DESHIMA is a completely new type of astronomical instrument with which researchers hope to construct a 3-D map of the early universe. In early October, Dutch and Japanese researchers installed the DESHIMA measurement instrument under the ASTE telescope in Chile. Last week, DESHIMA achieved first light.
To study the early universe, astronomers need to measure infrared light that has taken between 10 and 13 billion years to reach Earth. Sensitive instruments are required for this. A team from TU Delft is collaborating with SRON, Leiden Observatory and Japanese astronomers to develop superconductive and extremely sensitive measurement equipment that speeds up the current measurement process 100-fold. Its members are currently on location in Chile to install and test the equipment.
The Japanese Atacama Submillimeter Telescope Experiment (ASTE) is located in the Atacama Desert in Chile at an altitude of 4.8 kilometres. In recent weeks, the Deep Spectroscopic High-redshift Mapper (DESHIMA) was installed on this telescope. This new type of spectrometer determines the exact distance to distant infrared star systems by measuring the redshift of the spectrum of the star systems. DESHIMA is the first broadband spectrometer for these specific infrared frequencies.
DESHIMA features microwave kinetic inductance detectors (MKIDs), which can detect the most minute changes in radiation energy with the greatest precision. Akira Endo (TU Delft) developed the concept of a spectrometer with a large number of MKIDs. Jochem Baselmans (SRON/TU Delft) later suggested creating the entire spectrometer on the same chip, without using optics, and the idea of the superconductive, on-chip spectrometer was born.
A single superconductive chip, further developed by these and other researchers from TU Delft and SRON, collects the far infrared radiation, filters it into narrower frequencies and detects the luminosity per frequency. The chip is cooled in a cryostat to a temperature of -273 degrees Celsius (120 millikelvins) and read by special electronics. The cryostat and electronics were both developed by SRON.
Proof of principle
Narrowband far infrared spectrometers are already available, but DESHIMA is the first spectrometer of its kind to be tested on a telescope. What makes DESHIMA special is its instantaneous bandwidth. DESHIMA will be tested in Chile as proof of principle at a frequency of 346 Gigahertz and an instantaneous bandwidth of 40 Gigahertz. Nobody has ever attempted to use such a large bandwidth to look so far back in time and deep into space.
The aim is to work towards a bandwidth of 240-720 GHz in a few years' time, which requires even more precise lithography. SRON and TU Delft are already working on a successor to DESHIMA called MOSAIC, a 25-pixel version that is expected to be operational in three years' time. If everything goes according to plan, researchers will soon be able to use it to create the first 3-D map of star systems dating back to the dawn of the universe.
Explore further: MATISSE to shed light on the formation of Earth and planets
To find out more about the technology behind DESHIMA, the research project in Chile and studying star systems in general, read the blog produced by TU Delft's Faculty of Electrical Engineering, Mathematics and Computer Science, see: