Ponente
Descripción
The KM3NeT project aims to build a neutrino telescope in the depth of the Mediterranean Sea. The detector consists of a Kilometer-cube grid of Optical Modules, photosensors encapsulated into transparent pressure resistant glass spheres. A crucial component is the acoustic positioning system, which provides the position of photodetectors and structures in the deep sea with an accuracy of about 10 cm. The system is based on measurements of acoustic signals between fixed seabed emitters and receiving hydrophones. A subset of the required acoustic beacons is powered by an autonomous voltage supply system, based on a battery pack.
The talk will describe the innovative design used to build the battery packs, deriving from the expertise of the Catania KM3NeT group in the construction of underwater detectors encapsulated in glass vessels. The battery pack uses a pressure resistant 17-inch glass sphere as housing, identical to those used for optical modules. It contains a cluster of 96 batteries connected to supply an output voltage of 12 Volt with a total capacity of 410 Ah. With a dimension of 44 cm and a weight of 42 kg, the final result has then a very high energy density, especially for deep underwater application. The cluster of batteries is surrounded by silicone glue, the same technology used in the optical modules, that stacks all the part together and ensures mechanical strength and a stable link with the vessel. In order to increase the operating time of the beacon, a custom designed wake-up board implements a duty cycle operating mode, where an electronic switch controlled by an ARDUINO microprocessor connects the battery pack to the beacon only for a defined time. So far, 6 supply systems have worked among the Italian and the France sea site of the KM3NeT project. The system, designed for beacons, could be easily used to supply voltage for also other kinds of detectors in underwater high-pressure environments.
| Affiliation | INFN sezione di Catania |
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