1. A gas cell comprising:
metal atoms which are sealed in an internal space; and
a buffer gas which is sealed in the internal space and includes nitrogen gas,
wherein a partial pressure of the nitrogen gas in the internal space is equal to or higher than 30 Torr.
2. The gas cell according to claim 1,
wherein the buffer gas further includes argon gas.
3. The gas cell according to claim 1,
wherein the buffer gas further includes krypton gas.
4. The gas cell according to claim 1,
wherein the metal atoms are cesium atoms.
5. The gas cell according to claim 1,
wherein the metal atoms are rubidium atoms.
6. The gas cell according to claim 1, further comprising:
a pair of window portions; and
a body portion which is disposed between the pair of window portions and forms the internal space along with the pair of window portions,
wherein a distance between the pair of window portions is equal to or less than 10 mm.
7. The gas cell according to claim 6,
wherein a width of the body portion along a direction perpendicular to a direction in which the pair of window portions are arranged is equal to or less than 10 mm.
8. The gas cell according to claim 1,
wherein the buffer gas does not substantially include neon gas.
9. A quantum interference device comprising:
the gas cell according to claim 1.
10. An atomic oscillator comprising:
the gas cell according to claim 1.
11. An electronic device comprising:
the gas cell according to claim 1.
12. A moving object comprising:
the gas cell according to claim 1.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. Process for the preparation of a vanadia SCR-catalyst supported on titania, characterised in that the catalyst is prepared by dispersing titania in an ammonium metavanadate (NH4VO3) solution, adjusting the pH of the solution to a value of 6.8-7.3 by NH4OH and HNO3, stirring the resulting suspension for a time sufficient for complete adsorption of the vanadium compound on titania, filtering the suspension and drying and calcining the resulting catalyst compound.