Metrology chain of the StarDICE experiment: with light detectors in the left column and light sources in the right column. Each arrow represents a step in the chain, and the label gives the order of magnitude of the beam intensity, irradiance, or spectral irradiance depending if the beam is contained or extended and monochromatic or not. The steps in gray were conducted at NIST (Houston 2008) and result in a silicon photodiode calibrated against an electrical substitution cryogenic radiometer. The two steps in red are covered in this paper and provide calibrated sensors with a much lower dark current than the photodiode. The rest of the chain leading to astrophysical standards will be the subject of forthcoming papers.