Characterization of 41Ar production in air at a PET cyclotron facility

Cicoria, Gianfranco; Cesarini, Francesco; Infantino, Angelo; Vichi, Sara; Zagni, Federico; Marengo, Mario

doi:10.1142/s0217732317400144

Cited by 9 publications

(2 citation statements)

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“…Owing to relevant 41 Ar decay parameters [ T 1/2 = 109.34 m, β ― (100%)], it will be attractive to consider this isotope as an appropriate tracer of the radiocarbon 14 C generation. In spite of the debugged technique of 41 Ar monitoring (for example for accelerators and reactors (Cicoria et al., 2017; Oyama et al., 2021), the detection of such low and changing 41 Ar concentration is a very complicated task. But it is possible that the detection will be more realistic in the case of gigantic terrestrial gamma flashes—the large‐scale atmospheric phenomena in which population of neutrons exceeds the ∼10 15 level (Babich, 2006).…”

Section: Resultsmentioning

confidence: 99%

Evaluation of Radiocarbon ¹⁴C Yield Under Conditions of Thunderstorms

Lyashuk

2021

Geophysical Research Letters

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The main mechanism of radiocarbon 14 C creation in the Earth's atmosphere is ensured by cosmogenic irradiation with a yield of 472 g-mole/year (Roth & Joos, 2013) in the reaction 14 N(n,p) 14 C. The generated isotope of 14 C is assimilated in the biomass and decays within it (T 1/2 = 5700 years) that allows us to date the age of investigated organic materials. Discovery of short-term secular fluctuations of radiocarbon in tree rings (Suess, 1965) and its correlation with sun spot number had raised questions that should be eliminated to explain the nature of the phenomenon. In addition to the solar mechanism of fluctuations, the hypothesis of short-term 14 C variation under thunderstorm generated neutrons in fusion reaction 2 H + 2 H → 3 He + n (due to acceleration of deuterium ions at lightning discharges) with a yield of ≃2.5 MeV neutrons (Libby & Lukens, 1973) was proposed. But the deuterium concentration in the atmospheric H 2 O vapor is small (1 2 H nucleus per ∼10 4 1 H nuclei) (Rozansky & Sonntag, 1982;Gerst & Quay, 2000), and the maximal electric field strength inside the thunderclouds (∼1 × 10 6 V/m) (Winn et al., 1974;Gunn, 1948) is too small for evident neutron generation, which results in negligible neutron creation (Babich, 2006); in conclusion, the fusion cannot be responsible for short-term radiocarbon fluctuation. Nevertheless, indications of the low-rate fusion are obtained; so, the authors of the experiment at the High Altitude Research Laboratory (India) registered that 2.45 MeV neutrons correlated with lightning strokes (Ishtiaq et al., 2016).The first evidence of thunderstorm neutron enrichment was obtained in high-altitude Himalayas experiment (Shah et al., 1985). The enrichment of neutron fluxes, γ-and X-rays in correlation with thunderstorms were also registered in the following experiments (as:

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Section: Resultsmentioning

confidence: 99%

Evaluation of Radiocarbon ¹⁴C Yield Under Conditions of Thunderstorms

Lyashuk

2021

Geophysical Research Letters

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“…Preventive measures, such as periodic leakage tests, delay lines for the release of effluents, or containment systems have proven to be effective (Marengo 2008). Planned releases of 41 Ar, due to neutron activation of natural 40 Ar contained in air during irradiation, are not radiologically relevant (Infantino et al (2015), Cicoria et al (2017)).…”

Section: Cyclotron Operationmentioning

confidence: 99%

Guidance on prevention of unintended and accidental radiation exposures in nuclear medicine

et al. 2019

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Nuclear medicine (NM) procedures for diagnosis and treatment of disease are performed routinely in hospitals throughout the world. These involve preparation and administration to patients of pharmaceuticals labelled with radioactive material. The International Atomic Energy Agency (IAEA) and the World Health Organisation highlighted the need for improvement in prevention of medical radiation incidents and accidents in the Bonn Call-for-Action in 2012. An IAEA Technical Meeting was held on prevention of unintended exposures and accidents in NM in 2018 to address the issue. Exposures can take place at any time when radioactive material is being produced and used, and the risk continues after procedures have been completed. Thus there is potential for staff or members of the general public to be exposed, as well as patients. This paper sets out guidelines for incident prevention based on presentations and discussions at the meeting, and review of reports from the literature. It deals with potential incidents in in-house radionuclide production, radiopharmaceutical preparation, administration to patients, and following a procedure, as well as aspects in management of radioactive materials. Special attention has been paid to therapeutic procedures, as these have the potential to cause more harm to patients from erroneous administrations, including tissue reactions from extravasation of radiopharmaceutical, and could lead to significant contamination events. Administration of NM therapy is generally contraindicated in pregnancy. Identification of any patient who may be pregnant is crucial and it might be necessary to verify this with a pregnancy test for patients within the age band considered to be fertile. Inclusion of NM therapy incidents in the IAEA automated reporting system SAFRON is recommended. In summary, the paper aims to highlight errors that could occur during different phases of NM procedures in order to aid prevention of incidents. The value of periodic audit in evaluating systems in place on a regular basis is emphasised. Approaches to incident investigation and follow-up are described, and the need to ensure corrective action is taken to address any deficiencies stressed.

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