ORTEC DSPEC Pro, Руководство пользователя по оборудованию

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DSPEC Pro
®
Digital Gamma-Ray Spectrometer User’s Manual 794380D / 0914
26
Figure 14. DSPEC Pro Amplifier 2 Tab.
rate guidance message on the lower-left of the Amplifier page will help you position the source
to deliver the correct count rate for optimization. You may also right-click in the spectrum
window and select Input Count Rate from the context menu to view the count-rate meter. The
Start Auto optimization button will remain disabled (gray) until the count rate is suitable. Click
it to start.
A series of short beeps indicates optimization is in progress. When optimizing is complete, the
beeping will stop. The process can take from 1 to 10 minutes, depending on count rate, but typi-
cally takes 5 minutes.
NOTE
As with any system, the DSPEC Pro should be optimized any time the detector is
replaced or the Flattop Width is changed.
The effect of optimization on the pulse can be seen in the InSight mode, on the Amplifier 2 tab.
Note, however, that if the settings were close to proper adjustment before starting optimization,
the pulse shape may not change enough for you to see. (In this situation, you also may not notice
a change in the shape of the spectrum peaks.) The most visible effect of incorrect settings is
high- or low-side peak tailing or poor resolution.
2.3.2. Amplifier 2
Figure 14 shows the Amplifier 2
tab, which accesses the advanced
shaping controls including the
InSight Virtual Oscilloscope mode.
The many choices of Rise Time let
you precisely control the tradeoff
between resolution and throughput;
see Section 2.4. This setting affects
both the rise and fall times, so
changing it spreads or narrows the
quasi-trapezoid symmetrically.
Use the up/down arrows to set the
Rise Time from 0.8 to 23.0
µ
s.
Once the unit has been optimized
according to Section 2.3.1, you can use any Rise Time without having to re-optimize.
The value of the rise time parameter in the DSPEC Pro is roughly equivalent to twice the inte-
gration time set on a conventional analog spectroscopy amplifier. Thus, a DSPEC Pro value
of 12
µ
s corresponds to 6
µ
s in a conventional amplifier. Starting with the nominal value of 12.0,