Through the experiment, it is indicated that regulated direct power makes the light source stable and provides the accurate UV radiation calibration with stable ultraviolet light source.

实验结果表明，带有光反馈的恒压恒流直流电源发光稳定，为精确紫外辐射定标提供了高稳定度的紫外光源。

youdao

At one end of the tube is a source of ultraviolet light and at the other a detector.

BBC: Hidden graves found using chemical 'sniffer' technology