Scaling factors for production rates of in situ produced cosmogenic nuclides: a critical reevaluation
نویسنده
چکیده
New scaling factors are presented describing the altitude and latitudinal dependence of production rates for in situ produced cosmogenic nuclides. The new factors incorporate the influence of the non-dipole contributions to the geomagnetic field on the cosmic ray flux. The currently used scaling factors of Lal [Earth Planet. Sci. Lett. 104 (1991) 424^439] are based on the assumption of a dipole field. The overall strategy used in deriving the new scaling factors is, however, very similar to that of Lal and relies on the same and/or similar nuclear data. In this reevaluation, data are only used if the effective geomagnetic parameters (inclination, horizontal field strength) can be reconstructed for the time of measurement. The absorption free pathlengths 1 for cosmic rays selected for this study are based on observational data at altitudes relevant for exposure age dating (sea level to 7000 m). At sea level and latitudes between 203 and 403, the new factors are up to 18% lower and at high altitudes more than 30% higher than those of Lal. In addition to accounting for the influence of the effective geomagnetic field and providing more applicable estimates of 1, the new factors also allow for correction for the significant deviations from the standard pressure^altitude relationship that exist in the atmosphere (910%). ß 2000 Elsevier Science B.V. All rights reserved.
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Comment on `Scaling factors for production rates of in situ produced cosmogenic nuclides: a critical reevaluation'
In a recent paper, Dunai [1] discusses several problems with the altitude and latitude scaling of production rates given by [2^4]. Dunai describes three major £aws in Lal's scaling: (1) cosmic-ray measurements are ordered according to geomagnetic latitude calculated from an axial dipole representation of the geomagnetic ¢eld; (2) the high-altitude (atmospheric depth 580^770 g cm32) attenuation ...
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متن کاملReply to comment on `Scaling factors for production rates of in situ produced cosmogenic nuclides: a critical reevaluation'
In their comment Desilets et al. [1] claim that several assumptions made in my paper [2] are false and that consequently the scaling factors derived in [2] are not an improvement on Lal's scaling model [3]. The comment of Desilets et al. [1] covers several points; my reply will follow their sequence of points raised for discussion. In part the assertions of Desilets et al. [1] arise from the br...
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