• 한국안광학회지
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• 제9권1호
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• pp.69-73
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• 2004

${\alpha}-Al_2O_3$ 단결정의 TSEE와 TSL을 $2{\pi}$비례계수기를 사용하여 측정하였다. ${\alpha}-Al_2O_3$ 단결정을 실온에서 500K 온도범위에서 X선과 자외선(UV)을 조사하였다. X선 조사 후에 3개의 TSEE와 3개의 TSL 봉우리가 관찰되었다. ${\alpha}-Al_2O_3$ 단결정의 TSEE와 TSL 그로우곡선은 여기 원의 종류에 관계없이 잘 대용되고 있음을 보여 주었다. 이 연구에서 우리는 $2{\pi}$ 비례계수기가 ${\alpha}$-입자의 에너지 스펙트럼 분석장치 뿐만 아니라 TSEE와 TSL의 측정에도 유익함을 알 수 있었다.

• Journal of Radiation Protection and Research
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• 제10권2호
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• pp.130-136
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• 1985

전자포획 핵종인 $^{133}Ba$ 용액의 방사능 측정이 ${\beta}-{\gamma}$ 동시계수 방법에 의하여 수행되었다. $4{\pi}$ 비례계수기와 두개의 NaI(Tl) 섬광검출기를 사용하여 베타, 감마 및 동시계수 채널에서 계수율을 측정하였다. 효율외삽법으로 산출된 용액의 비 방사능은 기준시간(1984년 3월 15일 0시, UT)에 대하여 $(1151.01{\pm})2.99)\;kBq{\cdot}g^{-1}$이었다. 국제도량형국이 주관한 방사능 측정의 국제비교에 의하면, 이 결과는 그 비교에서 얻어진 평균값에 대하여 약 0.84%의 차이를 나타냈다.

• Journal of Radiation Protection and Research
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• 제45권2호
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• pp.76-80
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• 2020

Background: To improve the measurement accuracy of liquid-scintillation counting for activity standardization, it is necessary to significantly reduce the background caused by thermal noise or after-pulses. We have therefore improved a movable 3 photomultiplier (3PM)-γ coincidence-counting method using the logical sum of three double coincidences for β events. Materials and Methods: We designed a new data-acquisition system in which β events are obtained by counting the logical sum of three double coincidences. The change in β-detection efficiency can be derived by moving three photomultiplier tubes sequentially from the liquid-scintillation vial. The validity of the method was investigated by activity measurement of ¹³⁴Cs calibrated at the Korea Research Institute of Standards and Science (KRISS) with 4π(PC)β-γ(NaI(Tl)) coincidence counting using a proportional counter (PC) for the β detector. Results and Discussion: Measurements were taken over 14 counting intervals for each liquidscintillation sample by displacing three photomultiplier tubes up to 45 mm from the sample. The dead time in each β- and γ-counting channel was adjusted to be a non-extending type of 20 ㎲. The background ranged about 1.2-3.3 s^-1, such that the contributions of thermal noise or after-pulses were negligible. As the β-detection unit was moved away from the sample, the β-detection efficiencies varied between 0.54 and 0.81. The result obtained by the method at the reference date was 396.3 ± 1.7 kBq/g. This is consistent with the KRISS-certified value of 396.0 ± 2.0 kBq/g within the uncertainty range. Conclusion: The movable 3PM-γ method developed in the present work not only succeeded in reducing background counts to negligible levels but enabled β-detection efficiency to be varied by a geometrical method to apply the efficiency extrapolation method. Compared with our earlier work shown in the study of Hwang et al. [2], the measurement accuracy has much improved. Consequently, the method developed in this study is an improved method suitable for activity standardization of β-γ emitters.