The continuous wave, optically pumped H- source at TRIUMF

After installation in a 300 key terminal and extensive experimentation with the ECR electrode system the TRIUMF optically pumped H- source is now operational in providing 5μA of current extracted from the TRIUMF cyclotron with 50% polarization. The optically pumped source consists of an ECR proton source operating at 28 GHz, an optically pumped Na vapor charge exchange cell, a Sona spin transition and an ionizer cell. The ECR source extraction system consists of 61 1 mm holes whose special extraction properties will be reported. One of the reasons for the relatively low polarization of the proton beam has been identified as being the background beam resulting from charge exchange with hydrogen. Experiments to determine the nature of this effect will be reported. The electronic polarization of the neutralizer cell sodium was measured by Faraday rotation