Neutron depth profiling system at CARR.

A neutron depth profiling (NDP) device was developed on China advanced research reactor (CARR) of China Institute of Atomic Energy (CIAE). The CARR-NDP device uses cold neutron beams transmitted by a neutron guide from the cold neutron source of CARR, and it is composed of a neutron beam collimator, and a vacuum target chamber containing a beam stopper and a detection system. The neutron flux at 1 m from the end of neutron guide is about 4.

Parametric normalization for full-energy peak efficiency of HPGe γ-ray spectrometers at different counting positions for bulky sources.

Application of effective interaction depth (EID) principle for parametric normalization of full energy peak efficiencies at different counting positions, originally for quasi-point sources, has been extended to bulky sources (within ∅30 mm×40 mm) with arbitrary matrices. It is also proved that the EID function for quasi-point source can be directly used for cylindrical bulky sources (within ∅30 mm×40 mm) with the geometric center as effective point source for low atomic number (Z) and low density (D) media and high energy γ-rays. It is also found that in general EID for bulky sources is dependent upon Z and D of the medium and the energy of the γ-rays in question.

Study on bubble detectors used as personal neutron dosimeters.

Neutron bubble detector is so far the only personal neutron dosimeter satisfying the energy response criteria of the International Committee of Radiation Protection 60 (ICRP 60). This paper presents our studies on neutron bubble detectors including the manufacture, the relevant equipments, the basic calibrations and on-site tests for monitoring personal neutron dose. The results of calibrations show that the highest sensitivity so far manufactured by the authors reaches about 4bubbles/μSv, the correlation coefficient of dose response is 0.

Study on anti-reflection of CR-39 by the nuclear track technique.

Nuclear tracks can be etched into pores in which the refractive indexes gradually increase, so that the sample surface reflects very few lights back. CR-39 samples were bombarded with sulfur ions from the Tandem Accelerator HI-13 of CIAE. Three kinds of procedures were performed in the following treatments.

Characterization of a stream sediment matrix material for sampling behavior in order to use it as a CRM.

Sampling behavior of multielements in a stream sediment matrix was studied with sample sizes in a range of 9 orders of magnitude by a combination of INAA, PIXE and SR-XRF. For accurately weighable sample sizes (>1mg), sampling uncertainties for 16 elements are better than 1% by INAA. For sample sizes that cannot be accurately weighed (<1mg), PIXE and SR-XRF were used and the effective sample sizes were estimated.

Urban air quality in the Asian region.

Over the past decade, member states of the Regional Co-operation Agreement (RCA), an intergovernmental agreement for the East Asia and Pacific region under the auspices of the IAEA with the assistance of international organizations and financial institutions such as the World Bank and the Asian Development Bank, have started to set in place policies and legislation for air pollution abatement. To support planning and evaluate the effectiveness of control programs, data are needed that characterizes urban air quality. The focus of this measurement program describe in this report is on size segregated particulate air pollution.

Radiochemical neutron-activation analysis of uncertified ultra-trace rare earth elements in two biological certified reference materials.

Radiochemical neutron activation analysis (RNAA) has been used for the determination of eight rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) in two Chinese certified reference materials (CRM), GBW 08503 (wheat powder) and GBW 09101 (human hair). These determinations are important for possible certification of the above mentioned ultra-trace elements, so far not certified. A simple one-step (REE)F3 precipitation was used.