Lisun Group can provide very fine Photo Detectors. They are NIM traceable (directly compared with NIM standard head) and is validated to PTB of Germany.
Problem of the part filtering technology: the tested light on the photo detector must be strictly uniform, otherwise even for a so called f1’=0.5% photo detector, its actual f1’ may exceed 10%.
Full-filtering technology: in order to achieve a high-performance photometer head, the filters should be specially designed, and the thickness error should be strictly limited within 1μm.
1. Requirements and Classification of Photometer Detectors as per JJG245-2005
2. Requirements and classification of Photometer Heads as per DIN.5032 Part 7