Identifying large chondrites using cosmogenic radionuclides

K. C. Welten; M. W. Caffee; D. J. Hillegonds; J. Masarik; K. Nishiizumi

doi:10.1016/j.nimb.2009.10.129

Identifying large chondrites using cosmogenic radionuclides

K. C. Welten, M. W. Caffee, D. J. Hillegonds, J. Masarik, K. Nishiizumi

Research output: Contribution to journal › Article › peer-review

4 Scopus citations

Abstract

We measured the concentrations of the cosmogenic radionuclides ¹⁰Be, ²⁶Al, ³⁶Cl and ⁴¹Ca in the metal and stone fractions of three large chondrite showers to determine their pre-atmospheric size. Large chondrites are characterized by substantial contributions of neutron-capture ⁴¹Ca in the stone fraction (up to ∼2 dpm/gCa), low radionuclide concentrations in the metal fraction and high ¹⁰Be(stone)/¹⁰Be(metal) ratios. Based on the measured concentrations in comparison with calculated cosmogenic nuclide depth profiles, using a semi-empirical and a purely physical model, we conclude that these objects had pre-atmospheric radii ranging from ∼80 cm to >3 m. We conclude that the semi-empirical model is more reliable for spallogenic production rates in large objects, while the purely physical model is more reliable for neutron-capture products.

Original language	English (US)
Pages (from-to)	1185-1188
Number of pages	4
Journal	Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
Volume	268
Issue number	7-8
DOIs	https://doi.org/10.1016/j.nimb.2009.10.129
State	Published - Apr 2010
Externally published	Yes

Keywords

Chondrites
Cosmogenic radionuclides
Model calculations
Pre-atmospheric size
Production rates

ASJC Scopus subject areas

Instrumentation
Nuclear and High Energy Physics

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@article{6dc34684d7094958b2ed04d1f481a9ec,

title = "Identifying large chondrites using cosmogenic radionuclides",

abstract = "We measured the concentrations of the cosmogenic radionuclides 10Be, 26Al, 36Cl and 41Ca in the metal and stone fractions of three large chondrite showers to determine their pre-atmospheric size. Large chondrites are characterized by substantial contributions of neutron-capture 41Ca in the stone fraction (up to ∼2 dpm/gCa), low radionuclide concentrations in the metal fraction and high 10Be(stone)/10Be(metal) ratios. Based on the measured concentrations in comparison with calculated cosmogenic nuclide depth profiles, using a semi-empirical and a purely physical model, we conclude that these objects had pre-atmospheric radii ranging from ∼80 cm to >3 m. We conclude that the semi-empirical model is more reliable for spallogenic production rates in large objects, while the purely physical model is more reliable for neutron-capture products.",

keywords = "Chondrites, Cosmogenic radionuclides, Model calculations, Pre-atmospheric size, Production rates",

author = "Welten, {K. C.} and Caffee, {M. W.} and Hillegonds, {D. J.} and J. Masarik and K. Nishiizumi",

year = "2010",

month = apr,

doi = "10.1016/j.nimb.2009.10.129",

language = "English (US)",

volume = "268",

pages = "1185--1188",

journal = "Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms",

issn = "0168-583X",

publisher = "Elsevier",

number = "7-8",

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TY - JOUR

T1 - Identifying large chondrites using cosmogenic radionuclides

AU - Welten, K. C.

AU - Caffee, M. W.

AU - Hillegonds, D. J.

AU - Masarik, J.

AU - Nishiizumi, K.

PY - 2010/4

Y1 - 2010/4

N2 - We measured the concentrations of the cosmogenic radionuclides 10Be, 26Al, 36Cl and 41Ca in the metal and stone fractions of three large chondrite showers to determine their pre-atmospheric size. Large chondrites are characterized by substantial contributions of neutron-capture 41Ca in the stone fraction (up to ∼2 dpm/gCa), low radionuclide concentrations in the metal fraction and high 10Be(stone)/10Be(metal) ratios. Based on the measured concentrations in comparison with calculated cosmogenic nuclide depth profiles, using a semi-empirical and a purely physical model, we conclude that these objects had pre-atmospheric radii ranging from ∼80 cm to >3 m. We conclude that the semi-empirical model is more reliable for spallogenic production rates in large objects, while the purely physical model is more reliable for neutron-capture products.

AB - We measured the concentrations of the cosmogenic radionuclides 10Be, 26Al, 36Cl and 41Ca in the metal and stone fractions of three large chondrite showers to determine their pre-atmospheric size. Large chondrites are characterized by substantial contributions of neutron-capture 41Ca in the stone fraction (up to ∼2 dpm/gCa), low radionuclide concentrations in the metal fraction and high 10Be(stone)/10Be(metal) ratios. Based on the measured concentrations in comparison with calculated cosmogenic nuclide depth profiles, using a semi-empirical and a purely physical model, we conclude that these objects had pre-atmospheric radii ranging from ∼80 cm to >3 m. We conclude that the semi-empirical model is more reliable for spallogenic production rates in large objects, while the purely physical model is more reliable for neutron-capture products.

KW - Chondrites

KW - Cosmogenic radionuclides

KW - Model calculations

KW - Pre-atmospheric size

KW - Production rates

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JO - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms

JF - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms

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