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The binding energies of 29 Si, 33 S, and 36 Cl have been measured with a relative uncertainty of <0.59 × 10 −6 using a flat-crystal spectrometer. The unique features of these measurements are (1) nearly perfect crystals whose lattice spacing is known in meters, (2) a highly precise angle scale that is derived from first principles, and (3) a γ -ray measurement facility that is coupled to a high-flux reactor with near-core source capability. The binding energy is obtained by measuring all γ -rays in a cascade scheme connecting the capture and ground states. The measurements require the extension of precision flat-crystal diffraction techniques to the 5-to 6-MeV energy region, a significant precision measurement challenge. The binding energies determined from these γ -ray measurements are consistent with recent highly accurate atomic-mass measurements within a relative uncertainty of 4.3 × 10 −7 . The γ -ray measurement uncertainties are the dominant contributors to the uncertainty of this consistency test. The measured γ -ray energies are in agreement with earlier precision γ -ray measurements.

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The lifetimes of the 2 ϩ states of the first excited K ϭ0 ϩ band in 168 Er and 164 Dy have been measured using the ␥-ray induced Doppler broadening technique. Although the deduced uncertainties for the lifetimes are rather large the data indicate that in 168 Er the decay to the ␥ band is moderately collective. In 164 Dy, however, a less collective decay pattern is observed. The transition rates are compared to the available theoretical descriptions. ͓S0556-2813͑98͒00902-9͔