In the last years, the interest in investigating nuclear moments seems to be increased. Several groups are starting this kind of research using different production schemes and experimental techniques. Many techniques, which were used with stable beams in the seventies and eighties have not been used on a very intensive level in the last twenty years, but since a few years they start to be more used again with the exotic beams. People are adapting old techniques to be used on new types of beams. My own research group is developing several techniques to study the moments of exotic ground states and isomers produced as fragmentation beams. I think it is a lively field.

        At the moment, we are running projects at GANIL, at ISOLDE and at GSI, where we just finished a big campaign. All this research concentrates on different regions of the nuclear chart. The common ingredient is that we try to stay close to magic nuclei, not doubly magic but magic in one or the other nucleon number. A region we are focusing on is the N=20 island of inversion that was a project that started at GANIL and that we continued also at ISOLDE because not all the beams unfortunately are intense enough with fragmentation. This project is more or less close to finishing. Of course, if the beam intensities would go up with a factor of ten or hundred in the future, we could go much further beyond N=20. The island of inversion is defined around N=20,21,22 but at N=22,23, nobody has ever done an experiment to confirm. The other region that we will start at GANIL very soon - it is an accepted proposal - is to do similar studies in the neutron-rich region below ⁴⁸Ca, where a similar island of inversion or, at least, an island of deformation seems to appear and also in particular to investigate there the migration of the proton s and d levels, which are changing dramatically with neutron number. At ISOLDE, we have a project accepted to study the Cu isotopes, which are close to Z=28 and that is with the aim again to study the monopole migration of the proton levels and in particular, fix some ground state spins, which are still being debated at the moment, in the neutron-rich Cu region. At GSI, the RISING campaign is just finished. It was concentrating on again another region, on the heavier mass region, mainly near ¹³²Sn, which is a region that is very hard to access for moment studies on isomers, microsecond isomers.

        For the future, post-accelerated beams could be used to study nuclear moments. I think that Georgi Georgiev will further develop techniques for that. This is something that I support very much, which I think is very interesting. It gives good perspectives with radioactive beams, although I think that he will have to solve a couple of questions, which we probably do not think about at the moment, particularly related to radioactive beams. For the ground state studies, fragmentation remains the ideal tool because of the orientation that comes for free, so I would most warmly welcome an upgrade in the fragmentation beam intensities at GANIL. But I do not think it is in any plan for the moment. This idea to develop a low energy facility coupled to the SPIRAL2 ion source could be potentially quite interesting. To my opinion, it will take a long time to obtain the diversity of beams that are now available at ISOLDE for example. But I am sure that with the increased beam intensities interesting physics problems can be tackled.  This DESIR facility should try to be complementary and find where they are the best and for which cases they can be unique. Then there is great potential in this idea.

More info:
    Gerda Neyens's talk
    Gerda Neyens's e-mail
    IKS web site
    Nuclear moments session


Words collected by K. Turzó at the XV^e Colloque GANIL, Giens, France, from May 29^th to June 2^nd, 2006.