B. Erlandsson

Investigation of the γ-ray strength function in 64, 66Zn by means of the average resonance method

Abstract A three-crystal pair spectrometer has been used to study the 50 Ti(p, γ) 51 V reaction for E p = 2.1–2.5MeV and2.6–3.1MeV The γ-ray spectra were measured throughout the proton energy interval in steps of about 15 keV. These spectra were added to get only one averaged spectrum. The intensities of high-energy γ-transitions populating the low-excited states of 51 V have been determined. The intensities of the γ-rays to final states with known J π values were tested against theoretical calculations based on the Hauser-Feshbach theory with good results. The γ-ray strength function for energies lower than 11 MeV has been evaluated from the measured average intensities of primary γ-rays.

The energy of levels of45Sc up to 3 MeV from the44Ca (p, γ)45Sc reaction

The gamma-ray decay of the 1658 keV resonance, which is a member of the isobaric analogues of the 1904 keV 3/2− level in44Ca, has been studied with a Ge(Li) detector. A number of gamma-ray transitions are described and associated with the decay of 15 levels between 1.50 and 3.05 MeV. These observations have made it possible to deduce spin and parity assignments to some of the levels. By comparing excited levels of43Sc and45Sc it has been possible to assign certain levels as members of one negative-parity band and two positive-parity bands withKπ=1/2+ and 3/2+.

A study of the50Cr(d, n)51Mn and54Fe(d, n)55Co reactions

The50Cr(d, n)51Mn and54Fe(d, n)55Co reactions have been studied at an incident deuteron energy of 5.5 MeV. Angular distributions of neutron groups to a number of low-lying levels in the residual nuclei have been recorded. Time-of-flight techniques have been used to record neutron spectra. A liquid scintillator with pulse-shape discrimination property has been used as neutron detector. DWBA calculations have been performed and relative spectroscopic strengths determined for transitions with variouslp values. The ratios between spectroscopic strengths forlp=3 andlp=1 transitions were found to be considerably larger than corresponding ratios obtained from the (3He,d) reactions. Two-step stripping processes competing with the direct stripping process are suggested as explanation of the discrepancy between the (d, n) and the (3He,d) results.

Energy levels in46Ti

The gamma-ray spectra of several resonances in the45Sc(p, γ)46Ti reaction were measured using a 5 cm3 Ge(Li) detector. A thick target was bombarded with 1377 and 1660 keV protons, several resonances were therefore excited at each proton bombarding energy. The decay and energy of 30 excited levels were investigated. The intensity of all transitions to the ground state agrees within an error of about 9% with the total intensity of all transitions starting from the proton capture states, which indicates that low energy transitions between high-excited levels are of no importance. We have calculated a theoretical primary gamma-ray spectrum that fits the experimental averaged spectrum rather well.

Low Spin States in 64Zn and 66Zn

The gamma decays following the 63Cu(p, γ)64Zn and 65Cu(p, γ)66Zn reactions have been studied with Ge (Li) spectrometers. Proton energies of about 2 MeV have been used. Level schemes up to about 4 MeV for 64Zn and 66Zn have been constructed from the data.

Gamma-ray strength function measurements for 59Co, 61Cu and 62Cu

Abstract The (p, γ) reaction on 58 Fe, 60 Ni, and 61 Ni has been used to study the radiative E1 strength in the 6–10 MeV energy region. Significant deviations from the lorentzian extrapolations have been found both in shape and absolute values of the strength functions.

Investigation of65Cu by means of the average resonance proton capture method

The64Ni(p, γ)65Cu reaction has been studied in the proton energy rangeEp=2.05–2.55 MeV. The gamma-ray spectra were recorded with a three-crystal pair spectrometer at proton energy differences of 19 keV covering the proton energy range. An average gamma-ray spectrum was formed by adding all the individual spectra after proper adjustment as a result of the alterations in proton energy. The intensities of the gamma rays to final states with knownJπ-values were tested against theoretical calculations based on the Hauser-Feshbach theory. The gamma-ray strength function for energies lower than 9 MeV has been extracted from the experiment.

Gamma-ray strength function measurement for 63Cu

Abstract The 62 Ni(p, γ) 63 Cu reaction has been studied in the proton energy range E p = 1.9–2.4 MeV. Using a three-crystal pair spectrometer, γ-ray spectra of primary transitions have been measured throughout this proton energy interval in steps of about 4 keV. An average γ-ray spectrum was formed by adding all the individual spectra after proper adjustment as a result of the alterations in proton energy. From the average intensities of the primary γ-rays the γ-ray strength function for energies between 5 and 8 MeV was deduced. It was found that the values of the γ-ray strength function, in the region investigated, display a much steeper slope than the giant dipole resonance predicts.

Cross Section of Rb at 14 MeV Neutron Energy and the Decay of Rb

The decay of the metastable state in 84Rb has been studied by means of the 85Rb(n, 2n)84Rb and the 85Rb(γ, n)84Rb reactions. A possible but very weak feeding of excited states in 84Kr directly from the metastable state is suggested. The cross sections for the (n, 2n), (n, p) and (n, α) reactions of the target nuclei 85Rb and 87Rb were measured by the activation method with 14.8 MeV neutrons.

The 69ga γ-ray strength function between 6–10 MeV

Abstract The (p, γ) reaction on 68 Zn has been studied for proton energies between 2.18–2.69 and 3.13–3.56 MeV. Hauser-Feshbach calculations for the two proton energy ranges have been performed. From these calculations the 69 Ga γ-ray strength function between 6–10 MeV has been deduced.