ALMA upgrade: ESO signs contract for advanced processor

Last week, at a virtual ceremony, ESO signed an agreement with the French National Centre for Scientific Research (CNRS) for the development of a wideband intermediate frequency processor (WIFP) for the Atacama Large Millimeter/submillimeter Array (ALMA). ESO’s Eric Villard and Martin Zwaan of the ALMA Development Team at ESO, as well as Elizabeth Humphreys, European ALMA Programme Manager, were present at the ceremony. From Bordeaux (France) Sean Raymond, Benoit Lavraud and Benjamin Quertier-Dagorn were at the signing, together with Álvaro González, the ALMA Deputy Director of Development, based at the Joint ALMA Observatory in Chile.

ALMA, located in Chile’s Atacama Desert, is currently undergoing a major revamp dubbed the Wideband Sensitivity Upgrade, aimed at keeping the array at the technological cutting edge. The upgrade encompasses most components of the array, from updates to the electronics in the 66 antennas to changes in the correlator (the supercomputer where the signals from the antennas are combined) and fibre-optics systems. The upgrade will increase ALMA’s observing bandwidth, that is, the range of frequencies in which it can observe simultaneously, by a factor of 2 in a first stage and 4 when finalised. It will also significantly improve the sensitivity of ALMA, meaning astronomers will be able to probe fainter and more distant objects, faster.

ALMA antennas capture signals from the cosmos with wavelengths in the millimetre and submillimetre range, equivalent to frequencies of tens of gigahertz to one terahertz. Because these frequencies are very high, they are converted to lower ‘intermediate frequencies’ (IF) that can be more easily processed. The WIFP project aims to develop and deliver the equipment needed to digitise the analogue IF signals from the antennas and prepare them for transportation to the correlator, where the signals are combined. The WIFP is, therefore, a critical component of the Wideband Sensitivity Upgrade.

As the European partner in ALMA, ESO is responsible for a significant part of the upgrade. The WIFP project is one of Europe’s most significant contributions to the upgrade. It will provide each ALMA antenna with digitisation of the receiver signals, digital signal processing, high-precision timestamping of the signals, and total power detection. Compared to the existing system, the signal will be sampled at a rate — 40 billion samples per second — that is ten times higher than at present.

Overall, the WIFP will significantly enhance ALMA data throughput and observing efficiency and can be compared to adding six antennas in terms of efficiency. The processor is developed in a collaboration between ESO and the Laboratoire d’Astrophysique de Bordeaux, part of the University of Bordeaux and CNRS, and is anticipated to be completed in mid 2028.

More information

ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSTC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO and NAOJ.

Courtesy of European Southern Observatory