Decay Of 153Sm Research Articles

Precision electron–gamma spectroscopic data from the beta decay of 153Sm

Abstract The decay of 153Sm was studied with a HPGe detector and a Si(Li) detector based electron transporter. Forty four gamma transitions belonging to sixteen excited levels in the daughter nucleus 153Eu were analyzed for their energies, emission intensities, conversion electron intensities and conversion coefficients. These values have resulted in the determination of precise beta emission intensities to the levels in 153Eu and in the construction of an internally consistent decay scheme. The present study will add to the decay data available on this radionuclide for reliable dose estimations for medical applications.

Determination of the intensity of X- and gamma-ray emissions in the decay of 153Sm

The activity of a 153Sm solution was determined by means of liquid scintillation counting and an ionization chamber. Several accurately calibrated X- and gamma-ray spectrometers were used to measure point sources. The use of different detectors results in improvements to the accuracy of the data around 100 keV where the efficiency curve changes significantly. Photon emission intensities have been derived for the main X- and gamma-rays, and the 103-keV emission has a measured intensity of (29.07 (20)) per 100 disintegrations.

Studies on the energy levels of153Eu following the ??-decay of153Sm

The level scheme of153Eu was investigated by observing the gamma-rays following theβ−-decay of the 47 h153Sm using a high purity Ge(HPGe) detector and a Ge(Li)-Nal(Tl) fast-slow coincidence spectrometer. The energies and relative intensities of about fifty six gamma-ray transitions were determined. Five of them at energies of 124.91, 431.65, 443.24, 487.75 and 623.73 keV were observed and confirmed for the first time in the present singles and/or gamma-gamma coincidence measurements. These new transitions could be fitted into a proposed level scheme of153Eu. Theβ−-decay branching ratios as well as the log (ft) values were obtained.

Design and performance of a γ-ray diffractometer at 0.12 Å

At the University of Missouri Research Reactor, a γ-ray diffractometer has been constructed which uses 0.12 Å radiation produced from the decay of 153Sm. Use of this source rather than 198Au (λ = 0.03 Å), which is used at several instruments in Europe, has important advantages which are discussed. Details of the design necessary to work with 1000 Ci (37 TBq) sources at this wavelength are presented. In addition, the results of several experiments intended to test the capability of the instrument for measuring extinction-free structure factors at low angles and for measuring to high sin θ/λ (~ 2 Å−1) are reported. These results show that it will be relatively straightforward to make absolute structure-factor determinations for light elements and to determine electron density distributions more accurately than has been done in the past with X-ray diffraction. Furthermore, determination of anharmonic thermal motion and form factors will be possible. Crystal perfection studies on small samples have also been performed and can be done routinely.

Decay of 153Sm (47h) to 153Eu

The decay of 153Sm (47h) to excited states in 153Eu has been studied with a lithium-drifted germanium detector and a scintillation spectrometer. Singles and coincidence spectra were obtained. The energies and relative photon intensities of the previously reported transitions of 103.18, 151.49, 172.85, 412.1, 424.3, 437.3, 463.6, 521.3, 531.4, 533.2, 539.2, 554.7, 578.5, 596.7, 603.0, 609.1 and 636.2 keV were obtained. The energies and relative photon intensities of hitherto unreported transitions of 481, 485, 509.2, 584.2, 615.9, 657.7, 683, 713 and 760 keV were determined. The present data are consistent with a level scheme with states at 83.37 keV ( 7 2 +) , 97.45 keV ( 5 2 −) , 103.18 keV ( 3 2 +) , 151.5 keV ( 7 2 −) , 172.85 keV ( 5 2 +) , 585 keV ( 3 2 +) , 589 keV ( 5 2 −) , 597 keV ( 1 2 +) , 604 keV ( 5 2 +) , 634.6 keV ( 1 2 +) , 636.4 keV ( 3 2 +) , 658 keV ( 3 2 +) , 683 keV ( 5 2 +) , 712 keV ( 3 2 −) and 760 keV ( 5 2 +) . The log ft values for transitions to these levels were obtained. Ratios of experimental gamma-ray transition probabilities from the 712, 683, 658, 636.4 and 172.85 keV states are presented. All gamma-ray transitions have been placed into a consistent d decay scheme which may be treated in terms of the Nilsson model.

Slow Neutron-induced Activities in Europium and Samarium

The activities produced by the neutron irradiation of europium and samarium have been investigated by means of a thin lens type β-ray spectrometer and by absorption and coincidence methods. The 9.2-hour activity in europium is due to the dual decay of 152Eu by β-emission and by K capture. The long period activity is due to both 152Eu and 154Eu, and again both β- emission and K capture are present. This long period K capture is due to 152Eu, and the β- emission is possibly due to both 152Eu and 154Eu. The energies of the emitted radiations are discussed and possible decay schemes proposed. The 47-hour activity induced in samarium is due to the β- decay of 153Sm, and measurement of the energies of the emitted radiations has been made.