White paper on suitability of HNScienceCloud and European Open Science Cloud for synchrotron and FEL applications

This paper identifies the needs specific to synchrotrons and FELs towards the European Open Science Cloud (EOSC) and how these research infrastructures and their user communities can best take advantage of the EOSC. The CALIPSOplus project [http://www.calipsoplus.eu/] brings together all photon sources in Europe. A significant number of them have participated in the Joint Research Activity 2 (JRA2 also referred to as WP24), to develop a prototype of a remote Data Analysis as a Service (DAAS) platform. The prototype was deployed and tested at the participants site and an online workshop was held at the end of 2020 to present the results. The prototype DAAS service was instrumental in identifying the needs for remote analysis and cloud-like access to IT resources for photon research infrastructures. This experience furthermore allowed the authors to reflect on the promise on "The European Open Science Cloud (EOSC) is an environment for hosting and processing research data to support EU science" made by the EOSC and its application to photon sources. The paper starts by defining the needs of the Photon and Neutron (PaN) community towards cloud computing and then presents the achievements from JRA2. It then goes on to analyse the situation for photon sources according to the services recommended by the EOSC: FAIR data, data storage, data processing, data re-use. It continues with a brief overview of the Helix Nebula Science cloud and then proceeds to an overview of EOSC services, their state and suitability for the PaN RIs