AMS measurements of fission products at CIAE

Shen, Hongtao; Jiang, Shan; He, Ming; Dong, Kun; Ouyang, Yu; Li, Zhenyu; Guan, Yao; Yin, Xinghui; Peng, Bo; Zhou, Dongmei; Yuan, Jian; Wu, Shaoyong

doi:10.1016/j.nimb.2012.06.019

Cited by 10 publications

(6 citation statements)

References 21 publications

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“…At the IsoTrace Laboratory (Toronto, Canada), the possibility to suppress the interference of 99 Ru already in the ion source with a matrix-assisted method was investigated, and a relative suppression of the sputtered 99 RuF 4 – with respect to 99 TcF 4 – by up to 2 orders of magnitude was achieved. Another possibility to suppress the background of 99 Ru in the ion source was then explored at the China Institute of Atomic Energy (CIAE, Beijing, China) with the extraction of carbide and the advantageous relative ionization yields of Tc – :TcC – = 1:25 and Ru – :RuC = 6:1; in this way, DLs of ∼1 × 10 9 atoms (164 fg) were obtained …”

Section: Analytical Techniquesmentioning

confidence: 99%

“…A known concentration of a suitable nuclide has to be added to the sample, and its count rate is used to normalize the count rate of the unknown concentration of 99 Tc. In the present study, we have tested the use of 93 Nb that was previously used at CAMS 9 and CIAE 21 and also that of 55 Mn as reference nuclide for instrumental normalization of the AMS measurements. We have then chosen to not use any yield tracer in the chemical preparation procedure but to employ an adapted chemical procedure for the reasons discussed below.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…Another possibility to suppress the background of 99 Ru in the ion source was then explored at the China Institute of Atomic Energy (CIAE, Beijing, China) with the extraction of carbide and the advantageous relative ionization yields of Tc − :TcC − = 1:25 and Ru − :RuC = 6:1; in this way, DLs of ∼1 × 10 9 atoms (164 fg) were obtained. 21 At the 14 MV Tandem AMS facility of the Maier-Leibnitz-Laboratorium (MLL) of the Technical University of Munich (TUM, Garching, Germany), a Gas-Filled Analyzing Magnet in addition to a 5-fold segmented ionization chamber (GAMS) 22,23 is available to suppress the interference from the isobar 99 Ru. 24 In this Article, we present a novel analytical procedure comprising the use of the GAMS setup for ultratrace determination of 99 Tc in groundwater samples from the longterm diffusion experiment of 99 Tc through bentonite at the GTS, a first result on the global fallout level of 99 Tc in a peat bog lake sample, and the testing of the analytical method with the reference material IAEA-443.…”

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confidence: 99%

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Ultratrace Determination of ⁹⁹Tc in Small Natural Water Samples by Accelerator Mass Spectrometry with the Gas-Filled Analyzing Magnet System

et al. 2019

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In the frame of studies on the safe disposal of nuclear waste, there is a great interest for understanding the migration behavior of 99Tc. 99Tc originating from nuclear energy production and global fallout shows environmental levels down to 107 atoms/g of soil (∼2 fg/g). Extremely low concentrations are also expected in groundwater after diffusion of 99Tc through the bentonite constituting the technical barrier for nuclear waste disposal. The main limitation to the sensitivity of the mass spectrometric analysis of 99Tc is the background of its stable isobar 99Ru. For ultratrace analysis, the Accelerator Mass Spectrometry (AMS) setup of the Technical University of Munich using a Gas-Filled Analyzing Magnet System (GAMS) and a 14 MV Tandem accelerator is greatly effective in suppressing this interference. In the present study, the GAMS setup is used for the analysis of 99Tc in samples of the seawater reference material IAEA-443, a peat bog lake, and groundwater from an experiment of in situ diffusion through bentonite in the controlled zone of the Grimsel Test Site (GTS) within the Colloid Formation and Migration (CFM) project. With an adapted chemical preparation procedure, measurements of 99Tc concentrations at the fg/g levels with a sensitivity down to 0.5 fg are accomplished in notably small natural water samples. The access to these low concentration levels allows for the long-term monitoring of in situ tracer tests over several years and for the determination of environmental levels of 99Tc in small samples.

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Section: Analytical Techniquesmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 99%

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confidence: 99%

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Ultratrace Determination of ⁹⁹Tc in Small Natural Water Samples by Accelerator Mass Spectrometry with the Gas-Filled Analyzing Magnet System

et al. 2019

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“…Previous work on AMS measurements of 93 Zr was predominantly undertaken at large tandem accelerators. The CIAE group at the 13 MV HI-13-AMS facility in Bejing achieved detection limits of <10 -10 for 93 Zr/Zr by extracting ZrObeams from ZrO2 targets and using a multi-anode ionization chamber [21]. This limit was reached with ion energies of ~90 MeV.…”

Section: Introductionmentioning

confidence: 99%

93Zr developments at the Heavy Ion Accelerator Facility at ANU

Pavetich

Carey

Fifield

et al. 2019

Nuclear Instruments and Methods in Physics Research Section B:

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The long-lived radionuclide 93 Zr t1/2 = (1.61±0.05) Ma plays an important role in nuclear astrophysics and nuclear technology. In stellar environments, it is mainly produced by neutron capture on the stable nuclide 92 Zr. On Earth high amounts of radioactive 93 Zr are produced in nuclear power plants directly from 235 U fission, but also by neutron capture on 92 Zr, as Zr-alloys are commonly used as cladding for nuclear fuel rods.Despite its importance, the neutron capture cross section of 92 Zr at thermal and stellar energies (keV) is not well known. Neutron irradiation of 92 Zr and subsequent determination of produced 93 Zr via AMS is a promising approach to resolve this issue. The main challenge in AMS measurements of 93 Zr is the interference from the stable isobar 93 Nb. The high particle energies available with the 14UD tandem accelerator at the Australian National University are ideal to tackle this challenge. Different sample materials, molecular ion species and sample holder materials were tested for their 93 Nb background. Commercial ZrO2 powder irradiated with thermal neutrons from the reactor at the Atominstitut in Vienna (ATI) was used as reference material for AMS measurements. In contrast to literature reports and γ-activity measurements of 95 Nb, which suggest that chemical Nb reduction works, elevated 93 Nb contents were measured in chemically pre-treated samples. The reasons are under investigation. At the ANU we developed AMS for ~210 MeV 93 Zr ions using an 8 anode ionisation chamber. We achieved background levels of 93 A/Zr~10 -12 with acceptance of 2 to 8% of the 93 Zr ions at the high-energy side. This is more than an order of magnitude better than previously reported. The 93 Nb isobar was suppressed by a factor between 13,000 and 90,000 in the detector.This performance allows measurements of the thermal and stellar neutron-capture cross section of 92 Zr for samples irradiated at the ATI and the Soreq Applied Research Accelerator Facility, respectively, using AMS.

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“…The CIAE group started the AMS development of 93 Zr using a gas ionization chamber [7]. With the partial isobar separation, the claimed sensitivity for 93 Zr/Zr was below 10 À10 (published in 2013 [8]). TU Munich group also spent great efforts on this development, during which different molecule forms (ZrF 4 ), isobar separation techniques (the passive absorber and the Gas-Filled Analyzing Magnet System) were used [9].…”

Section: Introductionmentioning

confidence: 99%

Zr/Nb isobar separation experiment for future 93Zr AMS measurement

Anderson

Bowers

et al. 2015

Nuclear Instruments and Methods in Physics Research Section B:

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Keywords:Accelerator mass spectrometry Bragg curve 93 Nb reduction chemistry a b s t r a c t 93 Zr (t 1/2 = 1.6 Ma) is mostly produced by the main s-process in low-to-intermediate mass AGB stars. Large uncertainty exists in the current 92 Zr(n,c) 93 Zr Maxwellian Average cross section. This could have significant impact on nucleosynthesis calculations. Large amounts of 93 Zr are also produced in nuclear reactors and pose long-term environmental radioactivity. Hence, measurement of 93 Zr by the AMS is important for both fields above. We report here on progress in the development of AMS method to measure 93 Zr. Compared with 98 MeV beam energy, Zr/Nb isobar position separation was improved using 155.2 MeV beam energy and Gas-Filled Magnet. Energy loss measurement with increased beam energy inside the detector indicates that higher beam energy can improve isobar energy loss separation. A chemical procedure to reduce the Nb content in Zr samples has been developed and tested. It reduces the 93 Nb content by a factor of 1000.

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AMS measurements of fission products at CIAE

Cited by 10 publications

References 21 publications

Ultratrace Determination of ⁹⁹Tc in Small Natural Water Samples by Accelerator Mass Spectrometry with the Gas-Filled Analyzing Magnet System

Ultratrace Determination of ⁹⁹Tc in Small Natural Water Samples by Accelerator Mass Spectrometry with the Gas-Filled Analyzing Magnet System

93Zr developments at the Heavy Ion Accelerator Facility at ANU

Zr/Nb isobar separation experiment for future 93Zr AMS measurement

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AMS measurements of fission products at CIAE

Cited by 10 publications

References 21 publications

Ultratrace Determination of 99Tc in Small Natural Water Samples by Accelerator Mass Spectrometry with the Gas-Filled Analyzing Magnet System

Ultratrace Determination of 99Tc in Small Natural Water Samples by Accelerator Mass Spectrometry with the Gas-Filled Analyzing Magnet System

93Zr developments at the Heavy Ion Accelerator Facility at ANU

Zr/Nb isobar separation experiment for future 93Zr AMS measurement

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Product

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Ultratrace Determination of ⁹⁹Tc in Small Natural Water Samples by Accelerator Mass Spectrometry with the Gas-Filled Analyzing Magnet System

Ultratrace Determination of ⁹⁹Tc in Small Natural Water Samples by Accelerator Mass Spectrometry with the Gas-Filled Analyzing Magnet System