Intrinsic reflection asymmetry in 225Ra

The level structure of 225Ra has been studied by measuring the radiations associated with the α-decay of 229Th. These measurements include α- and γ-singles spectra, and αγ-, αe--, and γγ-coincidence measurements. The α-spectra were measured with a high-resolution magnetic spectrometer and Si surface-barrier detectors, the γ-ray spectra with Ge and Ge(Li) semiconductor detectors and the electron spectra with a Si(Li) detector. Chemically purified and isotope-separated sources were used for various experiments. These data provide the energies and intensities for 20 α-branches and for ≅ 87 γ-rays. From this information and previous e- spectrograph measurements, ≅ 81 γ-rays are placed in a level scheme involving 22 excited states below 400 keV. Twenty of these excited states (excluding only tentative levels at 203 and 248 keV) can be assigned as members of four bands having Kπ = 1/2+ (ground state), 1/2- (55.1 keV), 3/2+ (149.9 keV) and 5/2+ (236.7 keV). (orig./HSI)