TY - JOUR A1 - Helsper, Christoph A1 - Fißan, H. J. A1 - Muggli, J. A1 - Scheidweiler, A. T1 - Verification of Ionization Chamber Theory JF - Fire Technology. 19 (1983), H. 1 Y1 - 1983 SN - 1572-8099 SP - 14 EP - 21 ER - TY - JOUR A1 - Helsper, Christoph A1 - Fißan, H. J. T1 - Calibration of the Polytec HC-15 and HC-70 Optical Particle Counters / Fißan, H. J. ; Helsper, C. JF - Aerosols in the mining and industrial work environments, Vol. 3. Instrumentation, Marple, Virgil A. ; Liu, Benjamin Y. Y1 - 1983 N1 - International Symposium on Aerosols in the Mining and Industrial Work Environment ; (1981.11.01-06 : ; Minneapolis/Minn.) SP - 825 EP - 829 PB - Ann Arbor Science CY - Ann Arbor, Mich. ER - TY - JOUR A1 - Helsper, Christoph A1 - Fißan, H. J. A1 - Thielen, H. J. T1 - Determination of Particle Size Distributions by Means of an Electrostatic Classifier / Fißan, H. J.; Helsper, C. ; Thielen, H. J. JF - Journal of Aerosol Science. 14 (1983), H. 3 Y1 - 1983 SN - 0021-8502 SP - 354 EP - 357 ER -