Coordination of the resources for gamma-ray spectroscopy in Europe

The objective of the GAMMAPOOL network is to improve the coordination of the European resources used for high-resolution gamma-ray spectroscopy and especially the equipment from the EUROBALL spectrometer including complementary equipment. These resources are available to the European nuclear physics community for experimental campaigns at accelerator laboratories offering unique new physics opportunities. The network facilitates novel programmes in gamma-ray spectroscopy of nuclei under extreme conditions.

Through this network, state-of-the-art equipment for gamma-ray spectroscopy is available to European research collaborations that plan to perform world-class experiments in dedicated campaigns at the major research infrastructures. Collaboration meetings are held in order to encourage new collaborations and to discuss and exchange information in the wide European nuclear physics community about novel possibilities arising from the use of the GAMMAPOOL equipment and the scientific achievements.

The goal is to allow large, focussed campaigns that become possible through an innovative combination of a large set of GAMMAPOOL detectors together with unique local infrastructure (e.g. separators, ancillary detectors, etc) not available elsewhere and give the community the opportunity to exploit this unique opportunity.

About GAMMAPOOL

The European Gamma-Ray Spectroscopy Pool (EGRSP) has been created in 2002 in the same meeting where the EUROBALL ended with the signature of an MoU to establish a joint management of the resources of the EUROBALL collaboration and other complementary equipment.

The idea behind this agreement was to allow the use the enormous potential of the EUROBALL equipment for specific experimental campaigns at accelerator laboratories that could offer unique new physics opportunities for a wide scientific community. The EGRSP started to be known as GAMMAPOOL when it was proposed as a network within EURONS in the Sixth Framework Programme of the EU (FP6) on Research Infrastructures Integrating activities.

Later on, the idea of a network for sharing resources and knowledge has been continued with the EGAN (within ENSAR in FP7) and NUSPIN (within ENSAR2 in Horizon2020) networks.

The first members of the EGRSP were chosen among the members of the last EUROBALL Steering Committee and the EUROBALL Infrastructure Group, combining management and technological expertise. The members of the GAMMAPOOL are 10 in proportion to the invested capital in EUROBALL.

The reasons for creating the EGRSP

In the book Achievements with the Euroball spectrometer the last section, Future perspectives tells us:

The EUROBALL coordination committee took the decision to stop the operation of the spectrometer in its current form once the campaign at IReS Strasbourg has been completed. From that moment, the resources from the EUROBALL array have been made available to the European Nuclear Physics community for dedicated campaigns at accelerator laboratories offering unique new physics opportunities. This programme, which has served the needs of the community since 2003, has been coordinated by a network pooling the European resources for γ-ray spectroscopy.

The EUROBALL campaigns have clearly shown that, besides a powerful gamma-ray spectrometer, efficient and dedicated particle detectors or spectrometers are the decisive ingredients if information from weakly populated nuclei is to be investigated. In fact, for a few years to come, until radioactive ion beams from the emerging new facilities reach appropriate intensities, gamma-ray spectrometers operated at a high intensity stable beam facility are competitive for many of these studies. For the first two years (2003/2004) campaigns at three different accelerator laboratories have been planned and performed. They have employed different parts of the EUROBALL spectrometer and have been performed in parallel.

• At the cyclotron laboratory of the University of Jyväskylä (Finland), 45 large-volume Ge detectors have been coupled to the gas-filled separator RITU to perform experiments on heavy exotic nuclei, with an emphasis on the study of very heavy nuclei beyond Z=100.
• At the Legnaro National Laboratory (Italy), the EUROBALL Clover detectors have been coupled to the PRISMA spectrometer to study neutron-rich nuclei by means of multi-nucleon transfer and deep-inelastic reactions.
• The EUROBALL Cluster detectors have been used for the “Rare Isotope Investigations at GSI” (RISING), i.e. spectroscopic studies of relativistic energy beams provided by the SIS-FRS facility.

More recent GAMMAPOOL activities can be found in the online brochure for the First 10 years of GAMMAPOOL operation.

EUROBALL and AGATA

Although EUROBALL has enabled the studies of very rare nuclear phenomena to be carried out, i.e. at the level of ~10E-5 of the production cross-section in a heavy-ion reaction, the development of a new generation of even more powerful γ-ray spectrometers is vital to make future progress. Further progress, beyond the capabilities of EUROBALL, however, requires a completely new detection concept. For this purpose all interactions of each γ-ray must be characterised in order to perform a full “γ-ray tracking”. Utilising this concept will allow the construction of a complete Germanium shell, which will have unprecedented qualities in terms of sensitivity and efficiency. γ-ray tracking is based on highly segmented, position sensitive Ge detectors and digital pulse processing electronics.

After the first Demonstration campaign at LNL (2010) AGATA has continued increasing the number of detectors at LNL (2010-2011), GSI (2012-2014) and presently at GANIL (2015-2021).

This array opens a broad range of new physics opportunities in connection with the (existing and future) radioactive and intense stable beam accelerators.

Visit the AGATA website for more information.