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Gamma-ray detection following the inelastic neutron scattering reaction on isotopically enriched material was used to study the nuclear structure of 74Ge. From these measurements, low-lying, low-spin excited states were characterized, new states and their decays were identified, level lifetimes were measured with the Doppler-shift attenuation method (DSAM), multipole mixing ratios were established, and transition probabilities were determined. New structural features in 74Ge were identified, and the reanalysis of older 76Ge data led to the placement of the 2+ member of the intruder band. In addition, a number of previously placed states in 74Ge were shown not to exist. A procedure for future work, which will lead to meaningful data for constraining calculations of the neutrinoless double-beta decay matrix element, is suggested.

Elastic and inelastic neutron scattering differential cross sections and γ-ray production cross sections have been measured on 54,56Fe at several incident energies in the fast neutron region between 1.5 and 4.7 MeV. All measurements were completed at the University of Kentucky Accelerator Laboratory (UKAL) using a 7-MV Model CN Van de Graaff accelerator, along with the neutron production and neutron and γ-ray detection systems located there. The facilities at UKAL allow the investigation of both elastic and inelastic scattering with nearly mono-energetic incident neutrons. Time-of-flight techniques were used to detect the scattered neutrons for the differential cross section measurements. The measured cross sections are important for fission reactor applications and also for testing global model calculations such as those found at ENDF, since describing both the elastic and inelastic scattering is important for determining the direct and compound components of the scattering mechanism. The γ-ray production cross sections are used to determine cross sections to unresolved levels in the neutron scattering experiments. Results from our measurements and comparisons to model calculations are presented.

Inelastic neutron scattering measurements were performed at the University of Kentucky Accelerator Laboratory on enriched 76Ge and 76Se scattering samples. From measurements at incident neutron energies from 2.0 to 4.0 MeV, many new levels were identified and characterized in each nucleus; level lifetimes, transition probabilities, multipole mixing ratios, and other properties were determined. In addition, γ-ray cross sections for the 76Ge(n,n′γ) reaction were measured at neutron energies up to 5.0 MeV, with the goal of determining the cross sections of γ rays in 2040-keV region, which corresponds to the region of interest in the neutrinoless double β decay of 76Ge. Gamma rays from the three strongest branches from the 3952-keV level were observed, but the previously reported 2041-keV γ ray was not. Population cross sections across the range of incident neutron energies were determined for the 3952-keV level, resulting in a cross section of ~0.1 mb for the 2041-keV branch using the previously determined branching ratios. Beyond this, the data from these experiments indicate that previously unreported γ rays from levels in 76Ge can be found in the 2039-keV region.

The lifetime of the second 2+ state in 94Zr was redetermined by the Doppler-shift attenuation method following inelastic neutron scattering (DSAM-INS) from metallic Zr and ZrO2 samples of natural isotopic abundance. The new value for the level lifetime differs significantly from the previously published value, with the new lifetime found to be roughly twice that value. A reanalysis of the original γ-ray data from the enriched 94ZrO2 sample failed to expose the source of this discrepancy; however, powder X-ray diffraction and scanning electron microscopy performed on each scattering sample, including the enriched sample used previously, provide clues to an explanation and reveal the role of the chemical properties of the sample material in DSAM-INS lifetime determinations.

The nature of low-lying excitations, Kπ=0+ bands in deformed nuclei remain enigmatic in the field, especially in relationship to quadrupole vibrations. One method of characterizing these states beyond excitation energies is through measurements of absolute transition probabilities. In the rare earth region of deformation, there are five stable Gd isotopes, 154Gd, 156Gd, and 158Gd have been studied to obtain B(E2) values, a fourth, 160Gd is the focus of this work. We have examined 160Gd with the (n, n′γ) reaction and neutron energies up to 3.0 MeV to confirm known 0+ states.

Transfer reactions at the high-precision Q3D spectrometer at the University of Munich have shown that there are many low-lying excited K π = 0 + states in well-deformed nuclei. A recent study of 162 Dy shows eleven 0 + states below an energy of 3 MeV. While this nucleus is studied extensively, the lifetimes of the new states were not known. We report on lifetime measurements of the newly observed states in order to determine their properties and allow the characterization of these states. Level lifetimes of 0 + states in 162 Dy were measured by the ( n , n ′ γ ) reaction and the Doppler-shift attenuation method at the University of Kentucky. This work allow us to report the transition probabilities from six of the eleven 0 + states. We suggest that the first excited K π = 0 + excitation at 1400.2 keV in 162 Dy may be the β vibrational excitation and not the γ γ excitation indicated in the past or a shape coexistence minimum. [ABSTRACT FROM AUTHOR]

Low-lying states of 94Zr are populated following - decay of 94Y, and the emitted rays from 94Zr are detected using the 8p spectrometer composed of 20 Compton-suppressed HPGe detectors. High- statistics coincidence data have been used for the placement of very weak decay branches in the level scheme. Combining the results of level lifetimes from a previous experiment and the precisely measured branching ratio values of the weak decay branches from the present experiment, it is possible to extract the B(E2) values for all the possible decay branches from a given level. These values are helpful for proper identification of the collective and non-collective states of 94Zr. The experimental findings have been compared with predictions from shell-model calculations with a limited valence space; however, these calculations are inadequate in reproducing all of the measured spectroscopic quantities. [ABSTRACT FROM AUTHOR]

The experimental signature in searches for the neutrinoless double-β decay of 76Ge is a peak near 2039 keV in the spectrum. Given the low probability of the process, it is important that the background in this region be well understood. Inelastic scattering reactions with neutrons from muon-induced interactions and (α,n) reactions in the surrounding materials or in the detector can provide contributions to the background. We have measured the production cross sections for γ rays from the 76Ge(n,n'γ) reaction in the 2039-keV region at incident neutron energies up to 4.9 MeV. In addition to determining that the cross sections of a previously known 2040.7-keV γ ray from the 3952-keV level in 76Ge are rather small, we find that a larger contribution arises from a 2037.5-keV γ ray which is attributed to a newly identified level at 3147 keV in 76Ge. A third contribution is also possible from another new level at 3577 keV. These results indicate that the 2039-keV region in 76Ge neutrinoless double-β decay searches is more complex than was previously thought. [ABSTRACT FROM AUTHOR]

The lifetime of the second excited 2+ state of 94Zr at 1671 keV was determined with the Doppler-shift attenuation method (DSAM) following the (n, n'y) reaction on scattering samples of Zr metal and Zr02 of natural isotopic abundance. The measured lifetime, r = 368-23+2 fs, is considerably longer than the previous measurement, as are measured lifetimes of other levels in 94Zr. However, lifetimes of low-lying, low-spin states in 90,9l,92,96Zr were also determined and found to be in good agreement with measurements employing non-DSAM methods. Possible reasons for the discrepant lifetimes measured for 94Zr are discussed and focus on the chemical properties of the scattering sample, specifically, the effects of using amorphous materials, or those composed of small particles as scattering samples. These properties have been investigated by x-ray powder diffraction and scanning electron microscopy. The effects of using these materials for lifetime measurements were investigated by employing, as scattering samples, Zr(OH)4 (a known amorphous material) and Zr02 with various crystalline domain sizes. [ABSTRACT FROM AUTHOR]

Based on results from a measurement of weak decay branches observed following the ß- decay of 94Y and on lifetime data from a study of 94Zr by inelastic neutron scattering, collective structure is deduced in the closed-subshell nucleus 94Zr. These results establish shape coexistence in 94Zr. The role of subshells for nuclear collectivity is suggested to be important. [ABSTRACT FROM AUTHOR]

A system for computerising histopathology/cytology records using a commercial data processing system is described. It is emphasised that any system of computerising records should have some flexibility as no two laboratories have the same requirement and new applications and requirements may arise as one goes along. It is suggested on the basis of the authors' experience over the past two years that it might be worthwhile for histopathologists/cytopathologists interested in computerisation of records to consider the possibility of "user-friendly" software systems, which can be adapted to their particular requirements, rather than a tailor made system, which might be difficult to modify. [ABSTRACT FROM PUBLISHER]

Two cases of eccrine tumour of sweat gland origin found in the hand are presented. They were on-tender rounded masses of eight months to two years duration, beneath and adherent to the pidermis but movable on underlying tissue. The pre-operative diagnosis in each case was that of sebaceous cyst. Histology revealed one to be an eccrine spiradenoma and the other a chondroid syringoma. The lesions were considered unusual in that such tumours usually occur on the trunk, head and back and are rarely found in the hand. [ABSTRACT FROM PUBLISHER]

Inelastic neutron scattering was used to study the low-lying nuclear structure of 132Xe. A comprehensive level scheme is presented, as well as new level lifetimes, multipole mixing ratios, branching ratios, and transition probabilities. Comparisons of these data as well as previously measured E2 strengths and g factors are made with new shell-model calculations for 132,134,136Xe to explore the emergence of collectivity in the Xe isotopes with N < 82 near the closed shell. [ABSTRACT FROM AUTHOR]

Internal conversion coefficients have been measured for transitions in 110Pd to allow the determination of electric monopole (E0) transition strengths. Excited states were populated through inelastic alpha scattering and the SPICE+TIGRESS detectors at TRIUMF-ISAC-II were used to detect the emitted gamma rays and internal conversion electrons. The E0 transition strengths are found to be small and are consistent with the expectation for transitions from a K = 2 band to the K = 0 ground-state band in the axial rotor model. [ABSTRACT FROM AUTHOR]

The level structure of the N=82 nucleus 136Xe was studied with the inelastic neutron scattering reaction followed byγ-ray detection. A number of the spins and parities were reassigned, and many level lifetimes were determined for the first time using the Doppler-shift attenuation method. New shell-model calculations were also performed using both the fullZ=50-82 model space, and a reduced model space including only the1d5/2 and0g7/2 orbitals. This new information characterizing 136Xe was used to identify the seniority structure of the low-lying levels and to assign(π0g7/2)4υ=0,(π0g7/2)4υ=2,(π0g7/2)4υ=4,(π1d5/2)(π0g7/2)3υ=1, and(π1d5/2)2(π0g7/2)²υ=0 configurations to describe all observed states below 2.8 MeV. [ABSTRACT FROM AUTHOR]

The level structure of 134 Xe was studied with the inelastic neutron scattering reaction followed by γ-ray detection. A number of level lifetimes were determined for the first time with the Doppler-shift attenuation method and the low-lying excited states were characterized. From this new spectroscopic information, the third excited state, a 0+ level which had only been observed in a previous inelastic neutron scattering study, was verified. Reduced transition probabilities were calculated; comparisons were drawn with a vibrational description of the nucleus and found lacking. The 3 - octupole phonon has been confirmed, and the complete negative-parity multiplet resulting from the ν (1h11/22d3/2) configuration has also been tentatively identified for the first time in the N = 80 isotones. [ABSTRACT FROM AUTHOR]

Excited states in 106Pd were studied with the (n,n'γ) reaction, and comprehensive information for excitations with spin ≤6ℏ was obtained. The data include level lifetimes in the femtosecond regime, spins and parities, transition multipolarities, and multipole mixing ratios, which allow the determination of reduced transition probabilities. The E2 decay strength to the low-lying states is mapped up to ≈2.4 MeV in excitation energy. The structures associated with quadrupole collectivity are elucidated and organized into bands. [ABSTRACT FROM AUTHOR]