| 1. |
- Belitsky, Victor, 1955, et al.
(författare)
-
SEPIA - A new single pixel receiver at the APEX telescope
- 2018
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 612
-
Tidskriftsartikel (refereegranskat)abstract
- Context. We describe the new Swedish-ESO PI Instrument for APEX (SEPIA) receiver, which was designed and built by the Group for Advanced Receiver Development (GARD), at Onsala Space Observatory (OSO) in collaboration with ESO. It was installed and commissioned at the APEX telescope during 2015 with an ALMA Band 5 receiver channel and updated with a new frequency channel (ALMA Band 9) in February 2016. Aim. This manuscript aims to provide, for observers who use the SEPIA receiver, a reference in terms of the hardware description, optics and performance as well as the commissioning results. Methods. Out of three available receiver cartridge positions in SEPIA, the two current frequency channels, corresponding to ALMA Band 5, the RF band 158-211 GHz, and Band 9, the RF band 600-722 GHz, provide state-of-the-art dual polarization receivers. The Band 5 frequency channel uses 2SB SIS mixers with an average SSB noise temperature around 45 K with IF (intermediate frequency) band 4-8 GHz for each sideband providing total 4 × 4 GHz IF band. The Band 9 frequency channel uses DSB SIS mixers with a noise temperature of 75-125 K with IF band 4-12 GHz for each polarization. Results. Both current SEPIA receiver channels are available to all APEX observers.
|
|
| 2. |
- Belitsky, Victor, 1955, et al.
(författare)
-
ALMA Band 5 receiver cartridge: Design, performance, and commissioning
- 2018
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 611
-
Tidskriftsartikel (refereegranskat)abstract
- We describe the design, performance, and commissioning results for the new ALMA Band 5 receiver channel, 163-211 GHz, which is in the final stage of full deployment and expected to be available for observations in 2018. This manuscript provides the description of the new ALMA Band 5 receiver cartridge and serves as a reference for observers using the ALMA Band 5 receiver for observations. At the time of writing this paper, the ALMA Band 5 Production Consortium consisting of NOVA Instrumentation group, based in Groningen, NL, and GARD in Sweden have produced and delivered to ALMA Observatory over 60 receiver cartridges. All 60 cartridges fulfil the new more stringent specifications for Band 5 and demonstrate excellent noise temperatures, typically below 45 K single sideband (SSB) at 4 K detector physical temperature and below 35 K SSB at 3.5 K (typical for operation at the ALMA Frontend), providing the average sideband rejection better than 15 dB, and the integrated cross-polarization level better than -25 dB. The 70 warm cartridge assemblies, hosting Band 5 local oscillator and DC bias electronics, have been produced and delivered to ALMA by NRAO. The commissioning results confirm the excellent performance of the receivers.
|
|
| 3. |
- Ermakov, Andrey, 1960, et al.
(författare)
-
Broken-step Phenomenon in SIS Mixers
- 2016
-
Ingår i: 27th International Symposium on Space Terahertz Technology, ISSTT 2016, Nanjing, China.
-
Konferensbidrag (refereegranskat)abstract
- In this paper, we discuss a “broken step” phenomenonin an SIS mixer. This phenomena was observed in the production version of the SIS mixers, designed for the 159-211 GHz RF band,being used for the construction of the ALMA Band 5 receiver The broken step typically appears at LO frequencies above 180 GHz and manifests itself as a sharp onset in the DC current at the middle of the quasiparticle step. Correspondingly, this affects the mixer IF response in a way that is similar to the Josephson step but is however of a different nature. Such behaviour affects the SIS mixer dynamic range and complicates the tuning of the 2SB mixer to optimize its performance, for both the receiver noise as well as the sideband rejection. In this paper, we describe results of a few experiments which were performed to understand this undesirable phenomenon.
|
|
| 4. |
- Lapkin, Igor, 1963, et al.
(författare)
-
New optics for SEPIA- Heterodyne facility instrument for the APEX telescope
- 2019
-
Ingår i: ISSTT 2019 - 30th International Symposium on Space Terahertz Technology, Proceedings Book. ; , s. 150-154
-
Konferensbidrag (refereegranskat)abstract
- The design of SEPIA (Swedish ESO PI Instrument for APEX) was driven by the idea of using ALMA receiver cartridges on the APEX telescope. SEPIA was installed at the guest position of the Naismith cabin A, APEX telescope in early 2015. The SEPIA cryostat and optics was designed to accommodate up to 3 ALMA cartridges. In 2017, the APEX facility instrument SHeFI was decommissioned and SEPIA was accepted as its successor. Moving SEPIA from its PI into Facility Instrument position brought additional constrains due to the severe limitations of the available space. That had led to the necessity of complete redesigning of the SEPIA tertiary optics. During February-March 2019, the new tertiary optics was installed in the APEX Cabin A and SEPIA was placed at its final Facility Instrument position. Here, we present the details of the optical design, layout of the optical component placement, the beam alignment technique, the results of the alignment and SEPIA technical commissioning results at the APEX telescope.
|
|
| 5. |
- Sundin, Erik, 1979, et al.
(författare)
-
Cryogenic IF Balanced LNAs Based on Superconducting Hybrids for Wideband 2SB THz receivers
- 2017
-
Ingår i: 28TH INTERNATIONAL SYMPOSIUM ON SPACE TERAHERTZ TECHNOLOGY. ; 2017-March
-
Konferensbidrag (refereegranskat)abstract
- Future heterodyne 2SB THz receivers for Radio astronomy shall require better sensitivity and higher IF bandwidth. This paper investigate, in a modular approach, the use of balanced amplifiers based on superconducting quadrature hybrids, as an option to realize wide band low noise amplifiers with improved input matching without compromising the noise performance. Measurements of the proposed wideband balanced amplifier shows very good agreement with the standalone amplifier in terms of gain and noise temperature. The input matching of the balanced amplifiers are limited by the input matching of the hybrids, still showing return loss better than 15 dB.
|
|
