Canberra Lynx - DSP Gain Parameters

Gain Spacing
Sets the spacing (in channels) between the upper and lower sampling windows. The
windows should be placed so that a shift in the reference peak reflects a significant
change in count rate through the window. For broad peaks, the spacing should be set
so that the windows’ edges are not on the flat part of the peak.
Gain Mode
Sets the Gain Stabilization mode to Off, On or Hold.
•
Off disables gain stabilization and sets the correction adjustment to 0.
•
On enables gain stabilization, allowing the Stabilizer to compare the incoming
data to the gain Centroid and Window settings, then compensate for data below
(or above) the Centroid.
•
Hold disables gain stabilization, but maintains the current correction adjustment
at the Stabilizer’s output.
Gain Ratio
The Gain ratio value is interpreted by the stabilizer as the ratio to maintain between
the two gain windows (ratio = upper window / lower window). For instance, a value of
1 would be appropriate for a pure Gaussian peak.
DSP Gain Parameters
The DSP Gain settings screen for the Lynx contains the following controls.
Coarse Gain
Sets the device’s coarse gain. It’s best to choose the highest Fine Gain which, com
-
bined with the Coarse and Super-Fine Gains, will produce the total desired gain.
Fine Gain
Sets the device’s Fine Gain multiplier.
The combination of Coarse and Fine Gain sets the overall system gain to match the re
-
quirements of the detector and energy application; overall gain is continuously vari
-
able from x2.0 to x1,536. The Fine Gain factor is dependent on the Super Fine Gain
(SFG) value. With the SFG set to 0.0000e
-2
, the Fine Gain covers a range of x0.4 to
x1.6. The SFG value adds to the Fine Gain factor and covers a range of 0.0000e
-2
to
3.0000e
-2
.
Offset
Sets the device's digital offset in channels. The digital offset shifts the memory as
-
signment of the device’s conversions to the left (e.g. an offset value of 4096 would
shift channel 4096 down to correspond to channel zero of the memory).
Using MCA Definition Tables
User’s Manual 45