Chapter 3 25
Introduction to WinPulse
Trigger Level Sets the current being generated by the PMT at which a pulse
is detected. The range for the trigger level is 10–2000 mV;
default is 100 mV. The actual trigger level is not critical, but it
must be set high enough to avoid the intermittent left/right
shifting of the emission (“gate jitter”). The optimal trigger
level is when the vertical screen line that marks the time zero is
at half the height of the first triggering light peak (peak 1 in
Figure 5.1).
Range Sets the desired electrometer range 1, 10, or 100, which corre-
spond to 0.1, 1.0, and 10.0 µA/V respectively; default is 10. A
range of 10 is used most. A range of 100 can provide slightly
larger dynamic range for some applications, but it is not
recommended for low-level analysis.
H
2
, Air 1, and Air 2
This control is reserved for future use.
Flow Rate and
Split Set Control
Mode Allows the operator to assign one of the current modes in the
Gate Parameters List to the channel.
Interpolation Sets the method for interpolating between observed output
values from each pulse to derive a higher output data fre-
quency. Linear provides point-to-point interpolation, and
Spline provides piecewise cubic smooth interpolation.
Attenuation Sets the integer (2
X
, x = 0 to 8) used to reduce the PMT signal
to ensure that the PFPD’s signal handling capacity is not
exceeded or that sufficient digital to analog conversion (DAC)
noise levels are observed in the output signal. As attenuation is
increased, insufficient DAC resolution may result and might
produce an inaccurate estimate of the signal to noise ratio. (See
Appendix C for a more detailed discussion of noise.)
Output Zero Shows the instantaneous average baseline between the gates
set for the reported output channel.
Output Set Sets the zero offset for the output channel. This can either be
the output zero or some lower value specified by the operator.
It is recommended that the lowest obtainable output zero in the
tick-tock mode be specified as the set value in order to maxi-
mize the dynamic range for chemiluminescence signals.
The function of each button along the bottom of the Board/Channel Parameters
screen is as follows:
Ok Saves any changes made and exits the Board/Channel Pa-
rameters screen.
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