Conclusions of PARIS meeting, Cracow 14^th-15^th May 2007

Collaboration:

We were very pleased to have new expressions of support to the PARIS collaboration at this meeting. The new collaborators include researchers from Milano, Surrey, Edinburgh, Debrecen, Groningen and Dubna. This means that the Physics interest in PARIS is expanding to include spectroscopy with fragmentation beams.

GEANT 4:

Olivier Stezowski and Christelle Schmitt demonstrated the excellent GEANT4 package which has been put together to carry out simulations of possible designs for the PARIS calorimeter. At present, the simulation can handle multiple spherical shells of different materials, and/or absorbers. In terms of the design of the calorimeter, two central issues were identified.

1)The required thickness of the LaBr₃ shell for different applications e.g. GDR, radiative capture and spectroscopy.

2)The necessary granularity of the array which would allow the multiplicity of a given decay cascade to be identified for cases where the multiplicity is around 40; as well as for the investigations with fast beams.

The tasks were to be divided as follows (with Olivier Stezowski acting as expert advice):

1)Polish and Mumbai groups to focus on simulations relating to GDR studies

2)ATOMKI, Orsay and Krakow groups to investigate simulations relevant to spectroscopy with fast beams using the PARIS array

3)York and Strasbourg to work on simulations of heavy ion radiative capture reactions

4)Lyon- the needed granularity for high multiplicity events

5)Turkey will support some of this simulations

It is also important to work on possible designs for the prototype PARIS detector. We decided that:

Cracow and York groups to collaborate on initial simulations of a prototype PARIS detector, composed of LaBr and BaF crystals

Detector testing:

It was considered important to begin detector testing even though we are far from being able to fix details of the design of the PARIS prototype detector. We do not have funds to purchase crystals at present and so will make use of crystals already owned by members of the collaboration e.g. Sofia, Orsay, Milano. David Jenkins will compile an inventory of what materials are available. The initial testing will consist of the following:

Strasbourg group to carry out tests of LaBr crystals in conjunction with APDs to determine whether this will be a viable solution to achieve a compact geometry. They will also investigate rates issues and digital electronics solutions.

York, Milan and Polish groups to carry out tests of LaBr crystals with conventional PMTs. The objective is to gain initial experience with this new material.

In parallel, the Sofia group are carrying out tests of the timing properties of LaBr₃ crystals including an in-beam test in the near future in Bucharest.

Dubna group will test the large pure CsI detector, as an alternative for BaF2 solution for measuring high energy gamma rays.

Liason with Saint-Gobain Crystals:

It was agreed that in order to avoid confusion on the part of Saint-Gobain crystals, it would be highly beneficial for there to be a sole point-of-contact with them. The most suitable person was Joel Pouthas from Orsay, who had had dealings with them over many years, especially with their engineers. He could therefore discuss detector designs with them on a technical level.

PARIS front end electronics

Different propositions were discusses, including the option for fully digital electronics. No real conclusion was yet achieved. Orsay, Milano and Polish groups shall think more about this.

JRA under EURONS2?

Some of the PARIS partner were discussing for some time the possibility of proposing a JRA under new EURONS. This initiative was proposed already in October 2007 during the EWON meeting in Zagreb, as a possibility that such an initiative could be launched by the EWON countries and by all PARIS members. Later this initiative was extended to include another future gamma (and charged particle calorimeters), as gamma calorimeter for R3B, GASPARS, EXL etc.

The conclusion on this subject was that we support this broader proposal for JRA, providing that the PARIS members will be visible in such a project. Adam Maj (PARIS project spokesman) will take care on this.

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PARIS Steering Committee

PARIS steering committee (PSC), which main task in this moment is to help the PARIS project spokesman (Adam Maj) in coordination of thewhole project, was extended by the leaders of new active groups. It was decided to have PSC chairmen and deputy chairman. After one year deputy chairman will replace the chairmen, and new deputy will be appointed. PSC appointed Faical Azaiez as the chairman and David Jenkins as the deputy.