Chemical ionization mass spectrometer instrument for the measurement of tropospheric HO2 and RO2 - Cantrell, Christopher A.; Edwards, Gavin D.; Eisele, Fred L.; Goyea, Olusegun.; Hill, Brian.; Kosciuch, Edward.; Mauldin, R. Leon, III.; Shetter, Richard E.; Stephens, Sherry.; Tanner, David J.