Patent Number: 
Section: claims

1. An optical filter material comprising doped quartz glass, which for UV operating radiation of a wavelength of 254 nm exhibits a spectral transmission of at least 80% cm−1 and has an edge wavelength λc in a wavelength range of 230 nm to 250 nm, wherein the edge wavelength λc is produced by doping with a gallium compound that has a maximum of an absorption band in a wavelength range below 250 mm. 2. The filter material according to claim 1, wherein the gallium compound is Ga2O3. 3. The filter material according to claim 1, wherein the gallium compound is present with a Ga concentration based on the undoped quartz glass that is in a range of 1 to 1000 wt. ppm. 4. The filter material according to claim 3, wherein the gallium compound is present with said Ga concentration based on the undoped quartz glass in a range of 50 to 500 wt. ppm. 5. The filter material according to claim 1, wherein the dopant comprises a titanium compound. 6. The filter material according to claim 5, wherein the titanium compound is present with a Ti concentration based on the undoped quartz glass that is in a range of 1 to 50 wt. ppm. 7. The filter material according to claim 6, wherein the titanium compound is present with the Ti concentration based on the undoped quartz glass less than 20 wt. ppm. 8. The filter material according to claim 1, wherein said doping comprises gallium oxide (Ga2O3) and titanium oxide (TiO2), the mol ratio of Ga:Ti being in a range of 10 to 100. 9. The filter material according to claim 1, wherein the quartz glass is synthetically produced silica. 10. The filter material according to claim 1, wherein the quartz glass has an SiO2 content that is at least 99.9%. 11. The filter material according to claim 1, wherein the quartz glass has a hydroxyl group content of less than 10 wt. ppm. 12. A method for irradiating a surface, a liquid or a gas comprising:providing a UV radiation source that emits operating radiation of a wavelength around 254 nm, and causing said operating radiation to pass which passes through a filter material of doped quartz glass that for the operating radiation exhibits a spectral transmission of at least 80% cm−1 and has an edge wavelength λc in a wavelength range of 230 nm to 250 nm, wherein the edge wavelength λc is produced by doping comprising a gallium compound that has an absorption band with a maximum in a wavelength range below 250 nm. 13. An optical filter component made of a filter material according to claim 1, wherein for UV operating radiation of a wavelength of 254 nm said optical filter component exhibits a spectral transmission of at least 80% cm−1 and has an edge wavelength λc in the wavelength range of 230 to 250 nm. 14. The filter material according to claim 1 wherein the dopant comprises a titanium compound in the form of TiO2. 15. The filter material according to claim 1, wherein the quartz glass has a hydroxyl group content of less than 1 wt. ppm. 16. The optical filter component according to claim 13, wherein the edge wavelength λc is produced by doping the filter material with a dopant, said dopant comprises a gallium compound that has a maximum of an absorption band in a wavelength range below 250 mm. 17. The optical filter component according to claim 13, wherein the gallium compound is Ga2O3, which is present with a Ga concentration based on the undoped quartz glass that is in a range of 1 to 1000 wt. ppm. 18. The optical filter component according to claim 17, wherein the gallium compound is present with a Ga concentration based on the undoped quartz glass that is in a range of 50 to 500 wt. ppm. 19. The optical filter component according to claim 16, wherein the dopant comprises a titanium compound, which is present with a Ti concentration based on the undoped quartz glass that is in the range of 1 to 50 wt. ppm. 20. The optical filter component according to claim 16, wherein the dopant comprises gallium oxide (Ga2O3) and titanium oxide (TiO2), the mol ratio of Ga:Ti being in the range of 10 to 100. 21. The optical filter component according to claim 13, wherein the filter material is made of quartz glass that is synthetically produced silica and wherein the SiO2 content of said optical filter material is at least 99.9%. 22. The optical filter component according to claim 21, wherein the quartz glass has a hydroxyl group content of less than 10 wt. ppm., preferably less than 1 wt. ppm.