| 31. |
- Kuzmin, Leonid, 1946, et al.
(författare)
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Multifrequency Seashell Slot Antenna With Cold-Electron Bolometers for Cosmology Space Missions
- 2016
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Ingår i: IEEE Transactions on Applied Superconductivity. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-2515 .- 1051-8223. ; 26:3
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Tidskriftsartikel (refereegranskat)abstract
- A novel type of the "seashell" multichroic polarized antenna is proposed for cosmology space missions. The polarized slot antennas are arranged in the compact form of a seashell with individual slots for each frequency and each polarization. Such an arrangement gives a unique opportunity for independent adjusting individual parameters of slots with microstrip lines (MSLs) and bolometers. For each frequency band, the seashell antenna contains two pairs of orthogonal slots for each polarization connected by MSLs with a bolometer in the middle for in-phase operation. To fit slots in the lambda/2 area for the best beam shape, lumped capacitances in the form of the H-slot were introduced. Ellipticity of a beam was improved to the level of better than 1%. The seashell antenna gives a unique opportunity to select the needed bandwidth using two options. The first option is the frequency selection by resonance properties of slots with MSLs and resistive cold-electron bolometer (CEB). The second option is the frequency selection by resonant CEB with an internal nanofilter organized by a kinetic inductance of the NbN superconducting nanostrip and a capacitance of the nanoscale superconductor-insulator-normal tunnel junction.
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| 32. |
- Kuzmin, Leonid, 1946, et al.
(författare)
-
Optimization of the cold-electron bolometer and a cascade quasiparticle amplifier in the voltage-biased mode
- 2022
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Ingår i: IEEE Transactions on Applied Superconductivity. - 1558-2515 .- 1051-8223. ; 32:4
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Tidskriftsartikel (refereegranskat)abstract
- An optimized concept of the Cold-Electron Bolometer (CEB) with Superconductor-Insulator-Normal (SIN) Tunnel Junction and Andreev SN contact for voltage-bias mode has been developed. The responsivity of this design is much better than the widespread concept of the CEB with two SIN tunnel junctions for the current-biased mode (SINIS structure) due to degradation of responsivity by a factor of two in voltage-bias (VB) mode. Besides that, for the realization of the CEB with the same capacitance, we need twice larger junctions that lead to four times larger area and volume of the absorber. As a result, the NEP of one SIN junction CEB is half that of two SIN junction CEB. A novel concept of the quasiparticle cascade amplifier (QCA) based on harvesting the waste energy of relaxed quasiparticles without any additional voltage bias has been developed. The distinguish feature of the cascade principle is utilizing the same dc voltage as used for CEB. The cascade principle of signal amplification proved to be possible due to the conversion of electrons to holes in the second absorber. The amplifier is based on the optimized CEB with one SIN junction and one SN contact. The coefficient of power amplification of the incoming signal to the potential energy of hot quasiparticles is huge and can achieve a level of 140 at the optimal bias point. The coefficient of power amplification of the QCA can reach a value of 30 and more to overcome the noise of the SQUID amplifier. For a power load of 6 pW, the total NEP of the CEB is decreased to the level of pho-ton noise NEP, down to 0.7*NEPphot.
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| 33. |
- Kuzmin, Leonid, 1946, et al.
(författare)
-
Realization of the resonant cold-electron bolometer with a kinetic inductance nanofilter for multichroic pixels
- 2018
-
Ingår i: IEEE Transactions on Applied Superconductivity. - 1558-2515 .- 1051-8223. ; 28:4
-
Tidskriftsartikel (refereegranskat)abstract
- A novel type of the resonant cold-electron bolometer (RCEB) has been realized for multichroic pixels. The internal resonance is organized by a kinetic inductance of the NbN superconducting nanostrip and a capacitance of the superconductor-insulator-normal (SIN) tunnel junctions. The basic idea of a multichroic system is to combine a wideband antenna and narrow-band RCEBs. We used a single Lambda slot with two RCEBs for 75 and 105 GHz, placed in the middle. Each RCEB included two SIN junctions with absorber connected to NbN kinetic inductance of 420 and 240 pH. SIN junctions had capacitances of 11 and 8 fF. Wave impedance of the slot antenna was near 15 Ω and resistance of the absorber was matched to this value. Matching of antenna with an external system was done by placing Si lens on the back side of a Si substrate. RF testing was done at 300 mK irradiating this chip by sweep generator from 60 to 120 GHz. The response curves showed clear resonances at 75 and 105 GHz with quality factor of 10 and 7. Kinetic inductance value was estimated at the level of 35 pH/sq. These experiments confirmed that the RCEB can be effectively used to create multiband elements.
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| 34. |
- Kuzmin, Leonid, 1946, et al.
(författare)
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Single Photon Counter Based on a Josephson Junction at 14 GHz for Searching Galactic Axions
- 2018
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Ingår i: IEEE Transactions on Applied Superconductivity. - 1558-2515 .- 1051-8223. ; 28:7
-
Tidskriftsartikel (refereegranskat)abstract
- Axions and axion-like particles appear in well-motivated extensions of the standard model of particle physics and may be the solution to the long-standing puzzle of the dark matter in our Universe. Several new experiments are foreseen in the next decade searching them in a wide range of the parameter space. In the mass region from few to several tens of microelectronvolt, detector sensitivity will be limited by the standard quantum limit of linear amplifiers and a new class of single microwave-photon detector will be needed. We have developed a single photon counter based on the voltage switching of an underdamped Josephson junction that is coupled to a coplanar waveguide. By measuring the switching voltage, we can register single photons at 14 GHz with the rate less than 1 photon per 3000 s.
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| 35. |
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| 36. |
- Mangiarotti, Franco J., et al.
(författare)
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Test of Short Model and Prototype of the HL-LHC D2 Orbit Corrector Based on CCT Technology
- 2019
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Ingår i: IEEE transactions on applied superconductivity (Print). - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1051-8223 .- 1558-2515. ; 29:5
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Tidskriftsartikel (refereegranskat)abstract
- In the frame of the high-luminosity upgrade project for the large hadron collider, new twin aperture beam orbit corrector magnets will be installed near the recombination dipole (D2). These magnets are 2.2 m long canted cosine theta NbTi dipoles, with two independently powered apertures oriented such that their field vectors are perpendicular to each other and to the direction of the beams. A 0.5 m model magnet in single and double aperture configuration and a full-length double aperture prototype were built and tested at CERN. In this paper, the performance of these magnets at 1.9 K in terms of training behavior, quench detection and protection, and other tests is discussed. In addition, the thermal response of the magnet to a hypothetical beam discharge is simulated and analyzed.
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| 37. |
- Mangiarotti, Franco J., et al.
(författare)
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Test of the First Full-Length Prototype of the HL-LHC D2 Orbit Corrector Based on Canted Cosine Theta Technology
- 2020
-
Ingår i: IEEE transactions on applied superconductivity (Print). - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1051-8223 .- 1558-2515. ; 30:4
-
Tidskriftsartikel (refereegranskat)abstract
- In the context of CERN's high-luminosity upgrade project (HL-LHC) for the Large Hadron Collider (LHC), a new double aperture beam orbit corrector magnets will be installed near the recombination dipole (D2). These 2.2 m long NbTi dipoles are built with the canted cosine theta (CCT) technique. The two independently powered apertures are oriented such that their field vectors are perpendicular to each other and to the direction of the beams. A full-length double aperture prototype was built and tested at CERN in the SM18 test facility. Here we present the results of powering tests at 1.9 and 4.5 K: training of each aperture, magnetic field quality and cross-talk effects, quench detection system effectiveness, quench protection performance and quench-back with several energy extraction systems.
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| 38. |
- Mangiarotti, Franco, et al.
(författare)
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Test Results of the CERN HL-LHC Low-beta Quadrupole Short Models MQXFS3c and MQXFS4
- 2019
-
Ingår i: IEEE transactions on applied superconductivity (Print). - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1051-8223 .- 1558-2515. ; 29:5
-
Tidskriftsartikel (refereegranskat)abstract
- For the high luminosity upgrade of the CERN large hadron collider, lower beta* quadrupole magnets based on advanced Nb3Sn conductors will be installed on each side of the ATLAS and compact muon solenoid (CMS) experiment insertion zones. As part of the technological developments needed to achieve the required field gradient of 132.6 T/m within a 150-mm aperture, short length model magnets, named MQXFS, are tested both at the CERN SM18 and Fermilab test facilities. The model magnets rely on two types of Nb3Sn conductors (restack rod process (RRP) and powderin-tube (PIT)) and on an innovative bladders and keys design to provide mechanical support against the Lorentz forces. In 2016 and 2017, the powering tests of the first two models MQXFS3 (RRP) and MQXFS5 (PIT) proved that nominal performance (16.5 kA) could be reached with excellent memory of the quench current after thermal cycle. However both magnets showed a slow training behavior with clear observations of voltage disturbances before the quench. Besides, only MQXFS5 could reach ultimate current (17.9 kA) whereas erratic behavior was observed on MQXFS3 due to conductor local degradation at the head of one of the coils. In 2018, this limiting coil was changed and the applied azimuthal prestress increased. While ultimate current could then be reached, no stable current could be maintained due to identified defect on the outer layer of the new coil. Finally the outcome of the test of the new model MQXFS4, featuring the final RRP conductors that will be used for the series production and variation on the inner layer quench heater designs are here reported in details.
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| 39. |
- Nawaz, Shahid, 1978, et al.
(författare)
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Transport Properties of YBCO Nanowires
- 2011
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Ingår i: IEEE Transactions on Applied Superconductivity. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-2515 .- 1051-8223. ; 21:3, s. 164-167
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Tidskriftsartikel (refereegranskat)abstract
- We have carried out transport studies of YBa2Cu3O7-x (YBCO) nanowires. By exposing nanowires with microwaves, we see that short wires which have a flux-flow like current-voltage characteristic (IVC) clearly manifest current steps in the IVC (Shapiro steps). On the contrary, the longer wires exhibiting a resistively and capacitively shunted junction (RCSJ) model like current-voltage characteristic do not feature any Shapiro steps. The second case can be explained by taking into consideration the longer wire lengths where the wires loose coherency of flux flow due to inhomogeneity along the wire.
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| 40. |
- Nilsson, P A, et al.
(författare)
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Planarized patterning of Y-Ba-Cu-O thin films for multilayer technology
- 1995
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Ingår i: IEEE transactions on applied superconductivity (Print). - : Institute of Electrical and Electronics Engineers (IEEE). - 1051-8223 .- 1558-2515. ; 5, s. 1653-1656
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Tidskriftsartikel (refereegranskat)abstract
- Planarized layers of YBa2Cu3O7 (YBCO) were made by etching trenches in SrTiO3 (STO) substrates, laser depositing a YBCO film and mechanically polishing the film down to the substrate surface. These structures exhibited critical temperatures (Tc) of 88 K and a critical-current density (Jc) of 106 A/cm2 at 77 K. The planarized surface was smooth, with a maximum height difference between the YBCO and STO of 20 nm. The surfaces were used as templates for epitaxial growth of multilayer insulators of STO and PrBa2Cu3O7 (PBCO) and top YBCO layers. Complete crossovers, free of superconducting shorts, with Tc of 86 K and critical current density (Jc) of 2×105 A/cm2 were made.
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