Environmental Monitoring Procedure Using the Radiation Alert® GammaView
The Radiation Alert® GammaView is purpose-built for sensitive gamma radiation detection. Its NaI scintillation detector provides the responsiveness needed to identify subtle changes in low-level gamma fields, making the instrument particularly well suited for environmental surveillance, background radiation trending, site boundary monitoring, NORM assessments, and post-incident environmental surveys.
The GammaView is specifically marketed for environmental monitoring, compliance monitoring, health physics, and remote monitoring applications.
- Purpose
The purpose of this procedure is to establish a standardized method for conducting environmental gamma radiation monitoring using the Radiation Alert® GammaView to:
- Establish environmental baseline radiation levels.
- Detect changes in gamma radiation fields.
- Evaluate radiological impacts from licensed activities.
- Monitor facility boundaries.
- Support regulatory compliance programs.
- Investigate abnormal radiation readings.
- Trend long-term environmental conditions.
- Capabilities of the GammaView
The GammaView utilizes a 1″ × 1″ or 2”x 2” NaI scintillation detector, providing substantially greater sensitivity to gamma radiation than a typical GM survey meter. It measures gamma dose rates, count rates, and total counts and is capable of detecting small changes in environmental background radiation.
Typical Operating Ranges
- Dose rate: 0.001 µSv/hr to 50 µSv/hr
- Exposure rate: 1 µR/hr to 5 mR/hr
Approximate Gamma Energy Range: 20 keV to 1.5 MeV, depending on probe configuration.
- Safety Requirements
Personnel shall:
- Complete radiation safety training.
- Follow facility ALARA principles.
- Wear required PPE when entering controlled areas.
- Avoid unnecessary exposure.
- Follow site-specific emergency procedures.
The GammaView is a monitoring instrument and should not be relied upon as a personal dosimeter.
- Instrument Verification
Prior to use:
Visual Inspection
Verify:
- Detector housing intact
- Cable undamaged
- Connectors secure
- Display functioning properly
Calibration
Confirm calibration is current.
Battery Check
Verify battery levels are acceptable.
Functional Check
Measure a known background location and verify instrument response is normal for the area.
The manufacturer’s operation manual recommends connecting or disconnecting the detector only when the instrument is powered off.
- Establishing Environmental Baseline
Before beginning a monitoring program:
- Select permanent monitoring locations.
- Obtain readings under normal operating conditions.
- Measure each location multiple times.
- Calculate average background values.
Record:
- Location ID
- GPS coordinates
- Date
- Time
- Weather conditions
- Dose rate (µSv/hr)
- Count rate (CPM)
- Technician
Baseline values become the comparison standard for future surveys.
- Fixed Environmental Monitoring Locations
Typical locations include:
Site Boundary Stations
- North boundary
- South boundary
- East boundary
- West boundary
Public Access Areas
- Parking lots
- Visitor centers
- Adjacent properties
Sensitive Environmental Areas
- Surface water discharge points
- Stormwater drainage channels
- Wetlands
- Wildlife areas
Facility Areas
- Waste storage locations
- Source storage facilities
- Material handling areas
- Static Environmental Survey Procedure
This is the preferred method for trend analysis.
Setup
Position the detector:
- 1 meter above the ground
- Away from vehicles
- Away from buildings, when possible
Measurement
Allow the detector to stabilize.
Collect readings for:
Recommended collection times:
- Minimum: 1 minute
- Preferred: 5 minutes
- High-sensitivity surveys: 10 minutes
Record the following:
- Average CPM
- Maximum CPM
- Dose rate
- Time
- Weather conditions
Because the GammaView is highly sensitive, using longer count times significantly improves environmental data quality.
- Environmental Walk-Over Surveys
Walk-over surveys are useful for locating unexpected radioactive material.
Survey Method
Detector Height
Hold the detector 0.5 to 1 meter above the ground.
Walking Speed
Walk slowly at approximately 1–2 mph.
Watch for:
- Count-rate increases
- Elevated dose rates
- Audible alarm activation
Investigate any readings significantly above established background levels.
- Soil Monitoring
For environmental screening:
Grid Survey Method
Establish a grid.
Example:
- 25-meter spacing
- 50-meter spacing
- 100-meter spacing
At each point:
- Measure at 1 meter above grade.
- Measure at ground level.
- Record CPM and dose rate.
Any statistically significant elevation above baseline should be investigated further.
- Surface Water Monitoring
The GammaView cannot directly quantify radionuclides in water, but it can identify elevated gamma activity associated with:
- Sediments
- Filter residues
- Shoreline deposits
Procedure:
- Collect sediment or filter samples.
- Place in a repeatable counting geometry.
- Count samples for a fixed interval.
- Compare against control samples.
- Vegetation Monitoring
Environmental surveillance programs often use:
- Grass
- Leaves
- Moss
- Agricultural products
Samples should:
- Be collected consistently.
- Be counted using the same geometry.
- Be measured for a fixed counting interval.
The GammaView’s scintillation detector is extremely effective at identifying subtle gamma activity from deposited radionuclides.
- Post-Incident Environmental Monitoring
Following a release, spill, or contamination event:
Initial Survey
Establish:
- Impacted area
- Radiation gradient
- Potential migration pathways
Follow-Up Monitoring
Survey:
- Drainage pathways
- Soil
- Vegetation
- Building surfaces
- Public boundaries
Map all measurements to identify contamination spread.
- Use of the Single Channel Analyzer (SCA)
One unique capability of the GammaView is its Single Channel Analyzer (SCA) mode.
This allows users to create an energy “window” that focuses on specific gamma energies while reducing background response. This can improve sensitivity to particular radionuclides in the field and reduce interference from naturally occurring background radiation.
Potential uses include:
- Environmental investigations
- Source searches
- NORM discrimination
- Focused surveillance of known radionuclides
- Investigation Levels
Example environmental action levels:
| Condition | Response |
| Within baseline range | Record only |
| 2× normal background | Repeat measurement |
| 3× normal background | Notify supervisor |
| Persistent elevated readings | RSO investigation |
| Confirmed abnormal radiation field | Implement corrective actions |
Actual investigation levels should be established by the Radiation Safety Officer.
- Data Trending
Environmental monitoring programs should develop long-term trend analyses.
Track:
- Monthly averages
- Quarterly averages
- Seasonal variations
- Rainfall impacts
- Operational changes
- Construction activities
Because the GammaView is highly sensitive to low-level gamma fields, it is well suited for detecting long-term changes that may not be noticeable with standard GM-based survey meters.
- Limitations
The GammaView:
Can Do
- Detect very low gamma radiation levels.
- Establish environmental baselines.
- Trend environmental conditions.
- Monitor facility boundaries.
- Perform compliance monitoring.
Cannot Do
- Positively identify radionuclides by itself.
- Replace laboratory gamma spectroscopy.
- Measure alpha contamination directly.
- Be used as a personal dosimeter.
Recommended Use
For a formal environmental radiation monitoring program, the GammaView is generally better suited than the Ranger. While the Ranger excels in contamination surveys and wipe testing, the GammaView’s NaI scintillation detector offers the sensitivity required for environmental background monitoring, perimeter surveillance, NORM investigations, and post-incident radiological assessments.