Nondestructive Gamma-ray Spectrometry Research Articles

Primordial Radioelements and Cosmogenic Radionuclides in Lunar Samples from Apollo 15

Two basalts, two breccias, and two soils from Apollo 15 were analyzed by nondestructive gamma-ray spectrometry. The concentrations of potassium, thorium, and uranium in the basalts were similar to those in the Apollo 12 basalts, but the potassium: uranium ratios were somewhat higher. Primordial radioelements were enriched in the soils and breccia, consistent with a two-component mixture of mare basalt and up to 20 percent foreign component (KREEP). The abundance patterns for cosmogenic radionuclides implied surface sampling for all specimens. The galactic cosmic-ray production rate of vanadium-48 was determined as 57 +/- 11 disintegrations per minute per kilogram of iron. Cobalt-56 concentrations were used to estimate the intensity of the solar flare of 25 January 1971.

Elemental Compositions and Ages of Lunar Samples by Nondestructive Gamma-Ray Spectrometry

A gamma-ray spectrometry system with low background was used to determine the radioactivity of crystalline rocks, breccias, and fine material. Nuclides identified were (40)K, (232)Th, (238)U, (7)Be, (22)Na (26)A1, (44)Ti, (46)Sc, (48)V, (52)Mn, (54)Mn, and (56)Co. Concentrations of K, Th, and U ranged between 480 and 2550, 1.01 and 3.30, and 0.26 and 0.83 parts per million, respectively. Concentrations of thorium and uranium were those of terrestrial basalts, while the potassium concentrations were near values for chondrites. Products of low-energy nuclear reactions showed pronounced concentration gradients at rock surfaces. Concentrations of K and of (22)Na determined here were combined with concentrations of rare gases to estimate gas-retention ages and cosmic-ray exposure ages with ranges of 2200 to 3200 and 34 to 340 million years, respectively, for three rocks.

Cosmogenic and Primordial Radionuclides in Lunar Samples by Nondestructive Gamma-Ray Spectrometry

The (7)Be, (22)Na, (26)Al, (44)Ti, (46)SC, (48)V (51)Cr, (54)Mn, (56)Co, (57)Co, (57)CO, (40)K, (238)U, and (232)Th were measured in lunar fines and portions of three rocks. Major production of cosmogenic radionuclides is due to solar protons, thus their concentrations are far different than those in meteorites. Surface exposures of the rocks and fines are long compared with the 0.74 million year half-life of (26)Al. Lunar fines show substantially higher concentrations of low energy reaction products. The ratios of thorium to uranium are extremely constant at 3.8, which indicates very little geochemical differentiation and are in good agreement with a common nucleosynthesis for lunar and earth materials.

Radionuclide Composition of the Allende Meteorite from Nondestructive Gamma-Ray Spectrometric Analysis

The concentrations of beryllium-7, sodium-22, aluminum-26, potassium-40, scandium-46, vanadium-48, chromium-51, manganese-54, cobalt-57, cobalt-60, and thorium-232 (thallium-208) have been measured in the Allende meteorite by nondestructive gamma-ray spectrometry. The high cobalt-60 content of the meteorite is indicative of a preatmospheric body with a minimum effective radius of 50 centimeters and a weight of 1650 kilograms; the aluminum-26 activity indicates a minimum exposure age of 3 million years.

Gamma-Ray Spectrometry as a Tool for a Rapid Investigation of Detritic Cores

ABSTRACT The nondestructive gamma-ray spectrometry of a sedimentary core allowed us to distinguish five great zones of variation for potassium and thorium content. A sedimentological and paleoclimatic study shows that those variations correspond to climatic fluctuations. It is then concluded that non destructive gamma-ray spectrometry may be a valuable tool for a rapid investigation of sedimentary cores.

Comparison of Adhesive Tapes by Neutron Activation Analysis

Abstract Adhesive tapes were compared by nondestructive gamma-ray spectrometry. Results show that neutron activation analysis can he used to characterize tapes through their elemental composition. Differences between manufacturers as well as hatch-tobatch and in-batch variations can be measured by neutron activation analysis.

Activation Analysis of Drugs

Abstract Activation analysis has been employed to compare and determine the source of manufacture of drugs. The irradiations were carried out with the DASA-TRIGA1 and Naval Research Laboratory nuclear reactors,2 and the induced radionuclides were identified by nondestructive gamma-ray spectrometry. The results show that the technique can be a useful tool for the identification of trace elements which serve to characterize drugs.

Activation Analysis of Physical Evidence Connected with Illicit Distilleries

Abstract Neutron-activation analysis has been employed to compare “moonshine,” soil, and paint collected as physical evidence during the investigation of illicit distilleries. These materials were irradiated in a DASA-TRIGA nuclear reactor and the induced radionuclides were identified by nondestructive gamma-ray spectrometry. The results obtained indicate the technique can be employed to compare these materials. The findings have been accepted for use in court as evidence.