Speaker
Description
To cross-check the longstanding DAMA/LIBRA dark matter claim, the COSINUS (Cryogenic Observatory for SIgnatures seen in Next generation Underground Searches) experiment applies the same target material, namely sodium iodide (NaI), operated as cryogenic calorimeters at temperatures around 15 mK. A COSINUS detector module consists of a NaI crystal, which is glued on a silicon disk, equipped with a phonon sensor and a silicon beaker surrounding the crystal in order to measure scintillation light produced in interactions. The beaker is equipped with a transition edge sensor (TES), directly deposited onto the silicon surface. Also the phonon signal is detected using a TES. However, due to the soft and hygroscopic nature of NaI, direct deposition of a TES onto a crystal is not possible. To overcome this limitation, a new sensor design, the so-called remoTES, was developed. In this design, only a gold pad on the NaI crystal is required, while the actual sensor is fabricated on a separate sapphire chip. The sensor and absorber crystal are then connected via a gold link, realized with a wire bond.
While in previous times gold pads were glued on NaI crystals, recent developments allow now for a thermal evaporation of the gold pads. Also the gluing of the NaI crystals to the silicon disks was refined and the module assembly process enhanced. In this contribution, we now want to present the recent improvements of the detector module, the latest prototype measurements as well as the final design, fabrication and assembly of the COSINUS run1 detectors.
| Main Contribution topic | Instrumentation for Dark Matter searches |
|---|---|
| Secondary contribution topic | Direct detection |