Radioactive rare gases and tritium in the sample return container, and the $sup 37$Ar and $sup 39$Ar depth profile in the Apollo 16 drill stem

Technical Report · Mon Jan 01 00:00:00 EST 1973

DOI:https://doi.org/10.2172/4333257· OSTI ID:4333257

Stoenner, R W; Davis, R Jr; Bauer, M

The gas was extracted from the sample return container from the Apollo 16 and 17 missions by adsorption on charcoal and activated vanadium metal. The hydrogen, argon, and radon were separated and counted to give the tritium, /sup 37/Ar, /suyp 39/Ar, and /sup 222 /Rn activities. The tritium and argon activities observed could be explained by diffusive losses of these gases from the fine material in the container. There was no excess tritium present in the Apollo 17 containers that could be attributed to solar tritons remaining from the intense flare of August 4, 1972. The /sup 222/Rn observed in the sample return container was interpreted as an emanation product from lunar fines and an emanation yield of 1 x 10/sup -4/ was calculated. This yield is consistent with the low radon content observed in the lunar atmosphere. The tritium, sup 37/Ar, / sup 39/Ar, and /sup 222/Rn activities and the K, Ca, Ti, Fe, and Mn contents were measured on a set of samples from the Apollo 16 deep drill stem at depths from 83 to 343 g/cm/sup 2/. The /sup 37/Ar and /sup 39/Ar activities combined with similar measurements at more shallow depth by Fireman and associates (SAO) give the complete activity proflle in the lunar regolith. Since /sup 37/Ar is produced mainly by the /sup 40/Ca(n, alpha )/su p 37/Ar reaction it is possible to determine the neutron production rate in the regolith as a function of the depth. The /sup 222/Rn extracted from the samples by vacuum melting was found to be lower than expected in some samples based upon their uranium contents. The hydrogen and helium contents of the drill stem samples were measured and found to be relatively uniform with depth in contrast to similar measurements on Apollo 15 and 17 drill stems. The H/He atom ratio was higher than the accepted solar-wind value by a factor of two, possibly due to water contamination. (auth)

• Research Organization: Brookhaven National Lab., Upton, N.Y. (USA)
• NSA Number: NSA-29-025062
• OSTI ID: 4333257
• Report Number(s): BNL--18580
• Country of Publication: United States
• Language: English

Related Subjects

*ARGON 37-- LUNAR MATERIALS
*ARGON 39-- LUNAR MATERIALS
*CALCIUM-- LUNAR MATERIALS
*HELIUM-- LUNAR MATERIALS
*HYDROGEN-- LUNAR MATERIALS
*IRON-- LUNAR MATERIALS
*LUNAR MATERIALS-- ISOTOPE RATIO
*MANGANESE-- LUNAR MATERIALS
*POTASSIUM-- LUNAR MATERIALS
*RADON 222-- LUNAR MATERIALS
*TITANIUM-- LUNAR MATERIALS
*TRITIUM-- LUNAR MATERIALS
APOLLO PROJECT
N56700* --Physics (Astrophysics & Cosmology)--Planetary Phenomena