[en] Modern neutron sources and modern neutron science share a common origin in mid twentieth century scientific investigations concerned with the study of the fundamental interactions between elementary particles. Since the time of that common origin, neutron science and the study of elementary particles have evolved into quite disparate disciplines. The neutron became recognized as a powerful tool for the study of condensed matter with modern neutron sources being primarily used (and primarily justified) as tools for condensed matter research. The study of elementary particles has, of course, led to the development of rather different tools and is now dominated by activities carried out at extremely high energies. Notwithstanding this trend, the study of fundamental interactions using neutrons has continued and remains a vigorous activity at many contemporary neutron sources. This research, like neutron scattering research, has benefited enormously by the development of modern high flux neutron facilities. Future sources, particularly high power spallation sources, offer exciting possibilities for the continuation of this program of research

[en] A neutron guide is disclosed in which lengths of cylindrical glass tubing have rectangular glass plates properly dimensioned to allow insertion into the cylindrical glass tubing so that a sealed geometrically precise polygonal cross-section is formed in the cylindrical glass tubing. The neutron guide provides easier alignment between adjacent sections than do the neutron guides of the prior art

[en] This paper discusses the start up plans for a free neutron lifetime experiment

[en] The purpose of the workshop was to provide guidance for a new National Cold Neutron Facility at the 20 MW research reactor at the National Bureau of Standard campus in Gaithersburg, Maryland. Separate abstracts were prepared for 25 papers in this report

[en] This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL) concerning the investigation of a new method for the experimental exploitation of ultra-cold neutrons. The production and storage of ultra cold neutrons in superfluid helium has been suggested as a tool for the production of high densities of ultra cold neutrons for fundamental nuclear physics as well as for sensitive measurements for condensed matter. A particular application of this technique has been suggested by Doyle and Lamoreaux that involves the trapping of neutrons in a magnetic field within the superfluid helium volume. Neutron decays within the trap volume are detected by the scintillation light produced in the liquid helium. A cryostat and magnetic trap have been constructed as well as a prototype light detection system. This system was installed on a cold neutron beam line at the NIST Cold Neutron Research Facility in the summer of 1997. Preliminary results indicate the detection of helium scintillation light from the detection vessel

[en] The weak pion-nucleon coupling constant H_π¹ remains poorly determined, despite many years of effort. The recent measurement of the ¹³³Cs anapole moment has been interpreted to give a value of H_π¹ almost an order of magnitude larger than the limit established in the ¹⁸F parity doublet experiments. A measurement of the gamma ray directional asymmetry A_γ for the capture of polarized neutrons by hydrogen has been proposed at Los Alamos National Laboratory. This experiment will determine H_π¹ independent of nuclear structure effects. However, since the predicted asymmetry is small, A_γ approximately 5 x 10^-8, systematic effects must be reduced to < 5 x 10^-9. The design of the experiment will is presented, with an emphasis on the techniques used for controlling systematic errors

[en] Ultra Cold Neutrons (UCN) can be produced at spallation sources using a variety of techniques. To date the technique used has been to Bragg scatter and Doppler shift cold neutrons into UCN from a moving crystal. This is particularly applicable to short-pulse spallation sources. We are presently constructing a UCN source at LANSCE using this method. In addition, large gains in UCN density should be possible using cryogenic UCN sources. Research is under way at Gatchina to demonstrate technical feasibility of a frozen deuterium source. If successful, a source of this type could be implemented at future spallation source, such as the long pulse source being planned at Los Alamos, with a UCN density that may be two orders of magnitude higher than that presently available at reactors

[en] It is proposed that the magnetic field associated with a helicoidal antiferromagnet can produce a rotation in the plane of polarization of a polarized neutron beam. An estimate of the magnitude of such an effect is made. Rotatory powers as large as 10^-4 radian cm^-1 may occur. (Auth.)

[en] A new determination of the ratio of the neutron to proton magnetic moments of the neutron is reported. The most appealing prediction of -2/3 (Beg et al. Phys. Rev. Lett.; 13:643 (1964), Sakita (Phys. Rev. Lett.; 13:643 (1964))) for the ratio lies approximately 10⁶ experimental standard deviations from the experimental value of -0.68497945(17) reported here. The experimental techniques used in the present determination are discussed and improvements and innovations in these examined. These included the employment of the Ramsey technique using flowing water, as a method of field determination, the use of 'cold neutrons' which allowed narrower resonance line-widths and the use of neutron guides which served to increase the neutron intensity. Major effects which gave rise to either errors of shifts in the present result are tabulated. (U.K.)

[en] Ultra Cold Neutrons (UCN) can be produced at spallation sources using a variety of techniques. To date the technique used has been to Bragg scatter and Doppler shift cold neutrons into UCN from a moving crystal. This is particularly applicable to short-pulse spallation sources. We are presently constructing a UCN source at LANSCE using this method. In addition, large gains in UCN density should be possible using cryogenic UCN sources. Research is under way at Gatchina to demonstrate technical feasibility of a frozen deuterium source. If successful, a source of this type could be implemented at future spallation sources, such as the long pulse source being planned at Los Alamos, with a UCN density that may be two orders of magnitude higher than that presently available at reactors