digiBASE
®
PMT Base with Integrated Bias Supply, Preamplifier and Digital Multichannel Analyzer
931003E / 0620
Figure 12
. digiBASE Stabilizer Tab
If set to
Coincidence
, when the ENABLE INPUT is low, real time and live time operate nor-
mally, but no counts are stored in memory. If the ENABLE INPUT is high, normal acquisition
occurs.
If set to
Event
, rising edges are counted by a 32-bit event counter. The contents of this counter
can be monitored in the
Enable Counter
field on the Status tab (Section 2.5.7). The input
impedance is 5 k
Ù
to +3.3V, protected to ±10 V.
The digiBASE operates at a
Conversion Gain
of 1024 only.
The
Lower Level Disc
riminator sets the level of the lowest amplitude pulse that will be stored.
This level establishes a lower-level cutoff by channel number for ADC conversions.
The
Upper Level Disc
riminator sets the level of the highest amplitude pulse that will be stored.
This level establishes an upper-level cutoff by channel number for storage.
2.5.4. Stabilizer
The digiBASE has both a gain stabilizer and a zero stabilizer; their operation is discussed in
more detail in the MAESTRO
User’s Manual
.
The Stabilizer tab (Fig. 12) shows
the current values for the stabilizers.
The value in each
Adjustment
sec-
tion shows how much adjustment
is currently applied. The
Initialize
buttons set the adjustment to 0. If
the value approaches 90% or above,
the amplifier gain should be ad-
justed so the stabilizer can continue
to function — when the adjustment
value reaches 100%, the stabilizer
cannot make further corrections in
that direction. The
Center Chan
nel
and
Width
fields show the peak
currently used for stabilization.
To enable the stabilizer, enter the
Center
Chan
nel
and
Width
values manually or click the
Suggest Region
button.
Suggest Region
reads the position of the marker and inserts values into
the fields. If the marker is in an ROI, the limits of the ROI are used. If the marker is not in an
ROI, the center channel is the marker channel and the width is 3 times the FWHM at this energy.
Now click the appropriate
Enabled
checkbox to turn the stabilizer on. Until changed in this
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Summary of Contents for ORTEC digiBASE
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