1. Description of the infrastructure, Relevance and S&T Excellence
KVI-Electron-Cyclotron ( ECR) ion source Groningen
(in charge: R. Hoekstra)
KVI is an accelerator institute with a cyclotron as its central facility. It was acknowledged as “Large Scale Facility” by the European Union within the network ‘LIFE’ (until 2004) and the new network ‘EURONS’ (since 2005). The institute traditionally has a lot of experience in receiving guests from abroad to perform experiments here and the administration is well prepared to handle all necessary official procedures. Guestrooms are available for people coming to Groningen for a shorter period.
The KVI electron-cyclotron ion source of the Atomic Physics Group is situated at the KVI in a large hall with an area of about 200 m 2 which is dedicated to atomic physics experiments (see drawing below). The source can deliver ion beams with ionic charges up to q=30 and bare ions up to Ne 10+. The source can be floated on a potential up to 25 kV, thus providing ions with energies up to q·25 keV. If higher energies are needed, the ions can be accelerated up to q·150 keV by means of a small two-gap linear accelerator. On the other hand ions can be decelerated to energies significantly less than 100 eV in some of the experimental setups by floating them on high potential. This implies that ion beams can be delivered in a wide range of kinetic energies that are interesting for atomic and molecular collision experiments, namely with ionic projectile velocities ranging from much below to significantly above typical velocities of target electrons.
By means of switching magnets the ion beams can be directed to 5 different experimental areas one of which is always reserved for guest experiments. This implies that guests can bring their own apparatus to Groningen to do experiments using the ion ECR ion beams.
Several high-vacuum and one ultra-high-vacuum apparatus are presently in use at the facility, equipped with various spectrometers: photon spectrometers for the visible, UV, VUV and soft X-ray range, electrostatic electron and ion spectrometers as well as time-of-flight reflectron spectrometers. The UHV apparatus , used for surface studies, is equipped with an evaporator which allows to produce thin films of e.g. C 60 fullerenes or biomolecules on clean surfaces.
Molecular fragmentation processes are investigated in an apparatus in which molecular targets can be exposed simultaneously to beams of highly charged ions and (pulsed) laser light, allowing pump-probe experiments.
1.2 New Opportunities of access to infrastructure
The Zernike-LEIF facility is already equipped with a setup for investigation of biomolecular radiation damage on the level of small isolated molecules. With the community funding, Zernike-Leif will also offer the possibility of studying larger biomolecules (oligonucleotides) as well as biomolecules embedded into water clusters. Such a wide range of research opportunities in the field of biomolecular radiation damage is certainly demanded by the research community. The community funding for beamtime and travelling will enable the access of smaller groups to these opportunities.
2. Management of the access provided
We envisage two types of users:
(i) those who will bring their whole apparatus to Groningen for a period of several weeks to months, during which experiments can be performed with the ion beams supplied by the Zernike-LEIF facility. Typically beam-time will be provided for about two days per week. Such a schedule is advantageous for the user and for the host group: the latter need not interrupt their own experiments for a longer period, and the users have a chance to perform a first analysis of their data and possibly improve their apparatus before starting new measurements. In the past such a flexible beam schedule has proven to be successful.
(ii) another type of users will participate in joint experiments whereby the user is providing special know how, parts of equipment to be integrated into setups available in Groningen, or equipment – such as atomic force microscopes (AFM) – for subsequent analysis of e.g. irradiated surface- or thin-film samples. During the time that the users are present in Groningen the joint experiments will get some priority, whereby – similar as described above – about two days per week will be available for these experiments.
In view of the fact that the operation of the ion source is not trivial the users will receive competent support from the staff in Groningen. For each user one of the senior research physicists or an experienced PhD student will be nominated to assist the user during the preparation-, the installation- and the running-period of the experiment. During their time in Groningen users will have the possibility to use the computer facilities and they will get a computer-account.
Also in the subsequent period of data-evaluation support will be given if necessary.