Time-resolved interstellar Pu-244 and Fe-60 Ppofiles in a Be- 10 dated ferromanganese crust
Loading...
Date
2021-11
Journal Title
Journal ISSN
Volume Title
Publisher
Australian Nuclear Science and Technology Organisation
Abstract
More than 20 years have passed since the first attempts to find live supernova Fe-60 (t1/2 = 2.6 Myr) in a deep-sea ferromanganese crust [1]. Within these 20 years, strong evidence was presented for a global influx of supernova dust into several geological samples around 2 Myr ago. Recently, a much younger continuous influx was found in Antarctic snow and in deep-sea sediments [2-4] and an older peak around 7 Myr in deep-sea crusts [5,6]. The long-lived isotope Pu-244 (t1/2 = 80 Myr) is produced in the astrophysical r-process similarly to most of the heaviest elements. Although the production mechanism is believed to be understood, the astrophysical site is heavily disputed. Most likely scenarios involve a combination of rare supernovae and neutron star mergers. The search for Pu-244 signatures in samples with known Fe-60 signatures allows to test for either common influx patterns or independent Pu-244 influxes disentangled from stellar Fe-60. Accordingly, this information provides a unique and direct experimental approach for identifying the production site of the heavy elements. Very recently and first reported in the AMS-14 conference, the first detection of interstellar Pu-244 was published [6]. This was only feasible by achieving the highest detection efficiencies for plutonium in AMS ever reported [7]. The achieved time resolution of 4.5 Myr integrates over the supernova influxes and is therefore not high enough to unequivocally show a correlated influx pattern of Fe-60 and Pu-244. Based on this progress, we are now aiming to measure highly time-resolved profiles of Fe-60 and Pu-244 in the largest ferromanganese crust used so far. Results on the characterization of the crust including cosmogenic Be-10 (t1/2 = 1.4 Myr) dating and a 10 Myr profile of interstellar Fe-60 including the confirmation of the 7 Myr influx will be presented along with first data on interstellar Pu-244.
Description
Keywords
Interstellar space, Nova model, Dusts, Plutonium 244, Iron 60, Mass spectroscopy, Carbon 14
Citation
Koll, D., Wallner, A., Hotchkis, M., Child, D., Fifield, K., Froehlich, M., Harnett, M., Lachner, J., Merchel, S., Pavetich, S., Rugel, G., Slavkovska, Z., & Tims, S., (2021). Time-resolved interstellar Pu-244 and Fe-60 Ppofiles in a Be- 10 dated ferromanganese crust. Paper presented to the 15th International Conference on Accelerator Mass Spectrometry. ANSTO Sydney, Australia. November 15th – 19th, 2021, (pp. 155). Retrieved from: https://ams15sydney.com/wp-content/uploads/2021/11/AMS-15-Full-Program-and-Abstract-Book-R-1.pdf