NASA Logo, External Link
Facebook icon, External Link to NASA STI page on Facebook Twitter icon, External Link to NASA STI on Twitter YouTube icon, External Link to NASA STI Channel on YouTube RSS icon, External Link to New NASA STI RSS Feed AddThis share icon
 

Record Details

Record 1 of 4428
Effects of proton irradiation on a gas phase in which condensation takes place. I Negative Mg-26 anomalies and Al-26. [applied to solar and meteoritic composition]
External Online Source: doi:10.1086/156570
Author and Affiliation:
Heymann, D.(Rice Univ., Houston, TX, United States)
Dziczkaniec, M.(Rice Univ., Houston, TX, United States)
Walker, A.(Rice Univ., Houston, TX, United States)
Huss, G.(Rice Univ., Houston, TX, United States)
Morgan, J. A.(Rice University, Houston, Tex., United States)
Abstract: In the present paper, isotopic effects in magnesium generated in a proton-irradiated gas phase are examined, taking only (p,n), (p,d), and (p, alpha) reactions in magnesium, aluminum, and silicon into consideration. In the presence of proton radiation, the three elements are 'removed' from the gas phase by condensation. It is required that a value of Al-26/Al-27 greater than 6 times 10 to the -5th must be reached, consistent with the value deduced by Lee Papanastassiou, and Wasserburg (1976) from their studies of the Allende meteorite. The calculations show that fast aluminum condensation reduces the required proton fluence substantially, that a significant fraction of aluminum remains uncondensed when the above value of the Al-26/Al-27 ratio is reached, that a detectable MG-24 excess is very likely to occur, that detectable negative MG-28 anomalies can be generated, and that proton fluxes and irradiation times can be varied simultaneously, and over a wide range of values, without significant changes in the required proton fluence.
Publication Date: Nov 01, 1978
Document ID:
19790029705
(Acquired Dec 01, 1995)
Accession Number: 79A13718
Subject Category: LUNAR AND PLANETARY EXPLORATION
Document Type: Journal Article
Publication Information: Astrophysical Journal; vol. 225
Publisher Information: United States
Contract/Grant/Task Num: NGL-44-006-127
Financial Sponsor: NASA; United States
Organization Source: Rice Univ.; Houston, TX, United States
Description: 15p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: ALUMINUM 26; ASTRONOMICAL MODELS; MAGNESIUM ISOTOPES; METEORITIC COMPOSITION; NUCLEAR REACTIONS; PROTON IRRADIATION; ABUNDANCE; ALUMINUM 27; DIFFERENTIAL EQUATIONS; ENERGY SPECTRA; PROTON ENERGY; PROTON FLUX DENSITY; SOLAR SYSTEM; TIME DEPENDENCE; VAPOR PHASES
Imprint And Other Notes: Astrophysical Journal, Part 1, vol. 225, Nov. 1, 1978, p. 1030-1044.
Miscellaneous Notes: Nov. 1, 1978, p. 1030-1044
Availability Source: Other Sources
› Back to Top
Find Similar Records
NASA Logo, External Link
NASA Official: Gerald Steeman
Site Curator: STI Program
Last Modified: August 16, 2011
Contact Us