The eight finalists of the Enlighten Your Research 4 contest (EYR4) wrote a blog about the projects they proposed. This week the blog from Matteo Alfonsi (Nikhef)
From XENON100 to XENON1T
Unveiling the nature of dark matter is one of the top priorities of astrophysics, cosmology and particle physics. I joined this field of research as a Nikhef postdoctoral researcher and as a XENON Collaboration member in 2010.
This is a very exciting time for me: last year I contributed to the most recent result of the XENON100 experiment, at the moment the world’s most sensitive apparatus for direct search of dark matter. At the same time, the next generation experiment, XENON1T, is under construction and we are keeping a tight schedule in order to start the data taking in 2015. The goal is to finally discover, within 2 years, the dark matter particle.
A lightpath can “liberate” the data from a single site
The new apparatus entails a wide range of technological challenges: high-tech cryogenics, state of the art photo-detectors, low radioactive materials selection, high volume data management. The latter is the reason of my participation in the Enlighten Your Research 4 competition. The competition is really timely as we are designing the XENON1T data flows: a lightpath, i.e. a dedicated high-speed optical connection from the experimental site in central Italy to Nikhef and SURFsara in Amsterdam, can “liberate” the data from a single site and distribute intensive computing tasks over more sites.
The problem of the dark matter nature dates back to 1933: the discrepancy between theory and observation in the orbital velocities of galaxies within clusters pointed to a “missing mass”. Nowadays there is an overwhelming evidence of dark matter existence coming from astrophysics information. It must be composed by diffused elementary particles rather than stars or other astronomical bodies. However, there is no sign of such particles in the Standard Model of particle physics and we have to look at extensions such as Supersymmetry, i.e. what we call new physics.
Deep underground laboratories
“Direct search” experiments such as XENON are based on the fact that the Earth travels in a space filled with dark matter particles, and there is an extremely rare chance that a dark matter particle strikes a nucleus of a target material. The XENON100 experiment uses 161kg of liquid xenon (at a temperature of about -95 °C) as target, while XENON1T will use more than 3 tons. The tiny energy deposition in a dark matter event must not be confused with the one caused by natural radioactivity. This is why such experiments are located in deep underground laboratories and a meticulous material selection is performed for all the detector components.
Nikhef – Dark Matter (XENON, DARWIN) and Detector R&D groups\