Isomerism, total decay energies, and absolute ?-ray intensities of the heavy Pd and Ag isotopes

Abstract

The decays of 113,114, 115g, 115m, 116pd have been studied with an emphasis on the determinations of total decay energies and absolute ?-ray intensities. The experiments also provided improved data on these quantities for the decays of 114'115g'llSm't16mAg. A search for isomeric transitions using a high resolution electron detector resuited in the identification of isomeric E3 transitions in 115pd and 113,115,116,117Ag" The isomeric branching was determined in all cases. The Qa-values of 113-116pd and 113 116Ag have been measured using a /?V-coincidence method. 21.10.Dr; 23.20.Lv The investigations reported here also include measurements of total decay energies using a/?y-coincidence method. Previous information on the Qp-values in this region was unprecise in most cases and unknown for llSpd" PACS:The first experimental studies of the short lived Pd and Ag activities discussed here were reported [3][4][5][6][7] several years ago. More detailed information is now becoming available through spectroscopic studies of 113,115pd ' see [8,9] and studies [10] of the even-A isobaric chains. The work reported here forms a part of a very detailed investigation of the level structure of Ag and Cd nuclei. The results of this work are now being prepared for publication [11].

Negative parity bands ofPd115and band structures inPd113,115Fong1, Hwang2, Ramayya3 et al. 2005Phys. Rev. C272260View full textAdd to dashboardCite

“…An assignment of 11/2 − for the J π of the isomeric state is in conflict with β − decay of 115 Pd to the states in the daughter nucleus 115 Ag. Specifically, the isomeric state is found to populate a state in 115 Ag that subsequently decays to the 1/2 − ground state [9]. The intermediate state most likely has a J π of 5/2 − , indicating the isomer should have a J π of 7/2 − rather than 11/2 − .…”

“…In the case of 115 Pd, rotational band interpretations [4][5][6] are in conflict with β − -decay results [7,9,14]. An assignment of 11/2 − for the J π of the isomeric state is in conflict with β − decay of 115 Pd to the states in the daughter nucleus 115 Ag.…”

“…The log ft value of 5.4 indicates a Gamow-Teller type of transition, pointing to a 5/2 + ground state for 113 Pd. In 115 Pd, the isomer at 89.3 keV β decays to an excited state in 115 Ag that subsequently deexcites to the 1/2 − ground state [9]. This state has previously been assigned a J π of 11/2 − because of the rotational band, but clearly this is questionable, as a 7/2 − assignment explains the β-decay results much better.…”

“…β decay studies [7][8][9] led to the identification of isomeric states in these nuclei leading to construction of decoupled rotational bands of negative parity built on these isomers. The isomeric states have been assigned spin and parity (J π ) of 11/2 − .…”

Approaching theN=82shell closure with mass measurements of Ag and Cd isotopes

“…The AME2003 mass was determined with a weighting of 50.3% from the β − decay of 114 Pd [38,39] with Q values of 1414(30) and 1451 (25) [42]. The value of the new AME is entirely determined by the corrected ISOLTRAP value.…”