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Author | Wampfler, S. F.; Herczeg, G. J.; Bruderer, S.; Benz, A. O.; van Dishoeck, E. F.; Kristensen, L. E.; Visser, R.; Doty, S. D.; Melchior, M.; van Kempen, T. A.; Yıldız, U. A.; Dedes, C.; Goicoechea, J. R.; Baudry, A.; Melnick, G.; Bachiller, R.; Benedettini, M.; Bergin, E.; Bjerkeli, P.; Blake, G. A.; Bontemps, S.; Braine, J.; Caselli, P.; Cernicharo, J.; Codella, C.; Daniel, F.; di Giorgio, A. M.; Dominik, C.; Encrenaz, P.; Fich, M.; Fuente, A.; Giannini, T.; de Graauw, Th.; Helmich, F.; Herpin, F.; Hogerheijde, M. R.; Jacq, T.; Johnstone, D.; Jørgensen, J. K.; Larsson, B.; Lis, D.; Liseau, R.; Marseille, M.; Mc Coey, C.; Neufeld, D.; Nisini, B.; Olberg, M.; Parise, B.; Pearson, J. C.; Plume, R.; Risacher, C.; Santiago-García, J.; Saraceno, P.; Shipman, R.; Tafalla, M.; van der Tak, F. F. S.; Wyrowski, F.; Roelfsema, P.; Jellema, W.; Dieleman, P.; Caux, E.; Stutzki, J. | ||||
Title | Herschel observations of the hydroxyl radical (OH) in young stellar objects | Type | Journal Article | ||
Year | 2010 | Publication | Astron. Astrophys. | Abbreviated Journal | |
Volume | 521 | Issue | Pages | L36 | |
Keywords | HEB mixer applications, HIFI, Herschel, astrochemistry / stars: formation / ISM: molecules / ISM: jets and outflows / ISM: individual objects: HH 46 | ||||
Abstract | Aims. “Water In Star-forming regions with Herschel†(WISH) is a Herschel key program investigating the water chemistry in young stellar objects (YSOs) during protostellar evolution. Hydroxyl (OH) is one of the reactants in the chemical network most closely linked to the formation and destruction of H2O. High-temperature (T 250 K) chemistry connects OH and H2O through the OH + H2 H2O + H reactions. Formation of H2O from OH is efficient in the high-temperature regime found in shocks and the innermost part of protostellar envelopes. Moreover, in the presence of UV photons, OH can be produced from the photo-dissociation of H2O through H2O + γUV OH + H. Methods. High-resolution spectroscopy of the 163.12 μm triplet of OH towards HH 46 and NGC 1333 IRAS 2A was carried out with the Heterodyne Instrument for the Far Infrared (HIFI) on board the Herschel Space Observatory. The low- and intermediate-mass protostars HH 46, TMR 1, IRAS 15398-3359, DK Cha, NGC 7129 FIRS 2, and NGC 1333 IRAS 2A were observed with the Photodetector Array Camera and Spectrometer (PACS) on Herschel in four transitions of OH and two [O i] lines. Results. The OH transitions at 79, 84, 119, and 163 μm and [O i] emission at 63 and 145μm were detected with PACS towards the class I low-mass YSOs as well as the intermediate-mass and class I Herbig Ae sources. No OH emission was detected from the class 0 YSO NGC 1333 IRAS 2A, though the 119 μm was detected in absorption. With HIFI, the 163.12 μm was not detected from HH 46 and only tentatively detected from NGC 1333 IRAS 2A. The combination of the PACS and HIFI results for HH 46 constrains the line width (FWHM 11 km s-1) and indicates that the OH emission likely originates from shocked gas. This scenario is supported by trends of the OH flux increasing with the [O i] flux and the bolometric luminosity, as found in our sample. Similar OH line ratios for most sources suggest that OH has comparable excitation temperatures despite the different physical properties of the sources. |
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Notes | Approved | no | |||
Call Number | Serial | 1103 | |||
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Author | Vystavkin, A. N. | ||||
Title | Estimation of noise equivalent power and design analysis of an andreev reflection hot-electron microbolometer for submillimeter radioastronomy | Type | Journal Article | ||
Year | 1999 | Publication | Rus. J. Radio Electron. | Abbreviated Journal | Rus. J. Radio Electron. |
Volume | Issue | 10 | Pages | ||
Keywords | HEB, detector, bolometer | ||||
Abstract | Results of theoretical estimations and measurements of characteristics of an Andreev reflection hot-electron microbolometer for submillimeter radioastronomy made by different researchers are reviewed and analysed. Peculiarities and characteristics of the microbolometers using two types of microthermometer for measurement of the electron temperature increment under influence of the radiation: the SIN-junction and the transition-edge sensor (TES) with electrothermal feedback – are compared. Advantages of the microbolometer with the second type of the microthermometer when the TES is used simultaneously as the absorber of radiation are shown. Methods of achievement of the best noise equivalent power of the microbolometer in such version as well as methods of the matching the microbolometer with the incident radiation flow using planar antennas and with the channel of output signal measurement using a SQUID-picoammeter are considered. | ||||
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Call Number | Serial | 496 | |||
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Author | Voronov, B. M.; Gershenzon, E. M.; Gol'tsman, G. N.; Gogidze, I. G.; Gusev, Yu. P.; Zorin, M. A.; Sejdman, L. A.; Semenov, A. D. | ||||
Title | Picosecond range detector base on superconducting niobium nitride film sensitive to radiation in spectral range from millimeter waves up to visible light | Type | Journal Article | ||
Year | 1992 | Publication | Sverkhprovodimost': Fizika, Khimiya, Tekhnika | Abbreviated Journal | Sverkhprovodimost': Fizika, Khimiya, Tekhnika |
Volume | 5 | Issue | 5 | Pages | 955-960 |
Keywords | NbN HEB detectors | ||||
Abstract | Fast-operating picosecond detector of electromagnetical radiation is developed on the basis of fine superconducting film of niobium nitride with high sensitivity within spectral range from millimetric waves up to visible light. Detector sensitive element represents structure covering narrow parallel strips with micron sizes included in the rupture of microstrip line. Detecting ability of the detector and time constant measured using amplitude-simulated radiation of reverse wave tubes and pulse radiation of picosecond gas and solid-body lasers, constitute D*≅1010 W-1·cm·Hz-1/2 and τ≤5 ps respectively, at 10 K temperature. The expected value of time constant of the detector at 10 K obtained via extrapolation of directly measured dependence that is, τ ∝ τ-1, constitutes 20 ps. Experimental data demonstrate that detection mechanism is linked with electron heating effect. | ||||
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Language | Russian | Summary Language | Original Title | ||
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ISSN | 0131-5366 | ISBN | Medium | ||
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Notes | Approved | no | |||
Call Number | Serial | 1670 | |||
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Author | Verevkin, A. A.; Ptitsina, N. G.; Smirnov, K. V.; Gol'tsman, G. N.; Voronov, B. M.; Gershenzon, E. M.; Yngvesson, K. S. | ||||
Title | Hot electron bolometer detectors and mixers based on a superconducting-two-dimensional electron gas-superconductor structure | Type | Conference Article | ||
Year | 1997 | Publication | Proc. 4-th Int. Semicond. Device Research Symp. | Abbreviated Journal | Proc. 4-th Int. Semicond. Device Research Symp. |
Volume | Issue | Pages | 163-166 | ||
Keywords | S-2DEG-S HEB mixers, detectors, AlGaAs/GaAs heterostructures, NbN | ||||
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Call Number | Serial | 1603 | |||
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Author | Vercruyssen, N.; Verhagen, T. G. A.; Flokstra, M. G.; Pekola, J. P.; Klapwijk, T. M. | ||||
Title | Evanescent states and nonequilibrium in driven superconducting nanowires | Type | Journal Article | ||
Year | 2012 | Publication | Phys. Rev. B | Abbreviated Journal | Phys. Rev. B |
Volume | 85 | Issue | Pages | 224503(1-10) | |
Keywords | Al HEB, Al superconducting nanowire, global state, bimodal state, quasiclassical kinetic equations, Usadel equation | ||||
Abstract | We study the nonlinear response of current transport in a superconducting diffusive nanowire between normal reservoirs. We demonstrate theoretically and experimentally the existence of two different superconducting states appearing when the wire is driven out of equilibrium by an applied bias, called the global and bimodal superconducting states. The different states are identified by using two-probe measurements of the wire, and measurements of the local density of states with tunneling probes. The analysis is performed within the framework of the quasiclassical kinetic equations for diffusive superconductors. | ||||
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Call Number | Serial | 898 | |||
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Author | Velusamy, T.; Langer, W. D.; Pineda, J. L.; Goldsmith, P. F.; Li, D.; Yorke, H. W. | ||||
Title | [CII] observations of H2 molecular layers in transition clouds | Type | Journal Article | ||
Year | 2010 | Publication | Astron. Astrophys. | Abbreviated Journal | |
Volume | 521 | Issue | Pages | L18 | |
Keywords | HEB mixer applications, HIFI, Herschel, ISM: structure / ISM: molecules / ISM: atoms / submillimeter: ISM | ||||
Abstract | We present the first results on the diffuse transition clouds observed in [CII] line emission at 158 μm (1.9 THz) towards Galactic longitudes near 340° (5 LOSs) & 20° (11 LOSs) as part of the HIFI tests and GOT C+ survey. Out of the total 146 [CII] velocity components detected by profile fitting we identify 53 as diffuse molecular clouds with associated 12CO emission but without 13CO emission and characterized by AV < 5 mag. We estimate the fraction of the [CII] emission in the diffuse HI layer in each cloud and then determine the [CII] emitted from the molecular layers in the cloud. We show that the excess [CII] intensities detected in a few clouds is indicative of a thick H2 layer around the CO core. The wide range of clouds in our sample with thin to thick H2 layers suggests that these are at various evolutionary states characterized by the formation of H2 and CO layers from HI and C+, respectively. In about 30% of the clouds the H2 column densities (“dark gasâ€) traced by the [CII] is 50% or more than that traced by 12CO emission. On the average ~25% of the total H2 in these clouds is in an H2 layer which is not traced by CO. We use the HI, [CII], and 12CO intensities in each cloud along with simple chemical models to obtain constraints on the FUV fields and cosmic ray ionization rates. | ||||
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Notes | Approved | no | |||
Call Number | Serial | 1102 | |||
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Author | Vakhtomin, Y. B.; Finkel, M. I.; Antipov, S. V.; Smirnov, K. V.; Kaurova, N. S.; Drakinskii, V. N.; Voronov, B. M.; Gol’tsman, G. N. | ||||
Title | The gain bandwidth of mixers based on the electron heating effect in an ultrathin NbN film on a Si substrate with a buffer MgO layer | Type | Journal Article | ||
Year | 2003 | Publication | J. of communications technol. & electronics | Abbreviated Journal | J. of communications technol. & electronics |
Volume | 48 | Issue | 6 | Pages | 671-675 |
Keywords | NbN HEB mixers | ||||
Abstract | Measurements of the intermediate frequency band 900 GHz of mixers based on the electron heating effect (EHE) in 2-nm- and 3.5-nm-thick superconducting NbN films sputtered on MgO and Si substrates with buffer MgO layers are presented. A 2-nm-thick superconducting NbN film with a critical temperature of 9.2 K has been obtained for the first time using a buffer MgO layer. | ||||
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Publisher | MAIK Nauka/Interperiodica, Birmingham, AL | Place of Publication | Editor | ||
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ISSN | 1064-2269 | ISBN | Medium | ||
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Notes | https://elibrary.ru/item.asp?id=17302119 (Полоса преобразования смесителей на эффекте разогрева электронов в ультратонких пленках NbN на подложках из Si с подслоем MgO) | Approved | no | ||
Call Number | Vakhtomin2003 | Serial | 1522 | ||
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Author | Vahtomin, Yuriy B.; Finkel, Matvey I.; Antipov, Sergey V.; Voronov, Boris M.; Smirnov, Konstantin V.; Kaurova, Natalia S.; Drakinski, Vladimir N.; Gol'tsman, Gregogy N. | ||||
Title | Gain bandwidth of phonon-cooled HEB mixer made of NbN thin film with MgO buffer layer on Si | Type | Conference Article | ||
Year | 2002 | Publication | Proc. 13th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 13th Int. Symp. Space Terahertz Technol. |
Volume | Issue | Pages | 259-270 | ||
Keywords | NbN HEB mixers, conversion gain bandwidth | ||||
Abstract | We present recently obtained values for gain bandwidth of NbN HEB mixers for different substrates and film thicknesses and for MgO buffer layer on Si at LO frequency of 0.85-1 THz. The maximal bandwidth, 5.2 GHz, was achieved for the device on MgO buffer layer on Si with a 2 nm thick NbN film. Functional devices based on NbN films of such thickness were fabricated for the first time due to an improvement of superconducting properties of NbN film deposited on MgO buffer layer on Si substrate. | ||||
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Publisher | Place of Publication | Cambridge, MA, USA | Editor | Harvard university | |
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Call Number | Serial | 325 | |||
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Author | Vachtomin, Y. B.; Antipov, S. V.; Maslennikov, S. N.; Smirnov, K. V.; Polyakov, S. L.; Zhang, W.; Svechnikov, S. I.; Kaurova, N. S.; Grishina, E. V.; Voronov, B. M.; Gol’tsman, G. N. | ||||
Title | Quasioptical hot electron bolometer mixers based on thin NBN films for terahertz region | Type | Conference Article | ||
Year | 2006 | Publication | Proc. 16th Int. Crimean Microwave and Telecommunication Technology | Abbreviated Journal | Proc. 16th Int. Crimean Microwave and Telecommunication Technology |
Volume | 2 | Issue | Pages | 688-689 | |
Keywords | NbN HEB mixers | ||||
Abstract | Presented in this paper are the performances of HEB mixers based on 2-3.5 nm thick NbN films integrated with log-periodic spiral antenna. Double side-band receiver noise temperature values are 1300 K and 3100 K at 2.5 THz and at 3.8 THz, respectively. Mixer gain bandwidth is 5.2 GHz. Local oscillator power is 1-3 muW for mixers with different active area | ||||
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Language | Russian | Summary Language | Original Title | ||
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Call Number | Serial | 1445 | |||
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Author | Vachtomin, Y. B.; Antipov, S. V.; Maslennikov, S. N.; Smirnov, K. V.; Polyakov, S. L.; Kaurova, N. S.; Grishina, E. V.; Voronov, B. M.; Gol'tsman, G. N. | ||||
Title | Noise temperature measurements of NbN phonon-cooled hot electron bolometer mixer at 2.5 and 3.8 THz | Type | Conference Article | ||
Year | 2004 | Publication | Proc. 15th Int. Symp. Space Terahertz Technol. | Abbreviated Journal | Proc. 15th Int. Symp. Space Terahertz Technol. |
Volume | Issue | Pages | 236-241 | ||
Keywords | HEB mixer, NbN, direct detection effect | ||||
Abstract | We present the results of noise temperature measurements of NbN phonon-cooled HEB mixers based on a 3.5 nm NbN film deposited on a high-resistivity Si substrate with a 200 nm – thick MgO buffer layer. The mixer element was integrated with a log-periodic spiral antenna. The noise temperature measurements were performed at 2.5 THz and at 3.8 THz local oscillator frequencies for the 3 µm x 0.2 µm active area devices. The best uncorrected receiver noise temperatures found for these frequencies are 1300 K and 3100 K, respectively. A water vapour discharge laser was used as the LO source. We also present the results of direct detection contribution to the measured Y-factor and of a possible error of noise temperature calculation. This error was more than 8% for the mixer with in-plane dimensions of 2.4 x 0.16 µm 2 at the optimal noise temperature point. The use of a mesh filter enabled us to avoid the effect of direct detection and decrease optical losses by 0.5 dB. The paper is concluded by the investigation results of the mixer polarization response. It was shown that the polarization can differ from the circular one at 3.8 THz by more than 2 dB. | ||||
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Publisher | Place of Publication | Northampton, Massachusetts, USA | Editor | ||
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Call Number | Serial | 344 | |||
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