XENON1T gears up to detect dark matter
An international collaboration of scientists inaugurated the new XENON1T experiment in the underground Gran Sasso laboratory in Italy today. XENON1T was designed to search for dark matter with an unprecedented sensitivity. The Universe consists of five times more dark matter than the ordinary matter we are familiar with, made up of atoms and molecules. Nonetheless, this mysterious dark matter has still not been detected directly. XENON1T is set to change that, in part due to the Dutch contributions.
Dark matter is one of the main ingredients of the universe, and for decades, laboratory-based experiments have searched for it. Dark matter has so far only been detected indirectly, via gravity interactions that govern the motion of astrophysical objects. Scientists expect that dark matter consists of a new, stable elementary particle that has thus far escaped detection. "We expect that every second about one hundred thousand dark matter particles pass through an area the size of a thumbnail," says Patrick Decowski, programme leader of the Dark Matter research group at Nikhef, the National institute for subatomic physics in Amsterdam. "The fact that we haven't detected them yet, tells us that the probability that the particles collide with atoms in our detector is very small and that we need more sensitive experiments to uncover them. XENON1T is such an experiment."
Underground laboratory
XENON1T is located in the Laboratori Nazionali del Gran Sasso in Italy, one of the largest underground laboratories in the world. "We perform our experiment in a water tank, 1400 meter underground, because we want to detect only dark matter, and filter out all other types of radiation. The massive layer of rock and the water shield off the sensitive equipment," according to Decowski. XENON1T is named after the noble gas xenon, with which the detector is filled. A collision of dark matter with xenon results in a tiny flash of light. 248 extremely sensitive light sensors will be searching for such flashes.
Most sensitive in the world
As soon as XENON1T is fully operational, it will take about a week for the experiment to become the most sensitive dark matter experiment in the world. The Dutch Nikhef team was responsible for, among other aspects, the vibration-free suspension of the xenon vessel, as well as the data acquisition and data analysis software. "The experiment can be made even more sensitive in the future. We'll do our utmost to finally unravel the mystery of dark matter." It took 20 research groups from ten countries five years to complete the experiment. XENON1T, with a total mass of 3,500 kg is the third generation of instruments in the XENON project that started 15 years ago with a detector weighing only three kilogramme. It succeeds XENON100, which was the world's most sensitive dark-matter detector up to 2013. The first results from XENON1T are expected early 2016.
About the XENON collaboration:
Nikhef is one of the institute participating in the international XENON collaboration, which consists of 20 research groups from the Netherlands, the United States, Germany, Italy, Switzerland, Portugal, France, Israel, Sweden and Abu Dhabi. Website: w ww.xenon1t.or g
About Nikhef:
The National institute for subatomic physics (Nikhef) performs research in the area of particle and astro-particle physics. Nikhef coordinates the Dutch contributions to major international experiments, such as based at CERN. The institute is a collaboration between the Foundation for Fundamental Research of Matter (FOM) and four universities in the Netherlands: Radboud University, University of Amsterdam, Utrecht University and the Vrije Universiteit Amsterdam. FOM is part of the Netherlands Organisation for Scientific Research (NWO). Nikhef is based in the Amsterdam Science Park.
More information:
Science Communication department at Nikhef: Melissa van der Sande, 020 592 20 75
Programme leader of the Dark Matter research group at Nikhef: Prof. Patrick Decowski, 020 592 21 45
Website of the subterranean laboratory in Gran Sasso
Website of the Dark Matter research group at Nikhef