Demonstration of a Generic Local Oscillator System for ALMA Band 2+3

The Atacama Large Millimeter/sub-millimeter Array (ALMA) is a world-class astronomical observatory operating in the millimetre and submillimetre wavelength range. It provides astronomers with an observing tool of unprecedented spatial resolution and sensitivity. ALMA will allow investigation of fundamental process associated with stellar and planetary formation, and galactic and extra-galactic evolution, revolutionising our understanding of how the Universe evolves. The UK Science and Technology Facilities Council (STFC) has long recognised the importance of ALMA within its strategic science plan, and has supported its development and construction through its membership of, and support for, the European Southern Observatory (ESO), which provides leadership of the ALMA project within Europe.
ALMA is now a functional instrument and is delivering high-grade science. However, it is not complete, and important technical upgrades are needed before it can reach its full, and originally planned, potential. For example, although the main production phase of the array has been successfully completed, and the return of science has already begun, ALMA presently lacks its proposed full frequency coverage and this is limiting its observational capability. Through a previous grant awarded to the UK by the European Southern Observatory (ESO), the University of Manchester has led a European consortium design study group during the conceptual development phase of a new ALMA receiver band, which both extends the operational frequency of the array to include Band 2, and provides increased operational efficiency through a simultaneous merger with the pre-existing Band 3. The new receiver band is currently designated Band 2+3, and it is the objective of this proposal to develop key and related Band 2+3 systems technology that provide a vital step towards its realisation as a new ALMA detection facility. We are therefore seeking Project Research and Development (PRD) resource to support a 21-month technical development activity that will establish the foundations of the new Band 2+3 through the manufacture and test of core technology, viz. a new and generic local oscillator (LO). During the course of our project, we will also demonstrate enhanced low noise amplifier (LNA) technology and prove a related, and critical, signal frequency mixing down-conversion stage. A core objective of our programme of work is therefore to ensure that Band 2+3 is adopted as a technical concept by the ALMA Project through the raising of its technical readiness status from a current level of 3, to a significantly higher level approaching that of 6. This would be followed by an ESO funded prototyping and deployment phase to be completed within a 10-year timescale.
Our activity will mean that ALMA gains increased observational capacity and improved operational infrastructure; ESO is placed in an excellent position to lead the new receiver concept within the international ALMA Project, and the UK is assured of gaining a leading technical role in a future prototype and full production programme, which also offers excellent potential for significant UK industrial involvement.

Maintaining a strong relationship within the ALMA community is essential if the UK is to build upon its already significant contribution, and if UK scientists are to achieve the best possible observational results. We have been very successful with our approach towards ALMA upgrades and have proposed new and important advances to technology that will benefit science. Band 2+3 now represents a key strategic development opportunity. For example, by engaging in Band 2+3 development, our respective institutes (the University of Manchester and the Rutherford Appleton Laboratory) can provide training to students in the field of highly-advanced receiver technologies, e.g. local oscillators and low noise amplifiers, and associated methods of microwave design, construction and test. This is of great interest and direct benefit to UK industry as we aware that there is considerable demand for microwave and millimetre-wave engineering skills in support of a vast range of related current and planned telecommunication, Earth observation, and defence ground base, airborne and space borne systems. Furthermore, UK leadership of Band 2+3 will establish a future opportunity for UK industry to participate in a follow-on sizable production phase, as has been demonstrated via previous ALMA UK led contributions. This brings direct financial return to the UK from its investment in ESO, and a general enhancement in engineering skill level.

Our proposed Band 2+3 technical programme will have even wider impact through broader application to other scientific disciplines. For instance, microwave and millimetre-wave spectroscopy is essential to allow sounding of the key chemical species in the Earth's atmosphere and is thus a key observation tool in Earth observation and understanding climate change effects associated with the upper atmosphere. Moreover, atmospheric observations of the giant planets, and Venus and Mars, is also relevant to Band 2+3 technology, and thus there is potential for use in planetary exploration. Wider beneficiaries of our work will therefore include atmospheric and planetary scientists.

Additionally, the technology associated with Band 2+3 has relevance to weather monitoring and forecasting, communications, navigation, and security surveillance, and telecommunication links are increasing in frequency in order to accommodate wider user bandwidth requirements. Applying our advanced technologies would greatly enhance existing capabilities through noise and physical form reduction, and there is consequently significant potential for industrial exploitation and spinout.
Our work generates training and employment opportunities that will result in highly qualified researchers, skilled mechanical technicians, semiconductor processing and experimental engineering personnel and application scientists. The beneficiaries of this training include undergraduate and postgraduates project students, post-doctoral researchers, apprentices and engineers, many of who will continue their careers outside of academia.

The proposed activity will therefore have beneficiates associated with academia (science and technology), education, and industry. It will directly benefit the STFC through an increase in ALMA science and a maintaining of its technical visibility, leadership and global presence with the international project. Public interest and awareness will benefit from the realisation that the UK continues to lead the way in developing state-of-the-art-technology that both increases scientific knowledge and creates jobs opportunities.