Positive corona discharge ion source with IMS/MS to detect impurities in high purity NitrogenM. Sabo, M. Klas, H. Wang, C. Huang, Y. Chu and Š. MatejčíkEur. Phys. J. Appl. Phys., 55 1 (2011) 13808DOI: https://doi.org/10.1051/epjap/2011100437