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Technical manual - collimator
Kredba, Jan; Steiger, Lukáš; Tomka, David; Václavík, Jan
2018 - English
The purpose of this document is to provide basic set of rules and instructions that allows using and maintaining of the NEOSTED collimator (COL).\nBe aware that it is not purpose of this document to provide detailed description of individual parts of the COL system. If necessary all the details and proper references can be found in [AD-2].
Keywords:
collimator; NEOSTED; TOPTEC; optical testing; interferometry
Available at various institutes of the ASCR
Technical manual - collimator
The purpose of this document is to provide basic set of rules and instructions that allows using and maintaining of the NEOSTED collimator (COL).\nBe aware that it is not purpose of this document to ...
Research report Project Midfree 2. phase
Beneš, Jiří; Karabyn, Vasyl; Matoušek, Ondřej; Špína, Michal
2018 - Czech
Research report describing the creation of an engineering model to predict possibilities of suppressing problematic surface structures. Výzkumná zpráva popisující tvorbu inženýrského modelu k predikci možností potlačení problematických povrchových struktur.
Keywords:
vibration analysis; MSF simulation
Available at various institutes of the ASCR
Research report Project Midfree 2. phase
Research report describing the creation of an engineering model to predict possibilities of suppressing problematic surface structures.
Fluctuations in the scrape-off layer and edge plasma of the COMPASS tokamak
Seidl, Jakub; Jiráková, Kateřina; Adámek, Jiří; Grover, Ondřej; Horáček, Jan; Hron, Martin; Vondráček, Petr
2018 - English
We have identified two distinct types of turbulent fluctuations in COMPASS plasmas, the high-frequency edge oscillations and low-frequency SOL blobs. The transition region is localized in the near SOL, where both types spatially overlap and interact and the radial particle transport gradually transfers from high to low frequencies. Even though skewness of isat fluctuations is positive even inside LCFS, distinguishable Gamma-distributed PDF, formed by the low-frequency fluctuations, arises in the near SOL. This supports, together with turbulence spreading rate being positive in the near SOL but negative in the edge, the picture presented in [3] that most of the fluctuations that form a positive skewness in the edge region disappear around LCFS and new blobs are formed in the near SOL. Further, we cannot confirm the assumption that the blobs are generated randomly according to a Poisson process. Oscillations of all measured quantities, incl. radial particle flux, in the near SOL are peaked around ∼13 kHz. This seems to correspond to a poloidally rotating structure with a rather large poloidal wave-length ∼ 15 − 20 cm, that at least partly modulates blob generation. Nevertheless, we note that time separation of blobs becomes more random further in the SOL, possibly due to differences in their individual propagation. These observations hold for diverted plasmas, but the situation may be different in limited low-elongation plasmas where the radius of zero skewness was observed to be shifted significantly (several cm) inwards, compared to diverted configuration, and Gamma-like PDF is detected even inside the LCFS. Study of these plasmas is ongoing.
Keywords:
plasma; tokamak; turbulence
Fulltext is available at external website.
Fluctuations in the scrape-off layer and edge plasma of the COMPASS tokamak
We have identified two distinct types of turbulent fluctuations in COMPASS plasmas, the high-frequency edge oscillations and low-frequency SOL blobs. The transition region is localized in the near ...
Use of holography for surface measurement and characteriaztion
Kaván, František
2018 - Czech
This research focuses on the use of digital holography for measuring the shape of optical and other surfaces. For the first experiments, we used a standard double-wave holographic interferometry method. This served as a reference. However, the main focus is Frequency Sweeping Digital Holography (FSDH), or scanning digital holography, which utilizes fluently translatable DFB laser diodes. The accuracy of this method can be further improved by combining measurements from multiple wavelengths - multiple diodes. When combined, this method can achieve accuracy of up to 2 μm. Tento výzkum je zaměřen na využití digitální holografie pro měření tvaru optických a jiných ploch. Pro první experimenty jsme použili standardní metodu dvojvlnné holografické interferometrie. Ta posloužila jako reference. Hlavním zaměřením je však Frequency Sweeping Digital Holography (FSDH) neboli skenovací digitální holografie, která využívá plynule přeladitelných DFB laserových diod. Přesnost této metody lze dále vylepšit spojením měření z více vlnových délek - více diod. Při spojení je možno pomocí této metody dosáhnout přesnosti až 2 µm.
Keywords:
holography; measurement
Fulltext is available at external website.
Use of holography for surface measurement and characteriaztion
This research focuses on the use of digital holography for measuring the shape of optical and other surfaces. For the first experiments, we used a standard double-wave holographic interferometry ...
Realization of thin films for final optical components
Budasz, Jiří
2018 - Czech
The report describes the realisation of the thin films coatings at the optical elements used for prototyping. It involves the testing of the coatings at sample substrates as well. Zpráva se zabývá realizací tenkých vrstev na optických elementech určených pro funkční vzorky a prototypy. Popisuje rovněž zátěžové testování soustav vrstev na vzorcích.
Keywords:
High reflective coatings; testing; laser
Available at various institutes of the ASCR
Realization of thin films for final optical components
The report describes the realisation of the thin films coatings at the optical elements used for prototyping. It involves the testing of the coatings at sample substrates as well.
Effect of sintering temperature on microstructure and mechanical properties of AE42 magnesium alloy prepared by spark plasma sintering
Minárik, P.; Lukáč, František; Cinert, Jakub; Šašek, S.; Král, R.
2018 - English
Magnesium alloy AE42 was prepared by powder metallurgy technique of spark plasma sintering. The effect of sintering parameters, particularly sintering temperature, on the microstructure and mechanical strength was investigated. The gas-atomized powder was sintered at four temperatures in the temperature range of 400-550 °C. It was found that mechanical strength of the sintered samples was significantly affected by several microstructural features. Application of relatively high load during sintering caused deformation of the individual particles and consequent recrystallization depending on the processing temperature resulted in the release of internal strain and in grain growth. As a result, the evolution of the mechanical strength as a function of the sintering temperature was significantly affected by residual stress, grain size and coarsening of secondary phase particles.
Keywords:
Magnesium; Mechanical properties; Microstructure; Spark plasma sintering
Available at various institutes of the ASCR
Effect of sintering temperature on microstructure and mechanical properties of AE42 magnesium alloy prepared by spark plasma sintering
Magnesium alloy AE42 was prepared by powder metallurgy technique of spark plasma sintering. The effect of sintering parameters, particularly sintering temperature, on the microstructure and mechanical ...
OLGA – efficient full wave code for the coupling of LH grills
Preinhaelter, Josef; Hillairet, J.; Urban, Jakub
2018 - English
The full wave code OLGA, for determining the coupling of a single row lower hybrid launcher (waveguide grills) to the plasma, is extended to handle multirow multijunction active passive structures (like the C3 and C4 launchers on TORE SUPRA) by implementing the scattering matrix formalism. The extended code is still computationally fast because of the use of (i) 2D splines of the plasma surface admittance in the accessibility region of the k-space, (ii) high order Gaussian quadrature rules for the integration of the coupling elements and (iii) utilizing the symmetries of the coupling elements in the multiperiodic structures. The extended OLGA code is benchmarked against the ALOHA-1D, ALOHA-2D and TOPLHA codes for the coupling of the C3 and C4 TORE SUPRA launchers for several plasma configurations derived from reflectometry and interferometery. Unlike nearly all codes (except the ALOHA-1D code), OLGA does not require large computational resources and can be used for everyday usage in planning experimental runs. In particular, it is shown that the OLGA code correctly handles the coupling of the C3 and C4 launchers over a very wide range of plasma densities in front of the grill.
Keywords:
lower hybrid waves; coupling; large multirow multijunction grills; tokamak; full-wave
Fulltext is available at external website.
OLGA – efficient full wave code for the coupling of LH grills
The full wave code OLGA, for determining the coupling of a single row lower hybrid launcher (waveguide grills) to the plasma, is extended to handle multirow multijunction active passive structures ...
Collimator - test readiness review
Budasz, Jiří; Kaván, František; Kredba, Jan; Lédl, Vít; Mach, Marek; Pleštil, Jan; Psota, Pavel; Steiger, Lukáš; Tomka, David; Václavík, Jan; Veselý, Martin
2018 - English
This document describes the test procedure applicable to the overall functional test of the NEOSTED collimator.\nThe test to be performed according to this procedure are to demonstrate the compliance of the above item to the requirements specified in the applicable document as part of the overall verification program. The test results shall be collected in a Test Report.
Keywords:
collimator; PLC system; telescope; interferometry
Available at various institutes of the ASCR
Collimator - test readiness review
This document describes the test procedure applicable to the overall functional test of the NEOSTED collimator.\nThe test to be performed according to this procedure are to demonstrate the compliance ...
Technical manual - neosted SOT test bench
Steiger, Lukáš
2018 - English
The purpose of this document is to provide basic set of rules and instructions that allows using and maintaining of the NEOSTED SOT test bench (BB).\nFurther detailed informations and proper references about individual parts of the BB system can be found in [AD-2, AD-3].
Keywords:
test bench; optical testing; collimator; neosted
Available at various institutes of the ASCR
Technical manual - neosted SOT test bench
The purpose of this document is to provide basic set of rules and instructions that allows using and maintaining of the NEOSTED SOT test bench (BB).\nFurther detailed informations and proper ...
Development of the cleaning process and predeposition treatment of an optical surface
Budasz, Jiří
2018 - Czech
The report deals with a development of cleaning precedure of substrates used for producing high reflective mirrors. It involves pre-deposition treatment of the surface in vacuum chamber. Zpráva popisuje vývoj mycího postupu substrátů pro výrobu superodrazných zrcadel. Zahrnuje také vývoj procesu ošetření povrchu ve vakuu.
Keywords:
High reflective coatings; cleaning; pre-deposition treatment
Available at various institutes of the ASCR
Development of the cleaning process and predeposition treatment of an optical surface
The report deals with a development of cleaning precedure of substrates used for producing high reflective mirrors. It involves pre-deposition treatment of the surface in vacuum chamber.
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