and above the limb as great as two solar radii. To determine plasma temperatures and densities in the solar atmosphere, the instrument needs an absolute spectral-sensitivity calibration. Here we describe the prelaunch calibration of the full instrument, which utilizes a radiometric transfer-standard source. The transfer standard was based on a high-current hollow-cathode discharge source. It had been calibrated in the laboratory for vacuum UV radiometry of the Physikalisch-Technische Bundesanstalt by use of the calculable spectral photon flux of the Berlin electron storage ring for synchrotron radiation (BESSY)-a primary radiometric source standard.

High-current hollow-cathode source as a radiant intensity standard in the 40-125-nm wavelength range.

The radiant intensity of VUV emission lines of a high-current hollow-cathode source has been determined for the 40-125-nm spectral range. The source is operated at a constant current of 1 A with an aluminum cathode. Different rare gases are alternatively used as the buffer gas at pressures of ~100 Pa. The radiant intensity has been determined by comparison with the calculable spectral radiant flux of the electron storage ring BESSY. Radiant intensities of the emission lines are in the 7-1400-µW/sr range. The long-term reproducibility of the radiant intensity of the source is within ±10% (2σ value). The systematic uncertainty of the radiometric calibration is better than 9% (√32σ value).

[Group therapy with selected forensic-psychiatric patients (dyssocial maldevelopment]. / Gruppengesprächstherapie mit ausgewählten forensisch-psychiatrischen Patienten (Dissoziale Fehlentwicklung).

The treatment of patients with medically relevant dissozial misdevelopment in a forensic-psychiatric clinic demands special methods corresponding to the subjective and objective conditions. The group therapy represents a possibility of activating those patients in a socially adequate way. There are being described the course and first results of this method.

Electron storage ring BESSY as a radiometric source of calculable spectral radiant power between 0.5 and 1000 nm.

The spectral radiant power of the electron storage ring BESSY was measured absolutely in the infrared and visible, and its angular distribution in the infrared, visible, and soft-x-ray ranges. The results prove BESSY to be a standard of calculable spectral radiant power, at least for wavelengths from 0.5 to 1000 nm.

Spectral radiant power measurements of VUV and soft x-ray sources using the electron storage ring BESSY as a radiometric standard source.

A method is described for measuring the spectral radiant power of VUV and soft x-ray sources using the electron storage ring BESSY as a radiometric standard source of calculable spectral radiant power and degree of polarization. An ellipsoidal grazing incidence mirror stigmatically images the stored electrons or the source under investigation in equal optical conditions into a toroidal grating monochromator. The monochromator can be rotated around its optical axis in UHV conditions to account for different degrees of polarization of the two sources. The accuracy presently available with this method is demonstrated by a measurement of the spectral concentration of radiant intensity of a laser-produced tungsten plasma in the wavelength range between 7 and 100 nm with an overall uncertainty of 10%. A detailed analysis of the contributions to this uncertainty shows that the major part of it is caused by the presently uncertain knowledge of the polarizing properties of the radiometric instrumentation and by the uncertainty of the correction procedure which accounts for the influence of higher diffraction orders of the monochromator grating. The results of the radiation measurements of the laser-produced tungsten plasma let us expect that this source type has the potential to serve as a radiometric transfer standard in the VUV and soft x-ray range below 100 nm.

Instrumental functions of a 5-m echelle spectrometer with diffraction-limited resolving power.

The resolving power R of a 5-m echelle Czerny-Turner spectrometer, designed for the spectral range between approximately 100 nm and approximately 1000 nm, was determined by measuring its instrumental functions using stabilized lasers. At lambda(1,air) = 514.534 nm in 11th order and at lambda(2,air) = 632.819 nm in 9th order the values of the resolving power are R1 = 8.38 x 10(5) +/- 2.5% and R(2) = 7.00 x 10(5) +/- 2.6%, which correspond to 95% or 97% of the theoretical values, respectively. Aberrations, particularly caused by coma as well as by imperfections of the grating and mirrors, are nearly eliminated. The resolving power is limited by diffraction at the aperture stop on the grating.