Neutron capture on (180)Ta(m): clue for an s-process origin of nature's rarest isotope

Phys Rev Lett. 2001 Dec 17;87(25):251102. doi: 10.1103/PhysRevLett.87.251102. Epub 2001 Nov 30.

Abstract

The neutron capture cross section of (180)Ta(m) has been measured in the keV range, yielding a stellar average of 1465+/-100 mb at kT = 30 keV. Though the sample contained only 6.7 mg (180)Ta(m) (at an enrichment of 5.5%), the few capture events could be separated from much larger backgrounds by a unique combination of high efficiency, good energy resolution, and high granularity of the Karlsruhe 4 pi BaF(2) detector. A detailed s-process analysis based on this first experimental value indicates that (180)Ta(m) is predominantly of s-process origin.