The AGATA demonstrator consists of five triplets (3 asymmetric Ge detectors in a common cryostat). The surface of each diode is electrically segmented into 36 segments (i.e. 5*3*36= 540 segments for the whole and 540+15=555 measurement channels).
AGATA (Advanced GAmma Tracking Array) is a new generation gamma spectrometer after the Euroball and EXOGAM detectors.
Agata's official website: https://www.agata.org
AGATA Web site at GANIL : https://www.ganil-spiral2.eu/scientists/ganil-spiral-2-facilities/instrumentation/agata/
Objectives.
The AGATA project aimed to build a 4Pi gamma spectrometer entirely made of Germanium detectors. These multi-segmented detectors are sensitive to the position of gamma ray interaction and thus make it possible to obtain a trace reconstruction, which was at the origin of the project a new concept in spectroscopy. This ultimate spectrometer, with unprecedented efficiency and sensitivity, has been designed to adapt to the extreme experimental conditions of the next generation of radioactive ion beam accelerators, such as SPIRAL2 at GANIL, FAIR at GSI and EURISOL, as well as very high-intensity, low-energy heavy ion accelerators (around the Coulomb barrier).
Context.
The nuclear physics community prepared the construction of this multi-detector, based on the gamma tracking technique, which was a major challenge in gamma spectroscopy. In its final phase AGATA will consist of 180 Germanium detectors. A major European collaboration contributed to the last phase of R&D, by implementing a demonstrator that validated the technique before deciding on the end of construction. More than 40 laboratories in eight European countries had planned an investment of around 6 millions € for this demonstration phase.
Location.
AGATA is a "nomad" detector that is intended to be used on future European installations: Spiral2, Fair, Eurisol. The first phase, the AGATA demonstrator, was hosted at three different sites: LNL (2010+), GANIL (2016+), GSI (~2015+).
Contributions from Irfu (scientific and technical)
Irfu has been deeply involved in the verification of germanium detectors, their triplet integration, infrastructure development (low and high voltage, cryogenics) and control command. Irfu also participated in the purchase of the French triplet. In particular, the Irfu teams were responsible for the design and manufacture of high-voltage modules in a limited space, designed to improve resolution by eliminating the wiring distance.
Irfu has also initiated with IPNO an R&D on cryogenics to replace Dewars.
For the construction phase, Irfu was involved in the acceptance for validation of detectors and became one of the triplet integration sites.
One of AGATA's first germanium detectors with its analog electronics mounted in an individual cryostat on the test bench at SEDI.
Installation of the High Voltage module on an AGATA germanium detector at the University of Cologne.
