The decay of45Ti to45Sc

The low intensity β⁺/E.C. branches in the decay of⁴⁵Ti to excited states of⁴⁵Sc have been reinvestigated in order to resolve discrepancies in reported branching ratios. A new branch to the 974 keV level, having an intensity of 9.9±1.2×10^?5/decay has been found. A previously reported branch to the 1237 keV level was found to be in error. The intensities for decay to the levels at 720, 1408 and 1661 keV levels were determined to be 154±12, 90.2±9.7 and 52.5±5.6, respectively, in units of 10^?5 per decay.     

Das Gammaspektrum des34Se81

The decay of Se⁸¹ (18 min) produced by neutron bombardement of natural Se and 98% enriched Se⁸¹ has been studied with the aid of scintillation-spectrometers. Gamma-rays have been observed and could be identified as belonging to the decay of Se⁸¹, revealing three excited levels in Br³¹ at (282±3) keV, (565±6) keV and (820±10) keV. The branching ratios of the beta-components are 98,7% leading to the ground state and (0,06±0,03)%, (0,85±0,20)% and (0,40±0,10)% leading to the excited states, respectively. The 565 keV-level decays to the ground state directly or by a cascade-transition with nearly equal intensities, the 820 keV-level mainly by a direct transition.     

Investigation of dual decay of70Ga (21 min)

The weakβ ^?-branchings in⁷⁰Ga decay leading to excited states in⁷⁰Ge at 1039 keV, and 1215 keV were measured byβ ^?-ray and γ-ray detection in 4π geometry to be 0.36 ±0.02%, and 0.32±0.01%, respectively. The weak electron capture decay of⁷⁰Ga was confirmed and its intensity measured to be 0.41±0.05%. The energy of the γ-rays was remeasured to be 176.17±0.02 keV, and 1039.20±0.08 keV.     

Search for correlated two-photon emission from e+(82Sr)+Th interactions

A previously observed electron line at INS at 330.3±0.4 keV in e⁺+Th interactions has been implied by these authors to originate from the decay of an unknown neutral object X⁰. QED predicts a two-photon decay mode of X⁰ leading to a correlated two-photon coincidence peak at 841.3±0.4 keV. To search for such a peak γγ-coincidence experiments were performed. From an observed peak-like structure in the spectrum at 841.7±0.3 keV and an associated cross section of 10.6±3.1 (stat) ± 6.9 (syst) μb an upper limit for the cross section of 15.2±1.5 (syst) μb for the production and 2γ decay of the X⁰ was deduced with a statistical confidence level of 95%.     

Decay of high-spin isomers in Os nuclei by barrier penetration

A decay scheme for the 130±20 ns high-spin isomer in ¹⁸²Os has been established. The excitation energy of the isomer is 7049±1 keV and it has I^π = 25⁽⁺⁾. A 2.4% decay directly to the yrast 24⁺ level at 5988 keV is observed. In ¹⁸⁴Os a 20±5 ns isomer is observed at 2366±1 keV excitation energy with I^π = 10⁺. Again, direct transitions into the yrast 8⁺ and 10⁺ levels are observed. Contrary to previous speculations, there is no compelling evidence for stable triaxial shapes in the structure of the levels through which the isomers decay. The abnormally short half-lives observed, as well as the unusual decay patterns, are best understood in terms of a γ-soft nuclear potential. Motion in the γ-direction allows the isomer to decay via barrier penetration from an axially symmetric prolate shape with the angular momentum along the nuclear symmetry axis (deformation aligned state) via oblate shapes to another prolate shape with the angular momentum perpendicular to the nuclear symmetry axis (rotation-aligned state).     

Der Zerfall des125m Xe,des127m Xe und des127g Xe

The decay of^125m Xe produced by the reaction¹²²Te(α, n)^125m Xe using a target enriched in¹²²Te (95.4%) and the decay of^127m Xe produced by the reaction¹²⁷J(d, 2n)^127m Xe have been investigated: ^125m Xe decays with a half-life ofT _1/2=(56±3) sec by ayy- cascade withE _γ1=(140.4 ±0.5) keV andE _γ2=(110.5 ±0.5) keV. The experimental conversion coefficients yield multipolarities ofE3 for the 140.4 keV isomeric transition and predominantlyM1 for the 110.5 keV-transition. ^127m Xe decays with a half-life ofT _1/2=(71±2) sec. The decay also proceeds by aγγ-cascade with an isomeric E3 transition ofE _γ1=(172.5±0.3) keV and a predominantlyM1 transition ofE _γ2=(124.6±0.3) keV. In the decay of^127g Xe an additional branching of the electron capture to a level at (618.1±0.3) keV was observed. The relative probability forK-captureP _K618/P_K375=0.40 ±0.07 yields a total transition energyQ _EC=(664 ±4)keV. A spin of 1/2⁺ was assigned to the ground state.     

Messung des Elektroneneinfangs am Kern176m Lu

The electron capture of^176m Lu to the ground state and to the first excited state of¹⁷⁶Yb has been observed by measuring the YbK x-rays and the 82,2 keV gamma-rays from the gamma decay of the first excited state in¹⁷⁶Yb. With the data of the 88,36 keV gammarays following the beta decay of^176m Lu to the first excited state of¹⁷⁶Hf the electron capture/beta decay ratio of^176m Lu was found to be (0,95±0,16)·10^?4. The electron capture branching ratio to the ground state and to the first excited state of¹⁷⁶Yb was found to be 40/60±30%. By analyzing the 88,36keV gamma-rays and the HfKx-rays the halflife of^176m Lu was evaluated to be 3,66±0,04 h. The value for theK-conversion coefficient of the 88,36keV transition was determined from the x-ray/gamma-ray ratio to be 1,19±0,09.     

Der Zerfall des 4,4 min-Rh104m

The decay of the 4.4 min-Rh^104m has been investigated by observing coincidences between conversion electrons and gamma quanta. The decay by a 77 keV?52 keV cascade has been confirmed. In addition, a highly converted (31±2) keV transition in coincidence with the known 97 keV gamma ray has been found. The multipole order of this transition has been determined asM3. The intensity of the 97 keV?31 keV cascade has been measured as 3.3 % of the intensity of the 77 keV?52 keV cascade. An indication of a 45 keV transition from the 97 keV level to the 52 keV level has been found with an intensity of at most 0.1 % of the intensity of the 77 keV?52 keV cascade.     

Nuclear spectroscopic studies of the 23.7 h 248Bk

Main features of the decay of the 23.7 h ²⁴⁸Bk have been determined by spectroscopy with scintillation and semiconductor detectors. The results are as follows: half-life 23.7 ± 0.2 h; branching is (30 ± 5)% to ²⁴⁸Cm (≈ 23% EC decay to 0⁺ ground state and ≈ 7% to first 2⁺ state) and (70 ± 5)%β^? decay to ²⁴⁸Cf(5 % to 592 keV K^π = 2^? state and (65 ± 5)% to the ground-state band). The β^? decay energy, Q_β^?, has been measured to be 860 ± 20 keV, and the electron capture decay energy, Q_EC, has been derived from closed cycle to be 705 ± 25 keV. The deduced logft values of β^? and EC transitions restrict the spin of the ²⁴⁸Bk ground state to 1, with configuration assignment $\text{{}\text{n}\text{[734]}\text{9}\text{2}{}^{\mathrm{?}}$; $\text{p}\text{[633]}\text{7}\text{2}{}^{\mathrm{+}}$. It has also been deduced that the long lived isomer lies 65 ± 40 keV abovethe 23.7h ²⁴⁸Bk ground state.     

Transition rates in97Tc

The de-excitation of the 215 keV $\text{7}\text{2}{}^{\mathrm{+}}$ and 324 keV $\text{5}\text{2}{}^{\mathrm{+}}$ levels in⁹⁷Tc, as observed in ⁹⁷Ru decay, was studied by means of internal conversion electron spectroscopy and the delayed electron-electron coincidence technique. From L-subshell intensity ratios, the E2 content in the 108 and 215 keV transitions were found to be (65 ± 12)% and (7 ± 4)%, respectively. The obtained level mean-lives were 0.75 ± 0.09 ns for the 324 keV level and 74 ± 15 ps for the 215 keV level.     

Decay of126m Sb and the energy levels of126Te

The decay characteristics of 19 min^126m Sb have been studied using Ge(Li) and scintillation spectrometers. The sources of^126m Sb were obtained by the (n, p) reaction on enriched¹²⁶Te. The gamma rays of energies 414.4±0.3, 666.7±0.5 and 696.1±0.5 keV were found decaying with a half-life of 19 min. The study of beta spectra employing an anthracene crystal yielded two beta groups with end-point energies of 1.9±0.15 and 2.5±0.15 MeV. The results of singles and coincidence measurements have been incorporated into a decay scheme with excited states of¹²⁶Te at 666.7, 1,362.8 and 1,777.2 keV.     

Multihadronic decays and partial widths of the J/Ψ (3100) resonance produced in e+e− annihilation at adone

The reactions e⁺e^?→ hadrons and e⁺e⁺e^?→e⁺e^? have been studied at the J/gY (3100) resonance). The relative weights of the topological cross sections for fixed charged multiplicity are σ₂=(32±5)%, σ₄=(49±8)%, σ₆=(18±3)%, and σ₈=(1±0.6)%. The average pion multiplicities are 〈n_ch〉=3.8±0.3 and 〈n_{π^o〉=3.1±0.8}. The decay widths are Γ_e=(4.6±0.8) keV, Γ_h=(59±24) keV, and Γ=(68±26) keV.     

Gamma branching and total conversion coefficients of intraband transitions in the groundstate rotational band of245Cm

With calibrated Ge(Li) detectors, γ-γ coincidences have been observed in the decay of²⁴⁹Cf. The total conversion coefficient of the 54.7 and 66.7 keV transitions in the first rotational band have been determined to be 237±30 and 69±15, respectively. The branching ratio of the 121.5keV crossover transition is (22±7)%. The errors are the 2σ statistical uncertainties, linearily added to the errors in the detector efficiencies.     

Gamma radiation in the decay of249Cf

Gamma radiation following alpha decay of²⁴⁹Cf was investigated with high resolution Ge(Li) detectors in singles and coincidence arrangements. Nine new γ-rays were identified and placed in the previously-known decay scheme. Their energies in keV and intensities relative to the 388 keV (100) γ-ray are: 37.5±0.1 (0.026), 65.87±0.1 (0.017), 121.5±0.4 (0.070), 229.2±0.2 (0.072), 255.7±0.2 (0.065), 390.5±0.2 (0.025), 405.9±0.1 (0.014), 588.8±0.1 (0.003), and 643.5±0.1 (0.007). Coincidence measurements revealed that the intensity of the 54.7 keV γ-ray is shared by three intraband transitions and that the 121.5 keV crossover transition is present in the ground-state band.     

The ft value for the superallowed Fermi decay 38mK(β+)38Ar

The threshold energy for the reaction ³⁵Cl(α, n)^38mK has been measured to be 6674.8±3.2 keV and the Q-value for the reaction ³⁵Cl(α, p)³⁸Ar to be 837.2±2.4 keV. From the measurements a value of 5021.2±3.4 keV was obtained for the end-point energy of the decay ^38mK(b⁺)³⁸Ar. The half-life was measured as 925.6±0.7ms and hence an “effective” $\text{?t}$ value was calculated, giving the result 3106±10 s with the inclusion of outer radiative corrections to order Z²α³ and 3088±10 s allowing also for calculated charge-dependent effects.     

Spin values of the low lying nuclear levels of201Hg

Gamma-gamma directional correlations have been investigated for the cascades of 135-30 keV and 135-32 keV in²⁰¹Hg from the decay of²⁰¹Tl. A combination of NaI (Tl) and Si (Li) detectors was used for the experiments. Spin values ofI=1/2, 3/2 and 1/2 have been assigned to 1.58, 32.19 and 167.49 keV energy levels. In addition, the relative intensities of theγ rays have been measured with a Ge (Li) detector system. The results are 2.2±0.2, 2.2±0.2, 26.5±1.3, 1.6±0.1 and 100 for theγ rays of 30.60, 32.19, 135.34, 165.88 and 167.43 keV energies, respectively.     

A new isotope andα-lines in the Th-Np region and their production cross-sections

In the fusion reactions of^20,22Ne with²⁰⁵Tl,²⁰⁸Pb, and²⁰⁹Bi the absolute production cross-sections of the²²⁷Np,^222–224Pa,^222–224Th, and²²¹Ac isotopes were measured and the products of the xn evaporation channels and theirα-decay properties were investigated. The identified isotope is²²⁷Np (7680±10 keV). A newα-line structure of²²⁴Pa was established (7460±10 keV (25±3 %) and 7555±10 keV (75±3 %)). Fourα-lines of²²³Th were identified (7290±10 keV (41±5 %), 7320±10 keV (29±5 %), 7350 ± 15 keV (20±5 %), and 7390±15 keV (10±4 %)). The half life of²¹⁷Fr was measured to be 16±2 μs and that of²²⁰Ra was found to be 17 ±2 ms.     

Electron capture intensities in the decay of133Ba

The ground state decay of¹³³Ba was investigated using NaI(Tl) scintillation crystals.P _L/P_K electron capture ratios were measured for the transitions to the 437 keV and to the 384 keV level of¹³³Cs. The results are: (P _L/P_K)₄₃₇=0.371±0.007 and (PP _L/P_K)₃₈₄=0.221±0.005. From these data a mass difference between the ground states of the¹³³Ba- and the¹³³Cs-atom of (515±3) keV was derived. Besides, these capture ratios yield an exchange correction of 1.03±0.03. Furthermore, the intensity of the transition to the 161 keV level was determined to be smaller than 0.5% of all decays.     

K conversion coefficients of transitions in87Sr

TheK conversion coefficients of the 388 and 483 keV transitions in⁸⁷Sr populated in the decay of⁸⁷Y have been measured with Ge(Li) and Si(Li) detectors by the NPG method. We find α _K values of 0.162 ± 0.010 and 0.00260 ± 0.00013 for the 388 and 483 keV transitions, respectively.     

The electron capture decay of 85gsr

In order to resolve the controversy concerning the existence of an 868 keV γ-transition in the decay of 65d ^85sSr and to determine the electron capture decay energy, radiochemically separated sources, Ge(Li), Ge(Li)-NaI(Tl), and NaI(Tl)-NaI(Tl) spectrometers have been used for singles and (X-ray-γ and γ-γ coincidence measurements. A γ-ray at 868.5±0.5 keV decaying with a 65±5 d half-life was conclusively identified in ^85gSr decay. From measurements of the ratio $\text{P}{}_{\mathrm{\kappa (868.5)}}\text{P}{}_{\mathrm{\kappa (514)}}$ of K-capture probabilities by (KX-ray-γ coincidences, a value of Q_EC was determined for the EC decay feeding the 868.5 keV transition. Thus, a level in ⁸⁵Rb is established at 868.5 keV, and an upper limit of 0.45 μsec is set on its lifetime.