JCNS Workshop on Modern Trends in Production and Applications of Polarized 3He

Abstract

Polarized neutron scattering techniques are an indispensable and highly requested tool for studying magnetic phenomena in condensed matter. The different coherent and incoherent scattering of isotopes such as protons and deuterons also allows applications of polarized neutrons in soft matter and biological studies of molecular and macromolecular dynamics.One method to polarize neutrons is to use polarized 3He gas which absorbs, or filters, one spin state of the neutron beam as it passes through it. Only about ten years ago, early polarized neutron scattering experiments using such 3He neutron spin filters (3He NSF) were being conducted using starting 3He polarizations of 55%. Currently there are two different commonly used methods to polarize high quantities of 3He. These methods both collisionally transfer spin polarization to ground state 3He nucleuses; one method uses optical pumping of an excited metastable state of 3He atoms, and the other uses optical pumping of the ground state of an alkali-metal vapour. Within the last decade immense progress in both methods has resulted in 3He polarizations of up to 80% being reported in atmosphere-pressure 3He cells by the world's leading labs.This progress in optical pumped 3He promises to give rise to much more efficient and novel polarized neutron scattering experiments as and also impacts other areas of science. Polarized 3He is additionally applied in research fields such as particle physics, fundamental studies and medicine. Thus not only the techniques and methods of polarization, but the research groups themselves exploring polarized 3He, have a large breadth and diversity spanning different fields of science and locations in the world. Given this diversity, it is rare for this community to meet as a group at any one meeting or conference.Because it is crucial to discuss new developments in 3He polarization in a multi-disciplinary international setting, an international workshop on "Modern Trends in Production and Applications of Polarized 3He" was held from 11–13 July 2010 in Ismaning, Germany. This workshop was organized by the Jülich Centre for Neutron Science (JCNS) as part of our ongoing series of topic-oriented JCNS workshops relating to specific activities of the JCNS. In particular this JCNS workshop discussed the techniques of polarization of 3He, 3He containers, magnetic holding systems, 3He spin manipulations and applications in neutron scattering, medicine and physics.The workshop was very well attended with intense discussions and inspiring presentations. In many ways the current workshop was a conceptual descendent of the HELION workshop in 2002 in Mainz, Germany. It is the hope of both us and many of the participants that such a workshop will be held again, perhaps 3 to 4 years in the future.The current proceedings is a collection of papers written within the spirit of the workshop to provide a documentation of the current status and perspectives in the polarization of 3He and its applications.Alexander Ioffe Earl Babcock Thomas Gutberlet Editors