GBS Elektronik MCA166-USB Behavior at different Temperatures User Manual
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Fig. 3. Gain change depending on temperature. The drift depends very much on the gain setting.
This behavior was evaluated a bit closer. So the drift between 20°C and 0°C was measured for gain settings
between 2.7 and 560 using logarithmic steps of the E12 series. A second measurement was made for the drift
between 10°C and -10°C using values between 10 and 150 and smaller steps (E24 series).
A few measurements were additionally performed using a different MCA (serial number 366, recent series) and a
different detector (GL0310)
1
10
100
G a in
-6E -4
-4E -4
-2E -4
0
2E -4
4E -4
6E -4
T
e
m
p
e
ra
tu
re
D
ri
ft
1
/°
C
D rift 2 0 °C - 0 °C
D rift 1 0 °C - -1 0 °C
D rift M C A #3 6 6, D et. G L0 3 10
Fig. 4. Temperature drift dependence on gain setting.
At the first glance, the drift dependence on gain seems to be absolutely erratic. It becomes only understandable
by knowing about the internal hardware of the MCA166. The most temperature sensitive component within the
MCA is the adjustable gain amplifier [1]. This contains internally a 6dB step (factor 2) attenuation ladder and a
circuit for interpolating between the interpolation steps. This corresponds to the drift coefficient oscillating with a