Single-Crystal 4π Time Scintillation Spectrometers of Delayed Coincidence

Two types of single-crystal time 4π spectrometers are considered, which are used the scintillators with a short decay time. These spectrometers allow searching for short lived excited and ground states of nuclei in the nano- and microsecond range. Single-crystal scintillation time spectrometry, which enables 4π detection of delayed coincidences, has been developed in two directions–using slow scintillators such as NaJ(Tl) [1] or plastic scintillators with a decay time in the nanosecond range [2]. The methods applied for detecting delayed coincidences were different: while in the former case, the fast-slow coincidence method with the measurement of level lifetimes in the microsecond range is employed, in the second case, it is the autocorrelation method, which allows the measurement of level lifetimes starting from the nanosecond range. The lower limit of the measured times in this range is determined by the duration of the scintillator decay pulse at the level of the integral discriminator response threshold and the dead time of the discriminator used.