Decay ofPm149(53 hr)

Abstract

The radioactive sources were obtained from neodymium oxide, enriched in Nd 148 , irradiated in the Argonne reactor CP-5. After the 1.8-hr activity of Nd 149 had decayed away, the 53-hr activity in 6iPni 149 remained. Some of the samples were purified by ion-exchange-column techniques before being studied. The radiations were investigated with a 180° focusing beta-ray spectrometer and the Argonne 256-channel scintillation coincidence spectrometer. The magnetic spectrometer resolved two components of the beta spectrum at 1.064±0.008 and 0.784±0.010 Mev. The beta rays were also studied by coincidence absorption techniques. In addition to the branch with a maximum energy of 0.784db0.010 Mev, this method revealed two more at 0.47±0.04 and 0.19±0.04 Mev. The scintillation pulse-height spectrum of the gamma rays revealed the presence of three transitions at 0.850±0.008, 0.582±0.006, and 0.285±0.001 Mev. A fourth gamma ray with an energy of 0.548±0.006 Mev was found in coincidence measurements. These radiations are fitted into a decay scheme comprising the ground state and four excited states in Sm 149 at 0.285, 0.582, 0.833, and 0.850 Mev. The log-// values, transition intensities, and possible spin and parity assignments are discussed.

Shape factor analysis of beta transitions in Pm-149

“…The 53 hour activity of 149pm has been investigated previously by several groups [1][2][3][4][5][6][7]. The 53 hour activity of 149pm has been investigated previously by several groups [1][2][3][4][5][6][7].…”

“…The 53 hour activity of 149pm has been investigated previously by several groups [1][2][3][4][5][6][7]. Artna et al [3] and Schmid et al [4] independently and simultaneously did beta-gamma coincidences by using long lens magnetic spectrometer and 180 ~ beta ray spectrometer respectively. However, found that the decay consisted of only a single beta group of end-point 1050keV leading to the ground state of 1498m.…”