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PG-200 Operation Manual
Version 2.D
of 1 nsec is entered, the display might return a value of 20 nsec (with a warning
message).
In setting the delay in conjunction with variable width pulses, it is often helpful to use a
high speed oscilloscope connected to the GATE MONITOR output. The monitor output
is nearly simultaneous with the output pulse. Be sure to allow for the delay in all cabling,
including the oscilloscope probes as appropriate, when making these measurements. The
pulse monitor output is a low level output for timing adjustment purposes only. It is not
meant for analysis of the output pulse waveform or amplitude. The pulse monitor output
may be used for the measurement of the delay and to some extent for the measurement of
pulse width. Precise pulse width measurements can only be done with a detector
simulator since pulse shape will be different at the detector than at the PG-200 rear
panel.
Gate pulse widths are entered directly, similar to gate pulse delays. The PG-200 is
calibrated for widths measured FWHM at a Princeton Instruments detector simulator. As
soon as the new width entry is confirmed, the output pulses will reflect the new value.
The PG-200 will automatically set the pulse width to the nearest legal value. For
example, if a width of 1 nsec is entered, the display might return a value of 4 nsec (with a
warning message).
To meet its performance specifications from a few nanoseconds to milliseconds, the PG-
200 uses multiple circuits for different pulse width ranges. For this reason there may be
delays when reprogramming gate pulse widths for things such as readjusting the high
voltage power supply, recalibration of the time base, etc. Such delays do not apply when
reprogramming gate pulse delays.
Inhibits
The PG-200 has two front panel inhibit inputs, positive and negative logic, +5 V signals.
This allows for inhibiting pulser operation with either type logic signal. Shortly after
receipt of an inhibit signal, all pulser operation is disabled including input triggering,
high voltage gating, and output triggering. Operation is restored shortly after all inhibits
are removed.
In a Princeton Instruments system,
INHIBIT
would typically be connected to either the
SHUTTER MONITOR output or NOTSCAN (
SCAN
) output of a Princeton Instruments
controller. For a CCD camera, use SHUTTER MONITOR. For a PDA detector, use
NOTSCAN (
SCAN
).
One exception to the above is that a high voltage gate pulse in progress will not be
disabled. (If a second gate pulse arrives during the inhibit period, that gate pulse will be
totally disabled.) Gate pulses are not truncated in order to maintain data integrity. It is
possible to truncate gate pulses during inhibit by inserting the INH GATE TOT jumper
on the Front Panel Board, although this is not recommended.
Trigger Outputs
The PG-200 has three BNC outputs that can be used for triggering other devices. The
INTERNAL TRIGGER OUT is time coincident, within a nanosecond, to the internal
frequency generator used for the internal trigger mode. It is usually configured for +5 V
negative logic TTL signal levels, although it can be configured for +5 V positive logic or
+15 V negative or positive logic signals.
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