The CRESST experiment – the search for dark matter

According to cosmological observations, ordinary matter, of which atoms, all living beings, stars, planets and galaxies consist, accounts for only 5 percent of the total matter in the universe. A larger portion by far, around 25 percent, is made up of so-called dark matter. It is, however, not yet clear what this consists of.

Our galaxy, the Milky Way, is surrounded by a large accumulation of dark matter. Its enormous mass has had a crucial impact on the evolution of the galaxy.

A number of well-founded theories state

  • that dark matter consists of particles that exert gravity and
  • interacts with visible matter - albeit very weakly.

If these dark matter particles exist, it should be possible to observe them from Earth with suitable measuring devices.

Scientists working on the CRESST experiment are on the lookout for dark matter. CRESST is an acronym for “Cryogenic Rare Event Search with Superconducting Thermometers”. The experiment is being conducted by a European research collaboration headed by the Max Planck Institute for Physics (MPP).

Tracking down dark matter with crystal detectors

The CRESST experiment is located in the underground laboratory below the Gran Sasso massif (Laboratori Nazionali del Gran Sasso, LNGS) in Italy. It comprises high-sensitivity detectors that react when a dark matter particle impinges on an atomic nucleus in the detector material.

Since a reaction between these particles and ordinary matter is an extremely rare event, researchers expect only a small number of observable events per year. In order to discover them with a high degree of certainty, the scientists have developed a special method.

The instruments consist of ultrapure, scintillating calcium tungstate crystals (CaWO4) whose operating temperature is at almost -273 degrees Celsius, i.e. close to absolute zero. When a dark matter particle collides with an atomic nucleus, the temperature in the crystal increases by around one millionth of a degree.

High-sensitivity sensors make all the difference

Highly sensitive thermometers in the detector measure this absolutely minute difference. In addition, the particle-particle interactions generate flashes of light in the crystal. The light particles – or photons, as they are known – are measured by a sapphire and silicon sensor.

The second signal has the important task of identifying which particle species has triggered the reaction. Signals caused by dark matter can thus be reliably distinguished from the radioactive background.

This technology is the basis for one of the most sensitive particle detectors ever built. In their search for dark matter, physicists can thereby venture into still unexplored mass regions. These properties make CRESST the top experiment in the search for particularly light particles of dark matter.

With its expertise in detector development, low-energy technology and data analysis, the MPP is playing a leading role in the CRESST research collaboration.

CRESST at the MPP

E-mail address: e-mail@mpp.mpg.de
Phone number: +49 89 32354-extension
name function e-mail extension office
Banerjee, Heerak Postdoc banerjee 473 A.1.59
Bento, Antonio, Dr. Senior Scientist bento 309 A.1.49
Bertolini, Anna PhD Student anbertol 327 A.1.59
Di Lorenzo, Stefano, Dr. Postdoc sdilo 316 A.1.55
Dominsky, Felix PhD Student dominsky 569 A.1.59
Fuchs, Dominik PhD Student fuchsdom 364 A.1.59
Hauff, Dieter Senior Scientist hauff 266 A.1.55
Langenkämper, Alexander, Dr. Postdoc langenk 270 A.1.51
Mancuso, Michele, Dr. Senior Scientist mancuso 756 A.1.55
Mauri, Beatrice, Dr. Postdoc bmauri 352 A.1.57
Oswald-Kloi, Melanie Secretary moswald 364 A.2.43
Petricca, Federica, Dr. Senior Scientist petricca 309 A.1.53
Pröbst, Franz, Dr. Senior Scientist proebst 270 A.1.51
Pucci, Francesca PhD Student frapucci 218 A.1.57
Werner, Diana Secretary dwerner 364 A.2.43
Zanirato, Marco Maria Student zanirato 473 A.1.49
de Santis, Alessio Ludovico PhD Student ludovico 218 A.1.57

CRESST detector module with H-shaped temperature sensor made of superconducting material (Photo: T. Dettlaff/MPP)

CRESST: Finetuning dark matter detectors

The CRESST experiment has specialized in the search for light dark matter particles, lighter than 1 Gigaelectronvolts (1 GeV). In order to reliably measure the tiny energy released by these particles in the detectors, those must be very precisely…

Read more
A look through the CRESST experiment that inspired Diogo da Cruz to propose the installation "A shot in the dark", now on display at Serralves Museum, Porto. (Photo: CRESST)

A shot in the dark: Dark matter in a museum

The scientific proof of dark matter in the universe is one of the most exciting research fields in physics. The CRESST experiment in the Gran Sasso underground laboratory in Italy is one of the institutions looking for particles that could form the…

Read more
One of the detector modules in the CRESST experiment

How much does dark matter weigh? CRESST explores new mass ranges

CRESST erobert neue Massebereiche

A variety of astronomical and cosmological observations have now placed the existence of dark matter beyond dispute. However, no experiment has yet succeeded in establishing just what dark matter is made of. For many years, scientists have been…

Read more
Dr. Federica Petricca

Federica Petricca becomes head of CRESST group

A change is announced in the CRESST scientific research group (Cryogenic Rare Event Search with Superconducting Thermometers) searching for dark matter. Federica Petricca, a scientist at the Max Planck Institute for Physics since 2005, succeeds Franz…

Read more
Installing the new detector modules into the CRESST experiment

The search for dark matter: Entering the next phase of the CRESST experiment

The CRESST experiment is continuing its search for dark matter. A few weeks ago, the detector reached its operating temperature of around -273 degrees Celsius, i.e. close to absolute zero. For the new measurement started in September, the experiment…

Read more

Stefan Schönert is a Fellow at the Max Planck Institute for Physics

Fellow at the MPP

Stefan Schönert, Professor for Experimental Astroparticle Physics at the Technical University of Munich (TUM), has been named a Max Planck Fellow at the MPP, where he will do research in the area of dark matter and neutrino physics. The Fellow…

Read more

Dark matter: Searching for "lightweights" with CRESST

Planets, stars, and galaxies form only the visible portion of the matter in the universe. Greater by far is the share accounted for by invisible "dark matter". Scientists have searched for the particles of dark matter in numerous experiments – so…

Read more

Results on light dark matter particles with a low-threshold CRESST-II detector
G. Angloher et al. (CRESST Collaboration)
Eur. Phys. J. C 76, 25 (2016)

Limits on Momentum-Dependent Asymmetric Dark Matter with CRESST-II
G. Angloher et al. (CRESST Collaboration),
Phys. Rev. Lett. 117, 021303

Beta/gamma and alpha backgrounds in CRESST-II Phase 2
R. Strauss et al. (CRESST Collaboration)
J. Cosmol. Astropart. Phys. 06 (2015) 030

A detector module with highly efficient surface-alpha event rejection operated in CRESST-II Phase 2
R. Strauss et al. (CRESST Collaboration)
Eur. Phys. J. C (2015) 75:352

Results on low-mass WIMPs using an upgraded CRESST-II detector
G. Angloher et al. (CRESST Collaboration)
Eur. Phys. J. C 74, 3184 (2014)