COSINUS: Test of the DAMA experiment

Can the controversial dark matter signals of DAMA be confirmed?

In the search for the hypothetical dark matter particles, there are different approaches and methods. Many experiments involve searching directly for possible traces left behind by particles of dark matter when the atomic nuclei of normal visible matter are encountered. Examples are CRESST, Edelweiss, SuperCDMS, LUX, PandaX, DarkSide, and XENON-nT.

This also includes the DAMA/LIBRA experiment, which uses detectors made of sodium iodide. Thanks to its large detector mass (250 kg), it can detect another characteristic of dark matter particles. This entails a seasonal fluctuation in the observed signals – with a peak in June. The reason: The solar system revolves around the center of the Milky Way and the Earth around the sun. Depending on the position, the two relative speeds add up. As a result, our planet (and thus also the detectors) sometimes experiences a stronger or weaker particle wind.

However, the DAMA results are so far unconfirmed. In order to confirm the reliable detection of dark matter, other experiments must also be able to detect particle traces. Indeed, there are several projects (ANAIS in Spain, COSINE in Korea, and SABRE in Italy) in which scientists hope to reproduce the DAMA signals. However, none of them have been able to confirm the evidence for dark matter.

Combination of two detection methods

COSINUS will be added as a new testing instrument. The idea: COSINUS uses the same detector material as DAMA – sodium iodide. This is combined with a second detection channel – a special thermometer. When a dark-matter particle collides with the crystal, energy is deposited. This is manifested as a brief flash of light and a minuscule increase in temperature.

Over the next few years, COSINUS will be set up in the underground laboratory of the Gran Sasso (LNGS, Laboratori Nazionali del Gran Sasso) in Italy. The laboratory is located inside a massif, a natural bulwark against the interfering radiation from space. The experiment itself consists of 25 detectors surrounded by a seven-meter high water tank and thus protected from natural radioactivity. In the clean room above this setup, the detectors are prepared and installed in the experiment. The initial measurements are scheduled for 2022.

The project is led by a team from the Max Planck Institute for Physics, HEPHY, TU Wien, and INFN and GSSI (Italy). Other actors include SICCAS (China) and the Helsinki Institute for Physics (Finland).


In the clean room: Karoline Schäffner and her team complete their work on the cryostat (Photo: COSINUS Collaboration)

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Erection of the water tank in the COSINUS experiment (Photos: U. di Sabatino/LNGS)

Dark Matter Experiment COSINUS: Preparations are in full swing

The construction of the COSINUS experiment in the underground laboratory at Gran Sasso LNGS (Laboratori Nazionali del Gran Sasso) is making great progress. The first large component has been erected in the last weeks. It is a water tank (7 meter in…

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3D design drawing of COSINUS in the Gran Sasso underground lab (LNGS) (Image: L. Giaffoni/U. di Sabatini/R. Stadler)

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Dr. Karoline Schäffner

Karoline Schäffner heads new Max Planck Research Group

A new research group is starting at the Max Planck Institute for Physics, which is setting up another experiment for the detection of dark matter, called COSINUS. It is headed by Dr. Karoline Schäffner, who most recently conducted research at the…

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Ackermann, Karlheinz Engineering ack 445 A.1.35
Angloher, Godehard, Dr. Senior Scientist angloher 445 A.1.35
Ansorge, Henrik Student ansorge 560 A.1.25
Bharadwaj, Mukund PhD Student mukund 560 A.1.27
Braun, Sarah Intern sbraun 497 A.1.21
Dittmar, Clemens Johannes Udo PhD Student dittmar 497 A.1.21
Figueroa Falla, Pablo Jose Student pablof 379 A.1.33
Gaido, Elisa Student eligaido 582 A.1.31
Gapp, Maximilian Student gapp 560 A.1.25
Heim, Kilian Student kheim 560 A.1.25
Hughes, Maximilian, Dr. Postdoc hughes 582 A.1.31
Kellermann, Moritz PhD Student mkellerm 497 A.1.27
Oswald-Kloi, Melanie Secretary moswald 364 A.2.43
Schäffner, Karoline, Dr. Senior Scientist kschaeff 445 A.1.35
Shera, Kumrie PhD Student kshera 560 A.1.25
Stadler, Robert Engineering stadlerr 330 B.2.35
Stahlberg, Martin, Dr. Postdoc mstahlbe 379 A.1.33
Werner, Diana Secretary dwerner 364 A.2.43
Zema, Vanessa, Dr. Postdoc vanezema 582 A.1.31

Model-independent comparison of annual modulation and total rate with direct detection experiments
F. Kahlhoefer, F. Reindl, K. Schäffner, K. Schmidt-Hoberg and S. Wild; JCAP05(2018)074

Results from the first cryogenic NaI detector for the COSINUS project
G. Angloher et al; 2017 JINST 12 P11007

A CsI low-temperature detector for dark matter search
G. Angloher et al.; Astroparticle Physics, Volume 84, Nov. 2016, arXiv:1602.08884

The COSINUS project: perspectives of a NaI scintillating calorimeter for dark matter search
G. Angloher et al.,; Eur. Phys. J. C, Volume 76, Aug. 2016, arXiv:1603.02214