Analogue mode

Q. What are the main differences between an electron multiplier operated in pulse counting and analogue mode ... 

Figure 6.1 Part of a mass spectrum measured by rf GDMS of a glass sample (NIST SRM 613) a) in the mass range m/z 10-90 (analogue mode, highly abundant peaks of 40Ar2+, 40 Ar+ and40ArH+ are skipped) and b) m/z 95-240 (measured in the counting mode). (A. I. Saprykin, ]. S. Becker and H. J. Dietze, Fresenius. Anal. Chem., 359, 449(1997), with permission of Springer Science and Business Media.)...

We should not forget that an appropriate detector, a Faraday cup or a secondary electron multiplier equipped with a conversion dynode, is needed for ion detection. Most commercial instruments are equipped with a secondary electron multiplier, which can be operated in a low amplification mode, the analogue mode, and with a high gain, the counting mode, where each ion is counted. With this dual mode, a linear dynamic range of up to nine orders of magnitude can be achieved, so that major and minor components of the sample can be measured in one run. 

Principle of TOF mass spectrum acquisition with ITR in analogue mode. Data from JEOL documentation. 

The resolution of frafis-piermethrinic acid was carried out in analogue mode." ... 

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