Search results for "Accelerator mass spectrometry"

Charge Exchange and Electron Stripping

2005

Certification of a 41Ca dose material for use in human studies (IRMM-3703) and a corresponding set of isotope reference materials for 41Ca measuremen…

2005

Abstract The long-living radioisotope 41Ca could overcome current limitations in assessing the impact of interventions on bone health in controlled human studies. Changes in bone Ca metabolism can be identified directly via the induced changes in 41Ca excretion from 41Ca-labelled bones via the n(41Ca)/n(40Ca) ratio in urine. A 41Ca dose material (IRMM-3703), for use in human studies, was produced by IRMM within the EC funded project OSTEODIET. The 41Ca base material was purified and the purified solution is certified for both isotopic composition and amount content by isotope dilution mass spectrometry. The 44Ca-enriched isotope reference material, IM-6009, was used as spike and the natural…

Isobar suppression in AMS using laser photodetachment

2008

Abstract We are investigating the possibility of using laser photodetachment of negative atomic and molecular ions as an additional isobaric selection filter in accelerator mass spectrometry. The aim of this study is to find a possibility to further improve the detection limit for long-lived heavy radionuclides at AMS facilities. We will focus on the astrophysical relevant radionuclide 182Hf, which is one of the isotopes measured with the 3 MV tandem AMS facility VERA (Vienna Environmental Research Accelerator) at the University of Vienna. Laser-induced isobar suppression is also of importance for radioactive-beam facilities. The present detection limit for measuring the isotope ratio 182Hf…

Resonant laser ionization mass spectrometry: An alternative to AMS?

2000

Resonant laser ionization mass spectrometry (RIMS) has developed into a versatile experimental method particularly concerning applications for highly selective ultratrace analysis. Apart from providing nearly complete isobaric suppression and high overall efficiency, the possibility for combining optical isotopic selectivity with that of the mass spectrometer leads to remarkable specifications. The widespread analytical potential and applicability of different techniques based on resonant laser ionization is demonstrated in investigations on stable and radioactive ultratrace isotopes with the focus on applications which require high selectivity, concerning, e.g., the noble gas isotopes 81,8…

Tritium retention measurements by accelerator mass spectrometry and full combustion of W-coated and uncoated CFC tiles from the JET divertor

2016

Abstract Accelerator mass spectrometry (AMS) and the full combustion method (FCM) followed by liquid scintillation counting were applied to quantitatively determine the tritium retention in the tungsten-coated carbon fibre composites (CFC), in comparison to uncoated CFC tiles from the JET divertor. The tiles were adjacent and exposed to plasma operations between 2007 and 2009. The tritium depth profiles are showing that the tritium retention on the W-coated tile was reduced by a factor of 13.5 in comparison to the uncoated tile whereas the bulk tritium concentration is approximately the same for both tiles.

Intercomparison measurements between accelerator and laser based mass spectrometry for ultra-trace determination of 41Ca in the 10−11–10−10 isotopic …

2005

Abstract Selective ultra-trace determination of the long-lived radioisotope 41 Ca has applications in environmental and biomedical research, as well as in cosmochemistry. We have conducted an intercomparison between the two currently available methods for measurement at these low (radio) activities: accelerator mass spectrometry (AMS) and resonance ionization mass spectrometry (RIMS). Three artificially produced 41 Ca samples, primarily of cosmochemical importance, with isotopic abundances in the range of 10 −11 –10 −10 were used and results of these measurements show good agreement between the two methods, within the experimental uncertainties.

Selective ultra trace isotope determination in environmental and biomedical studies by high-resolution resonance ionization mass spectrometry

2002

The precise determination of relative abundances of ultra trace isotopes in the range below 10 -9 is of importance for a wide spectrum of applications in fields like environmental protection, cosmo-chemistry, bio-medical tracer studies or geological and geo-chronological investigations. The necessary high isotopic selectivity, rather complete isobaric suppression and good overall efficiency for these investigations is provided by high-resolution resonance ionization mass spectrometry. Multi-step continuous wave laser excitation and ionization using diode lasers at a compact quadrupole mass spectrometer has been optimized to become a powerful and reliable experimental method, which is just b…

Stellar(n,γ)Cross Section ofNi62

2005

The 62Ni(n,gamma)63Ni(t(1/2)=100+/-2 yr) reaction plays an important role in the control of the flow path of the slow neutron-capture (s) nucleosynthesis process. We have measured for the first time the total cross section of this reaction for a quasi-Maxwellian (kT=25 keV) neutron flux. The measurement was performed by fast-neutron activation, combined with accelerator mass spectrometry to detect directly the 63Ni product nuclei. The experimental value of 28.4+/-2.8 mb, fairly consistent with a recent calculation, affects the calculated net yield of 62Ni itself and the whole distribution of nuclei with 62<A<90 produced by the weak s process in massive stars.

Gas-filled separators – An overview

2003

Gas-filled recoil separators have been used in nuclear physics studies since the early fifties. Most notably, they have found use in the separation of evaporation residues of heavy and very heavy elements from unwanted background. Gas-filled separators, alone or coupled to a detector array, offer an efficient, fast, compact and relatively inexpensive solution for nuclear structure studies. A new application is the use of a gas-filled device as a pre-separator in the study of chemical properties of the heaviest elements. Other uses include systematic study of fusion evaporation cross sections and accelerator mass spectrometry. In this contribution, an overview on gas-filled recoil separators…

Feasibility of photodetachment isobar suppression of WF with respect to HfF

2014

Abstract The feasibility of using laser photodetachment as a means for isobar suppression in accelerator mass spectrometry has been investigated for the special case of HfF 5 − /WF 5 − . A method for absolute photodetachment cross section measurements was applied and the cross sections of tungsten pentafluoride and hafnium pentafluoride negative ions were measured. The measurements indicate that the photodetachment cross section for WF 5 − is at least 100 times larger than for HfF 5 − at the wavelength of the fourth harmonic of the Nd:YAG laser at 266 nm. The absolute cross section for WF 5 − at this photon energy was found to be (2.8 ± 0.3) × 10 −18  cm 2 , while an upper limit of 2 × 10 −…