Delayed detectors for neutron flux measurement in fusion experiments

Following dependences are investigated: pulse front duration on the commutation current; pulse duration on the length of a formation line and its duration limit at a slight reduction of a voltage on a load; load pulse amplitude on the wave resistance and on the line length. The circuit of thyratron and neutron tube test is presented. The expression for the pulse front duration and its constituent quantities are obtained. The graphical dependence of the front duration on the commutation current is given for seven different thyratrons and for NT-8 neutron tubes. Graphs of variation in the front duration are given for neutron tubes. Dependences of relative pulse durations on those obtained by calculation are shown for different wave resistances and different thyratrons, and also for NT-8 neutron tubes. Dependences of load pulse amplitudes on the length of the formation line and on the calculated pulse duration, and also dependences of amplitude on the wave resistance of the line at different line lengths for different thyratrons and neutron tubes are presented. It is shown that there is a considerable spread in tube parameters. The conclusions made are the following: 1) front duration increases with current through thyratron, 2) a pulse with the front of over 14 ns, increasing with current, can be formed in neutron tubes, 3) overloading of current in thyratrons may reach 10 at the pulse duration less than 120 ns, 4) the minimum duration of the NT-8 tube pulse is 36 ns at current of 10 A