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| Author | Pentin, I. V.; Smirnov, A. V.; Ryabchun, S. A.; Ozhegov, R. V.; Gol’tsman, G. N.; Vaks, V. L.; Pripolzin, S. I.; Pavel’ev, D. G.; Koshurinov, Y. I.; Ivanov, A. S. | ||||
| Title | Semiconducting superlattice as a solid-state terahertz local oscillator for NbN hot-electron bolometer mixers | Type | Journal Article | ||
| Year | 2012 | Publication | Tech. Phys. | Abbreviated Journal | Tech. Phys. |
| Volume | 57 | Issue | 7 | Pages | 971-974 |
| Keywords | semiconducting superlattice frequency multiplier, NbN HEB mixers | ||||
| Abstract | We present the results of our studies of the semiconducting superlattice (SSL) frequency multiplier and its application as part of the solid state local oscillator (LO) in the terahertz heterodyne receiver based on a NbN hot-electron bolometer (HEB) mixer. We show that the SSL output power level increases as the ambient temperature is lowered to 4.2 K, the standard HEB operation temperature. | ||||
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| Language | Summary Language | Original Title | |||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1063-7842 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
Call Number  |
Serial | 1378 | |||
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| Author | Ozhegov, R. V.; Gorshkov, K. N.; Okunev, O. V.; Gol’tsman, G. N. | ||||
| Title | Superconducting hot-electron bolometer mixer as element of thermal imager matrix | Type | Journal Article | ||
| Year | 2010 | Publication | Tech. Phys. Lett. | Abbreviated Journal | Tech. Phys. Lett. |
| Volume | 36 | Issue | 11 | Pages | 1006-1008 |
| Keywords | HEB mixers | ||||
| Abstract | The possibility of using a matrix of sensitive elements on a 12-mm-diameter hyperhemispherical lens in a thermal imager operating in the terahertz range has been studied. Dimensions of a lens region acceptable for arrangement of the matrix, in which the receiver noise temperature varies within 16% of the mean value, are determined to be 3.3% of the lens diameter. Deviations of the main lobe of the directivity pattern are evaluated, which amount to ±1.25° relative to the direction toward the optimum position of a mixer. The fluctuation sensitivity of the receiver measured in experiment is 0.5 K at a frequency of 300 GHz. | ||||
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| ISSN | 1063-7850 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number |
Serial | 1390 | |||
| Permanent link to this record | |||||
| Author | Cherednichenko, S.; Yagoubov, P.; Il'in, K.; Gol'tsman, G.; Gershenzon, E. | ||||
| Title | Large bandwidth of NbN phonon-cooled hot-electron bolometer mixers | Type | Conference Article | ||
| Year | 1997 | Publication | Proc. 27th Eur. Microwave Conf. | Abbreviated Journal | |
| Volume | 2 | Issue | Pages | 972-977 | |
| Keywords | HEB mixer, fabrication process | ||||
| Abstract | The bandwidth of NbN phonon-cooled hot electron bolometer mixers has been systematically investigated with respect to the film thickness and film quality variation. The films, 2.5 to 10 nm thick, were fabricated on sapphire substrates using DC reactive magnetron sputtering. All devices consisted of several parallel strips, each 1 um wide and 2 um long, placed between Ti-Au contact pads. To measure the gain bandwidth we used two identical BWOs operating in the 120-140 GHz frequency range, one functioning as a local oscillator and the other as a signal source. The majority of the measurements were made at an ambient temperature of 4.2 K with optimal LO and DC bias. The maximum 3 dB bandwidth (about 4 GHz) was achieved for the devices made of films which were 2.5-3.5 nm thick, had a high critical temperature, and high critical current density. A theoretical analysis of bandwidth for these mixers based on the two-temperature model gives a good description of the experimental results if one assumes that the electron temperature is equal to the critical temperature. | ||||
| Address | Jerusalem, Israel | ||||
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| Publisher | IEEE | Place of Publication | Editor | ||
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| ISSN | ISBN | Medium | |||
| Area | Expedition | Conference | 27th Eur. Microwave Conf. | ||
| Notes | Approved | no | |||
| Call Number |
Serial | 1075 | |||
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| Author | Benz, A. O.; Bruderer, S.; van Dishoeck, E. F.; Stäuber, P.; Wampfler, S. F.; Melchior, M.; Dedes, C.; Wyrowski, F.; Doty, S. D.; van der Tak, F.; Bächtold, W.; Csillaghy, A.; Megej, A.; Monstein, C.; Soldati, M.; Bachiller, R.; Baudry, A.; 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.; Dieleman, P.; Dominik, C.; Encrenaz, P.; Fich, M.; Fuente, A.; Giannini, T.; Goicoechea, J. R.; de Graauw, Th.; Helmich, F.; Herczeg, G. J.; Herpin, F.; Hogerheijde, M. R.; Jacq, T.; Jellema, W.; Johnstone, D.; Jørgensen, J. K.; Kristensen, L. E.; Larsson, B.; Lis, D.; Liseau, R.; Marseille, M.; McCoey, C.; Melnick, G.; Neufeld, D.; Nisini, B.; Olberg, M.; Ossenkopf, V.; Parise, B.; Pearson, J. C.; Plume, R.; Risacher, C.; Santiago-García, J.; Saraceno, P.; Schieder, R.; Shipman, R.; Stutzki, J.; Tafalla, M.; Tielens, A. G. G. M.; van Kempen, T. A.; Visser, R.; Yıldız, U. A. | ||||
| Title | Hydrides in young stellar objects: Radiation tracers in a protostar-disk-outflow system | Type | Journal Article | ||
| Year | 2010 | Publication | Astron. Astrophys. | Abbreviated Journal | |
| Volume | 521 | Issue | Pages | L35 (1 to 5) | |
| Keywords | HEB mixer applications, HIFI, Herschel | ||||
| Abstract | Context. Hydrides of the most abundant heavier elements are fundamental molecules in cosmic chemistry. Some of them trace gas irradiated by UV or X-rays. Aims. We explore the abundances of major hydrides in W3 IRS5, a prototypical region of high-mass star formation. Methods. W3 IRS5 was observed by HIFI on the Herschel Space Observatory with deep integration (2500 s) in 8 spectral regions. Results. The target lines including CH, NH, H3O+, and the new molecules SH+, H2O+, and OH+ are detected. The H2O+ and OH+ J = 1–0 lines are found mostly in absorption, but also appear to exhibit weak emission (P-Cyg-like). Emission requires high density, thus originates most likely near the protostar. This is corroborated by the absence of line shifts relative to the young stellar object (YSO). In addition, H2O+ and OH+ also contain strong absorption components at a velocity shifted relative to W3 IRS5, which are attributed to foreground clouds. Conclusions. The molecular column densities derived from observations correlate well with the predictions of a model that assumes the main emission region is in outflow walls, heated and irradiated by protostellar UV radiation. |
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| Notes | Approved | no | |||
| Call Number |
Serial | 1082 | |||
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| Author | Bujarrabal, V.; Alcolea, J.; Soria-Ruiz, R.; Planesas, P.; Teyssier, D.; Marston, A. P.; Cernicharo, J.; Decin, L.; Dominik, C.; Justtanont, K.; de Koter, A.; Melnick, G.; Menten, K. M.; Neufeld, D. A.; Olofsson, H.; Schmidt, M.; Schöier, F. L.; Szczerba, R.; Waters, L. B. F. M.; Quintana-Lacaci, G.; Güsten, R.; Gallego, J. D.; Díez-González, M. C.; Barcia, A.; López-Fernández, I.; Wildeman, K.; Tielens, A. G. G. M.; Jacobs, K. | ||||
| Title | Herschel/HIFI observations of high-J CO transitions in the protoplanetary nebula CRL 618 | Type | Journal Article | ||
| Year | 2010 | Publication | Astron. Astrophys. | Abbreviated Journal | |
| Volume | 521 | Issue | Pages | L3 (1 to 5) | |
| Keywords | HEB mixer applications, HIFI, Herschel | ||||
| Abstract | Aims. We aim to study the physical conditions, particularly the excitation state, of the intermediate-temperature gas components in the protoplanetary nebula CRL 618. These components are particularly important for understanding the evolution of the nebula. Methods. We performed Herschel/HIFI observations of several CO lines in the far-infrared/sub-mm in the protoplanetary nebula CRL 618. The high spectral resolution provided by HIFI allows measurement of the line profiles. Since the dynamics and structure of the nebula is well known from mm-wave interferometric maps, it is possible to identify the contributions of the different nebular components (fast bipolar outflows, double shells, compact slow shell) to the line profiles. The observation of these relatively high-energy transitions allows an accurate study of the excitation conditions in these components, particularly in the warm ones, which cannot be properly studied from the low-energy lines. Results. The 12CO J = 16–15, 10–9, and 6–5 lines are easily detected in this source. Both 13CO J = 10–9 and 6–5 are also detected. Wide profiles showing spectacular line wings have been found, particularly in 12CO J = 16–15. Other lines observed simultaneously with CO are also shown. Our analysis of the CO high-J transitions, when compared with the existing models, confirms the very low expansion velocity of the central, dense component, which probably indicates that the shells ejected during the last AGB phases were driven by radiation pressure under a regime of maximum transfer of momentum. No contribution of the diffuse halo found from mm-wave data is identified in our spectra, because of its low temperature. We find that the fast bipolar outflow is quite hot, much hotter than previously estimated; for instance, gas flowing at 100 km s-1 must have a temperature higher than ~200 K. Probably, this very fast outflow, with a kinematic age <100 yr, has been accelerated by a shock and has not yet cooled down. The double empty shell found from mm-wave mapping must also be relatively hot, in agreement with the previous estimate. |
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| Notes | Approved | no | |||
| Call Number |
Serial | 1084 | |||
| Permanent link to this record | |||||