Speaker
Description
Scintillating crystals are among the most widely used particle detectors in research laboratories, industry, nuclear medicine, and physics experiments. Some of these tend to degrade when exposed to environmental humidity, such as NaI(Tl). This makes the crystals difficult to handle, can limit their use in specific applications or forces the selection of alternative materials with suboptimal properties.
In the long-standing search for dark matter, the use of NaI(Tl) crystals is motivated by the results of the DAMA/LIBRA experiment at the Gran Sasso National Laboratories. In this context, several experiments worldwide (e.g. ANAIS, COSINE, SABRE, PICOLON) are operating NaI(Tl) crystals canned in metal enclosures. Scintillation light is read out by photomultiplier tubes through one or two optical windows.
Other projects, such as ASTAROTH, are developing the next generation of detectors by coupling these crystals with arrays of Silicon Photomultipliers. Operating such detectors at cryogenic temperatures greatly enhances the signal-to-noise ratio in the keV recoil energy region of interest and allows to lower the detection threshold below 1 keV, where a potentially large fraction of the signal remains undetected.
Within the ASTAROTH project, an innovative technique has been developed for encapsulating 5-cm cubic NaI(Tl) crystals in epoxy resin. This method provides mechanical strength, environmental protection, ease of handling, transparency on all crystal faces, resistance to vacuum and cryogenic operations, and low radioactivity contribution, all of which are an advantage with respect to the state of the art enclosures.
We report on the technology developed and on the tests performed on the first working detector.
| Main Contribution topic | Instrumentation for Dark Matter searches |
|---|---|
| Secondary contribution topic | Direct detection |