  The electronics of the LUX-ZEPLIN (LZ) experiment, the 10-tonne dark matter
detector to be installed at the Sanford Underground Research Facility (SURF),
consists of low-noise dual-gain amplifiers and a 100-MHz, 14-bit data
acquisition system for the TPC PMTs. Pre-prototypes of the analog amplifiers
and the 32-channel digitizers were tested extensively with simulated pulses
that are similar to the prompt scintillation light and the electroluminescence
signals expected in LZ. These studies are used to characterize the noise and to
measure the linearity of the system. By increasing the amplitude of the test
signals, the effect of saturating the amplifier and the digitizers was studied.
The RMS ADC noise of the digitizer channels was measured to be 1.19 $\pm$ 0.01
ADCC. When a high-energy channel of the amplifier is connected to the
digitizer, the measured noise remained virtually unchanged, while the noise
added by a low-energy channel was estimated to be 0.38 $\pm$ 0.02 ADCC (46
$\pm$ 2$\mu$V). A test facility is under construction to study saturation,
mitigate noise and measure the performance of the LZ electronics and data
acquisition chain.
