| Analog mode | Mode of electron multiplier operation where the output is measured as a continuously variable current which is directly proportional to the input. | |
| Anode | Last and most positive electrode of an electron multiplier from which the signal is drawn (also called the collector). | |
| Bias Current | The DC current that flows through the dynode resistor chain of the multiplier. The bias current is supplied by the multiplier high voltage. | |
| CDEM | (or CEM, or channel multiplier) Type of electron multiplier which uses a small glass tube (or channel) to perform the multiplication process. | |
| Channel Multiplier | see CDEM. | |
| Dark Current | The signal from the output of the multiplier in the absence of any input signal. | |
| Detector | Alternative name for an electron multiplier. | |
| Discrete-dynode | Type of electron multiplier which uses a series of discrete electrodes to perform the multiplication process. | |
| Dynamic Range | Range of output currents over which the electron multiplier will give a linear response to an input signal. | |
| Gain | Ratio of the multiplier output current to the input ion current. | |
| HED (High Energy Dynode) | High voltage electrode used for conversion of ions to electrons. It is particularly useful for detection of high mass ions. | |
| Life | Time over which a multiplier can operate efficiently as an ion detector. Multiplier life depends on many factors such as usage and environmental conditions. Typical life of an ACTIVE FILM Multiplier™ in an average application is 1-2 years (but can be as long as 3-4 years). | |
| Linearity | Ability of the multiplier to respond to an input ion current with a current at the output which varies linearly with the input. | |
| Negative Ion Mode | Operating mode of the mass spectrometer (and electron multiplier) in which negatively charged ions are analysed and detected by the electron multiplier. | |
| Operating Voltage | The high voltage applied to the electron multiplier to obtain the required performance. | |
| Positive Ion Mode | Operating mode of the mass spectrometer (and electron multiplier) in which positively charged ions are analysed and detected by the electron multiplier. | |
| PPINICI | Pulsed Positive Ion Negative Ion Chemical Ionisation. Uses a set of re-useable conversion dynodes (originally supplied by Finnigan) for the detection of both positive ions and negative ions. | |
| Pulse Counting Mode | Mode of electron multiplier operation where the output is measured by counting the individual pulses present at the multiplier output. Each pulse represents one detected ion. | |
| Sensitivity | At a set gain, the sensitivity of an electron multiplier is the level of output for a given amount of input signal (not to be confused with gain which is the multiplier's amplification). | |
| Signal-to-Noise | The multiplier signal-to-noise is the ratio of the output signal to the background noise detected (or picked up) by the multiplier. |
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