Natural Gamma, Self Potential and Single-point Resistance Probe HGSPR-380
It is a combined probe for measuring GR Gamma Ray, SP Self Potential and SPR Single-point Resistance.
After installing the probe into the logging system by connecting the cable head measuring of the SP
parameters is activated. SP method is measured first, when winching the probe down. Voltage is measured
against a grounding rod on the surface. After reaching the lowest point, increasing the power supply
by about 5 V DC for 5 sec will switch the measurement to SPR + GR method, which is activated during
pulling the probe upwards. Speed of the movement should be low, due to the GR method.
Used crystal is Nal, diameter 24 mm, length 45 up to 65 mm.
Probe Parameters
| Diameter | 38 mm |
| Length | 1200 mm |
| Weight | 7.0 kg |
| Max. Working Temperature/Pressure | 75°C/10 MPa |
| Power Supply | 30 up to 45 VDC @ 120 mA |
Measuring Ranges
| SP Method | −2.5 VDC up to +2.5 VDC |
| SPR Method | 1 up to 2000 Ω |
| GR Method | 60 keV up to 3 MeV |
Output Signals
Frequency of positive and negative pulses (amplitude and width is adjustable) or Voltage 0 to +5 VDC