ENVIRO GO · Profectronics

Measuring instrument

Construction and handling

The wheel has a drive, and the brake is part of the scope of delivery. One person moves 150 kg into position, extends the mast and starts the measurement. A first indication is available after minutes, a reliable measured value in 1 hour.

Mass 150 to 170 kg
Flow rate 1 to 6 m³/h
Degree of protection IP54
Ambient −10 to 55 °C
Dimensions for transport 550 × 1 650 × 400 mm, mast retracted, head removed

Screenshot from the shared operating software, sampling view with flow rate, volume and time left. Operating language English, example values.

Sampling on the filter pad A replaceable filter pad holds aerosols on a PTFE layer. Gaseous iodine bonds to the activated charcoal below it. Each layer has 1 700 mm². An NFC chip is in the seal ring.
Measurement during sampling A silicon semiconductor detector for alpha and beta is at the pad. The gamma detector looks at the same pad from a lead chamber with 25 mm walls and identifies the nuclides.
Result as activity concentration Results in Bq/m³, referred to 0 °C and 1 013 hPa, with the detection limit for the listed nuclides. The count rate stays visible as a diagnostic value.
Chassis and power supply Driven wheel, parking brake and support feet. Turning circle approximately 1.2 m. Power supply from the mains or from a generator with 100 to 240 V, cable drum with 10 m.

Measurement chain

Measurement chain in 6 stages

From the outside air to the result in Bq/m³, the sample goes through 6 stages.

Stage	Assembly	Design
01 · Intake	Intake head	TSP head with weather louvres and insect screen. Head for PM2.5 as an option.
02 · Collection	Filter pad	PTFE on activated charcoal, each 1 700 mm², NFC chip in the seal ring.
03 · Air flow	Blower	Radial, brushless, 24 V, 250 W. The flow rate stays constant while the pad becomes clogged.
04 · Count	Alpha and beta	Silicon semiconductor detector, 1 700 mm², 35 %. 55 keV alpha, 30 keV beta, spectrally separated.
05 · Identification	Gamma spectrometry	NaI(Tl) or HPGe in a lead chamber with 25 mm walls, with a lining of copper and tin.
06 · Reference	Volume	Referred to 0 °C and 1 013 hPa, collection efficiency 0.95. Result in Bq/m³.

Data on the pad

The chip keeps the pad identifier, the pad type and the instrument number. It also keeps start and end in UTC, the volume, the mean flow rate, the campaign and the cycle. In addition, it keeps the 6 listed nuclides with activity and detection limit, a checksum and a link to the full report.

The chip is a copy

The full data set stays in the measuring instrument. A spectrum is too large for an NFC chip. The chip has the profile of the measurement and a link. In the default setting, the link points to the measuring instrument. The data do not have to go out of the site.

Background

Radon progeny on the filter pad

On each filter pad, the short-lived progeny of radon-222 are larger than the artificial nuclides by orders of magnitude. Without compensation, false alarms occur.

Fig. 1 · Alpha spectrum at the filter, schematic. Full width at half maximum 55 keV, data from the manufacturer. The diagram shows the low-energy tail of the artificial emitter.

Alpha spectroscopy separates the radon progeny polonium-218 at 6.00 MeV and polonium-214 at 7.69 MeV from the artificial alpha emitters. An example is americium-241 at 5.49 MeV. A correction compensates for the low-energy tail.

The software adjusts the beta channel with the measured alpha-to-beta ratio of the same pad. After the compensation, the measuring instrument reports gross alpha and gross beta in Bq/m³.

Versions

Version S and version G

The 2 versions are the same, but the gamma detector is different. Intake, pad, blower, silicon detector, software and data paths are the same.

Version S · Scintillator

NaI(Tl) 2″ × 2″ with photomultiplier
Resolution approximately 7 % at 662 keV
No cooling, ready to measure immediately
Gain stabilised against temperature
Library with 10 to 15 nuclides
Power consumption up to 130 W lower than version G

Version G · High-purity germanium

Coaxial HPGe, 40 % relative efficiency
1.90 keV at 1.33 MeV, 0.87 keV at 122 keV
Electric cooler, cool-down time 5 to 8 h
Peak-to-Compton ratio 64 : 1
Library with more than 50 nuclides
Lower detection limits with long counting times

Detection limits

Detection limits for each nuclide

In accordance with ISO 11929 at 95 %, at 4.0 m³/h and a radon level of 40 Bq/m³ in the air.

Nuclide	S · 1 h	G · 1 h	S · 24 h	G · 24 h
Cs-137	1.0 Bq/m³	0.60 Bq/m³	60 mBq/m³	8.0 mBq/m³
Cs-134	0.85 Bq/m³	0.50 Bq/m³	52 mBq/m³	6.6 mBq/m³
I-131	0.95 Bq/m³	0.50 Bq/m³	58 mBq/m³	7.3 mBq/m³
Co-60	1.0 Bq/m³	0.70 Bq/m³	60 mBq/m³	8.4 mBq/m³
Am-241 · alpha	0.060 Bq/m³	0.060 Bq/m³	0.50 mBq/m³	0.50 mBq/m³
Sr-90 · beta	not given	not given	4.5 mBq/m³	4.5 mBq/m³
Gross alpha	0.10 Bq/m³	0.10 Bq/m³	0.85 mBq/m³	0.85 mBq/m³
Gross beta	0.50 Bq/m³	0.50 Bq/m³	4.3 mBq/m³	4.3 mBq/m³

Alpha and beta are the same in the 2 versions, because the 2 versions use the same silicon detector. In version S, the limit for Cs-134 increases by a factor of approximately 2 when Cs-137 is dominant. The table gives values at the level of comparable measuring instruments in the field. It does not give the values of our own calculation model. The type test sets the final values.

The Environmental Solutions overview gives the calculation of the detection limit and the radon subtraction.

Operation

Screen on the handle

Screen 1920 × 1080, control areas a minimum of 20 mm, for operation with gloves. The measuring instrument uses the same software as the stations. Operating language English.

Start

One button gives access to each function.

Calibration

Energy calibration curve of the gamma detector.

History

Calendar grid, trends and reports.

Screenshots from the shared operating software. Example values, no measurements.

Programmes

P01 Continuous operation
P02 Campaign
P03 Single sample
P05 Background
P06 Filter change
P07 Cool-down, only version G
P08 Energy calibration
P10 Self-test

Data

Report interval and interfaces

You can set the report interval from 2 minutes to several hours.

2 minutes Shortest interval. With shorter intervals, the counting statistics are not sufficient for a measured value.
10 minutes Recommended value. Sufficient counts for a stable value, and short enough to find a change during the event.
Several hours For monitoring. Long campaigns at low concentration, where the detection limit is more important than the response time.
Interfaces Only Ethernet, no radio, no mobile network modem. ANSI/IEEE N42.42, REST and a documented manufacturer interface with an example client in Python. We implement protocols of the customer.

Technical data

Differences between the versions

The only differences between the versions are the gamma detector and the values that follow from the detector.

Parameter	ENVIRO GO S	ENVIRO GO G
Gamma detector	NaI(Tl) 2″ × 2″, PMT	coaxial HPGe, 40 % relative efficiency
Energy resolution	approximately 7 % at 662 keV	1.90 keV at 1.33 MeV
Cooling	none	electric cooler
Ready to measure	immediately	after a cool-down time of 5 to 8 h
Nuclide library	10 to 15 nuclides	more than 50 nuclides
Peak-to-Compton ratio	not applicable	64 : 1
Power consumption	up to 130 W lower	1.2 kVA at full cooling
Mass	150 kg	170 kg

Technical data

Common data

These values apply to the 2 versions.

Parameter	Value
Alpha and beta	Silicon semiconductor detector 1 700 mm², 35 %, 55 keV alpha, 30 keV beta
Filter pad	PTFE on activated charcoal, each 1 700 mm², with NFC chip
Flow rate	1 to 6 m³/h, nominal 4.0 m³/h, constant while the pad loads
Volume	referred to 0 °C and 1 013 hPa, collection efficiency 0.95
Shielding	25 mm lead, lining of copper and tin
Power supply	100 to 240 V, 50/60 Hz, mains or generator, cable 10 m
Ambient temperature	−10 to 55 °C, the air conditioner keeps the inside below 40 °C
Degree of protection	IP54, outdoors below a rain hood
Dimensions for transport	550 × 1 650 × 400 mm, mast retracted, head removed
Dimensions in operation	approximately 550 × 2 100 × 600 mm, turning circle approximately 1.2 m
Handling	driven wheel, brake, support feet, one person sets up the instrument
Interface	only Ethernet, no radio, no mobile network modem

The detector values come from the data sheets of the component manufacturers. All other data are design values.

Scope of delivery

Scope of delivery and options

The scope of delivery includes calibration in the factory and at the installation site.

Included

Measuring instrument with intake head and mast
Air conditioner
Cable drum, 10 m
Transport beaker, without measurement geometry
Parking brake and support feet for the mast
Factory calibration certificate
Sphere calibration at the installation site
Interface description and example client

Options

Intake head for PM2.5
External uninterruptible power supply, recommended
External intake line
External ambient dose rate meter
Spare pads and seal rings
Vehicle operation through an inverter
Loading ramp

Validity

Development status

The measuring instrument is not built at this time. A type test on the first measuring instrument confirms or corrects the values on this page.

Each performance value on this page is a design value or a value from experience with comparable systems. The detector values come from the data sheets of the component manufacturers.

The design follows IEC 60761-1, -2 and -4, ISO 2889 and ISO 11929. We write “tested in accordance with” only after a satisfactory type test. For the CE marking in accordance with EN 61326 and EN 61010, an external test house does the tests. For the Machinery Regulation (EU) 2023/1230, Profectronics prepares a written risk assessment.

Enquiry

Enquiry and other measuring instruments

Give us the nuclide, the necessary detection limit, the measurement duration, the installation site and the date. We tell you the applicable version and the limit of the method.

Measurement cabin · aerosols ENVIRO Station Aerosol
Measurement cabin · iodine ENVIRO Station Iodine
Air and vehicle ENVIRO AIR
Under water ENVIRO NAUTA
Overview All measuring instruments

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