Didymium Glass Filter
| Description | Didymium glass filter, solid filter, certified |
| Use | Assessment of the photometric accuracy in the UV region (270 nm to 340 nm) |
| Material | Glass BG 36 of SCHOTT Glaswerke |
666-F7 Didymium glass filter
The F7 marked didymium glass filter is actually a standard to check for wavelength accuracy in the UV region, but it can also be used for checking the photometric accuracy.
Checking the photometric accuracy in the UV range is possible at the following wavelengths: 270 nm, 280 nm, 297 nm, 320 nm and 340 nm. As a standard, the thickness of the filter is manufactured in a way that it will have an absorbance of approx. 0.5 A at a wavelength of 340 nm. Absorbance values will increase with decreasing wavelengths up to ca. 1.5 A at 270 nm.
Typical spectrum of a Didymium glass filter between 270 nm and 370 nm
| Catalogue- No. | Description | Material | Thick- ness mm | Nominal Absorbance | Absorbance value at nm |
| 666-F7 | Didymium Glass Filter, Certified | BG 36 | ca. 1,2 | depending on wavelength | 270, 280, 297, 320, 340 |