Excimer lamp

An excimer lamp comprising:

• a discharge vessel in which a rare gas and a halogen are enclosed and sealed as light emitting gases;
• and
• at least one first electrode and at least one second electrode for generating a dielectric barrier discharge inside the discharge vessel,
• the rare gas being xenon or krypton,
• the discharge vessel having a discharge forming region and a non-discharge region therein such that discharging takes place in the discharge forming region and no discharging takes place in the non-discharge region, the discharge forming region being formed between the at least one first electrode and the at least one second electrode, the non-discharge region communicating with the discharge forming region,
• the excimer lamp being configured to satisfy following equations:
• (Vb×Ph)/Sd≥4.50
• Ph≤5.0
• where Vb [mm3] represents a space volume inside the discharge vessel, Sd [mm2] represents an inner surface area of the discharge vessel in the discharge forming region, and Ph [Torr] represents a halogen-atoms partial pressure enclosed in the discharge vessel.