Comparison of Multiple Prompt γ-Ray Analysis and Prompt γ-Ray Analysis for the Elemental Analysis of Geological and Cosmochemical Samples

Abstract

Multiple prompt γ-ray analysis (MPGA) and conventional neutron-induced prompt γ-ray analysis (PGA) are nondestructive analytical methods for bulk chemical compositions, and their analytical capabilities were compared for elemental analyses of geological and cosmochemical samples. Detection sensitivities of PGA are often restricted by poor signal-to-noise ratios and interferences from different origins. MPGA can substantially reduce the background level, especially for hydrogenous samples, relative to PGA, which opens up a possibility to use lower energy prompt γ-rays of some trace elements. Although it is one of the major constituent elements of rock samples, Mg is hard to be determined by PGA. With MPGA, Mg contents could be determined with reasonable consistency with their corresponding recommended values in geological and cosmochemical samples by carefully selecting suitable coincident prompt γ-ray energy pairs without interference correction. MPGA was applied to a hydrogenous meteorite, Ivuna, which contains H at 2% mass level. MPGA detection limits for most of the elements studied can be reduced up to 1 order of magnitude when compared with PGA detection limits under the present experimental conditions.

Solar system abundances and condensation temperatures of the halogens fluorine, chlorine, bromine, and iodine

“…The only other chondrite falls to which we can compare chlorine data from Clay et al 1) their analysis method is unsuitable for the water-bearing CI-chondrites because samples with large intrinsic water content enable halogen leaching in the reactor during irradiation, (2) the small samples analyzed are not representative for the whole rock, (3) the naturally fine-grained powdery CI-chondrites facilitate recoil-loss, and (4) losses of volatile halogen-bearing salts and organics during sample heating cannot be excluded (see section 2). Chlorine concentrations agree well in larger (> 50 mg) aliquots of larger homogenized samples in the CIchondrite Orgueil (Table 6) analyzed with nuclear radiation techniques (e.g., Dreibus et al 1979, Islam et al 2011, Palme 2019). The values by Dreibus et al (1979) with chemical separation agree within uncertainties to data from ion-chromatography (Menard et al 2013, Magenheim et al 1994, and Tarter 1980.…”

Effect of sample density in prompt γ-ray analysis

“…PGA is a powerful analytical method that has high measurement accuracy, enables us to non-destructive analysis of bulk samples, and can be applied to light elements which are difficult to measure by most other analytical methods 3 – 5 . Owing to the aforementioned advantages, PGA can be applied in many fields such as measurements of cadmium in rice 6 , measurement of boron in volcanic rock 7 , elemental analysis of meteorites 8 , 9 , and measurement of hydrogen in metal samples by focusing on hydrogen embrittlement in the industrial field 10 .…”

Nondestructive Quantitative Analysis of Difficult-to-Measure Radionuclides 107Pd and 99Tc

“…Although some specific elements can be quantified by these methods with higher sensitivities than those by INAA, overall analytical capability is quite similar. Later, S/N ratios were highly improved with great innovation using multiple prompt γ-ray analysis (MPGA), − which uses a γ–γ coincidence method. Even with these methods, however, 107 Pd cannot be quantitatively determined.…”