The irradiation device (10) has two types of tubular, low pressure radiators emitting ultraviolet-A and ultraviolet-B radiations. The low pressure radiator (12) of a type B has a high ultraviolet-B radiation against the low pressure radiator (11) of the type A and the diameter of the low pressure radiator of the type B is smaller than the low pressure radiator of the type A, the ratio amounts 5:12. An independent claim is also included for method for operating an irradiation device, particularly for irradiating a human body.
