GEMINI2

Acquisition system + integrated 3D Geophone

GEMINI-2 is a compact solution for HVSR, MASW and Building Resonance Frequency Analysis: a single waterproof case with an integrated low frequency, high performing 3D geophone assembly (2Hz properly coupled sensors) and a powerful true 24 bit data acquisition board with USB port for external PC. Through Gemini USB interface and the related data acquisition software, your PC becomes a perfect, high performance instrument for both data recording and post-processing analysis. Created as an instrument mainly dedicated to HVSR measurements, Gemini-2 can be used for other passive applications like vibration analysis. Completed with the appropriate accessories, it may become an active seismic acquisition system (3 channels + trigger) for MASW and "unconventional" applications.

Models

Methodologies

SURFACE WAVES

HVSR / NAKAMURA

P&S REFRACTION

DISCOVER THE SOLUTIONS GEMINI2

for HVSR / NAKAMURA

Thanks to the dedicated acquisition software, Gemini2 and your PC will become a perfect passive seismic acquisition system. The standard version can capture up to 720 min (12 hours), depending with the memory and autonomy of your laptop PC (customization on demand for applications requiring longer recording length, even in remote conditions).

The output data format of Gemini2 is selectable between standard SAF-Sesame ASCII Format and standard SEG2, compatible with the best freeware and software on the market.

With the GPS option it will be possible georeferencing and timing the acquisition; in the same way, more Gemini 2 units can be synchronized to the thousandth of a second, regardless of their location.

In the absence of GPS signal (such as inside a building), two or more Gemini2 units can still be synchronized by purchasing the trigger option and the multitrigger box.

for ACTIVE SEISMICS

With the integrated sensor assembly you can run an “active” 3C acquisition for each single shot; the trigger option - connected to the auxiliary channel Gemini2 AUX - allows the use of a geophone, a piezoelectric hammer switch or even a radiotrigger to start the acquisition.

Thanks to the multitrigger box, two (or more) Gemini2 units can be synchronized via cable using trigger extension cables, or by radio using the radiotrigger.
With the GPS option it will be possible georeferencing the acquisition (obviously in presence of GPS signal)

TECHNICAL
SPECIFICATIONS
GEMINI2

2-YEAR WARRANTY

DATA ACQUISITION BOARD

Power Supply /
Data Recording

Through USB port of an external PC (not included)

Data Conversion

24 real bits Sigma-Delta ADC

Sampling Frequency

Max. Freq. 8ksps, simultaneously on 3+1 channels

S/N Ratio

Max 117 db

Bandwidth +/- 0.1 dB

108 Hz @ 1ksps

Bandwidth –3 dB

212 Hz @ 1ksps

No. Of Channel

3 + 1 (trigger)

Data Output Format

SAF (Sesame ASCII Format) / SEG2 (.dat)

SENSORS GEMINI2

Nat.Resonance Frequency

2 Hz ± 10%

Sensibility

2 V / cm / s ± 5%

Internal Resistance

5.8 kΩ ± 5%

Damping

0.7 ± 10%

Harmonic Distortion

≤ 0.2%

Working Temperature

From –25°C to +55°C

Sensor Clamping

Automatic when not in use

Dimensions

Diam. 128 mm h. 175mm (spike excl.)

Weight

2.4 Kg

Technical specifications subject to change without notice