| 1. |
- Abel, I, et al.
(författare)
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Overview of the JET results with the ITER-like wall
- 2013
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 53:10, s. 104002-
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Tidskriftsartikel (refereegranskat)abstract
- Following the completion in May 2011 of the shutdown for the installation of the beryllium wall and the tungsten divertor, the first set of JET campaigns have addressed the investigation of the retention properties and the development of operational scenarios with the new plasma-facing materials. The large reduction in the carbon content (more than a factor ten) led to a much lower Z(eff) (1.2-1.4) during L- and H-mode plasmas, and radiation during the burn-through phase of the plasma initiation with the consequence that breakdown failures are almost absent. Gas balance experiments have shown that the fuel retention rate with the new wall is substantially reduced with respect to the C wall. The re-establishment of the baseline H-mode and hybrid scenarios compatible with the new wall has required an optimization of the control of metallic impurity sources and heat loads. Stable type-I ELMy H-mode regimes with H-98,H-y2 close to 1 and beta(N) similar to 1.6 have been achieved using gas injection. ELM frequency is a key factor for the control of the metallic impurity accumulation. Pedestal temperatures tend to be lower with the new wall, leading to reduced confinement, but nitrogen seeding restores high pedestal temperatures and confinement. Compared with the carbon wall, major disruptions with the new wall show a lower radiated power and a slower current quench. The higher heat loads on Be wall plasma-facing components due to lower radiation made the routine use of massive gas injection for disruption mitigation essential.
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| 2. |
- Romanelli, F, et al.
(författare)
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Overview of the JET results
- 2011
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 1741-4326 .- 0029-5515. ; 51:9
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Tidskriftsartikel (refereegranskat)abstract
- Since the last IAEA Conference JET has been in operation for one year with a programmatic focus on the qualification of ITER operating scenarios, the consolidation of ITER design choices and preparation for plasma operation with the ITER-like wall presently being installed in JET. Good progress has been achieved, including stationary ELMy H-mode operation at 4.5 MA. The high confinement hybrid scenario has been extended to high triangularity, lower ρ*and to pulse lengths comparable to the resistive time. The steady-state scenario has also been extended to lower ρ*and ν*and optimized to simultaneously achieve, under stationary conditions, ITER-like values of all other relevant normalized parameters. A dedicated helium campaign has allowed key aspects of plasma control and H-mode operation for the ITER non-activated phase to be evaluated. Effective sawtooth control by fast ions has been demonstrated with3He minority ICRH, a scenario with negligible minority current drive. Edge localized mode (ELM) control studies using external n = 1 and n = 2 perturbation fields have found a resonance effect in ELM frequency for specific q95values. Complete ELM suppression has, however, not been observed, even with an edge Chirikov parameter larger than 1. Pellet ELM pacing has been demonstrated and the minimum pellet size needed to trigger an ELM has been estimated. For both natural and mitigated ELMs a broadening of the divertor ELM-wetted area with increasing ELM size has been found. In disruption studies with massive gas injection up to 50% of the thermal energy could be radiated before, and 20% during, the thermal quench. Halo currents could be reduced by 60% and, using argon/deuterium and neon/deuterium gas mixtures, runaway electron generation could be avoided. Most objectives of the ITER-like ICRH antenna have been demonstrated; matching with closely packed straps, ELM resilience, scattering matrix arc detection and operation at high power density (6.2 MW m-2) and antenna strap voltages (42 kV). Coupling measurements are in very good agreement with TOPICA modelling. © 2011 IAEA, Vienna.
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| 3. |
- Wild, W., et al.
(författare)
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Millimetron—a large Russian-European submillimeter space observatory
- 2009
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Ingår i: Experimental Astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 23:1, s. 221-244
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Tidskriftsartikel (refereegranskat)abstract
- Millimetron is a Russian-led 12 m diameter submillimeter and far-infrared space observatory which is included in the Space Plan of the Russian Federation for launch around 2017. With its large collecting area and state-of-the-art receivers, it will enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory. Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space very long baseline interferometry (VLBI) system. As single-dish, angular resolutions on the order of 3 to 12 arc sec will be achieved and spectral resolutions of up to a million employing heterodyne techniques. As VLBI antenna, the chosen elliptical orbit will provide extremely large VLBI baselines (beyond 300,000 km) resulting in micro-arc second angular resolution.
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| 4. |
- Lerche, E., et al.
(författare)
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Optimizing ion-cyclotron resonance frequency heating for ITER : dedicated JET experiments
- 2011
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Ingår i: Plasma Physics and Controlled Fusion. - : IOP Publishing. - 0741-3335 .- 1361-6587. ; 53:12, s. 124019-
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Tidskriftsartikel (refereegranskat)abstract
- In the past years, one of the focal points of the JET experimental programme was on ion-cyclotron resonance heating (ICRH) studies in view of the design and exploitation of the ICRH system being developed for ITER. In this brief review, some of the main achievements obtained in JET in this field during the last 5 years will be summarized. The results reported here include important aspects of a more engineering nature, such as (i) the appropriate design of the RF feeding circuits for optimal load resilient operation and (ii) the test of a compact high-power density antenna array, as well as RF physics oriented studies aiming at refining the numerical models used for predicting the performance of the ICRH system in ITER. The latter include (i) experiments designed for improving the modelling of the antenna coupling resistance under various plasma conditions and (ii) the assessment of the heating performance of ICRH scenarios to be used in the non-active operation phase of ITER.
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| 5. |
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| 6. |
- Smirnov, A. V., et al.
(författare)
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The Current Stage of Development of the Receiving Complex of the Millimetron Space Observatory
- 2012
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Ingår i: Radiophysics and Quantum Electronics (English Translation of Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika). - : Springer Science and Business Media LLC. - 0033-8443 .- 1573-9120. ; 54:8-9, s. 557-568
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Tidskriftsartikel (refereegranskat)abstract
- We present an overview of the state of the onboard receiving complex of the Millimetron space observatory in the development phase of its preliminary design. The basic parameters of the onboard equipment planned to create and required for astrophysical observations are considered. A review of coherent and incoherent detectors, which are central to each receiver of the observatory, is given. Their characteristics and limiting parameters feasible at the present level of technology are reported.
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| 7. |
- Gunbina, A. A., et al.
(författare)
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A 90 GHz SINIS detector with 2 GHz readout
- 2021
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Ingår i: IEEE Transactions on Applied Superconductivity. - 1558-2515 .- 1051-8223. ; 31:5
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Tidskriftsartikel (refereegranskat)abstract
- A superconductor-insulator-normal metal-insulator-superconductor (SINIS) detector integrated in a planar 90 GHz band twin-slot antenna with a 2 GHz superconducting resonator readout was fabricated and experimentally studied. In order to achieve high pixel count, the traditional dc readout of the SINIS detector is replaced by NbN coplanar 13.850 mm long superconducting resonator. SINIS detectors have traditionally dc Junction Field Effect Transistor (JFET) room-temperature readout. Such readout requires individual wiring for each pixel, while the microwave readout is far less cluttered as only one coaxial line is needed for hundreds of devices. Such readout operates similar to frequency domain multiplexing (FDM) for microwave kinetic inductance detectors (MKID). The planar twin slot antenna has two parallel slots in a metal ground plane which are excited coherently by short sections of a coplanar waveguide (CPW) line with a SINIS detector at the center. One section of the CPW is extended past the slot in a long superconducting section which functions as a quarter wavelength resonator. This resonator is short circuited to the ground plane at the far end, with the expected open circuited end terminated by the SINIS detector in the antenna. We measured the response of sample to black body radiation temperatures 6 K and 9 K. The corresponding dynamic resistance maximum drops from 50 k down to 30 k. An RF readout channel comprising a coplanar coupler and a coplanar resonator has a resonant frequency of 1.8 GHz. Unloaded Q factor (without incoming irradiation) is 200. The signal spectral characteristics and the response to the black body radiation have shown design values as expected.
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| 8. |
- Hoots, W. K., et al.
(författare)
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Secondary prophylaxis with recombinant activated factor VII improves health-related quality of life of haemophilia patients with inhibitors
- 2008
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Ingår i: Haemophilia. - : Wiley. - 1351-8216 .- 1365-2516. ; 14:3, s. 466-466
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Tidskriftsartikel (refereegranskat)abstract
- Haemophilia patients with inhibitors characteristically have impaired joint function and reduced health-related quality of life (HRQoL). This analysis examined whether secondary prophylaxis with recombinant activated factor VII (rFVIIa) improves HRQoL vs. conventional on-demand therapy in patients with haemophilia with inhibitors and frequent bleeds. After a 3-month preprophylaxis period, 22 patients received daily rFVIIa prophylaxis (90 or 270 mu g kg(-1)) for 3 months, followed by 3 months' postprophylaxis. Days of hospitalization, absence from school/work and mobility aids requirements were recorded. HRQoL was assessed by EuroQoL (EQ-5D) questionnaire, visual analogue scale (VAS), derived Time to Trade-Off (TTO) scores and Quality Adjusted Life Years (QALYs). rFVIIa prophylaxis significantly (P < 0.0001) reduced bleeding frequency vs. prior on-demand therapy. Hospitalization (5.9% vs. 13.5%; P = 0.0026) and absenteeism from school/work (16.7% vs. 38.7%; P = 0.0127) decreased during prophylaxis; these effects tended to be maintained during postprophylaxis. HRQoL (evaluated by EQ-5D) tended to improve during and after rFVIIa prophylaxis. Notably, pain decreased and mobility increased in 40.9% and 27.3% of patients, respectively, at the end of the postprophylaxis period vs. preprophylaxis. Median VAS score increased from 66 to 73 (P = 0.048), and TTO scores suggested better HRQoL (0.62 vs. 0.76; P = 0.054) during postprophylaxis than preprophylaxis. Small to moderate changes in effect sizes were reported for VAS and TTO scores. Median QALYs were 0.68 (VAS) and 0.73 (TTO). Reductions in bleeding frequency with secondary rFVIIa prophylaxis were associated with improved HRQoL vs. on-demand therapy.
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| 9. |
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| 10. |
- Gunbina, A. A., et al.
(författare)
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Spectral Response of Arrays of Half-wave and Electrically Small Antennas with SINIS Bolometers
- 2020
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Ingår i: Physics of the Solid State. - 1063-7834 .- 1090-6460. ; 62:9, s. 1604-1611
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Tidskriftsartikel (refereegranskat)abstract
- Two types arrays of annular half-wave and electrically small antennas with typical sizes of the elements corresponding to 1/10 of the wavelength at SubTHz band with integrated superconductor-insulator-normal metal-insulator-superconductor (SINIS) bolometers have been developed, fabricated and experimentally studied. We performed numerical modeling of the full structure and use additional reference channels in experimental studies to enhance the accuracy of the spectral response estimations of receiving arrays. In experiments three reference channels were used for normalization of the spectral response: a pyroelectric detector outside the cryostat, and two cold channels-a RuO(2)bolometer and on-chip thermometer comprising series array of NIS-junctions.
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