NPL secondary standard radionuclide calibrator: new calibration figures for 106Ru, 153Sm and 188re

The NPL secondary standard radionuclide calibrator was introduced in 1985 in order to provide a highly stable, sensitive and accurate facility for the assay of radionuclides. One of its principal advantages is the direct traceability of its calibration figures to national standards of radioactivity. Since its introduction, several additional calibration figures have been measured for radionuclides which had not been previously standardised at NPL. Details of these new calibration figures are presented together with their appropriate volume correction factors.