A high-resolution spectroscopic study of the gamma radiation from the decay of96Nb

The decay of 24h⁹⁶Nb has been studied with a Ge(Li) spectrometer and with a Ge(Li)-NaI(Tl) coincidence spectrometer. A total of 27 gamma-ray transitions were observed, their energies and intensities measured. All but one of these have been incorporated into the level scheme of⁹⁶Mo. The level at 1,625.9 keV reported recently in (n _th, γ) work on⁹⁵Nb has also been observed through the decay of⁹⁶Nb. No experimental evidence has been found for previously proposed levels at 2,657 and 2,791 keV in⁹⁶Mo.     

Decay of78Br

The decay of⁷⁸Br was investigated with a Ge(Li) spectrometer and Ge(Li)-NaI(Tl) coincidence methods. Accurate energy and intensity determinations of 14 gamma rays have been performed. A level scheme with levels at 614.0, 1,308.1, 1,498.4, 1,758.5, 1,993.7, 2,334.4, 2,538, 3,090 and 3,253 keV is deduced. Spin and parity indications for most of the observed levels are given from electron capture and positon decay considerations and gamma branches.     

Low-lying 134Cs excited states from the (n, γ) reaction

Low-energy γ-ray and conversion electron spectra from the ¹³³Cs(n,γ)¹³⁴Cs reaction have been investigated with a bent cyrstal spectrometer, β-speetrometer, Ge(Li) and Si(Li) detectors. Gamma-gamma coincidence measurements were made with the Ge(Li)-Ge(Li) arrangement. Gamma-gamma delayed coincidences have been studied with the use of the Ge(Li)-NaI(Tl) coincidence set-up. The decay of 2.9 h ^134mCs has been investigated with the prism β-spectrometer and Ge(Li) detector. The half-lives of the 176.403 and 257.112 keV levels have been measured to be 49.7 ± 0.8ns and 12.3 ± 1.1 ns respectively. The neutron binding energy B_n have been calculated to be 6891.4 ± 1.3 keV. Spin and parity assignments have been made for almost all the levels. The possible structure of the levels deduced is discussed.     

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.     

The decay of131Ba

The decay of¹³¹Ba has been studied by Ge(Li) detector supplemented by Ge(Li)-Ge(Li) fast-slow coincidence and NaI(Tl)-NaI(Tl) sum-coincidence spectrometer. The existence of 31 gamma rays and the levels at 78.8, 123.5, 133.4, 215.7, 373.0, 585.0, 620.0, 696.3 and 1084.4 keV have been confirmed. No evidences are found for the level at 1170 keV and 215.7?78.8 and 696.3?373.0 transitions. Some transitions are found to be connected with the impurities which were attributed to¹³¹Ba decay in earlier studies. The relative intensities and conversion coefficients have been determined and multipolarities of some of the transitions infered from the comparison of the conversion coefficients with the theoretical values.     

The 63Cu(p,p'γ) reaction and the structure of 63Cu

Levels in ⁶³Cu were studied by means of the ⁶³Cu(p, p'γ) reaction at incident proton energies E_p = 4.2, 5.0 and 6.0 MeV. Singles γ-ray spectra were obtained with a Ge(Li)-NaI(Tl) spectrometer. A total of 57 γ-transitions up to 2889.4 keV have been found and a detailed level scheme for the de-excitation of 22 levels in ⁶³Cu is proposed.     

Levels and transitions in125Te

Gamma transitions and levels of¹²⁵Te following the decay of¹²⁵Sb have been studied using Ge(Li) detector and NaI(Tl)-NaI(Tl) sum-coincidence spectrometer incorporated with a fast-slow coincidence circuit. In all, twenty five gamma rays have been reported, out of which two weak gamma rays with energies 366·0 and 402·0 keV have been observed and confirmed for the first time. These gamma rays have been fitted by assigning a new level of 402 keV energy. An ambiguous transition of energy 122·1 keV has also been confirmed. No evidence was found for the existence of 145·9, 315·0, 489·8, and 497·4 keV transitions. The accurate intensities for various transitions have been determined.     

The decay of Ag

The γ-radiation following the decay of ¹¹²Ag has been studied with a Ge(Li) detector. A total of 76 γ-rays was observed. The γ-γ coincidence and angular correlation relations involving the 617 keV 2⁺-0⁺ transition have been measured using Ge(Li)-NaI(Tl) and NaI(Tl)-NaI(Tl) detectors. These results have been used to confirm spins and parities of some levels of ¹¹²Cd in the proposed decay scheme. Cross sections for ¹¹²Ag production by ¹¹⁵In(n,α) and ¹¹²Cd(n, p) reactions have been measured; the ¹¹²Ag half-life has been determined as 3.14 ± 0.02 h.     

A coincidence study of the decay of 35.8y150m Eu

The decay of 35.8y^150m Eu was studied with a Ge(Li) counter and a Ge(Li)-NaI(Tl) coincidence spectrometer. A total of 64 gamma rays were observed, their energies and intensities measured. A partial level scheme for¹⁵⁰Sm containing 24 energy levels was constructed from the coincidence data. Radioactivity ^150mEu (from¹⁵⁰Sm(d,2n))γγ coincidence; measuredE _y I _y ; deduced levels, decay scheme. Enriched target, Ge(Li) and NaI(Tl) detectors.     

Gamma-gamma directional correlations in69Ga

Employing a Ge(Li)-NaI(Tl) detector system, gamma-gamma directional correlations for nine cascades in⁶⁹Ga have been measured. The result of the present measurements combined with other existing data allowed the adoption of a 5/2^? spin and parity for the 1106.4 keV level, and a 7/2^? for the 1 336.1 and 1487.5 keV levels. A tentative 7/2^? spin and parity has been adopted for 1923.1 keV level. Mixing ratios have been determined for six transitions. The data obtained are utilized to extractM1 andE2 reduced transition probabilities. A comparison of the experimental data is made with the predictions of the one particle-core and three particles-core coupling models.     

Beta decay of 28P

The β⁺ decay of ²⁸P has been studied with a Ge(Li)-NaI(Tl) escape-suppression spectrometer. The number of ²⁸Si γ-transitions observed following ²⁸P decay has been increased from 15 to 34. New β⁺ branches were observed to ²⁸Si levels at 7416, 9796 and 10209 keV and sharper limits were placed on unobserved gb⁺ transitions.     

Directional correlations of some γ-ray cascades in200Hg

Directional correlation functions of 10 γ-ray cascades in²⁰⁰Hg have been measured using a²⁰⁰Tl source and a Ge(Li)-NaI(Tl) coincidence spectrometer arrangement. Values of the mixing parameter δ for several transitions are determined, and the spin assignments for the following levels in²⁰⁰Hg are established (level energies are given in keV): 1029.4 (0⁺), 1254.2 (2⁺), 1573.7 (2⁺), 1593.4 (2⁺), 1641.5 (2⁺), 1730.9 (2⁺) and 1775.6 (3⁺).     

Der Zerfall des Zn63

The decay of the 38.4 min-Zn⁶³ has been investigated using Ge(Li)-counters and a Ge(Li)-NaJ(Tl)-coincidence circuit. 43γ-transitions in the energy range from 364.5 keV to 3100.9 keV have been found and their relative intensities have been determined. A level scheme for Zn⁶³→Cu⁶³ having 24 levels is proposed. This accounts for all observedγ-transitions except one.     

Decay of193m Hg

The decay of^193m Hg to¹⁹³Au levels was investigated by means of Ge(Li) and Ge(Li)-NaI(Tl) coincidence spectrometers. In theγ-ray spectrum about 120 transitions were observed, about 80 of them being new. Forty coincidences betweenγ-transitions were observed. The level scheme of¹⁹³Au, including 12 earlier known levels as well as 17 new and corrected levels, has been constructed on the basis of the balance of energy sums and the observed coincidences. Possible multipolarities of 33 transitions were determined. Possible spins and parities of several levels were deduced from the determined multipolarities.     

Band mixing in156Gd and158Gd

A detailed investigation of the energies and intensities of the γ-rays that depopulate the low spin levels of the β- and γ-vibrational bands of¹⁵⁶Gd and the γ-vibrational band of¹⁵⁸Gd has been conducted. Both singles and γ-γ coincidence measurements were made on sources of 15-d¹⁵⁶Eu and 46-min¹⁵⁸Eu by use of large volume, high resolution Ge(Li) detectors. In addition to the γ-band at 1154.09 keV, twoK ^π=0⁺ bands were observed in¹⁵⁶Gd with band heads at 1049.45 and 1168.11 keV, respectively. The 2⁺ and 3⁺ members of the γ-vibrational band in¹⁵⁸Gd were observed at 1187.12 and 1265.43 keV, respectively, as well as a newK ^π=0⁺ band at 1195.98 keV. A first order perturbational treatment of the branching ratios was applied to both nuclei. In addition, the mixing between the ground state, the β-, and the γ-vibrational bands of¹⁵⁶Gd is considered from two approaches, but neither satisfactorily explains all the experimentalB(E2) ratios.     

Gamma rays from thermal-neutron capture in natural and K enriched potassium

Gamma rays following thermal-neutron capture in natural and in ³⁹K enriched potassium have been investigated with a Ge(Li) and a Ge(Li)-NaI spectrometer. In the ³⁹K(n,γ)⁴⁰K reaction 222 γ-rays were found, of which 187 could be fitted into the level scheme of ⁴⁰K. Fifteen γ-rays could be ascribed to the ⁴¹K(n, γ)⁴²K reaction. Excitation energies of 54 levels in ⁴⁰K and of 9 levels in ⁴²K have been determined with 0.2−1.0 keV errors. The Q-values of the ³⁹K(n, γ)⁴⁰K and ⁴¹K(n, γ)⁴²K reactions are Q = 7799.7 ±0.8 keV and 7533.9±1.2 keV, respectively.     

Der zerfall des J121 (T 1/2=2,12 h)

I¹²¹ was produced by bombarding a target of enriched Te¹²² with deuterons of 25 MeV. Theγ rays associated with the decay of I¹²¹ have been investigated using a Ge(Li) detector and a Ge(Li)-NaI coincidence set up. 58γ transitions ranging from 212.5 to 1841.8 keV have been identified. A decay scheme for the I¹²¹→Te¹²¹ decay which accounts for 50 of the observedγ transitions is proposed.     

Der Zerfall des122Xe (T 1/2=20,l h) und des122J (T 1/2=3,6min)

Theγ spectra emitted in the decay of¹²²Xe and¹²²I have been investigated using Ge(Li) detectors and a Ge(Li)-NaI coincidence apparatus. 14γ transitions with energies between 61.8 and 416.9 keV have been identified in the decay of¹²²Xe, 44 transitions between 564.0 and 3,291.0 keV in the decay of¹²²I. Level schemes having 7 excited levels for¹²²I and 21 excited levels for¹²²Te are proposed.     

Der Zerfall des Xe123,T 1/2=2,08h

Xe¹²³ (T _1/2=2.08 h) was produced by bombarding Te¹²² with 48 MeV α-particles. The radioactive Xe¹²³ gas was collected during irradiation in liquid air cooled glass ampoules. The gamma rays associated with the decay of Xe¹²³ have been investigated using Ge(Li)- and NaJ(Tl)-counters and a Ge(Li)-NaJ(Tl)-coincidence circuit. 57 gamma transitions in the energy range from 148.7 keV to 2559.1 keV have been found. By depositing the radioactive Xe-ions on Ti-foils sources were obtained thin enough to study the conversion electrons using a Si(Li)-counter. The conversion coefficients for the intensive J¹²³ transitions with low energy were determined. A level scheme for Xe¹²³→J¹²³ which accounts for almost all observed γ-transitions having 16 levels is proposed. Furthermore some new data for the J¹²¹ and J¹²³ decay are presented.     

The four quasi-particle 178Hf isomeric state,its excitation energy and multipolarities of deexciting transitions

The decay properties of the 31 y ¹⁷⁸Hf isomeric state have been investigated by means of a Ge(Li)-NaI(Tl) Compton suppression device and a Si(Li) detector, as well as with Ge(Li) and Ge(Li), intrinsic Ge and Si(Li) coincidence arrangements. From the E3 character of the unobserved isomeric transition (11.7 ≦ E_IT ≦ 16.7 keV), deduced from L-subshell and M/L ratios, I^π, K of the isomeric level was determined as 16⁺, 16. The {p[404] ↓ + p1514] ↑ + n[514] ↓ + n[624]↑}_16⁺ + four quasi-particle configuration was assigned to this level at 2447.5 ± 2.5 keV. As proposed earlier the isomeric E3 transition decays to the 13^? level of the band built upon the I^π = 8^? isomer. The |g_K?g_R| values derived from $\text{E}\text{2}\text{M}\text{1}$ ratios of interband transitions show that the 8^? isomer contains about 36 % of the p[404] ↓ + p[514] ↑ configuration and about 64 % of the n[624] ↑ + n[514] ↓ configuration.