Low-Energy Grazing Ion-Scattering From Alkali-Halide Surfaces: A Novel Approach To C-14 Detection

Meyer, F. W.; Galutschek, Ernst; Hotchkis, M.A.C.; McDaniel, F. D.; Doyle, B.L.

doi:10.1063/1.3120038

Cited by 8 publications

(10 citation statements)

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“…This was subsequently realised in practice by Michael Hotchkis and Tao Wei who managed measurement of radiocarbon-enriched materials [5]. Fred Meyer et al achieved similar results by grazing ion-scatter charge-exchange [6]. In contrast AMS measurement background is a million-fold lower.…”

Section: Introductionmentioning

confidence: 62%

Radiocarbon positive-ion mass spectrometry

Freeman

Shanks

Donzel³

et al. 2015

Nuclear Instruments and Methods in Physics Research Section B:

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a b s t r a c tProof-of-principle of a new mass spectrometric technique for radiocarbon measurement is demonstrated. Interfering nitrogen and hydrocarbon molecules are largely eliminated in a charge-exchange cell operating on non-metallic gas. The positive-to-negative ion conversion is the reverse of that conventionally used in accelerator mass spectrometry (AMS) and is compatible with plasma ion sources that may be significantly more efficient and capable of greater output than are AMS sputter ion sources. The Nanogan electron cyclotron resonance (ECR) ion source employed exhibited no sample memory and the >50 kyrs age range of AMS was reproduced. A bespoke prototype new instrument is now required to optimise the plasma and cell physics and to realise hypothetical performance gains over AMS.

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Section: Introductionmentioning

confidence: 62%

Radiocarbon positive-ion mass spectrometry

Freeman

Shanks

Donzel³

et al. 2015

Nuclear Instruments and Methods in Physics Research Section B:

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“…In the past ten years, to produce high-intensity C 3+ /C 2+ beams for PIMS, Australian Nuclear Science and Technology Organization (ANSTO), Oak Ridge National Laboratory (ORNL) and Scottish Universities Environmental Research Centre (SUERC) have carried out relevant researches on ECR ion sources with high microwave frequency of 7 GHz (C 3+ ), 14 GHz (C 3+ and 10 GHz (C 2+ , molecular cation 12 CH2 2+ is metastable, can be eliminated by change exchange target.) respectively [8][9][10]. The feasibility of high-frequency ECR ion sources in PIMS has been proven by these works.…”

Section: Introductionmentioning

confidence: 89%

“…However, due to its low optimal charge exchange energy, high maintenance and operation cost, and short service life of the alkali metal CXC, it is not convenient for the stable operation of PIMS. ANSTO, ORNL, and SUERC use Rubidium vapor target, single-crystal alkali halide (LiF) target, and non-metallic gas isobutane target to form Cion by charge exchange, respectively [8][9][10]. At present, there is still no consistent recommendation on the selection of efficient, stable, and reliable charge exchange targets, which also limits the development of PIMS.…”

Section: Introductionmentioning

confidence: 99%

Preliminary results of positive ion mass spectrometry based on a 2.45 GHz ECR ion source and a non-metallic gas target

Peng

et al. 2022

J. Phys.: Conf. Ser.

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Positive-ion mass spectrometry (PIMS) is a positive-to-negative ion conversion metrology that just operated on the opposite of traditional accelerator mass spectrometry (AMS) on high-precision radiocarbon dating. With a higher efficient simple structure plasma ion sources instead of AMS sputter ion sources, lower ion energy (tens keV) in place of MeV, and limited footprint facility, PIMS will be a powerful competitor to AMS in the future. To precisely measure 14C, interference of molecular isobars (such as 12CH2, 13CH) will be eliminated with higher charged ions (charge state ≥ 3; molecular cations 12CH2 2+ is metastable, can be eliminated by higher stripping pressure.), nitrogen will be eliminated inside the charge-exchange cell (CXC) through charge exchanging with target gas. To demonstrate the probability of PIMS with a 2.45 GHz ECR ion source, an experiment was launched at Peking University (PKU). A compact permanent magnet 2.45 GHz ECR ion source is designed to produce carbon ions from CO2. A CXC unit was installed after the extraction system and ethylene is chosen as charge exchange gas. Preliminary experiments prove that more than hundreds of microamp of C2+ beam can be produced with this ECR source. By injecting ethylene into CXC, several microamp C- beam was detected and the C2+ ions charge exchange efficiency to C- ions can reach close to 5%.

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“…11 This large negative ion conversion yield and the related chargetransfer mechanism have received much attention because of the wide applications of negative ions in various elds, such as laser cooling, [12][13][14] using C À ions to facilitate nerve tissue growth, 15 using O 2 À ions for indoor environment purication, 16 using H À ions as a probe for the subband electronic structures of nanosurfaces, 17 applying H À /D À ion beam implantation to ITER devices, 18 using negative ions in astrophysics evolution studies, 19 designing negative ion sources 20 and constructing neutral particle detectors in space research. 21 The negative ion conversion mechanism of atomic particle scattering at grazing angles on metal surfaces has already been comprehensively studied. [22][23][24][25] In this case, charge-exchange is dominated by electronic resonant transitions between states of metal surface and the affinity level of a projectile.…”

Section: Introductionmentioning

confidence: 99%

“… 11 This large negative ion conversion yield and the related charge-transfer mechanism have received much attention because of the wide applications of negative ions in various fields, such as laser cooling, 12–14 using C − ions to facilitate nerve tissue growth, 15 using O 2 − ions for indoor environment purification, 16 using H − ions as a probe for the subband electronic structures of nanosurfaces, 17 applying H − /D − ion beam implantation to ITER devices, 18 using negative ions in astrophysics evolution studies, 19 designing negative ion sources 20 and constructing neutral particle detectors in space research. 21 …”

Section: Introductionmentioning

confidence: 99%