Recommendation 4 of the 10th CCL (2001)

Radiations of spectral lamps and other sources

The Consultative Committee for Length,

considering that

• a significant number of new and high-accuracy frequency values for various cold atoms and ions have been recently measured, which should be added to the Consultative Committee for Length list of recommended radiations;
• new and more accurate gas-cell based standards have also been developed and measured;
• a number of existing recommended radiations such as certain iodine-stabilized laser standards have values that are unlikely to be further improved;

recognizes that these radiations (including the iodine-stabilized references at 640 nm, 612 nm, 515 nm and 543 nm) should be moved to the list for radiations of spectral lamps and other sources, but reiterates that these radiations continue to be appropriate radiations for the realization of the metre

DOI : 10.59161/CCL2001REC4E