Instrumentation
The CIEN Stations were built through recycled hardware. They started to monitor the electric field in the atmosphere and were recently updated with magnetic field detectors. The other instruments, such as the radon meter, the ionic counter, or GPS are only at some of the stations.
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The electric field detector
It is a self-built dynamic detector which can be
constituted by a minimum of two to a maximum
of three electrodes, which are the external
sensors. Electrode length is 10 m at about 10 m
above the ground, two of which are arranged
along the two horizontal directions (see picture
on the right) while the third is vertical.
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The instrument is sensitive to non-stationary
electric fields from 4 Hz to 25, 50 and 100 kHz,
covering ELF, VLF, and part of LF bands.
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Digital, with a 16 bit AD conversion.
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For uniform atmospheric electric fields,
depending on meteorological conditions
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Accuracy 1 micro V/m;
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Precision 0.2 micro V/m;
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Sensitivity 0.1 micro V/m;
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Dynamic range 90 dB.
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The magnetic field detector
The magnetometer is a 40-120 turns wire loops
which are electrically shielded with respect to the
electric field. It is a self-built dynamic detector, at the
moment one for each CIEN station, and has the axis
directed NNW to SSE, parallel to the Appennine
Chain. It is equipped with software for automatic
discrimination of pulses and send emails when their
number exceeds a threshold.
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Sensitive to non-stationary magnetic fields from 0.5 to
450 Hz, covering part of ULF and ELF bands.
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Digital, with a 16 bit AD conversion.
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Accuracy 1 nT;
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Sensitivity 0.1 nT;
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Dynamic range 90 dB.
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The air ion counter
This instrument DLY-6A2 Smart Air Ion Counter
from kilter, is equipped with a USB connector for
the PC storage of data. It is positioned outdoors
and therefore it has been adapted to work with
high levels of humidity through heaters.
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It is able to detect both positive and negative air
ions with a sampling time of one minute.
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Sensitivity 1 ions/cm^3
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Mobility 0.4 cm^2/V*sec
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Accuracy ± 10%rdg
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Auto Range 1~1.5×10^6 ions/cm^3
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It is coupled with humidity and temperature
detectors at the same place.
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The Radon detector
It has been modified to use the PC power supply and to have a remote lecture of
data. The AER plus of Algade instrument, on the right,t uses the USB connection
to download data. Its time of measure is one hour with humidity and temperature.
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Sensitivity 20 Bq/m^3
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The GPS
A synchronization of the VLF signal was realized by using a special GPS NAVMAN Jupiter GPS receiver, see the system on the left, TU30-D400 Series Data Sheet. The sampling system realized by a pc sound card can be synchronized by mixing the signal with an appropriate GPS output clock. NAVMAN output clock is a 10 kHz square wave that is precisely aligned with the UTC second.
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The temperature, humidity and CO2 detector
Carbon dioxide sensor + termometer + hygrometer, with RS485 trasmitter and IPV65 shell.
Temperature: Humidity: CO2:
range -40°C +80°C; range 0-100%RH; range 0-10000ppm;
accuracy ±5°C (25°C) ; accuracy ±3%; accuracy ±40ppm (25°C);
stability ≤0.1°C/y; stability ≤1%RH; stability <2%;
response ≤15s. response ≤4s. non-linearity <1%;
data update time 2s;
response time <90s (90%step change).
