Precise measurement of theXK emission rate following the electron capture-decay of54Mn-fluorescence yield ωK of Cr
This determination was made using the electron capture decay of54Mn. Two methods were employed to measure theK X-ray emission rate: by means of a pressurized 4π proportional counter with the gas at 1.5 MPa, and by means of a medium geometry-defined solid angle counter. The final result wasωk=0.2901±0.003. Special care was taken in determining the corrections, some of which do not appear to have been allowed for so far. It is noteworthy that additional corrections, each about +3 %, had to be applied to the results obtained with each of the two methods. Thus there remains complete agreement between them, but at a higher value ofωk than those appearing in recent publications.