The MPI_1.1THz is a multi-pixel heterodyne receiver that was mounted in the Nasmyth–A cabin of the Atacama Pathfinder Experiment (APEX) telescope on the Chajnantor plateau, in Chile’s Atacama region in 2014. The receiver is a collaboration between ESO and the Max-Planck-Institut für Radioastronomie (MPIfR).

With a cartridge-type receiver system that includes two cartridges, it follows the concept that was introduced for the ALMA receivers. Its design allows for easy maintenance and troubleshooting since it is possible to remove and repair cartridge components without having to open the whole cryostat. It also isn’t necessary to dismount it from the telescope and thus reduced observing downtime.

The MPI_1.1THz receiver covers the spectral window from 0.28 to 0.30 (1000–1080 GHz), where important spectral lines are located and whose observations with high-resolution spectroscopy allow for the study of the chemical and physical states in starburst galaxies, active galactic nuclei of external galaxies or in hot cores in the galactic interstellar medium.

The detectors used by the MPI_1.1THz receiver are superconductor-insulator-superconductor (SIS) mixers due to their high sensitivity and a larger instantaneous intermediate frequency (IF) bandwidth.

The MPI_1.1THz receiver is also the best replacement for the Herschel Space Observatory that had completed its operations in 2013.

MPI_1.1THz on APEX

This table lists the global capabilities of the instrument.

Location: Decommissioned
Telescope: APEX
Focus: Nasmyth
Type: Receiver
Wavelength coverage:

0.28–0.30 mm

Spatial resolution:


Spectral resolution:


First light date: 2014
Science goals:
  • High-resolution spectroscopy
Images taken with the instrument: N/A
Images of the instrument: N/A
Press Releases with the instrument: N/A
Data papers:


ESO data citation policy


  • ESO
  • MPIfR