PASI - Model GFA 50/100 -3D Borehole Geophone - FOR FOR DOWNHOLE/CROSSHOLE

GFA 50/100 3D borehole geophone is realized with 3x high sensitive geophones (nat.freq.10 Hz- 1 vertical and 2 horizontal sensors) oriented according to a triad of orthogonal Cartesian axes XYZ. Delivered with a cleat assembly to sustain its weight at the requested depth (GFA cable is graduated in meters), this borehole geophone has a pneumatic-mechanical clamping system. You will simply have to connect the air pump to the GFA panel and you will be ready to operate in the field: by inflating air at 2- 3 bars, you will obtain the best coupling of the sensors to the borehole wall (diameter between 50 and 110mm. if used with the standard spacer block).

The GFA is lightweight and easy to carry; the aluminium anodized case of the probe is suitable for field use and easy to maintain. Moreover, two GFA can be mounted one over the other by using the optional joining accessory.

• 3 x 10 Hz geophones (1vert.+2horiz.)
• cable length 50 or 100m, graduation 1 meter 
• for boreholes with diameter from 50 and 110mm (larger diam. on request)
• probe dimensions: diam. 50mm, length 570mm
• cable reel dimensions: 540x400x250mm
• total weight (reel+cable+probe): less then 12 kg for Mod. GFA-50
• Cannon NK2721C or Souriau connector (other on request)
• cable reel with 50/100 m of cable
• pneumatic-mechanical clamping (with manual pump included)
• air purge valve

• Number of geophones: 3 geophones with nat.freq.10Hz+/-5% (1 vert.+ 2 horiz.), high sensitivity (100V/m/sec +/-5%)
• Cable lengths: 50m or 100m, graduation in meters, mounted on cable reel with probe support
• Probe dimensions: Ø50mm, length 570mm (aluminium anodized case)
• Borehole diameter: Min. 50mm, max. 110mm (with standard spacer block; larger diameter can be supported on request)
• Cable reel dimensions: 540x400x250mm
• Weight: GFA-50: <12kg; GFA-100: <17kg
• Connection to seismograph
• Standard: Cannon type NK2721C (GEA24, 16SN-U-P) or Souriau conn. (GEA3, Anteo)
• Other adapters available on request