| 1. |
- Bidgoli, Hosein, 1987, et al.
(författare)
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Terahertz Spectroscopy for Real-Time Monitoring of Water Vapor and CO Levels in the Producer Gas From an Industrial Biomass Gasifier
- 2014
-
Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 4:6, s. 722-733
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we present a study of THz transmission spectroscopy as a novel tool for the monitoring of the steam and CO contents of the raw gas from industrial biomass gasifiers. A THz gas spectrometer with a frequency range of 300–500 GHz was designed and constructed. Proof-of-principle testing was performed at laboratory conditions using mixtures of different gases at high temperatures (600–700 K). The results demonstrate the feasibility of applying strong rotational water vapor lines at 448 and 383 GHz, so as to obtain reliable online measurements of water vapor with an absolute precision of about 0.2 vol.% for the current device. CO lines were identified at 461 and 346 GHz, facilitating measurement of this gas. The gas spectrometer was integrated into an industrial gasifier and boiler, and its performance was tested in terms of online measurements of steam and CO in the hot raw gas and flue gases under real-life conditions. Considering the error intervals, the results are in complete agreement with data acquired by solving loose mass balances around the system. The onsite experiments demonstrate that THz gas spectroscopy is a promising tool for fast, robust, and reliable monitoring in industrial applications.
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| 2. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Online Detection of H2O and CO in the Humid Raw Gas from the Gasifier Using Terahertz Spectroscopy
- 2013
-
Ingår i: ICPS, 13 International Conference on Polygeneration Strategies, Sept.5-13, Vienna, Austria. - 9783950275483 ; , s. 51-58
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Konferensbidrag (refereegranskat)abstract
- The integration of a gasifier with a complex multistage synthesis process, such as SNG synthesis, demands a fast monitoring of the gasifier performance. However, despite the availability of standard analyzers for determination of dry gas composition, there are still many practical difficulties remaining in the online measurement of tar and steam in the raw gas. For the detection of steam concentration, electromagnetic waves at terahertz frequencies (102-104 GHz) are promising with regard to development of a robust online measurement device for industrial application. The main reason for the high potential is the low risk for interference with the wide range of other molecules and that the transmission of electromagnetic waves at THz frequencies is rather low sensitive to deposits and particulate matter in the course of the beam compared to the conventional and well established wavelengths like infrared. In the present work, a THz gas spectrometer was designed and constructed to check the feasibility of applying this measurement technique at industrial scale. For this purpose, continuous flows of raw gas with various water and CO contents from the Chalmers gasifier as well as a flue gas with known water content from the biomass combustor were introduced to the spectrometer set-up. H2O and CO compositions in each stream were determined in an online manner. The results confirmed the possibility of applying strong rotational water lines at 448 and 380 GHz to develop reliable devices for online measurement of water vapor with excellent error interval. However, some difficulties were encountered for simultaneous detection CO concentration with water within the frequency range studied in this work (300-500 GHz).
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| 3. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
-
Terahertz Gas Spectrometer
- 2014
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Ingår i: Swedish Microwave Days March 11-12, 2014, Gothenburg, Sweden.
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Konferensbidrag (refereegranskat)abstract
- We present a 300-500GHz gas spectrometer built for and practically tested at the 2–4-MW indirect gasifier at the Chalmers Power Center. The primary goal is precise online measurements of H2O vapor and CO concentrations in the producer gas. Experimentally obtained H2O vapor concentration resolution was about 1% at the conditions of 50% VMR and 400 deg.C.
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| 4. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Terahertz Spectroscopy Instrumentation for Thermal Bio-Mass Conversion
- 2016
-
Ingår i: Swedish Microwave Days March 15-16, 2016, Linköping, Sweden. ; , s. 53-
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Konferensbidrag (refereegranskat)abstract
- THz spectroscopy appears to be a valuable tool for gas sensing in “complicated” environments where conventional IR techniques may not be able to work: high dust and particleconcentrations. We also observe that existing spectral data basis and gas line models have to be updated for specific conditions in combustion and gasification processes.
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| 5. |
- Meledin, Denis, 1974, et al.
(författare)
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Balanced Waveguide HEB Mixer for APEX 1.3 THz Receiver
- 2006
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Ingår i: Proceedings of 16th International Symposium on Space Terahertz Technology, Chalmers University of Technology, Gothenburg, Sweden, May 2-4, 2005. - 1652-0769. ; , s. 214-216
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Abbasi, Morteza, 1982, et al.
(författare)
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Single-Chip 220-GHz Active Heterodyne Receiver and Transmitter MMICs With On-Chip Integrated Antenna
- 2011
-
Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 59:2, s. 466-478
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents the design and characterization of single-chip 220-GHz heterodyne receiver (RX) and transmitter (TX) monolithic microwave integrated circuits (MMICs) with integrated antennas fabricated in 0.1-mu m GaAs metamorphic high electron-mobility transistor technology. The MMIC receiver consists of a modified square-slot antenna, a three-stage low-noise amplifier, and a sub-harmonically pumped resistive mixer with on-chip local oscillator frequency multiplication chain. The transmitter chip is the dual of the receiver chip by inverting the direction of the RF amplifier. The chips are mounted on 5-mm silicon lenses in order to interface the antenna to the free space and are packaged into two separate modules. The double-sideband noise figure (NF) and conversion gain of the receiver module are measured with the Y-factor method. The total noise temperature of 1310 +/- 100K(corresponding to an NF of 7.4 dB), including the losses in the lens and antenna, is measured at 220 GHz with a respective conversion gain of 3.5 dB. The radiated continuous-wave power from the transmitter module is measured to be up to -6 dBm from 212 to 226 GHz. The transmitter and receiver are linked in a quasi-optical setup and the IF to IF response is measured to be flat up to 10 GHz. This is verified to be usable for transmission of a 12.5-Gb/s data stream between the transmit and receive modules over a 0.5-m wireless link. The modules operate with a 1.3-V supply and each consume 110-mW dc power. The presented 220-GHz integrated circuits and modules can be used in a variety of applications, including passive and active imaging, as well as high-speed data communications. To the best of our knowledge, these MMICs are the highest frequency single-chip low-noise heterodyne receiver and transmitter pair reported to date.
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| 7. |
- Acharya, Narendra, 1982, et al.
(författare)
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Analysis of the broad IF-band performance of MgB2 HEB mixers
- 2019
-
Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 9:6, s. 565-571
-
Tidskriftsartikel (refereegranskat)abstract
- We present an experimental study of gain and noise bandwidths in superconducting MgB2 hot-electron bolometer (HEB) terahertz mixers in a 0.1-20 GHz intermediate frequency (IF) range. At an elevated temperature and with a 90-GHz local oscillator (LO), we measure a gain bandwidth of 13-14 GHz, which is the first accurate data for ultrathin MgB2 films. The output noise spectrum has its maximum in the 100-200 K range, depending on the temperature (or the LO power) and the bias point, and its spectrum also confirms the gain bandwidth data obtained with the mixing experiment. Using both the gain and the output noise spectra, we obtain the mixer input noise temperature, which is nearly constant up to 20 GHz. Using the measured data and the HEB mixer theory, we argue that noise bandwidth in the current MgB2 HEB mixers is ∼30 GHz.
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| 8. |
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| 9. |
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| 10. |
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| 11. |
- Baubert, Jean, 1976, et al.
(författare)
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IF Gain Bandwidth of membrane-based NbN Hot Electron Bolometers for SHAHIRA
- 2005
-
Ingår i: IEEE Applied Superconductivity. ; 15:2, s. 505-510
-
Tidskriftsartikel (refereegranskat)abstract
- SHAHIRA (Submm Heterodyne Array for HIghspeedRadio Astronomy) is a project supported by the EuropeanSpace Agency (ESA) and is designed to fly on the SOFIA observatory.A quasi-optic design has been chosen for 2.5/2.7 THz and4.7 THz, for hydroxyde radical OH, deuterated hydrogen HD andneutral atomic oxygen OI lines observations. Hot electron bolometers(HEBs) have been processed on 1 um thick SiO2 Si3N4stress-less membranes. In this paper we analyse the intermediatefrequency (IF) gain bandwidth from the theoretical point of view,and compare it to measurements.
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| 12. |
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| 13. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
Characterisation and Modeling of MgB2 HEBs IF impedance
- 2016
-
Ingår i: Swedish Microwave Days March 15-16, 2016, Linköping, Sweden. ; , s. 55-
-
Konferensbidrag (refereegranskat)abstract
- Here we present the method which allows to measure quiteaccurately the HEB impedance employing just one cooling.By knowing the HEB IF impedance a coupling matchingnetwork can be designed for a possible packaged receiver.
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| 14. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
Fast room temperature THz bolometers
- 2013
-
Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035. - 9781467347174 ; , s. 1-2
-
Konferensbidrag (refereegranskat)abstract
- A responsivity of >100 V/W was measured at roomtemperature for nano scale bolometers integrated with planar spiral antennas covering a frequency range from 100 GHz to 3 THz. Currently a NEP of about 200 pW/Hz^0.5 was experimentally obtained.
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| 15. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
Fast room temperature THz microbolometers
- 2012
-
Ingår i: 23rd International Symposium on Space Terahertz Technology.
-
Konferensbidrag (refereegranskat)abstract
- We will present experimental and theoretical investigation of room temperature high speed THz detectors based on thin YBa2Cu3O7 films. These films have TCR of 0.35%/K, and can sustain large bias current densities. With a resistivity of 100-200 µOhm×cm for a film thickness of 50nm, it is very straightforward to impedance match such bolometers with planar antennas. The responsivity is a function of the bolometer planar dimensions and the films thickness. The currently achieved responsivity is 30 V/W and Johnson noise limited NEP is 70pW/Hz^0.5. The bolometer bandwidth is limited by the antenna bandwidth and spans from microwaves to over a few THz. Experimenatl investigation is done from 100GHz to 2.5THz. The measured response time is 2ns. We will also present results of the bolometer performance as their dimensions reduce to sub-µm.
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| 16. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
HEB mixers for THz radio astronomy
- 2014
-
Ingår i: Swedish Microwave Days March 11-12, 2014.
-
Konferensbidrag (refereegranskat)abstract
- Hot-Electron Bolometer (HEB) mixers made of 10 nm superconducting MgB2 films are discussed for high sensitivity high spectral resolution spectrometers for radio astronomy. The key advantage of the used MgB2 films is in achievement of wider Intermediate Frequency (IF) bandwidth.
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| 17. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
High Sensitivity Terahertz Bolometers as Room Temperature Detectors
- 2014
-
Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035. - 9781479938773 ; , s. Art. no. 6956197-
-
Konferensbidrag (refereegranskat)abstract
- High sensitivity room temperature THz direct detectors made of YBa2Cu3O7-x nano-bridges, with a broadband optical coupling (0.1-2THz) are presented. An optical responsivity (RV) up to 45 V/W was measured at 400 GHz. For bolometers with an electrical responsivity of 70 V/W a noise equivalent power (NEP) of 50 pW/Hz0.5 was experimental obtained.
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| 18. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
Investigation of MgB2 HEB mixer gain bandwidth
- 2011
-
Ingår i: International Conference on Infrared, Millimeter and Terahertz Waves (IRMMW-THz), 2011. - 2162-2027. - 9781457705083 ; , s. 1 - 2
-
Konferensbidrag (refereegranskat)abstract
- THz mixers based on superconducting MgB2 bolometers were fabricated by photolithography and Ar-ion beam milling on sapphire substrates. The mixer gain bandwidth of 3.4 GHz, 2.3 GHz and 1.3 GHz were measured for 10, 15 and 30 nm films respectively.
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| 19. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
Low noise MgB2 terahertz hot-electron bolometer mixers
- 2012
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 100:3
-
Tidskriftsartikel (refereegranskat)abstract
- We report on low noise terahertz bolometric mixers made of MgB2 superconducting thin films. For a 10-nm-thick MgB2 film, the lowest mixer noise temperature was 600 K at 600 GHz. For 30 to 10-nm-thick films, the mixer gain bandwidth is an inverse function of the film thickness, reaching 3.4 GHz for the 10-nm film. As the critical temperature of the film decreases, the gain bandwidth also decreases, indicating the importance of high quality thin films for large gain bandwidth mixers. The results indicate the prospect of achieving a mixer gain bandwidth as large as 10-8 GHz for 3 to 5-nm-thick MgB2 films.
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| 20. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
Low Noise Nanometer Scale Room-Temperature YBa2Cu3O7-x Bolometers for THz Direct Detection
- 2014
-
Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 4:6, s. 653- 660
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Tidskriftsartikel (refereegranskat)abstract
- We present a detailed investigation of the responsivity and the noise in room temperature THz direct detectors made of YBa2Cu3O7-x (YBCO) thin film nano bolometers. The YBCO nano bolometers are integrated with planar spiral antennas covering a frequency range from 100 GHz to 2 THz. The detectors were characterized at 1.6 THz, 0.7 THz, 400 GHz and 100 GHz. The maximum electrical responsivity of 70 V/W and a minimum noise equivalent power (NEP) of 50 pW/Hz0.5 were measured, whereas the highest optical responsivity was 45 V/W. The 1/f noise in nano bolometers is independent on the device volume and can be found as (VN/V)2=6×10-11×1/f Hz-1 for a given modulation frequency f and a dc voltage V.
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| 21. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
MgB2 Hot-Electron Bolometer Mixers at Terahertz Frequencies
- 2015
-
Ingår i: IEEE Transactions on Applied Superconductivity. - 1558-2515 .- 1051-8223. ; 25:3, s. 2301104-
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, we compare the performance of MgB2 Hot-Electron Bolometer Mixers operating at Local Oscillator frequencies of 0.6 and 1.63 THz. The minimum noise temperatures that were obtained are 700 and 1150 K for 0.6 and 1.63 THz, respectively. The receiver noise bandwidth is of the order of 2.2-3 GHz for 10-nm-thick HEB devices with a Tc of 8.5 K. Sub-micrometer size HEBs were also fabricated with no degradation of the initial film quality when a 20-nm MgB2 film with a Tc of 22 K was used. In the direct detection mode, the maximum voltage responsivity is in the range of 1-2 kV/W at 1.63 THz and the optimal bias current is around 1/4-1/3 of the Ic at 4.2 K.
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| 22. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
MgB2 Hot Electron Bolometers for THz radio astronomy
- 2012
-
Ingår i: 23rd International Symposium on Space Terahertz Technology.
-
Konferensbidrag (refereegranskat)abstract
- We discuss Hot Electron Bolometer (HEB) THz mixers made of superconducting Magnesium Diboride (MgB2) films. The films of 30 nm, 15 nm and 10 nm thick were deposited on sapphire substrates. The MgB2 HEBs were patterned as a bridge at the feed point of a spiral antenna. The performance of the devices was investigated with respect to the gain bandwidth (GBW) and the noise temperature. The GBW was measured via mixing two signal sources (BWOs at 600 GHz). For the given films thicknesses, the GBW was measured to be 1.3 GHz, 2.3 GHz and 3.4 GHz, which is larger than for the NbN HEB mixers made of the same films thicknesses. Using the Y-factor technique a noise temperature of 800 K at 600 GHz local oscillator (LO) frequency was measured for mixers made of 10 nm MgB2 film. Besides the films thickness, the gain and the noise bandwidths are functions of the films critical temperature, Tc. For 10nm films, with Tc=15K, a noise bandwidth on the order of 8GHz was measured. From these measurements and from the material parameters a GBWof 8 GHz (noise bandwidth >10GHz) is expected for 3-5 nm MgB2 films.
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| 23. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
Room Temperature THz Detectors with Fast Response Rate.
- 2014
-
Ingår i: Swedish Microwave Days March 11-12, 2014, Gothenburg, Sweden.
-
Konferensbidrag (refereegranskat)abstract
- We present high sensitivity room temperature THz direct detectors made of YBa2Cu3O7-x nano-bridges, with a broadband optical coupling (0.1-2THz). A responsivity (Rv) up to 100 V/W and a noise equivalent power (NEP) of 200 pW/Hz0.5 were measured for a device area of 0.15 μm2 -0.25 μm2.
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| 24. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
Study of IF bandwidth of MgB2 phonon-cooled hot-electron bolometer mixers
- 2013
-
Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 3:4, s. 409-415
-
Tidskriftsartikel (refereegranskat)abstract
- A noise bandwidth (NBW) of 6-7 GHz was obtained for Hot-Electron Bolometer (HEB) mixers made of 10 nm MgB2 films. A systematic investigation of the (IF) gain bandwidth as a function of the MgB2 film thickness (30 nm, 15 nm and 10 nm) is also presented. The gain bandwidth (GBW) of 3.4 GHz was measured for a 10 nm film, corresponding to a mixer time constant of 47 ps. For 10 nm films a reduction of the GBW was observed with the reduction of the critical temperature (Tc). Experimental data were analyzed using the two-temperature model. From the theoretical analysis, the electron-phonon time (τe-ph), the phonon escape time (τesc) and the electron and phonon specific heats (ce, cph) were extrapolated giving the first model for HEB mixers of MgB2 films.
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| 25. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
Submicrometer MgB2 hot electron bolometer mixers
- 2013
-
Ingår i: The 24th International Symposium on Space Terahertz Technology.
-
Konferensbidrag (refereegranskat)abstract
- Phonon-cooled hot electron bolometer mixers based on MgB2 film are promising candidates for THz radio astronomy at frequency above 1 THz. The short electron-phonon interaction time and the high critical temperature of the MgB2 (39 K in the bulk), compared to other intermetallic compounds, make it suitable for applications where wide IF bandwidth and low noise are needed. The currently achieved gain and noise bandwidths are 3.4 GHz and 7 GHz for HEBs fabricated in 10 nm MgB2 films. The noise temperature of 800 K was measured at 600 GHz local oscillator (LO) frequency using the Y-factor technique.MgB2 has been demonstrated to be sensitive to the oxygen as well as water, therefore it makes the fabrication of sub-µm HEBs very challenging. HEBs were fabricated using electron beam lithography in 10 nm MgB2 films with a bolometer area in the range of 0.09 and 0.25 µm2. We report the performance of the devices respect to the noise temperature at LO frequency up to 2.5 THz. Using the isothermal technique the LO power requirement was estimated respect to the bolometer area. Based on the material parameters obtained from the experiments, the two temperature model simulations showed a gain bandwidth as large as 8-10 GHz for thin MgB2 films.
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| 26. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
Wideband MgB2 Hot-Electron Bolometer Mixers: IF Impedance Characterisation and Modeling
- 2016
-
Ingår i: IEEE Transactions on Applied Superconductivity. - 1558-2515 .- 1051-8223. ; 26:3, s. 2300105-
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper we present a method for low signal S11 parameter vector measurements of a cryogenic device in the microwave frequency range. In particular, the intermediate frequency (IF) impedance of MgB2 Hot-electron Bolometer (HEB) mixers was investigated over a frequency range of 100 MHz to 10 GHz. A new cryogenic calibration technique, which employs the HEB as a calibration kitandrequires two consecutive thermal cycles, was developed for this purpose.The real part of measured IF impedance showed a strong correlationwith the differential resistance (dV/dI) obtained from the dc I-V curves while the imaginary partwas capacitive for almost the entire frequency range.
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| 27. |
- Bevilacqua, Stella, 1981, et al.
(författare)
-
YBCO Terahertz Detectors at Room Temperature and at 77K.
- 2014
-
Ingår i: 12th HTSHFF Workshop High Temperature Superconductors in High Frequency Fields, June 9-12, 2014, Fréjus, France.
-
Konferensbidrag (refereegranskat)abstract
- The diversity of THz detectors is as wide as the range of applications for THz waves. Requirements for the detectors vary and so do the detectors. Extremely high sensitivities (NEP 200V/W) for frequencies from 100GHz to 2THz and a drop of NEP to about 70 pW/Hz0.5. As the responsivity grows, the nano bolometers become more sensitive to the external electrical disturbances, as well as to the internal 1/f noise. We will discuss the noise properties of the YBCO nano bolometers, their optical characterization, as well as some of their application for the gas spectroscopy and prospects of the array integration.
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| 28. |
- Charaev, Ilya, et al.
(författare)
-
Single-photon detection using large-scale high-temperature MgB 2 sensors at 20 K
- 2024
-
Ingår i: Nature Communications. - 2041-1723 .- 2041-1723. ; 15:1
-
Tidskriftsartikel (refereegranskat)abstract
- Ultra-fast single-photon detectors with high current density and operating temperature can benefit space and ground applications, including quantum optical communication systems, lightweight cryogenics for space crafts, and medical use. Here we demonstrate magnesium diboride (MgB2) thin-film superconducting microwires capable of single-photon detection at 1.55 μm optical wavelength. We used helium ions to alter the properties of MgB2, resulting in microwire-based detectors exhibiting single-photon sensitivity across a broad temperature range of up to 20 K, and detection efficiency saturation for 1 μm wide microwires at 3.7 K. Linearity of detection rate vs incident power was preserved up to at least 100 Mcps. Despite the large active area of up to 400 × 400 μm2, the reset time was found to be as low as ~ 1 ns. Our research provides possibilities for breaking the operating temperature limit and maximum single-pixel count rate, expanding the detector area, and raises inquiries about the fundamental mechanisms of single-photon detection in high-critical-temperature superconductors.
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| 29. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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16 Pixel HEB Heterodyne Receiver for 2.5 THz
- 2006
-
Ingår i: in Proc.17th Intern. Symp. Space THz Technology, Paris, France, May. 2006..
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A 16 pixel heterodyne receiver for 2.5 THz has been developed based on NbN superconducting hot-electron bolometer (HEB) mixers. The receiver uses a quasioptical RF coupling approach where HEB mixers are integrated into double dipole antennas on 1.5m thick Si3N4/ SiO2 membranes. Spherical mirrors (one per pixel) and backshort distance from the antenna have been used to design the output mixer beam profile. We present here the results of the antenna simulations using HFSS and ADS, as well as the beam calculations after the collimating mirror.
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| 30. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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2.5THz multipixel heterodyne receiver based on NbN HEB mixers
- 2006
-
Ingår i: Proc.SPIE. - 081946340X ; 6275, s. 62750I-1
-
Tidskriftsartikel (refereegranskat)abstract
- A 16 pixel heterodyne receiver for 2.5 THz has been developed based on NbN superconducting hot-electron bolometer (HEB) mixers. The receiver uses a quasioptical RF coupling approach where HEB mixers are integrated into double dipole antennas on 1.5m thick Si3N4/ SiO2 membranes. Spherical mirrors (one per pixel) and backshort distance from the antenna have been used to design the output mixer beam profile. The camera design allows all 16 pixel IF readout in parallel. The gain bandwidth of the HEB mixers on Si3N4/ SiO2 membranes was found to be 0.70.9 GHz, which is much smaller than for similar devices on silicon. Application of buffer layers and use of alternative types of membranes (e.g. silicon-on-insulator) is under investigation.
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| 31. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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A room temperature bolometer for terahertz coherent and incoherent detection
- 2011
-
Ingår i: IEEE Transactions on Terahertz Science and Technology. - 2156-342X .- 2156-3446. ; 1:2, s. 395 - 402
-
Tidskriftsartikel (refereegranskat)abstract
- We present a novel room temperature bolometer with nanosecond response that can be used both for coherent and incoherent detection through the entire terahertz frequency range. A responsivity of up to 15 V/W, and a noise equivalent power (NEP) = 450 pW/Hz0.5 were measured at modulation frequencies from 0.5 kHz to 100 kHz. A conversion gain of -28 dB was demonstrated at an intermediate frequency of 20 MHz with a Local Oscillator power of 0.74 mW. Possible improvements of the bolometer characteristics are discussed.
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| 32. |
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| 33. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Gain bandwidth of NbN hot-electron bolometer terahertz mixers on 1.5 um Si3N4 /SiO2 membranes
- 2007
-
Ingår i: Journal of Applied Physics. ; 101:12, s. 124508-1-(6)-
-
Tidskriftsartikel (refereegranskat)abstract
- The gain bandwidth of NbN hot-electron bolometer terahertz mixers on electrically thin Si3N4 /SiO2 membranes was experimentally investigated and compared with that of HEB mixers on bulk substrates. A gain bandwidth of 3.5 GHz is achieved on bulk silicon, whereas the gain bandwidth is reduced down to 0.6–0.9 GHz for mixers on 1.5 um Si3 N4 /SiO2 membranes. We show that application of a MgO buffer layer on the membrane extends the gain bandwidth to 3 GHz. The experimental data were analyzed using the film-substrate acoustic mismatch approach.
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| 34. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
-
Hot-electron bolometer terahertz mixers for the Herschel Space Observatory
- 2008
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 79:034501, s. 034501-1 to 034501-10-
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Tidskriftsartikel (refereegranskat)abstract
- We report on low noise terahertz mixers (1.4–1.9 THz) developed for the heterodyne spectrometer onboard the Herschel Space Observatory. The mixers employ double slot antenna integrated superconducting hot-electron bolometers (HEBs) made of thin NbN films. The mixer performancewas characterized in terms of detection sensitivity across the entire rf band by using a Fourier transform spectrometer (from 0.5 to 2.5 THz, with 30 GHz resolution) and also by measuring the mixer noise temperature at a limited number of discrete frequencies. The lowest mixer noise temperature recorded was 750 K (double sideband (DSB)) at 1.6 THz and 950 K DSB at 1.9 THz local oscillator (LO) frequencies. Averaged across the intermediate frequency band of 2.4–4.8 GHz,the mixer noise temperature was 1100 K DSB at 1.6 THz and 1450 K DSB at 1.9 THz LO frequencies. The HEB heterodyne receiver stability has been analyzed and compared to the HEBstability in the direct detection mode. The optimal local oscillator power was determined and found to be in a 200–500 nW range.
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| 35. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Low kinetic inductance superconducting MgB2 nanowires with a 130-picosecond relaxation time for single-photon detection applications
- 2021
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Ingår i: Superconductor Science and Technology. - : IOP Publishing. - 0953-2048 .- 1361-6668. ; 34:4
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Tidskriftsartikel (refereegranskat)abstract
- Properties of superconducting nanowires set the performance level for Superconducting Nanowire Single Photon Detectors (SNSPD). Reset time in commonly employed large area SNSPDs, 1-10ns, is known to be limited by the nanowire's kinetic inductance to the load impedance ratio. On the other hand, reduction of the kinetic inductance in small area (waveguide integrated) SNSPDs prevents biasing them close to the critical current due to latching into a permanent resistive state. In order to reduce the reset time in SNSPDs, superconducting nanowires with both low kinetic inductance and fast electron energy relaxation are required. In this paper, we report on a study of kinetic inductance in narrow (15-100nm) and long (up to 120m) superconducting MgB2 nanowires made from 5 nm-thick films, offering such combination of properties. Such films were grown using Hybrid Physical Chemical Vapor Deposition, resulting in a critical temperature of 32K, and a switch current density of 5107A/cm2 (at 4.8K). Using microwave reflectometry, we measured a kinetic inductance of Lk0(4.8K)=1.3-1.6 pH/ regardless of the nanowire width, which results in a magnetic field penetration depth of 90 nm. These values are very close to those in pristine MgB2. We showed that after excitations by a 50 fs pulsed laser the reset time in 35nm120m MgB2 nanowires is 130 ps, which is more than a factor of 10 shorter than in NbN nanowires of similar length-to-width ratios. Depending on the bias current, such MgB2 nanowires function as single-, double , or triple- photon detectors for both visible (= 630 nm) and infrared (= 1550 nm) photons, with a dark count rate of <10 cps. Although the apparent photon detection efficiency seems so far to be low, further technological advances (uniform nanowire width, smaller thickness, increasing the switching current closer to the pair-breaking current) may improve this figure of merit.
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| 36. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Low noise hot-electron bolometer mixers for terahertz frequencies
- 2007
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Ingår i: Journal of Low Temperature Physics. - : Springer Science and Business Media LLC. - 0022-2291 .- 1573-7357. ; 151:1-2, s. 575-579
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Konferensbidrag (refereegranskat)abstract
- Hot-electron bolometer (HEB) mixers are used in many low noise heterodyne radio astronomical receivers. Their noise temperature is at the level of 10-15 times the quantum limit. However, their gain bandwidth is a serious limiting factor. Here we review the state of the art of the HEB mixers gain bandwidth for different materials and substrates. We compare the gain bandwidth of HEB mixers made on bulk substrates and thin membranes. Finally, results for MgB2 thin films for broadband HEB mixers are discussed.
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| 37. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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MgB2 thin film terahertz mixers
- 2006
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Ingår i: in Proc.17th Intern. Symp. Space THz Technology, Paris, France, May. 2006.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Thin film (20 nm) MgB2 bolometric devices were made on silicon substrates. The performance of the devices as THz mixers was investigated with respect to the gain bandwidth and the noise temperature. For the given film thickness the 3 dB gain roll-off frequency is 2.5 GHz, which is much higher than for the NbN HEB mixers of the same thickness. Corrected DSB mixer noise temperature is 2000 K at 2 GHz IF. The noise bandwidth was measured in the IF range of 2-5 GHz.
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| 38. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Online water vapor detection in the product gas from indirect gasification
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The integration of a gasifier into a complex synthesis process, such like SNG synthesis,with several process steps asks for a better monitoring of the gasifier performance.While the dry gas composition is often known, tar concentration andsteam concentration in the raw producer gas are usually not available online. A setof standard analyzers for dry gas composition (GC or NDIR) and online tar measurementcombined with an online water measurement could allow the continuouscalculation of simple mass and energy balances. Those balances, that characterizethe gasification process, could enable the operator to monitor the effects ofvarying fuel properties and eventually counter the effects on the downstreamequipment.For the detection of steam concentration in raw gas electromagnetic waves ofterahertz frequencies (hundreds of gigahertz) are promising with regard to developa robust online measurement device for industrial application. Main reasons for thehigh potential are the low risk for interference with the wide range of other moleculesand the fact that THz frequencies are rather insensitive to deposits and particulatematter in the course of the beam, compared to laser technology at IR.Aiming to test the feasibility of applying this measurement technique in the industrialscale, a gas cell was designed and constructed providing conditions close tothe onsite operation (i.e. T, P, gas composition, etc.) for primary laboratory tests.The experiments were then followed with onsite tests at Chalmers power central.Within those experiments the application of THz spectroscopy as a promisingtechnique for detection and measurement of steam and CO at real industrial processeswas proven. Current report demonstrates the procedure of implementing aTHz spectrometer to acquire data in both laboratory and industrial scale and discusshow those data could be interpreted to gain a precise measurement of desiredgaseous components.
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| 39. |
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| 40. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Study of MgB2 HEB mixers vs the LO frequency and the bath temperature
- 2015
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Ingår i: 26th International Symposium on Space Terahertz Technology March 16-18, 2015, Cambridge, United States. ; , s. M2-1
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Konferensbidrag (refereegranskat)abstract
- We investigate the noise and the gain of MgB2 Hot-Electron Bolometer (HEB) mixers at 1.63THz LO. The critical temperature of the HEB was 22K and the film thickness was 20nm. At 4.2K and 12K bath temperatures the lowest obtained receiver noise temperatures are 1700K and 2100K,respectively, with a noise bandwidth of about 4.6GHz. The gain bandwidth is about 3GHz in both cases.
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| 41. |
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| 42. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Terahertz mixing in MgB2 microbolometers
- 2007
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 90:2
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Tidskriftsartikel (refereegranskat)abstract
- Authors report on a terahertz (600 GHz) mixing experiment with MgB2 microbolometers in the resistive state. We observed that for a 20 nm film a mixer gain bandwidth of 2.3 GHz can be achieved, corresponding to an energy relaxation time of 70 ps. The experimental results were analyzed using a two-temperature model. As a result, the phonon escape time 20 ps was deduced. At 1.6THz the MgB2 mixer uncorrected noise temperature was 11000K. The obtained results show that MgB2 bolometers are good prospects for the terahertz range as both broadband mixers and fast direct detectors.
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| 43. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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The Direct Detection Effect in the Hot-Electron Bolometer Mixer Sensitivity Calibration
- 2007
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Ingår i: IEEE Transactions on Microwave Theory and Techniques. - 0018-9480 .- 1557-9670. ; 55:3, s. 504-510
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Tidskriftsartikel (refereegranskat)abstract
- We investigate an error in the noise temperature measurements of the hot-electron bolometer mixers caused by the so-called "direct detection effect". The effect originates in the changing of the mixer parameters when the mixer is loaded on calibration black body sources at different temperatures (300 and 77 K). A correction factor was obtained from the mixer output power versus the bias current dependence, measured by: 1) the local oscillator (LO) power tuning: 2) mixer heating: and 3) application of an external RF source. Furthermore, the direct detection effect was assessed by elimination of the heterodyne response using a LO frequency, which is far off the mixer RF band. We show that the direct detection effect can be mitigated by using an isolator between the mixer and the IF amplifier.
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| 44. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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THz Hot-Electron Bolometer Mixers
- 2014
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Ingår i: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035. - 9781479938773
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Konferensbidrag (refereegranskat)abstract
- We overview the technology of superconductingHot-Electron Bolometer mixers in the field of terahertzheterodyne detection. HEB mixer performance is analyzed vs competing technologies and application fields, with emphasize on radio astronomy. We discuss materials which have been reported in the past to be used for such devices with both phonon-substrate and electron-diffusion cooling mechanisms. It caused a splash of interesting theories with attempts of describing both dc and RF characteristics of HEB mixers. Development of HEB mixers made possible to extend high spectral resolution radio astronomy beyond 1THz.
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| 45. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Water vapor radiometer for ALMA: Optical design and verification
- 2010
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Ingår i: 21st International Symposium on Space Terahertz Technology 2010, ISSTT 2010; Oxford; United Kingdom; 23 March 2010 through 25 March 2010. - 9781617823626 ; , s. 340-
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Konferensbidrag (refereegranskat)abstract
- Atacama Large Millimeter wave Array (ALMA) is being built at a high altitude Atacama Desert in Chile. It will consist of 50 12m telescopes with heterodyne instruments to cover a large frequency range from about 30GHz to nearly 1THz. In order to facilitate the interferometer mode of operation all receivers have to be phase synchronized. It will be accomplished by phase locking of all local oscillators from a single reference source. However, a noticeable part of the phase error is caused as the signal propagates through the Earth atmosphere. Since this effect originates from the fluctuations of water vapors, it can be accounted for by carefully measuring the spectral width of one of water vapor resonance absorption lines. This will be done with a submillimeter heterodyne radiometer, Water Vapor Radiometer (WVR) [1]. WVR will measure the sky brightness temperature in the beam path of every telescope across the 183GHz water line with a spectral resolution of about 1GHz. Accuracy of the calculated optical delay is determined by the combination of the radiometric accuracy of the WVR and of the errors originated in the WVR illumination of the telescope. We will describe major challenges in the design of the WVR to comply with the stringent requirements set to the WVR. Several approaches to simulate the quasioptical waveguide which brings the signal from the telescope's subreflector to the mixer horn, were used: fundamental mode Gaussian beam propagation, combined ray tracing with diffraction effects (using package ZEMAX), and a full vector electromagnetic simulations (using GRASP). The computational time increases rapidly from the first method to the last one. We have found that ZEMAX results are quite close to the one from GRASP, however obtained with nearly instant computation, which allows multiple iterations during system optimization. The beam pattern of the WVR and of WVR with the optical Relay (used to bring the signal from the telescope's main axis to the WVR input window) was measured by a scalar beam scan at four planes in the far field. The experimental results correspond to the simulated ones with a high accuracy. The WVR illuminates the telescope subreflector with a spillover of less than 1.5% while maintaining high aperture efficiency. We developed an approach to calculate the beam center position at the subreflector (with is at 6m from the WVR) from our test data (at maximum 2m from the WVR) in order confirm the maximum beam deviation does not exceed 20mm, i.e. 1/15 of the beam width.
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| 46. |
- Cherednichenko, Serguei, 1970, et al.
(författare)
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Wideband THz detectors based on YBCO thin films at 77K and at room temperature
- 2011
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Ingår i: 6th ESA Workshop on Millimetre-Wave Technology and Applications.
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Konferensbidrag (refereegranskat)abstract
- We present results of experimental investigation of THz direct detectors based on ultrathin YBCO films. The detectors are integrated with a spiral planar antenna. In the frequency band of 0.1-1.6THz the optical responsivity is from 170V/W for 77K. It increases to 400 V/W for operation temperature about 76K. The responsivity was constant up to 100kHz. Using mixing technique, the measured time constant is 0.5-2ns. Currently, at 77K, the NEP is 20pW/Hz0.5. At room temperature, the NEP is about 250pW/Hz0.5. For the same devices as coherent detector, the mixer gain was -21dB at 77K (and -28dB) at room temperature for an LO power of 0.4mW. With the present devices a mixer gain of up to -23dB is possible at 300K for an LO power of 1.5mW. Using smaller devices, similar gain can be achieved for a much smaller LO power.
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| 47. |
- Drakinskiy, Vladimir, 1977, et al.
(författare)
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Gain bandwidth of NbN Heterodyne Hot Electron Bolometer Superconducting Mixers made on thin SiO2/Si3N4 membrane
- 2006
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Ingår i: in Proc.17th Intern. Symp. Space THz Technology, Paris, France, May. 2006..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We present results of the gain bandwidth investigationof NbN HEB mixers made on 1.4 µm thick SiO2/Si3N4stress-less membrane, and bulk-Si/SiO2/Si3N4. We have foundthat the gain bandwidth of the devices made on these substrates is 0.6-0.9 GHz while on bare-Si it is 3.5 GHz. The final objective of this work is to process membrane based NbN HEB mixers for a 4x4 pixel heterodyne camera for 2.5 and 4.7 THz. SHAHIRA (Submm Heterodyne Array for HIgh speed Radio Astronomy) is a project supported by ESA.
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| 48. |
- Emrich, Anders, 1962, et al.
(författare)
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Water Vapor Radiometer for ALMA
- 2009
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Ingår i: Proc. of 20th International Symposium on Space Terahertz Technology, Charlottesville, USA, 20-22 April, 2009. ; , s. 174-177
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Konferensbidrag (refereegranskat)abstract
- Radiometer for the ALMA project from scratch in 18 months and will deliver 50 units within the next 18 months. Theradiometer includes an Optical Relay, Mounting Frame as well as the Radiometer core module. The radiometer core include optics and calibration system as well as a schottky mixer based frontend and a filterbank back-end. These subsystems are supported by a thermal management subsystem, control and communication subsystem as well as a power subsystem. The system and subsystems will be described in the paper.
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| 49. |
- Gan, Yuner, et al.
(författare)
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Heterodyne performance and characteristics of terahertz MgB2hot electron bolometers
- 2023
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 133:7
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Tidskriftsartikel (refereegranskat)abstract
- We have studied THz heterodyne detection in sub-micrometer MgB2 hot electron bolometer (HEB) mixers based on superconducting MgB2 films of ∼5nm (HEB-A), corresponding to a critical temperature (Tc) of 33.9 K, and ∼7nm (HEB-B), corresponding to a ?? of 38.4 K. We have measured a double sideband (DSB) receiver noise temperature of 2590 K for HEB-A and 2160 K for HEB-B at 1.6 THz and 5 K. By correcting for optical losses, both HEBs show receiver noise temperatures of ∼1600 K referenced to the front of anti-reflection (AR)-coated Si lenses. An intermediate frequency (IF) noise bandwidth of 11 GHz has been measured for both devices. The required local oscillator (LO) power is about 13 μW for both HEBs. We have also measured a DSB receiver noise temperature of 3290 K at 2.5 THz and 5 K but with an AR-coated lens optimized for 1.6 THz. Besides, we have observed a step-like structure in current voltage (IV) curves, which becomes weaker when the LO power increases and observable only in their differential resistance. Such a correlated structure appears also in the receiver output power as a function of voltage, which is likely due to electronic inhomogeneities intrinsic to the variations in the thickness of the MgB2 films. Different behavior in the IV curves around the low bias voltages, pumped with the same LO power at 1.6 and 5.3 THz, was observed for HEB-B, suggesting the presence of a high-energy σ-gap in the MgB2 film.
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| 50. |
- Gan, Y., et al.
(författare)
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Low noise MgB2 hot electron bolometer mixer operated at 5.3 THz and at 20 K
- 2021
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 119:20
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Tidskriftsartikel (refereegranskat)abstract
- We have demonstrated a low noise superconducting MgB2 hot electron bolometer (HEB) mixer working at the frequency of 5.3 terahertz (THz) with 20 K operation temperature. The bolometer consists of a 7 nm thick MgB2 submicrometer bridge contacted with a spiral antenna to couple THz radiation through a high resistive Si lens, and it has a superconducting critical temperature of 38 K. By using hot/cold blackbody loads and a Mylar beam splitter all in vacuum and applying a 5.25 THz far-infrared gas laser as a local oscillator, we measured a minimal double sideband receiver noise temperature of 3960 K at the LO power of 9.5 mu W. This can be further reduced to 2920 K if a Si lens with an antireflection coating optimized at this frequency and a 3 mu m beam splitter are used. The measured intermediate frequency (IF) noise bandwidth is 9.5 GHz. The low noise, wide IF bandwidth mixers, which can be operated in a compact, low dissipation Stirling cooler, are more suitable for space applications than the existing HEB mixers. Furthermore, we likely observed a signature of the double-gap in MgB2 by comparing current-voltage curves pumped at 5.3 and 1.6 THz.
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