The beta decay of176m Lu

The shape factors of the 1^?→2⁺ and 1^?→0⁺ beta transitions and theβ-γ directional correlation of^176m Lu have been measured. An analysis in terms of nuclear matrix elements is given.     

Der Zerfall des Lu176m

The decay of Lu^176m has been investigated. TheK-conversion coefficient α _K of the 88,3 keV niveau of Hf¹⁷⁶ has been determined to α _K =1,35±0,07. Theβ-branching ratio to the 0+ and 2+ niveau of Hf¹⁷⁶ has been measured by means of aβ-γ-coincidental technique. (60,4±6,1)% of Lu^176m decay into the 2+ niveau and (39,6±6,1)% into the 0+ niveau of Hf¹⁷⁶.K-capture of Lu^176m to Yb¹⁷⁶ was not found. If there is any, it is less than 0,1% of all decays.     

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.     

Study of the 176Lu(n, γ)177Lu reaction using a gamma band-filter spectrometer

The γ-ray spectrum from the ¹⁷⁶Lu(n, γ)¹⁷⁷Lu reaction has been investigated in the energy range 450 to 1420 keV using a newly developed gamma band-filter spectrometer. A total of 153 transitions have been observed. Improvements to the ¹⁷⁷Lu scheme are suggested, and in particular the γ-decay of several levels of the $\text{1}\text{2}$^?[530↑] and $\text{3}\text{2}$^?[532↓] rotational bands is proposed. Special attention has been given to the Coriolis coupling between the two latter bands and the $\text{1}\text{2}$^?[541↓] band. Results on a complementary investigation of the ¹⁷⁵Lu(n, γ)¹⁷⁶Lu reaction are presented.     

Studying the low-energy region of the 177m Lu gamma spectrum

High-precision measurements of the relative intensities of KX- and γ-rays associated with the decay of the isomer state in ¹⁷⁷Lu (T _1/2 = 160.44 days) are performed using a γ spectrometer that incorporates four different types of semiconductor detectors. Detailed analysis of the balance of intensities of the excited levels in ¹⁷⁷Lu and ¹⁷⁷Hf confirms the consistency of the obtained data. The intensities of the γ- and β—decay branches of the isomer and the internal conversion coefficients of the K-forbidden transitions are determined.     

Preparation of the 178m2Hf isomer used in the induced gamma decay experiment by X-ray from synchrotron radiation facility

It is widely acknowledged that the ^178m2Hf nuclide is the most suitable substance to study the decay characteristic of the isomer induced by low-energy X-ray. In order to conduct the experiment on the induced gamma emission, the research group has started producing the ^178m2Hf nuclide based on the ¹⁷⁶Yb(??, 2n)^178m2Hf reaction. After the chemical purification is conducted, the sample is prepared and used in Shanghai Synchrotron Radiation Facility. During the production of isomer, the natural metal Yb target is got through magnetron sputtering. Bombarded by ?? particles about 27 MeV, the ^178m2Hf nuclide reaches about 10¹². Yb target prepared in this way is most suitable for the production of ^178m2Hf nuclide in the CS30 cyclotron. There are various nuclides in the irradiated target and the main long-lived nuclides are ¹⁷³Lu, ¹⁷²Lu, ¹⁷⁵Hf, ¹⁷²Hf and ⁶⁵Zn. The chemical separation of ^178m2Hf is studied and its process is monitored by radioactive tracer. The above result shows that decontamination factors of Zn and Lu are 10⁵ and 10³, respectively, and the yield of hafnium is 69%. Under the protection of vacuum filtration technology, the purified ^178m2Hf isomers are entirely transferred to the surface of filter paper, in order to form the sample which satisfies requirements of X-ray triggering the ^178m2Hf isomer decay experiment in Shanghai Synchrotron Radiation Facility in the future.     

Niederenergetische Gammalinien vom Neutroneneinfang in Lu 175 und Lu 176

The low energy gamma-rays from neutron-capture in Lu 175 and Lu 176 have been investigated by means of the bent crystal-spectrometer at the DR-3-reactor at Risø. From the transitions in Lu 177 3 rotational bands have been determined. The levels of the (404)K=7/2⁺ groundstate rotational band are: 121,62 keV (I=9/2), 268,79keV (I=11/2), 440,66 keV (I=13/2), 636,22 keV (I=15/2), 854,34 keV (I=17/2). The level-sequence of the (514)K=9/2^?-band is: 150,39 keV (I=9/2), 288,99 keV (I=11/2), 451,49 keV (I=13/2), 637,05 keV (I=15/2) and 844,88 keV (I=17/2). At 457,92 keV is the basis for the (402)K=5/2⁺-band the higher levels of which are 552,05 keV (I=7/2), 671,89 keV (I=9/2), 816,63 keV (I=11/2), 985,23 keV (I=13/2), 1176,73keV (I=15/2) and probably 1389,5 keV (I=17/2). The energies of the levels apart from the 1389 keV-level have an accuracy of 7×10^?5. The energy differences between the 3 bands agree very well with the values expected from the Bohr-Mottelson-formulaE=A·I(I+1)+B·I ²(I+1)². The calculated branching-ratios within the 3 bands are in fairly good agreement with the experimental values. Theg _K -factors have been determined for 2 bands: It was found that for the (514)-bandg _K =1,16±0,04 and for the (402)-bandg _K =1,33±0,07.     

The quadrupole moment of176Lu

The intrinsic quadrupole moment of¹⁷⁶Lu has been determined by Coulomb excitation with α-particles to be 6.98±0.10 b. Evidence for a new level at approximately 578 keV with presumably collective structure is presented.     

Half-life measurements and gamma spectroscopy in the decay184Re m →184W

The half-lives of the intrinsic states at 1,285.8 and 1,502.2 keV in¹⁸⁴W have been measured in the decay of¹⁸⁴Re ^m to be 8.33±0.18Μs and 2.35±0.10 ns, respectively. These half-lives determine absolute gamma-ray transition probabilities of eight transitions and yield upper limits for three transitions. The decay scheme of¹⁸⁴Re ^m →¹⁸⁴W is improved through measurements of delayed gamma-ray spectra with a Ge(Li) detector. Spin and Nilsson model interpretations are discussed.     

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.     

The decay of the isotopes176Ir and177Ir

^176,177Ir were produced by irradiation of¹⁴¹Pr with⁴⁰Ar. β-delayed γ-rays of^176,177Ir were observed for the first time. From γγ-coincidence data decay schemes could be constructed. A new half-life of¹⁷⁷Ir was obtained yielding t_1/2=30 (2) s. α-branching ratios of 3.1(6) % for¹⁷⁶Ir and 0.06(1)% for¹⁷⁷Ir were measured.     

Pulsed NMRON oscillatory free induction decay signals in the angular distribution of gamma radiation from plated60CoFe

Results for an inhomogeneously broadened⁶⁰CoFe NMRON sample have been obtained for gamma detected single pulse (nutation) and two pulse (free induction decay) experiments in the region of intermediate-to-lowR(=₁/). Here ₁ is the angular frequency measure of the strength of the ferromagnetically enhanced RF field at the nucleus and is the HWHM of the inhomogeneously broadened line. Comparisons of the oscillatory FID signals obtained are made with the theoretical predictions of the following paper [6].     

Measurement of gamow-teller strength for 176Yb --> 176Lu and the efficiency of a solar neutrino detector

We report a 0 degrees 176Yb(p,n)176Lu measurement at IUCF where we used 120 and 160 MeV protons and the energy dependence method to determine Gamow-Teller (GT) matrix elements relative to the model independent Fermi matrix element. The data show that there is an isolated concentration of GT strength in the low-lying 1(+) states making the proposed Low Energy Neutrino Spectroscopy detector (based on neutrino captures on 176Yb) sensitive to pp and 7Be neutrinos and a promising detector to resolve the solar neutrino problem.     

Levels in160Yb from the radioactive decay of160Lu

Theγ-rays following the radioactive decay of¹⁶⁰Lu into¹⁶⁰Yb have been studied. The Lu source was produced in the¹⁴⁴Sm(¹⁹F, 3n) reaction at 85 MeV. Excitation functions, half-lives,γ-γ andγ-X-ray coincidences and conversion electrons were measured. Twoβ ⁺ decaying states in¹⁶⁰Lu were found with half-lives of 36.2(3) s and 40(1) s.¹⁶⁰Yb levels deduced from the decay of¹⁶⁰Lu are presented.