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Automated mobile heliometric survey

A complete field workflow — equipment package, QC and anomaly verification — that takes a soil-gas station to a georeferenced helium anomaly map.

MS detection limit*
5 ppb
He qualification level
~5 ppm
Probe depth
0.5–1.5 m
Field crew
4 people

Helium exploration by shallow soil-gas geochemistry

From a soil-gas station to a georeferenced helium anomaly map.

  1. 01 · SamplingSoil-gas probe
  2. 02 · Sample trainConditioning & flow
  3. 03 · AnalysisHPR-20 R&D MS
  4. 04 · RegistrationGNSS + field PC
  5. 05 · OutputQC + ΔHe map

Primary objective: quantify weak helium anomalies relative to the local atmospheric and soil-gas background — not merely detect the presence of He.

Mobile field laboratory van with a gas line to a soil-gas probe and a GNSS tripod
Illustration — the survey concept: a mobile analytical laboratory with a gas-tight line to a soil-gas probe and a GNSS station.

01Measurement philosophy

Survey objective and measurement philosophy

Helium exploration requires quantitative stability around the natural background level.

01 · Background

Establish the local He baseline using ambient-air checks and low-anomaly soil-gas stations.

02 · Anomaly

Measure absolute He concentration and calculate ΔHe relative to a controlled reference / background.

03 · Confirmation

Repeat anomalous stations, apply QC flags and verify persistent targets with longer-term monitoring.

Critical procurement principle

A low instrument detection limit is not enough. Vendor qualification must demonstrate accuracy, repeatability and drift performance at approximately 5.0–5.5 ppm He using certified reference mixtures.

02Field workflow

Seven steps at every station

A standardised station sequence is essential for reproducible anomaly mapping.

  1. 01PositionNavigate to station; record GNSS, terrain and metadata.
  2. 02ProbeInstall a gas-tight probe, typically 0.5–1.5 m below ground.
  3. 03PurgeRemove dead volume; verify stable flow and no line leakage.
  4. 04ConditionFilter particles; control moisture and condensation without He loss.
  5. 05AnalyseContinuous He measurement, repeated until a stable plateau.
  6. 06QCReference, blank and duplicate checks; flag unstable stations.
  7. 07MapStore coordinates, He, ΔHe and environment; update the field map.

Target productivity is validated during the pilot. In practice, probe installation, purge and stabilisation, station spacing and QC control daily output more than analyser speed.

03Core analytical system

Core analytical system — Hiden HPR-20 R&D

The central real-time gas analyser, subject to a helium-specific factory acceptance test at ~5 ppm.

HPR-20 R&DSPECIFICATION
Analyser
Triple-filter quadrupole mass spectrometer
Detection limit
5 ppb ultimate*
Sampling
Continuous gas sampling
Sample flow
Configurable, < 1 to > 20 mL/min
Software
MASsoft Professional + external I/O
Configuration
Benchtop / mobile

* Subject to spectral interference.

Why it fits the survey concept

  • Real-time response enables stabilisation-based station acceptance rather than a single grab reading.
  • Mass-selective measurement supports multi-gas context and interference assessment.
  • External I/O synchronises GNSS, pressure, temperature and other sensors with MS data.
  • Vehicle installation keeps the analytical core in a controlled environment while the probe stays in the field.

Mandatory qualification: certified 4.5 / 5.0 / 5.2 / 5.5 / 6 / 10 ppm He mixtures; replicate measurements and a long-term drift test.

04Sampling train

Soil-gas sampling and sample-conditioning train

The sampling train must preserve weak He anomalies and prevent air ingress, moisture problems and memory effects.

  1. A

    Probe set

    5–10 reusable stainless-steel probes; replaceable tips; insertion tools; depth marks.

  2. B

    Gas-tight line

    Low-permeability tubing, quick-connect fittings, isolation valves and spare seals.

  3. C

    Particulate control

    Replaceable inline filter upstream of analytical components.

  4. D

    Moisture control

    Water trap / condenser strategy selected to avoid helium fractionation or contamination.

  5. E

    Pump + flow

    Low-leak pump, flowmeter / MFC, vacuum indication and blocked-line alarm.

  6. F

    Selector

    Manual or automatic valve manifold for sample / ambient / zero / span gas.

A field leak check and a controlled purge volume are part of every station procedure.

05Equipment package

Complete equipment package — one mobile field crew

Base configuration for production work; quantities can be adjusted after pilot testing.

  • 01Analytical core

    1 × HPR-20 R&D; selected MS inlet; scroll pumping; MASsoft; interface cables.

  • 02Sampling kit

    10 × soil-gas probes; insertion / extraction tools; spare tips; low-permeability tubing; valves.

  • 03Flow & conditioning

    Sampling pump; flow controller / flowmeter; vacuum gauge; filters; moisture traps; manifold.

  • 04Calibration & QC

    Certified zero and He standards around 5 ppm and higher; regulators; lines; leak-test accessories.

  • 05GNSS / navigation

    GNSS receiver (sub-metre preferred, RTK optional); antenna / pole; station navigation software.

  • 06Field computing

    Rugged Windows laptop / tablet; survey database; automatic station ID; GIS / CSV export.

  • 07Environmental sensors

    Barometric pressure, ambient temperature / RH, soil temperature; optional soil moisture.

  • 08Power system

    230 VAC + vehicle 12/24 VDC inverter / UPS; surge protection; backup battery.

  • 09Mobile laboratory

    4×4 / van; vibration-isolated instrument rack; ventilation; clean, dry analytical zone.

  • 10Spares & consumables

    Filters, seals, tubing, connectors, pump kit, probe tips, tools, labels, backup sample vials.

06Mobile laboratory

Mobile laboratory layout

The dirty, wet field interface is kept apart from the clean analytical and control zones.

Zone A

Field / wet zone

  • · Probe tools and consumables
  • · Sampling-line entry panel
  • · Filters / primary moisture protection
  • · PPE and decontamination kit

Zone B

Analytical zone

  • · HPR-20 R&D
  • · Vibration isolation
  • · Stable power
  • · Controlled temperature / ventilation

Zone C

Control / power

  • · Rugged PC / data acquisition
  • · GNSS interface
  • · UPS / inverter
  • · Calibration-gas secure rack
  • · Reference sensors
  • · Daily backup / communications

Design rule: keep dust, wet tools and open soil-gas connections away from the mass spectrometer and calibration hardware.

07Calibration

Calibration and QA/QC programme

Weak anomalies are credible only when analytical drift and sampling artefacts are controlled.

Start of day

Zero / ambient check; reference gas; line leak check; flow verification.

During survey

Ambient reference at a defined interval; duplicates; repeated anomaly stations; QC flags.

End of day

Reference gas repeat; drift review; database completeness; raw-data backup.

FAT / periodic

Certified He standards around 5 ppm; ≥ 10 replicates at critical concentrations; stability test.

Recommended helium FAT sequenceHe, ppm · log scale
0
4.5
5
5.2
5.5
6
10
20
50

Critical standards 5.0 / 5.2 / 5.5 ppm — at least 10 replicate measurements each.

08Data acquisition

Data acquisition and real-time field QC

Every analytical result is tied to position, sampling conditions and QC state.

STATION RECORD
Station
Survey ID, station ID, date / time, operator
Position
Lat / lon / elevation, GNSS quality
Sampling
Probe depth, purge time / volume, flow, vacuum
Helium
He ppm, stabilised value, ΔHe, replicate statistics
Context gases
Optional H₂, CH₄, CO₂, O₂, N₂ / Ar
Environment
Pressure, ambient T / RH, soil T, optional moisture
QC
Calibration status, blank / reference, duplicate, flags
Output
CSV + GIS layer + raw MS file + daily QC report

Stations are accepted automatically only once predefined stability criteria are met; anomalous or unstable stations are highlighted immediately for repeat measurement.

09Second-level verification

Second-level verification — SurfMoG®-He

Autonomous near-surface monitoring after reconnaissance tests whether anomalies persist through time.

  • Near-surface soil-gas monitoring
  • Approx. 1 m installation depth
  • Standalone logger + battery
  • Wireless / IoT data transmission
  • Temperature + optional humidity
  • Large local data memory
  1. 01Reconnaissance mobile survey
  2. 02Rank anomaly targets
  3. 03Install selected SurfMoG-He
  4. 04Monitor days to weeks
  5. 05Persistent anomaly?

Purpose: separate a stable geological signal from short-term atmospheric, barometric, soil-moisture and sampling variability.

Vendor helium-sensor range and precision are confirmed for each project.

10Field crew

Field crew and responsibilities

A compact crew operates efficiently when station preparation and analysis run in parallel.

01

Crew lead / geochemist

Survey design, QC decisions, anomaly ranking, daily technical report.

02

Probe technician

Station preparation, probe installation, leak check, purge, line maintenance.

03

Analyser / data operator

HPR-20 operation, calibration, stability acceptance, database and backups.

04

Driver / field assistant

Navigation, safety, equipment movement, consumables, optional second probe team.

While one station is analysed and logged, the next probe location is prepared — without compromising leak checks or QC.

11Deployment

Deployment sequence and deliverables

The analytical chain is qualified first; production scales up only after field repeatability is demonstrated.

  1. 1RFQ / vendor reviewConfirm complete configuration and helium performance near 5 ppm.
  2. 2Bench test / FATCertified standards, blind samples, replicate precision and drift.
  3. 3Pilot survey1–2 profiles; duplicates; background stations; environmental controls.
  4. 4Method freezeFinalise probe depth, purge, stability threshold and QC frequency.
  5. 5Production surveyGrid / profile acquisition with daily QC and anomaly ranking.
  6. 6VerificationRepeat targets + SurfMoG-He monitoring on selected anomalies.

Core deliverables

  • Validated station database
  • Raw analytical files
  • QC report
  • He and ΔHe maps
  • Anomaly ranking
  • Repeat / monitoring recommendations
Discuss a survey H-Logic 2/24 field system

Rental enquiry

Planning a helium survey?

Tell us the area, the objectives and the timeline. We will propose the equipment package, crew and QA/QC programme to match.

Contact our team info@geogals.ee