TY - JOUR
T1 - Identification of radionuclides for the spectroscopic radiation portal monitor for pedestrian screening under a low signal-to-noise ratio condition
AU - Min, Eungi
AU - Ko, Mincheol
AU - Lee, Hakjae
AU - Kim, Yongkwon
AU - Joung, Jinhun
AU - Joo, Sung Kwan
AU - Lee, Kisung
N1 - Funding Information:
This research was supported by the Basic Atomic Energy Research Institute through the National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning of the Korean government (BAERI) ( NRF-2010-0018616 ) and Radiation Technology R&D Program through the National Research Foundation of Korea funded by the Ministry of Science, ICT & Future Planning of the Korean government (Grant no. 2013M2A2A7029685 ).
PY - 2014/9/11
Y1 - 2014/9/11
N2 - The spectroscopic radiation portal monitor (SPM) is widely used for homeland security. Many research groups are studying the radionuclide identification method which is one of the most important factors in the performance of the SPM using the large size of a thallium activated sodium iodide (NaI(Tl)) detector. In this study, we developed the radionuclide identification method for the SPM for pedestrian screening using a single NaI(Tl) detector that is small in size (2 in.), which is much smaller than those in the existing studies under the low signal-to-noise-ratio (SNR) condition. From the anomalous radionuclide spectrum, the noise component was effectively reduced by the wavelet decomposition and the proposed background subtraction method, and the signal component was enhanced by the principal component analysis. Finally, peak locations which have been determined by the peak search algorithm with a valley check method were compared with a pre-calibrated and constructed radionuclide database. To verify the radiation identification performance of the proposed method, experiments with various kinds of sources (137Cs, 133Ba, 22Na, and 57Co) and different SNR values (from distances of 10-150 cm and for scan times of 1-5 s) were performed. Although the high-SNR condition was explored as well, most experiments were conducted under the low-SNR condition to verify the robustness and reproducibility of the proposed algorithm. The results showed that over 98.3% of the single radionuclide detection rate was achieved regardless of which radionuclides were used, up to 50 cm under the worst SNR condition (1 s of scan time) and up to 90 cm under the best SNR condition (5 s of scan time). Furthermore we achieved accurate identification of multiple radionuclides at 40 cm with only 1 s of scan time. The results show that the proposed algorithm is competitive with the commercial method and our radionuclide identification method can be successfully applied to the SPM for pedestrian monitoring, with a small detector size and a short scan time.
AB - The spectroscopic radiation portal monitor (SPM) is widely used for homeland security. Many research groups are studying the radionuclide identification method which is one of the most important factors in the performance of the SPM using the large size of a thallium activated sodium iodide (NaI(Tl)) detector. In this study, we developed the radionuclide identification method for the SPM for pedestrian screening using a single NaI(Tl) detector that is small in size (2 in.), which is much smaller than those in the existing studies under the low signal-to-noise-ratio (SNR) condition. From the anomalous radionuclide spectrum, the noise component was effectively reduced by the wavelet decomposition and the proposed background subtraction method, and the signal component was enhanced by the principal component analysis. Finally, peak locations which have been determined by the peak search algorithm with a valley check method were compared with a pre-calibrated and constructed radionuclide database. To verify the radiation identification performance of the proposed method, experiments with various kinds of sources (137Cs, 133Ba, 22Na, and 57Co) and different SNR values (from distances of 10-150 cm and for scan times of 1-5 s) were performed. Although the high-SNR condition was explored as well, most experiments were conducted under the low-SNR condition to verify the robustness and reproducibility of the proposed algorithm. The results showed that over 98.3% of the single radionuclide detection rate was achieved regardless of which radionuclides were used, up to 50 cm under the worst SNR condition (1 s of scan time) and up to 90 cm under the best SNR condition (5 s of scan time). Furthermore we achieved accurate identification of multiple radionuclides at 40 cm with only 1 s of scan time. The results show that the proposed algorithm is competitive with the commercial method and our radionuclide identification method can be successfully applied to the SPM for pedestrian monitoring, with a small detector size and a short scan time.
KW - Detection rate
KW - Pedestrian screening
KW - Radionuclide identification
KW - Signal-to-noise ratio
KW - Spectroscopic radiation portal monitor
UR - http://www.scopus.com/inward/record.url?scp=84901920901&partnerID=8YFLogxK
U2 - 10.1016/j.nima.2014.05.021
DO - 10.1016/j.nima.2014.05.021
M3 - Article
AN - SCOPUS:84901920901
SN - 0168-9002
VL - 758
SP - 62
EP - 68
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
ER -