Druck-Materie 20b.qxd - JUWEL - Forschungszentrum Jülich

Preface
These are the Proceedings of the 6th Meeting of the International Collaboration on
Advanced Cold Moderators. We apologize for the long delay in publishing these lecture
notes, which is mainly the editor’s fault. On the other hand, despite the long time since our
meeting, it was not possible to obtain all contributions to the Proceedings in full text version.
Like in the editor’s case this is certainly due to the many other duties of our colleagues. In
order to nevertheless present a complete account of the meeting we have included in an
Appendix copies of what was collected from the authors during the meeting.
The collaboration on Advanced Cold Moderators was initiated during a meeting at
Forschungszentrum Jülich in July of 1997, when a small working group of experts from numerous
institutions was established. After this inaugural meeting we had the second one, arranged
by Renate Bercher and Günter Bauer of the Paul-Scherrer-Institut in Villigen (Switzerland)
in February of 1998. The third meeting, ACoM-3, took place in Oak Ridge under the
supervision of Trevor Lukas in June of the same year. The fourth meeting was organized by
Heidrun Barnert-Wiemer of Forschungszentrum Jülich and held there in February of 1999.
The fifth meeting took place in Berlin in connexion with a general workshop on moderator
concepts for spallation sources organized by Thomas Gutberlet, then at the Hahn-Meitner-Institut
in Berlin.
Of the first three meetings only minutes were written up and supplemented with copies
of a few presentations, which were available. The first “formal” proceedings were printed and
distributed among the collaboration members and meeting participants for ACoM-4.
Our sixth meeting, the proceedings of which we deliver here, was attended by thirtyfour
colleagues from eight countries on three continents – a small but impressive assembly of
experts in the field. They presented their latest results in theory, numerical computation and
experiments on advanced cold moderator media like methane-hydrate, tri-methyl-benzene or
ammonia. With the sponsorship of Forschungszentrum Jülich and the support of members of
the project team of the European Spallation Source (ESS) we were able to have a pleasant and
fruitful meeting on site in the seminar room of the ESS project building. Taking care of
transportation and hotel accommodation of the external participants, the ladies Julia Philippen
and Andrea Fournier warranted a smooth course of the meeting. Lunches were served in one
of Forschungszentrum’s Cafeterias and coffee and snacks during the breaks were provided
next to the lecture hall. Günter Mank and Alf Bauer from the ESS project team efficiently
assisted with technical support regarding computers and beamer facilities.
The European Spallation Source project is unfortunately dormant for an unspecified
term and the two major megawatt spallation facilities in Japan and the US are in a very advanced
stage of construction employing conventional cryogenic moderators only. Nevertheless,
the performance prospects of advanced cold sources (if we consider an all para-hydrogen
moderator a conventional one) are so intriguing that we can expect their development to continue.
In this respect we are looking forward to our next meeting.
Harald Conrad, editor
March 2004