We have installed the NSM spectrometer at the C2-2 beam port of the JRR-3M guide hall, and have tested its performance. The NSM method encodes the scattering function from the sample in the spread of the incident neutron spectrum, which is modulated in intensity and in time by neutron polarization. The scattering functioncan then be retrieved by means of the maximum entropy pattern analysis from the time-of-flight data. The NSM combined with the small-angle scattering is considered as a powerful method for studies of small q,small w excitations such as macromolecular dynamics. The measured time-of-flight data are shown in Fig.1, that is a 3D representation of the nsm-modulated spectrum as functions of time channel, detector number and intensity by way of AVS software interface on the X-window of the Titan computer display. The performance tests indicated, however, that both intensity and polarization of the incident neutrons were not what was expected from the design specifications, and the cause of the poor performance results were searched for. After thorough investigation,at the re- adjustment process of the supermirror polarizers, which was learned directly from Dr.Schrf at ILL, we found that about half of supermirror glass blades of each polarizer were broken as shown in the picture in Fig.2. In view of the difficulty to replace the broken glasses, we realigned each polarizer with the remaining blades,that we believe is the best we could do at the existing conditions.The performance test will be continued with the newly align- ed polarizers ( although with less supermirror glass blades) in the coming year.
Contact person : Yuji ITO Fuculty of Education, Yamanashi University