Be aware of the temperature in the area when using the UV light meter.
When using, care must be taken to avoid receiving strong light, because the cathode of the phototube will be fatigued if it is exposed to strong light for a long time, which will cause the photocathode to emit abnormally. Therefore, the protective cover of the window should be covered when the illuminance meter is not used. In addition, the ambient temperature of the ultraviolet illuminance meter should not be very high or low. Especially the ultraviolet illuminance meter that uses thermoelectric effect elements as the receiver has stricter requirements on the ambient temperature (generally at 20°C); and when the photoelectric cell GD-5 is used as the receiver, the requirements on the ambient temperature are not very strict. Generally speaking, the lower the temperature, the better; to reduce the dark current. In addition, when measuring the radiation of the light source, it should be perpendicular to the window of the receiver. If it is tilted, it will produce a large error. Angle correction is required at this time.
The main difference between single beam and double beam of lux meter
Single beam: suitable for measuring absorbance or transmittance at a given wavelength, generally unable to scan the entire band spectrum, requiring high stability of the light source and detector.
Dual beams: automatic recording, fast full-band scanning. It can eliminate the influence of factors such as unstable light sources and detector sensitivity changes, and is especially suitable for structural analysis. The instrument is complicated and the price is high. False double beam is also proportional double beam. Its principle is that the light emitted by the same monochromator is divided into two beams, one beam directly reaches the detector, and the other beam passes through the sample and then reaches another detector. . The advantage of this instrument is that it can monitor the error caused by light source changes, but it cannot eliminate the influence caused by the reference.
