ALMA Advanced Radiometric Phase Calibration Techniques

Welcome! This page describes work undertaken at the Cavendish Astrophysics Group, developing phase correction algorithms and software for the Atacama Large Millimetre Array (ALMA). Without correction, phase fluctuations, mainly arising from the water content of the atmosphere, would limit ALMA's performance. Our main aim is computing optimal phase corrections using the measurements from ALMA's water vapour radiometry system . Ultimately, this will ensure ALMA is more sensitive, produces better quality images and can exploit wider weather conditions (an increase in efficiency). At the end of our project we will deliver a complete software package to perform these optimal corrections, which is fully integrated into the ALMA system. In the mean time, we have been making all of our software available as we go along (see our software page). For further details on our methods, see the algorithms page or our publications.

Our work is supported by the European Commission's Sixth Framework Programme as part of the wider 'Enhancement of Early ALMA Science' project, managed by the European Southern Observatory (ESO). This infrastructure enhancement comprises six distinct workpackages:

• WP1-4: Design, manufacture and integration of six Band 5 (163-211 GHz) receivers for ALMA
• WP5: Advanced Radiometric Phase Calibration (this work)
• WP6: Design and implementation of data reduction software for on-the-fly interferometry