Hid sodium lamp which incorporates a high pressure of xenon and a trigger starting electrode

Abstract From the Canadian patent

High-intensity-discharge sodium lamp incorporates as a starting gas xenon at a pressure between 50 and 300 torrs, in order to improve the lamp efficiency and the spectral power distribution of the discharge. To facilitate lamp starting on a conventional pulse-type starting circuit a trigger electrode is wrapped about the exterior of the arc tube proximate one of the lamp electrodes with the poten-, tial applied to the trigger electrode during lamp starting being the same as that which is applied to the other or more remote lamp electrode. The starting pulse applied between the trigger electrode and the proximate lamp electrode initiates the lamp discharge. The trigger electrode also extends …