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We have employed VEPP-4 synchrotron radiation to measure CCD detector absolute responsivity in vacuum ultraviolet (115-310 nm) spectral range. The detector is designed in the form of a stainless steel enclosure containing a backside-illuminated CCD to protect the CCD from contamination. The entrance window of the enclosure is a round MgF2 spectral filter transparent for ultraviolet radiation with wavelengths longer than 112 nm. The measurements were carried out at Kosmos Metrological Station at the operating temperature of -100°C on the sensitive surface of the CCD. We utilized SPD calibrated silicon photodiode with 1 cm2 sensitive area and a known spectral sensitivity profile as a reference detector. The resultant measurements show a clear CCD responsivity dip near 280 nm, and a great potential to improve the CCD responsivity values using specially designed anti-reflection coatings.

We have numerically optimized several broadband aperiodic normal-incidence multilayer mirrors based on Sb/B 4 C for the 85 – 125 A spectral domain for spectroscopy applications below the silicon L-edge (λ = 125 A). Three multilayer mirrors were then synthesized. The designed multilayer structures were optimized for a maximum uniform reflectivity in the 90 – 100, 95 – 105 and 100 – 120 A wavebands, respectively. All the Sb/B 4 C multilayer mirrors were synthesized via magnetron sputtering in argon medium. The multilayers reflection spectra were evaluated with the use of a laboratory XUV spectrograph employing a laser-plasma radiation source, the mirror under study, a transmission diffraction grating and a backside-illuminated CCD matrix. The experimentally recorded spectra were compared with the theoretical ones. Numerical calculations of aperiodic Sb/B 4 C multilayer structures with different layer densities are presented. Effects of lower densities and small random variations of the individual layer widths on the reflection spectra are discussed.

We present the design, calculations and simulations of high-resolution concave-VLS-grating-based soft X-ray and VUV spectrographs, as well as a plane VLS grating instrument. We have designed a normal-incidence imaging VLS grating spectrograph for a 820 – 1690 A spectral interval and a series of grazing-incidence VLS spectrographs with imaging capabilities. The experimentally recorded spectral images of laboratory laser plasmas were obtained with the aid of a VLS spectrometer based on a concave aperiodic multilayer mirror and a plane VLS grating. Two modifications of this spectrometer were implemented with two different VLS gratings. These modifications exhibit spectral resolution of 500 and 800 over the 125 – 300 A spectral waveband. Spatial resolution corresponds to double CCD-detector pixel size.

Our intention is to develop high-resolution stigmatic spectral imaging in the XUV (2 – 40 nm). We have designed, aligned and tested a broadband stigmatic spectrometer for a range of 12–30 nm, which makes combined use of a normalincidence multilayer mirror (MM) (in particular, a broadband aperiodic MM) and a grazing-incidence plane varied linespace (VLS) reflection grating. The concave MM produces a slightly astigmatic image of the radiation source (for instance, the entrance slit), and the VLS grating produces a set of its dispersed stigmatic spectral images. The multilayer structure determines the spectral width of the operating range, which may amount to more than an octave in wavelength (e.g. 12.5–30 nm for an aperiodic Mo/Si MM), while the VLS grating controls the spectral focal curve. The stigmatism condition is satisfied simultaneously for two wavelengths, 14 and 27 nm. In this case, the condition of non-rigorous stigmatism is fulfilled for the entire wavelength range. A LiF laser plasma spectrum was recorded in one 0.5 J laser shot. A spatial resolution of 26 μm and a spectral resolution of 900 were demonstrated in the 12.5 – 25 nm range. We also report the design of a set of flat-field spectrometers of Harada type with VLS gratings. VLS gratings were made by ebeam and interference lithography. A technique (analytical + numerical) was developed for calculating optical schemes for writing plane and concave VLS gratings with predefined line density variation.

We present a laboratory high-aperture monochromator-reflectometer employing laser-plasma radiation source and three replaceable Schwarzschild objectives for a certain range of applications in the soft X-ray spectral waveband. Three sets of X-ray multilayer mirrors for the Schwarzschild objectives enable operation of the reflectometer at the wavelengths of 135, 171 and 304 A, while a goniometer with three degrees of freedom allows different measurement modes. We have used the facility for a laboratory CCD calibration at the wavelengths specified. Combined with the results of the CCD sensitivity measurements conducted in the VUV spectral waveband, the total outcome provides a more comprehensive understanding of the CCD effectivity in a wide spectral range.

ARKA and KORTES are two upcoming solar space missions in extreme ultraviolet and X-ray wavebands. KORTES is a sun-oriented mission designed for the Russian segment of International Space Station. KORTES consists of several imaging and spectroscopic instruments that will observe the solar corona in a number of wavebands, covering EUV and X-ray ranges. The surveillance strategy of KORTES is to cover a wide range of observations including simultaneous imaging, spectroscopic and polarization measurements. ARKA is a small satellite solar mission intended to take highresolution images of the Sun at the extreme ultraviolet wavelengths. ARKA will be equipped with two high-resolution EUV telescopes designed to collect images of the Sun with approximately 150 km spatial resolution in the field of view of about 10'×10'. The scientific results of the mission may have a significant impact on the theory of coronal heating and may help to clarify the physics of small-scale solar structures and phenomena including oscillations of fine coronal structures and the physics of micro- and nanoflares.

We present measurements of spectral sensitivity of CCD-matrices designed for future space missions. Three wavebands were under investigation: UV-visible range (300-600 nm), UV (250-300 nm) and VUV (110-250 nm). We used a halogen lamp, a deuterium lamp and a tungsten laser-driven plasma as sources of radiation. IRD UV silicon photodiodes and a photomultiplier tube fulfilled the function of calibrated detectors. Using a calibrated CCD, we measured initial spectral effectivity of the tungsten laser-driven plasma radiation source in the 110-250 nm waveband. Afterwards we experimentally evaluated spectral transmittance functions of three VUV multilayer filters for future space telescopes.

We report on the current status of the KORTES project – the first sun-oriented mission for the International Space Station to be launched in 2016-2017. KORTES will comprise several imaging and spectroscopic instruments that will observe solar corona in a number of wavebands, covering EUV and X-Ray ranges. A brief overview of the instrumentation of KORTES, its’ layout, technical parameters and scientific objectives is given. An additional attention is given to the design of multilayer optics and filters to be employed in EUV instruments of KORTES.