[en] The detection efficiency of a planar HPGe detector was calibrated in the energy range from 30 to 1500 keV by measuring the air sampling cylinder box. And the ¹³¹I box sampled in the environment was measured with the calibrated efficiency curve. Satisfied results had been achieved. (authors)

[en] The liquid scintillation counting system recently constructed for absolute activity measurement was introduced, and it uses TDCR method to measure activity of β nuclide. The system is equipped with three PMTs connected to a de-focusing voltage divider base developed by ourselves. After varying the efficiency by de-focusing of the PM tube, the activity of the "3H source was determined. The analysis of uncertainty and discussion of measurement result were given. The activity determined with TDCR is in agreement with certified value within the range of 0.9%. The combined uncertainty of results is 0.6% (k = 1). (authors)

No abstract available

[en] For the absolute measurement requirement of trace tritium activity in ITER-TBS system, a micro-calorimeter was designed. The solid tritiated samples were used to demarcate the output thermal potential (E_out) and the input thermal power (P). The results show a good linear relationship between E_out and P, and the sensitivity coefficient reaching 0.13 V/W. The minimum detection limit of micro thermal meter is below 0.2 μW, and the calorimetric cup volume is more than 500 mL. The performance is expected to have a good application prospect for quantitative measurement of the trace tritium activity under various complicated situation in ITER-TBS system. (authors)

[en] The paper introduces the comparative measurements of CNNC Radiation Metrology and Measurement Center and RI_CN-NIM for tritiated water activity. The structure and electronics circuit of liquid scintillation TDCR devices are described in detail. Comparison methods, results and uncertainty assessment are described. The experiment results verify the consistency of two systems. The activity determined with TDCR by two laboratories is in agreement within the range of 0.24%. (authors)

[en] Counting under a precise small solid angle is one of the oldest methods developed for the radioactivities measurement of α-nuclides. The principle of solid angle counting is very simple and the accuracy is much better. The advantages of an equipment developed by the authors, in which a large area Au-Si surface barrier detector (450 mm²) is used, are introduced. Some comparisons on measurement results have been obtained with the gridded ionization chamber, and a national comparison result of ²⁴¹Am which deviated from the average result is less than 0.2% are presented in detail

[en] Radioactive standard solution is a standard reference material. It is an important standard measuring instrument and used for transferring and inter-comparing of quantity value. According to requirement for the preparation of radioactive standard solution, ⁶⁰Co, ⁹⁰Sr-⁹⁰Y, ¹³⁷Cs, ¹³⁴Cs, ⁶³Ni, ²⁴¹Am, ¹²⁵I, ¹³¹I standard solutions have been developed. The medium includes about 20∼50 μg stable carrier per gram solution and 0.1 mol/L HCl. For iodine radioactive solutions., the medium is alkaline and the stabilizer is added into it. The solutions are all stable and uniform in the long term. The specific activities are accurate and the uncertainties are 0.10%, 0.27%, 0.18%, 0.12%, 0.24%, 0.18%, 0.20%, 0.22% respectively (1 σ)

[en] A method of preparing radioactive source was introduced. A 4πβ(ppc)-γ coincidence measurement method was employed to measure the specific activity of radioactive solution of ¹⁹²Ir nuclide

[en] Short communications only

[en] A sample of ⁵⁹Fe solution for international comparison was measured in authors' laboratory by 4πγ pressured ionization chamber and 4πβ-γ coincidence apparatus as well, and a similar ⁵⁹Fe solution in a NIST/SIR ampoule was send to BIPM to be measured by the International Reference System for activity measurements of gamma-ray emitting nuclides(SIR) by ETL. The result is in a good agreement with the one measured by ETL, and both results are very near to SIR mean value