The ? decay of90Ru

Abstract

By means of X-~f and 7-~f coincidence measurements of the SSCi + 5SNi reaction products, 38 7 lines have been identiffed to be in coincidence with KX(Tc)-rays and assigned to the decay of 9~Its hulf-lis of 11 4-3 s has been deduced from the 154.6 keV ")'-decay. The result supports ou~ previous identification of 9~ produced in the same reactions.The nuclei near the N:Z=50 region have resently been the subject of intensive study [I-6], mostly due to their significance for both nuclear structure and astrophysics. The stability of these nuclei against proton emission is important to the astrophysical rapid proton capture process. In a previous paper lines are 154.6,178.9, 184.6, 192.3, 203.3, 216.0, 228.3, 258.2, 281.8, 295.4, 319.4, 336.5, 345.1,355.2, 366.1,377.4, 398.6, 425.5, 439.6, 452.9, 477.6, 491.8, 518.3, 625.9, 644.8, 720.3, 771.6, 795.8, 821.3, 831.6,849.9, 986.2, 991.0, 1003, 1033, 1178, 1237 and 1551. As an example, the Kc~X(Tc) gated 7 spectrum for the 7-ray energy range from 100 to 300 keV is shown in figure 1 a). To assist the assignment of these 7 lines, data were analysed from a separate experiment, in which 124 MeV 35C1 beam was used to bombard a 2mg/cm 2 ~SNi target enriched to 99.8% and evaporated on a 30 mg/cm 2 lead backing. 7-7 coincidences were measured by five HPGe spectro-

The beta decay of neutron-deficient rhodium and ruthenium isotopes

“…The 155 keV line however, being more intense, was seen in the earlier measurement with an area of 1595(94) counts. This data is summed with data from the later experiment and is used to determine a half-life of 11.7(9) s for 90 Ru which is in agreement with the previous measurement of 11(3) s [Zho94]. The fit is shown in figure 5.22.…”

“…Figure 5.20 shows a selection of the data collected at mass 90 using a 32/32 s beam ON/OFF macrocycle. Prior to this work, measurements without the aid mass separation identified the line at 154.6 keV, along with 37 others, as belonging to the decay of 90 Ru [Zho94]. The line reported there at 491.8 keV is probably that placed here at 492.8 keV.…”