The Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile has recently been upgraded with the installation of 145 new low-noise amplifiers (LNAs). This enhancement aims to significantly improve the telescope’s capacity to observe the cosmos, particularly the cold molecular clouds that are crucial for star formation. With a total of 66 parabolic antennas, ALMA is recognized as one of the world’s most powerful radio telescopes, allowing researchers to visualize regions of the universe that are not observable through visible light.
The new amplifiers augment ALMA’s Band 2 coverage, which spans from 67 to 116 Gigahertz (GHz). This expanded range will facilitate the study of the “cold interstellar medium,” encompassing the dust, gas, and magnetic fields involved in star formation. Additionally, astronomers will benefit from enhanced observations of planet-forming disks and complex organic molecules (COMs) in nearby galaxies, which are considered essential components for the emergence of life.
Each low-noise amplifier incorporates a series of monolithic microwave integrated circuits (MMICs) developed by the Fraunhofer Institute for Applied Solid State Physics (IAF). These circuits utilize the semiconducting material indium gallium arsenide (InGaAs) and are based on metamorphic high-electron-mobility transistor (mHEMT) technology. This advanced method enables the creation of flexible transistors that optimize performance for high-frequency receivers. The improved sensitivity of ALMA’s receivers will allow scientists to capture low-noise signals more effectively, thereby minimizing background interference.
Dr. Fabian Thome, head of the subproject at Fraunhofer IAF, highlighted the importance of this collaboration between IAF and the Max Planck Institute for Radio Astronomy (MPIfR). The European Southern Observatory (ESO) commissioned both institutions to provide the amplifiers. Fraunhofer IAF was responsible for the design, manufacture, and initial testing of the MMICs at room temperature, while MPIfR focused on assembling and qualifying the LNA modules under cryogenic conditions.
Prof. Dr. Michael Kramer, executive director at MPIfR, expressed pride in the partnership. He stated, “This is a wonderful recognition of our fantastic collaboration with Fraunhofer IAF, which shows that our amplifiers are not only ‘made in Germany’ but also the best in the world.”
The completion of this upgrade marks a significant milestone in ALMA’s mission to deepen our understanding of the universe. With the enhanced capabilities provided by the new low-noise amplifiers, astronomers and cosmologists are poised to gain unprecedented insights into the processes of star and planetary system formation, as well as the role of organic molecules in the origins of life.
