ORTEC DSPEC Pro, Hardware User Manual

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DSPEC Pro
®
Digital Gamma-Ray Spectrometer User’s Manual 794380D / 0914
30
BaseLineR This shows when the baseline restorer is actively restoring the baseline.
PosBLDisc This shows when the positive baseline discriminator has been triggered. The
signal is used internally in the live-time correction, baseline restoration, and
pile-up rejection circuits.
Busy When the DSPEC Pro busy signal is active, Busy shows in the Mark box. It
represents the dead time.
Gate This shows when the gate signal is present on the gate input connector. If
the Gate mode on the ADC tab (see Fig. 18) is set to Off, then all regions
are marked. If the mode is set to Coincidence, then the marked region must
overlap the pulse peak (that is, must start before the beginning of the flattop
and stop after the end of the flattop) for the pulse to be counted. If the mode
is set to Anticoincidence, then the marked region will show the pulses that
are accepted. That is, the rejected peaks will not be marked. Simply put, in
all modes the accepted peaks are marked.
Peak This is the peak detect pulse. It indicates when the peak detect circuit has
detected a valid pulse. The Mark occurs about 1.5
µ
s after the pulse
maximum on the display.
On the lower right of the InSight display are the shaping parameter controls. The controls are
split into two groups, and the other controls... button switches between them.
One group includes Rise Time, Flattop, Tilt, and the Optimize button. The Rise Time value is
for both the rise and fall times; thus, changing the rise time has the effect of spreading or
narrowing the quasi-trapezoid symmetrically.
The Flattop controls adjust the top of the quasi-trapezoid. The Width adjusts the extent of the
flattop (from 0.3 to 2.4
µ
s). The Tilt adjustment varies the “flatness” of this section slightly. The
Tilt can be positive or negative. Choosing a positive value results in a flattop that slopes down-
ward; choosing a negative value gives an upward slope. Alternatively, Optimize can set the tilt
value automatically. This value is normally the best for resolution, but it can be changed on this
dialog and in the InSight mode to accommodate particular throughput/resolution tradeoffs. The
Optimize button also automatically adjusts the pole-zero setting.
2.3.3. Amplifier PRO
This tab (Fig. 17) contains the controls for the Low Frequency Rejector (LFR) filter, Resolu-
tion Enhancer, and Enhanced Throughput Mode. To enable a particular feature, mark the cor-