New lab for developing astronomical instruments

The first instrument TU Delft researchers will make in this laboratory can detect sub-millimetre waves emitted by distant, dust-obscured galaxies.

“Our instrument, which we call DESHIMA, will be the size of a fridge,” said the Japanese astronomer and physicist Dr. Akira Endo of the Tera-Hertz Sensing Group. He works together on this apparatus with Dr. Jochem Baselmans, also from the Tera-Hertz Sensing Group. “Inside however, it is much colder; just a tenth of a degree above the absolute zero (−273 degrees Celsius). We will mount the instrument on the ASTE-telescope in the Atacama desert in Chile. It should allow us to detect light from distant and ancient galaxies that existed up to 12.5 billion years ago.”

Inside DESHIMA is a spectrometer, an instrument that measures the wavelength of photons in the submillimetre wavelength spectrum. Much can be learned from studying this radiation, more specifically from studying the ‘redshift’. This is the Doppler-like frequency shift due to the expansion of the space of the radiation. It can tell what the age and distance is of the observed galaxies.

The researchers hope to have DESHIMA ready next year. “At the end of the month we are going to the ASTE-telescope in the Atacama desert to prepare for the installation,” said Endo. “This will be a good exercise. Hopefully we will not get altitude sickness. The Telescope is located at an altitude of 4800 meters.”

DESHIMA is an acronym that refers to an artificial island built in the bay of Nagasaki in 1634. This island remained as the single place of direct trade and exchange between Japan and the Netherlands during the Edo period.

The opening of the lab wasn’t only about hard core science. “We did some fun stuff too,” said Endo. The name Cryolab implies that this is a lab where materials are cooled down to almost zero. “To get people acquainted with very cold stuff we offered them frozen popcorn, frozen to – 196 degrees. When you have such a popcorn in your mouth the damp air you exhale looks like thick smoke. It doesn’t hurt because popcorn has little heat capacity as it consists almost entirely of air.”

“Cooling down to almost zero in itself is not so spectacular,” said Endo. “The TU Delft already has labs where this happens all the time. What is special about this lab, is that it enables the development of complete astronomical instruments, which of course have windows to link light from the telescope to the detectors. Here in Delft we are used to working on chips used in astronomy. Now we are also making complete instruments, thanks to a strong partnership with SRON (Netherlands Institute for Space Research).”

In the future, the CryoLab is envisioned to also host new coolers from QuTech. Superconducting electronics used for astronomical instrumentation and quantum electronics have much in common, because they both push the limits of what can be observed.