The Atacama Large Millimeter/submillimeter Array (ALMA) Band 1 receiver covers the frequency band between 35-50 GHz. The project achieved the successful delivery of 73 Band 1 receiver units to ALMA telescope site and ready for cycle 10 observation. This paper delves into the implementation of Project management methodologies applied during the both receiver development and production phases. Furthermore, the paper presents the lessons learned and challenges faced, and offer for the future endeavors in applying the project management in the scientific research projects.
The idea of ALMA Band-4+5 receivers are proposed for the upgrade after 2030. The new receiver will cover the RF frequency of the original Band-4 and Band-5 with continuous frequency tuning over 125 –211 GHz with dual polarizations, dual sidebands capability. The instantaneous intermediate frequency (IF) bandwidth is up to 16 GHz per sideband and per polarization. Both the SIS-based receiver and HEMT-based receiver schemes are considered. For the SIS receiver scheme, the niobium-based SIS junctions will be fabricated to form mixer chips, and integrated into the mixer blocks with broadband waveguide 3-dB quadrature hybrid couplers with LO couplers, cryogenic IF low-noise amplifiers, and 2-20 GHz coaxial 3-dB quadrature hybrid couplers to form sideband separating down-converters. The inputs of the sideband separating down-converters are fed by the ellipsoidal mirror pairs, corrugated feedhorn and the orthomode transducer. For the HEMT-based receiver scheme, using the same optics configuration as the SIS-based receiver, the cryogenic InP HEMT low-noise amplifiers (LNAs) chains cover 125 – 211 GHz operated in 15-K ambient temperature will be the key components of the cold cartridge assembly (CCA). For the warm cartridge assembly, a pair of sideband-separating diode or resistive transistor mixers will provide four-channel 16-GHz IF instantaneous bandwidth. To avoid the possible interference between LO and IF signals, considering the possible 16 GHz IF bandwidth over 4 – 20 GHz, the LO fundamental frequency will be chosen in 24 - 32 GHz, followed by an active frequency tripler to form the phase-lock loop with 72 – 96 GHz frequency tuning range. The key components with 51.2% relative bandwidth to be developed in-house are Nb SIS mixers, RF InP HEMT LNAs, 3-dB waveguide hybrid couplers, orthomode transducers, corrugated horn antenna, and optics mirror pairs.
KEYWORDS: Receivers, Optical amplifiers, Radio astronomy, Antennas, Astronomy, Observatories, Cryogenics, Simulation of CCA and DLA aggregates, Roads, Galactic astronomy
The Atacama large millimeter/submillimeter array (ALMA) band-1 receiver covers the frequency band between 35-50 GHz. An extension of up to 52 GHz is on a best-effort basis. Covering the longest wavelengths visible with ALMA, this receiver is enabling studies of dust grain evolution in proto-planetary systems probing dust grain sizes close to 1 cm, and with multiple red-shifted molecular lines it will open up a new window in the high-redshift universe. The band-1 project has recently achieved first light and with this passed a major project milestone. We present the challenges, from initial development to prototype, to establishing the infrastructure, integration, and evaluation of 73 production receiver units, and to the final tasks to complete the project. We conclude with the initial performance and characterization of the first band-1 receivers installed on ALMA.
The Ka-/Q-band in the microwave region of the electromagnetic spectrum is important for astrophysical and astrochemical research, particularly in the subfield of interstellar medium (ISM). The two bands cover not only the fundamental lines of the abundant dense gas tracer CS and its isotopologues but also a vast number of transitions of relatively large, long-chain, and/or complex organic species. Here, through a Taiwan-Japan collaboration, an extended Q-band (30-50GHz) receiver is built for Nobeyama 45-m telescope. The receiver front-end was installed at Nobeyama 45-m telescope in Nov. 2021 and obtained its first light in the same month. Commissioning and science verification (CSV) of the receiver was conducted in the first half of 2022. After commissioning, this receiver will be the only one in the world providing capability to cover 3 Zeeman transitions simultaneously at 7mm wavelength installed at large single dish telescope. It will be one of the most powerful facilities to explore the magnetic fields towards the pre-protostellar cores.
The Atacama Large Millimeter/submillimeter Array (ALMA) Band 1 receiver covers the frequency range of 35-50 GHz. An extension of up to 52 GHz is on a best-effort basis. A total of 73 units have to be built in two phases: 8 preproduction and then 65 production units. This paper reports on the assembly, testing, and performance of the preproduction Band 1 receiver. The infrastructure, integration, and evaluation of the fully-assembled Band 1 receiver system will be covered. Finally, a discussion of the technical and managerial challenges encountered for this large number of receivers will be presented.
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