선택한 단어 수는 입니다.
최소 단어 이상 선택하여야 합니다.
최소 단어 이상 선택하여야 합니다.
선택한 단어 수는 30입니다.
최대 10 단어까지만 선택 가능합니다.
최대 10 단어까지만 선택 가능합니다.
제안 방법
- 8. (A) PSD plot at full energy range and (B) distribution of PSD parameter at various energies obtained with the CTD method in the optimized set-up, using the stilbene scintillator measuring 252Cf and 137Cs sources. (C) PSD plot at full energy range and (D) distribution of PSD parameter at various energies obtained with the CTD method in the optimized set-up, using the EJ-301 liquid scintillator measuring 252Cf and 137Cs sources.
- For data analysis, data was stored in PC, and the PSD parameter was calculated with the Matlab® software. A standard disk type 137Cs source was used as a gamma-ray source and a capsule type 252Cf source was used as a fast neutron source to investigate the PSD response of the detector. Detailed information of radiation sources is shown in Table 1.
- As an attempt to maximize the FOM value, we calculated FOM values while changing thresholds for starting time (Tt,s) and stopping time (Tt,e) in both methods, the time interval (∆Ts,s) for the CC method and the fractionating instance (Ts,e) after Tt,s in the CTD method. In case of the stilbene scintillator, the time interval (∆Ts,s) and the fractionating instance (Ts,e) were varied from 20 ns to 42 ns, increasing by 2 ns.
- As an initiative attempt to implement the digital PSD technique on the stilbene scintillator detector and the EJ-301 liq uid scintillator detector using a high-band width digitizer DT5730, this study was performed to deduce optimized PSD variables for the CC method and the CTD method using the two types of scintillator detectors. Optimized PSD variables was selected by comparing FOM values depending on thresholds, time interval (∆Ts,s for CC) and constant time (Ts,e for CTD) at the full energy range.
- 9. At each energy steps, FOM values calculated for (A) the CC method and (B) the CTD method of the stilbene scintillator and (C) the CC method and (D) the CTD method of the EJ-301 liquid scintillator applying various time parameter (∆Ts,s and Ts,e) and threshold conditions.
- In this study, EJ-301 liquid scintillator showed slightly better FOM values than stilbene, however, one cannot simply conclude the EJ-301 liquid scintillator is a better detector for PSD methods, as we did not bring other factors that can be still optimized – PMTs used for each detector, detector efficiency, handling issues etc.
- To calculate the FOM value, both neutron and gamma-ray peaks of PSD parameter distribution were fitted with Gaussian-shaped curves. In principle, two particles are considered to be completely distinguished from each other, if the FOM value is greater than 1.
이론/모형
- First, we performed the digital PSD using the charge comparison method. As mentioned above, the neutron pulse has a longer decay time than that of gamma-ray pulses because the recoil proton, generated by the neutron elastic scattering, provokes longer delayed emissions from the scintillator than electrons from gamma ray interactions do.
- Therefore, the CC method makes use of the difference in the fraction of delayed fluorescence between the signal generated by the neutron and the signal generated by the gamma ray as shown in Figure 3. This method uses the ratio of Qslow to Qlong as a PSD parameter. In here, Qlong is integrated charge of the total signal and Qslow is integrated charge from a specific beginning point to end of radiation signal.
- Two types of PSD algorithms were implemented on off-line analysis using a Matlab® code to calculate PSD parameters for each signal.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.