Hardware
Lynx II DSA User's Manual – 7096089 105
Coarse Gain
Sets the amplifier’s Coarse Gain. The product of the Coarse Gain, Fine Gain, and Input
Attenuator represent the total amplification gain. Coarse Gain can be set from 2 to
430.54. Default is 2. Coarse Gain cannot be changed while the spectrum stabilizer is
active.
As a general guideline when establishing a working energy range, the best signal to noise
characteristics are obtained when the preamplifier gain (if selectable) is set as high as
possible, Attenuator setting is off (no input/gain attenuation), Fine Gain is set as low as
possible, and Coarse Gain set as high as possible.
Fine Gain
Sets the amplifier’s Fine Gain. Fine Gain setting ranges from x0.80000 to x1.20000.
Default is x1.00000. Fine Gain cannot be changed while the spectrum stabilizer is active.
Refer to the Coarse Gain setting (above) for additional information.
LLD Mode
The Lower Level Discriminator (LLD) selects the minimum acceptable level for the input
energy signal to be processed. The LLD Mode can be set to Automatic or Manual. With
Automatic selected the LLD cutoff is automatically optimized just above the spectral noise
threshold. Manual allows the LLD cutoff to be set manually using the LLD (%) setting as
a percentage of the input’s full scale range.
The LLD (%) manual setting is only used when LLD Mode is set to Manual.
Important:
For some low energy applications, even the manual LLD cutoff
may still prevent the processing of extremely low energy events.
For this purpose, in addition to the Manual LLD Mode and LLD(%)
setting, additional parameters are exposed in the Digital Filter
settings to provide extended flexibility specifically for low energy
applications. Please refer to the Low Energy Applications on page
111 for more details.
LLD (%) manual setting
The LLD manual setting is in effect when the LLD Mode is set to Manual and establishes
the minimum acceptable level for the input energy signal to be processed as a function of
the percentage of the Input Size, or full scale of the energy range. Range is 0.0% to
100.0%.
ULD (%) manual setting
The ULD manual setting is in effect at all times; it establishes the maximum acceptable
level for the input energy signal to be processed as a function of the percentage of the
Input Size, or full scale of the energy range. Range is 0.0% to 110.0%, however spectral
storage above 100.0% is prevented by the storage logic.
Polarity
The Input Polarity setting sets the detector signal polarity for the rear panel’s ENERGY
input as Positive or Negative. Typically, the Input Polarity must be set to the polarity of
the preamplifier's output. Default is Positive.
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