Results from the New JT-60U Neutron Time-of-flight Spectrometer

摘要

In this paper, the first results from measurements with the new 2.45 MeV neutron time-of-flight spectrometer at JT-60U are described. The spectrometer was installed August 1999 and neutrons from NBI-heated deuterium plasmas were measured for a time-period of 1-month (Sep 1999). these measurements showed that neutron energy distributions can be obtained when the neutron yields from the plasma are below 10~15 neutrons/s. with higher neutron yields, only random coincidences were detected. Improvements of the spectrometer involves a smaller first scattering detector with an active voltage divider. An improved calibration procedure for the second detector has also been suggested and will be implemented.