A Measuring System for Time of Flight Spectrum of Neutron Based on Pulse Time Sequences Detection

To measure the time of flight (TOF) spectrum for the 252Cf fission neutron, a TOF measuring system based on the detected time sequences of neutron pulse has been proposed and set up. A 252Cf fast ionization chamber combined with traditional electronic circuit is applied in the system to form the neutron flight pulse signals. It can not only detect the pulse sequence on-line with 1 nanosecond precision, but also realize time-digital-convertion simultaneously. The cross correlation function is to calculate the measured spectrum and the numerical statistics of the flight time of neutron and γ photons are sent to PC and obtained through data processing. Meanwhile, the timing precision of the system can be judged by the γ-shape. The distinguishing neutron vs. γ-photons (n-γ) can also be achieved by setting a delaying factor. Experimental results show that the proposed system can accurately obtain the TOF spectrum whose precision is better than that of the traditional measuring system.