Analogue versus Digital Signal Processing

Very high count rates cause a potential problem for pulse counting. If the count rate becomes too high then it is possible that two ions may arrive at the detector at essentially the same time, that is, within the time period of a single time bin. Since only one ion count 

The speed at which the current pulse is discharged to Earth (ground) is proportional to the time constant. RC. where R is the resistance and C is the capacitance. Although we have no capacitor deliberately placed in the circuit, thoe is always some capacitance arising in the detector circuitry. Since the circuit resistance can easily be controlled, low R is chosen to generate an acceptably small time constant. 

Chambers, A., Fitch, R. F, Halliday, B. S. (1998) Basic Vacuum Technology, loP Publishing, Bristol. 

O Hanlon, J. F. (2003) A User s Guide to Vacuum Technology, John Wiley Sons, Inc. 

Yoshimura, N. (2007) Vacuum Technology Practice for Scientific Instruments, Springer-Verlag, Berlin. 

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