A comparison between neutron-fluence measurements using metal-activation monitors and standard glasses calibrated via thin uranium-fission monitors and via ηq method

Curvo, Eduardo Augusto Campos; Jonckheere, Raymond; Guedes, S.; Iunes, P.J.; Tello, C.A.; Hadler, J.C.; Unterricker, S.; Ratschbacher, Lothar

doi:10.1016/j.radmeas.2013.03.002

Cited by 8 publications

(15 citation statements)

References 24 publications

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“…Earlier studies (Bellemans, 1996;Bigazzi et al, 1990;Curvo et al, 2013;De Corte et al, 1991, 1995Jonckheere, 1995;Van den haute et al, 1988Van den haute et al, , 1998 give reason for trusting that the calculated neutron fluences are accurate. The agreement of the uranium concentrations calculated with Eq.…”

Section: Apparent Fission-track Agementioning

confidence: 97%

“…Our contribution sets out from the premise that neutron-fluence measurements using the recommended metal monitors (Au, Co) and wellthermalized irradiation facilities are no longer an issue (Bigazzi et al, 1990;Curvo et al, 2013;De Corte et al, 1991, 1995Van den haute et al, 1988Van den haute et al, , 1998. Our second assumption is that the matter of the fission constant has been settled following recent redeterminations (Eikenberg et al, 1993;Guedes et al, 2000Guedes et al, , 2003Suzuki, 2005;Yoshioka et al, 2005) and reassessments (Holden, 1989;Holden and Hoffman, 2000).…”

Section: Introduction: Premisesmentioning

confidence: 98%

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Standardless fission-track dating of the Durango apatite age standard

2015

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Five dating strategies were used for determining the standardless fission-track age of the Durango apatite. These use the same fossil-track densities but differ in the manner in which the induced-track densities are determined. A conventional age calculation, without correction for experimental factors, gives inconsistent ages with methodrelated differences N 15%. Correcting for these factors brings the ages in line with each other and with the reference age but leaves no room for a partial-annealing correction based on the confined-track lengths. Three further reasons suggest that a length correction is not appropriate. (1) The evidence for lengthbased corrections is inconclusive. (2) The plateau age of the Durango apatite is consistent with its apparent fission-track age to within 1%. (3) The calculated effective etchable length of the fossil tracks agrees within error with that of the induced tracks; both are further consistent with the measured mean length of confined induced tracks. The circumstance that the (U,Th)/He ages of the accepted and proposed apatite age standards are consistent with their reference ages leaves no margin for a lowered fission-track age resulting from partial annealing, although the case of the Durango apatite itself is inconclusive because of its exceptional crystal size. It is conjectured that the shortening of the fossil tacks in the Durango apatite is due to a lowering of the track etch rate over time. In this case, annealing equations fitted to induced-track data underestimate the extent of confined-track-length reduction in geological samples.

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Section: Apparent Fission-track Agementioning

confidence: 97%

Section: Introduction: Premisesmentioning

confidence: 98%

Standardless fission-track dating of the Durango apatite age standard

2015

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“…The observed differences could come from the thin film calibration, from the glass calibration procedure or from efficiency calibrations necessary for dating. Curvo et al [26] advanced in the solution of this problem firstly recalibrating the thin films using a more reliable a-spectrometry calibration instead of alpha activity detected in polyallyldiglycol carbonate (PADC) alpha-track detectors calibrated via nuclear emulsion [20,22,23] because this procedure makes U-thin films calibration very ingenious and etching/observation efficiencies have to be taken into account. With electronic alpha particle spectrometry, this laborious procedure can be avoided and U-thin films can be calibrated directly.…”

Section: Introductionmentioning

confidence: 99%

“…With electronic alpha particle spectrometry, this laborious procedure can be avoided and U-thin films can be calibrated directly. In a second experiment, Curvo et al [26] carried out joint irradiations of standard glasses, metallic monitors (Au and Co) and standard age samples. The recalibration of the thin films confirmed the previous calibration by Iunes et al [22].…”

Section: Introductionmentioning

confidence: 99%

Recalibration of U-doped standard glasses through uranium thin film for neutron-fluence measurements

Soares

Guedes

Curvo

et al. 2014

J Radioanal Nucl Chem

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This work presents a recalibration of U-doped standard glasses using natural uranium thin films to be used as most dedicated neutron monitor for fission-track dating. The recalibrated U-doped glasses were used to determine fission-track ages in apatite samples from Brazilian alkaline formations (Alto Paranaíba) and standard Durango apatite. Samples were irradiated in two nuclear reactors with different characteristics and the results were compared. For well-thermalized neutron facility, metal activation monitor was also used. The ages of Alto Paranaíba arch and Durango apatite agree with those determined by other radiometric dating methods and metal activation monitors. These results suggest that the presented recalibration is suitable to be used routinely for fission-track dating studies even in a non-well thermalized neutron facility.

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“…the 238 U spontaneous fission decay constant) and the detection efficiencies are included into an empirical parameter Green 1982, 1983;Hurford 1990a, b). Thermal neutron fluence can be accurately measured by either metal-activation monitors (Van den haute et al 1988;de Corte et al 1991de Corte et al , 1995Enkelmann et al 2005;Curvo et al 2013) or standard glasses calibrated through uranium thin films Soares et al 2014a). The 238 U spontaneous fission decay constant was accurately determined by measurements of etched tracks in solid-state detectors (Hadler et al 1981;Guedes et al 2000Guedes et al , 2002Guedes et al , 2003aYoshioka et al 2005).…”

Section: Introductionmentioning

confidence: 99%