GAMMA RADIATION DETECTION UNIT

BDG3-РМ1403

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Contents 1 GENERAL ............................................................................................................................... 4 2 BDG3 Delivery Set .................................................................................................................. 5 3 TECHNICAL SPECIFICATIONS ......................................................................................... 6 4 Design and Operation Principle ............................................................................................ 10 5 Making BDG3 Ready for Operation .................................................................................... 13

5.1 General notes..................................................................................................................... 13 5.2 BDG3 power ..................................................................................................................... 13 5.3 Safety measures ................................................................................................................. 13

6 Use BDG3 with BOI .............................................................................................................. 14 6.1 Switch BDG3 On/Off ........................................................................................................ 14 6.2 Check BDG3 operability ................................................................................................... 16 6.3 Connect BDG3 to PC ........................................................................................................ 16 6.4 Operation modes ............................................................................................................... 17

6.4.1 Measurement mode of photon radiation DER .............................................................. 17 6.4.2 Scintillation spectra registration and accumulation mode ............................................. 18 6.4.3 Radionuclide matter composition identification mode .................................................. 20 6.4.4 Photon radiation sources search mode .......................................................................... 21

6.4.4.1 Detection of gamma-radiation sources ................................................................ 22 6.4.4.2 Localization of gamma-radiation sources ............................................................ 23

6.4.5 PC communication mode ............................................................................................. 23 7 Using BDG3 with BDOI ........................................................................................................ 24

7.1 Switch BDG3 On/Off ........................................................................................................ 24 7.2 Operation modes ............................................................................................................... 27

7.2.1 Measurement mode of photon radiation DER .............................................................. 27 7.2.2 Scintillation spectrum registration mode ...................................................................... 28 7.2.3 Identification mode of radionuclide matter composition ............................................... 31 7.2.4 Search mode of the photon radiation sources ............................................................... 32

7.2.4.1 Detection of gamma-radiation sources ................................................................ 33 7.2.4.2 Localization of gamma-radiation sources ............................................................ 33

7.2.5 PC communication mode ............................................................................................. 34 7.2.6 Mode of BDG3 operation settings ................................................................................ 34

8 TECHNICAL MAINTANANCE .......................................................................................... 36 9 TROUBLESHOOTING ........................................................................................................ 37 10 Utilization .............................................................................................................................. 38

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Thank You for purchasing the BDG3-РМ1403 gamma-radiation detection unit manufactured by the polimaster company.

Current operation manual contains information on design, construction and operation of the

BDG3-РМ1403 gamma-radiation detection unit (further - BDG3). The operation manual contains key technical specifications of the unit, operation and maintenance guidelines, metrological examination as well as other necessary information on correct BDG3 operation, and full use of its capabilities.

BDG3 is documented as follows (according to state standard of manufacturer country: “BDG3-РМ1403 TU BY 100345122.060-2012 gamma radiation detection unit" Documented instruments and their electric circuit, internal and external design, and software

are subject to change in the manufacturing process with no substantial effect on their functionality or technical and metrological performance. Hence, Polimaster reserves the right not to mention such changes in the current Operation Manual.

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1 GENERAL

1.1 Designation and application range

1.1.1 BDG3 detection unit is designed to:

- measure ambient dose equivalent rate Н

*(10) (further– DER) of roentgen and gamma-radiation (further – photon radiation);

- search for photon radiation sources; - register and accumulate photon radiation scintillation spectra. BDG3 enables programming of the operation modes.

BDG3 can be used by radiological and isotope tracing laboratories, customs officers,

emergency services to search and detect unionizing radiation sources. BDG3 can also used by specialists in various industries, including agriculture, transportation, medicine, and in nuclear-engineering facilities where nuclear engineering facilities and radiation sources are used.

BDG3 is connected to BDOI-РМ1403 detection and information processing unit of the Radiation Monitor РМ1403 (further – BDOI), information display unit of the BOI-РМ1403 Radiation Monitor (further – BOI) or personal computer (PC) by RS-485 or USB interface.

BDG3 corresponds to third-class dosimeters according to GOST 12997 (local standard of

manufacturing country). The instrument corresponds by rigidness class and climate effects tolerance to the С4 group by GOST 12997.

Operation conditions of BDG3: ambient air temperature …………… from -20 up to +50 °С Relative air humidity…………………up to 95 % at 35 °С atmospheric pressure ……………… from 84 up to 106.7 kPa.

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2 BDG3 Delivery Set BDG3 delivery set corresponds to Table 2.1. Table 2.1

Name, type Quantity

BDG3-РМ1403 Gamma-radiation detection unit 1 Telescopic lengthening bar 1) 1 Bracket 1) 1 Handle 1) 1 Cable № 2 (1.5 m) 1) 1 Cable № 2-1 (25 m) 1) 1 Cable № 2-2 (0.25 m) 1) 1 Cable № 3 1 Instrument Certificate 1 Data medium (Software, Operation Manual2)) 1) 1 Packaging3) 1 1) Supplied by user request, on separate order 2) Verification Method is included into the delivery set 3) Another packaging can be used according to the customer order and delivery conditions (under the TU requirements).

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3 TECHNICAL SPECIFICATIONS

BDG3 technical specifications are given in the Table 3.1. Table 3.1

3.1 Operation modes: - measurement of photon radiation DER; - search for the photon radiation sources; - registration, accumulation of the photon radiation scintillation spectra; - identification of the radionuclide matter composition; - programming of operation modes 3.2 Measurement range of the photon radiation DER*

from 0.1 to 40 µSv/h

3.3 Limits of permissible main relative photon radiation DER measurement error of 137Cs radionuclide by 0.662 MeV energy in the collimated irradiation, no more than

± 25 %

3.4 BDG3 in the programming mode enables recording data into non-volatile memory and continuous control over DER threshold value, as well as sound and light alarming if set DER level is detected or exceeded. In the photon radiation DER measurement mode the BDG3 must emit discontinuous sound signal if set DER level is detected or exceeded.

3.5 DER threshold level setting discreteness - unit of least significant indicated bit. DER levels setting range

from 0.1 to 40 µSv/h

3.6 Energies range of registered photon radiation

from 0.05 to 3.0 MeV

3.7 Energy dependence relative to 0.662 MeV energy (137Cs) can differ from the typical dependence stated in Figure 3.1, no more then

minus 30 %

3.8 Unstable BDG3 readings when measuring DER during 8 hours of continuous working, no more than

5 %

3.9 BDG3 sensitivity to photon radiation in the search mode, no less than

2000.0 s-1/(µSv/h) – for 241Am; 300.0 s-1/(µSv/h) – for 137Cs

3.10 Count rate indication range during photon radiation registration in the search mode

from 1.0 to 9999 s-1

3.11 False operation rate of BDG3 in the gamma-radiation search mode at the radiation background no more than 0.25 µSv/h

No more than 1 operation during 10 minutes of discontinuous work**

3.12 Setting range of the quantity of the radiation gamma-background mean square deviations (further - n coefficient) within the limits

from 0.1 to 9.9

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Table 3.1 continued

3.13 Limits of permissible additional relative DER measurement error, no more than: when ambient air temperature changes from nor-mal to -20 °С and from normal to +50 °С at ambient air relative humidity 95 % at 35 °С when power supply voltage changes from nominal to extreme during photon radiation DER measurement at exposure of 400 A/m magnetic-field strength during photon radiation DER measurement at radiofrequency magnetic fields effect during photon radiation DER measurement

10 %; 10 %; 10 %; 10 %; 10 %

3.14 BDG3 at set n coefficient value corresponding to the value at which the false operation rate quantity is no more than one operation per 10 minutes of discontinuous work and external gamma radiation background (further gamma-background) no more than 0.25 µSv/h, must be able to detect standard radioactive sources (RS) and alternative gamma-radiation sources according to the Table 3.1.1, with probability more than 0.5: Table 3.1.1

Parameter name Source type 133Ba 137Cs 60Co

Activity of the gamma-radiation source, kBq (μCu (curie)), 30 % 55.0 (1.5) 100.0 (2.7) 50.0 (1.35)

Movement speed (source/instrument), m/s 0.50.05 0.50.05 0.50.05 Distance between the source and detector sensitive surface, m 0.20.005 0.20.005 0.20.005

3.15 Quantity of the gamma-radiation scintillation spectra accumulation channels

1024

3.16 Relative energy resolution of BDG3 during registration of the scintillation spectra by the 0.662 MeV (137Cs) line, no more than

8.5 %

3.17 Limit of permissible main error of the conversion response of the BDG3 integral nonlinearity BDG3 at registration of the scintillation spectra, no more than

1 %

3.18 Maximum input statistical load of BDG3 during scintillation spectra registration, no less than 104 s-1

3.19 Information exchange with BOI/BDOI or PC RS-485 interface or USB

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Table 3.1 continued

3.20 Registration effectiveness in the total absorption peak for the 137Cs gamma-radiation energy 662 keV of OSGI-3 point source located close to the BDG3 end surface, no less than

0.3±0.03 3.21 Instability of BDG3 graduated conversion response during 24 hours of continuous working, no more than

1 %

3.22 BDG3 power supply voltage: - from the accumulator battery - from the PC USB

3.6 (-0.6; +0.7) V; 5.0 (-0.1; +0.7) V

3.23 BDG3 is resistive to exposure of ambient air temperature from -20 to +50 °С; ambient air relative humidity up to 95 % at 35 °С temperature; atmospheric pressure from 84 to 106.7 kPa; frost-dew

3.24 BDG3 is resistant to exposure of 400 A/m industrial magnetic fields 3.25 BDG3 is resistant to radiofrequency electromagnetic fields, test level 4 (30 V/m) within frequencies range 80-1000 МHz, from 800 to 960 МHz, and from 1,4 to 2,5 GHz (when there is electromagnetic emission of digital radiophones), performance criterion А. 3.26 BDG3 is resistive to BDG2 is resistant to electrostatic discharges, test level 3 (air discharge of 8kV, contact discharge of 6 kV), performance criterion В 3.27 BDG3 corresponds to STB EN 55022-2012 (B class) requirements by the level of emitted radio-noise by the level of the radiated disturbance corresponds to STB ЕN 55022-2012 (B class) 3.28 Operation conditions: ambient air temperature range ambient air relative humidity atmospheric pressure

from -20 to +50 °С; up to 95 % at 35 С; from 84 to 106.7 kPa

3.29 BDG3 is resistant to: sinusoidal vibrations within the range from 5 to 500 Hz frequencies range with shift amplitude for frequency lower than crossover frequency 0.075 mm; blows with 100 m/s2 impact acceleration, shock pulse time 2-50 ms, blows repetition rate: 60 -180 per minute 3.30 Protection degree of BDG3 body

IP65

3.31 BDG3 in the transport packaging is resistant to

ambient air temperature from -50 to +50 оС; ambient air relative humidity up to 100 % at 40 оС temperature; sinusoidal vibrations within the range from 10 to 55 Hz with shift amplitude for frequency lower than crossover frequency 0.35 mm

3.32 BDG3 weight, no more than 0.16 kg 3.33 BDG3 packaged weight, no more than 0.3 kg 3.34 Overall dimensions of BDG3, no more than 133x40 mm

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Table 3.1 continued

3.35 Reliability figures: - mean time between failures, no less than

20000 h;

- mean life time, no less than 10 years; - mean recovery time, no more than 60 min. * * Manufacturer warrants technical parameters of BDG3 in the sphere of sources detection and false operation rate at factory set coefficients n for gamma-radiation n=4.0.

Figure 3.1 – Typical energy dependence Additional information on BDG3 can be obtained from the manufacturer or after visiting the

www.polimaster.ru.

-150-5050

150250350450550

10 100 1000 10000

%

кэВ

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4 Design and Operation Principle 4.1 BDG3 DESIGN

BDG3 is enclosed into a monoblock shock-proof body. A scintillation unit based on the

CsI(Tl) mono crystal is used as a detector. General view of BDG3 is given in the Figure 4.1.

Figure 4.1 –BDG3 general view BDG3 end surface bears the following: 1 – green LED – indication of operation; 2 – sound alarm – sound alarm is activated when set thresholds are exceeded; 3 – “ALARM” LED (blue) – light alarm is activated when set thresholds are exceeded; 4 – connector to connect BOI/BDOI or PC (RS485 or USB interfaces). The geometrical (effective) center of the detector is marked by “X” on the BDG3 end surface

and on the lid protecting the counter window, Figure 4.2.

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Figure 4.2 – Graduation direction and BDG2 detector’s geometrical (effective) center

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4.2 Operation Principle Operation principle of BDG3 in the search mode is based on comparison of the count rate of

the photon radiation impulses and with a threshold value calculated on the basis of measured value of current gamma-background count rate value and set n coefficient.

A built-in microcontroller processes impulses from BDG3, and controls sound and light alarms.

BDG3 operation algorithm enables continuous measurement process, statistical processing of measurement results and quick adaptation to radiation intensity changes (measurement time changes are inversely related to radiation intensity).

BDG3 exchanges information with PC by the data transmission channel (USB and RS-485). BDOI/BOI or USB port of PC are used to power BDG3.

4.3 Marking BDG3 end surface bears the following markings as a name plate: - unit’s name – BDG3-РМ1403; - manufacturer name; - manufacturer logotype; - serial number; - production year; - IP65 protection degree; - national register sign. 4.4 Packaging BDG3 is packaged into a polyethylene pack with operation documentation and delivery kit;

and placed into a carton box.

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5 Making BDG3 Ready for Operation 5.1 General notes Before starting to work with BDG3 carefully read current Operation Manual and Operational

Manual on BDOI/BOI, if BDG3 will be used with BDOI/BOI. Illustrations given in the Manual represent the information displayed on the BDOI/BOI LCD.

They are used to explain BDG3 operation together with BDOI/BOI. When purchasing BDG3 check the completeness of the delivery kit, according to the Table

2.1. During operation protect BDG3 against blows and mechanical injuries, corrosive substances,

organic solvents, open fire sources.

5.2 BDG3 power BDG3 is powered by BDOI/BOI or PC by RS-485 or USB interface. If the unit is connected to BDOI/BOI or PC by the cable№ 2 by RS-485 or USB interfaces,

then the LED1 will lighted on the BDG3 end surface (Figure 4.1, pos. 1). 5.3 Safety measures BDG3 corresponds to safety requirements of GOST27451-87 and GOST 12.2.091-2002.

BDG3 corresponds to III GOST 12.2.091-2002 by the degree of protection against electric shock. All settings, checking, repairs, technical maintenance and verification procedures of BDG3

when radiation sources are used, must be done according to state and local safety instructions for radioactive sources and other ionizing radiation sources.

Observe actual rules on working with radioactive materials and sources as well as radiation safety rules when radioactive sources are detected.

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6 Use BDG3 with BOI 6.1 Switch BDG3 On/Off 6.1.1 BDG3 is connected to BOI by means of the Cable № 2 by the RS-485 interface or to PC

by the USB interface. 6.1.2 Connect BDG3 to BOI BDG3 is connected to BOI by means of the cable №2. Switch BOI on. To switch BOI On/Off: press and hold the “DOWN” button (Figure 6.2(4)) until the LCD

displays and image (Figure 6.2(1)). BDG3 is automatically energized after the BOI is powered on. At that the LED on the end

surface of the BDG3 (Figure 4.1(1)) will light.

1 – color LCD 3.5” (89 mm); 2 – keypad buttons; 3 – connector to connect external detection units (RS485 interface); 4 – connector to connect PC and to charge accumulator batteries (USB interface); 5 – “ALARM” LEDs; 6 – “BATTERY” LED; 7 – sound alarm.

Figure 6.1 – External view of BOI

External view of the BOI keypad is given in the Figure 6.2.

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1 – “LEFT” button; 2 – “UP” button; 3 – “RIGHT” button; 4 – “DOWN” button.

Figure 6.2 – External view of the BOI keypad

The buttons are located under the LCD. Press any button to run a corresponding command

(the command is indicated under the button on LCD). After testing and calibration are over, the menu will display "Search ", "Measure ",

"Identify ". If so, BDG3 is correctly connected to BOI, Figure 6.3 (1). If BDG3 is connected, but BOI LCD doesn’t display above-mentioned menu items, then select “Find detector” menu item in the BOI menu, Figure 6.3 (2).

1) 2) 3)

Figure 6.3 Use keypad buttons to control BOI (Figure 6.2).

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BDG3 is switched on and ready for operation. BDG3 will be switched off after the cable is disconnected from BOI or after BOI is switched

off. To switch BOI off: select “Power Off” menu option, Figure 6.3 (3). 6.2 Check BDG3 operability Switch BDG3 on, as stated in 6.1. A green LED will light on the BDG3 end surface. check if every mode of BDG3 can be switched On: LED lights green – it indicates BDG3 test mode start succeeded by the operation mode

(Figure 4.1, pos. 1). Switch the BDG3 on as stated in 6.1. 6.3 Connect BDG3 to PC Connect BDG3 by the cable № 3 to the USB port of the running PC. Start user software. Select any of available operation modes.

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6.4 Operation modes

The operation modes of BDG3 are as follows: - measurement of the photon radiation DER; - search for the photon radiation sources; - registration, accumulation of the photon radiation scintillation spectra; - identification of the radionuclide matter composition; - programming of the operation modes.

Select line by the BOI cursor keys as follows: Search mode → Measurement mode →

Identification mode → Spectrum accumulation. Use “Select” button to select the operation mode. BDG3 enters test mode each time after connection to BOI. BOI LCD displays a linear scale showing a time interval left to the test end, Figure 6.4 (1). BDG3 automatically starts calibration to the gamma-background after test is finished, Figure

6.4 (2). Analogue scale displays time spent from the calibration start in relative units. If the scale is totally filled then the calibration is finished. BDG3 will enter the search mode of photon radiation sources after calibration is finished.

1) 2)

Figure 6.4 6.4.1 Measurement mode of photon radiation DER

BDG3 enters measurement mode of photon radiation DER if the “Measure γ” menu option is

selected, Figure 6.3 (1-3). In this mode the LCD of BOI indicates continuously measured photon radiation DER values µSv/h, mSv/h, Sv/h or µR/h, mR/h, R/h.

Statistical mean square error of average DER values (further – statistical error) is indicated under the measurement units on LCD with 0.95% probability. Read DER value when statistical error is 10% or less. The lower statistical error is, the more accurate measurement result can be get.

Level of measured DER is displayed on the analogue scale graphically and digitally. Quantity of lighting analog scale segments corresponds to the measured DER value according to the set DER threshold value.

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1) 2)

Figure 6.5

When set DER threshold is exceeded, the analogue scale will be filled completely, and audio

alarm (monotonous single signals being repeated every 3 s) will be activated. BOI LCD will display measured DER value in blinking red digits, Figure 6.5 (1). At that DER exceeded event will be recorded into non-volatile memory of BOI.

When DER measurement range is exceeded (overload), BDG3 emits sound alarm and indicates the “OVL” message on the LCD.

DER measurement mode enables the following, Figure 6.5 (2): – “Reset statistics” start count rate and DER measurement; − “Alarm mute/Unmute” sound alarm on/off; − “Threshold” set DER detection threshold. 6.4.2 Scintillation spectra registration and accumulation mode To enter the scintillation spectra registration and accumulation mode: successively select

“Spectrum “ → "Accumulate" menu options, Figure 6.6: − “Accumulate” – for statistics reset and new spectrum accumulation start; − “Open” open saved spectra.

1) 2) 3)

Figure 6.6

N o t e to check the spectrometric channel calibration: take reference spectrum from

reference source under the same conditions that will be applied when taking spectra from tested

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object. Sources of OSGI-3-2 152Eu, 228Th type with 50-100 kBq activity can be used as reference sources. To take the reference spectrum: place a reference source as close to the geometrical (effective) center as possible and do the following procedure. Take the reference source away from BDG3 when the reference spectrum accumulation is over, and the spectrum is saved into BDG3 memory.

LCD will display average count rate of the registered photon radiation impulses. A scale graphically displaying gamma channel load is shown under the digital count rate

indication on the LCD, Figure 6.7.

1) 2) 3)

Figure 6.7

A green arrow, Figure 6.7 (1), means that average count rate of gamma-channel is too low: "Low count rate", (below 200 cps). Low gamma-channel load results in uncertain spectrum.

A “Radiation danger” sign, Figure 6.7 (2), means that average count rate of gamma-channel corresponds to optimal load (from 200 to 20000 cps). Optimal gamma-channel load results in reliable and undistorted spectrum.

An orange arrow, Figure 6.7 (3), means that average count rate of gamma-channel is too high: "High Count Rate" (more than 20000 cps). Too high gamma-channel load results in distorted spectrum.

Move BDG3 as close to the tested object as necessary so that the count rate by detection unit is from 200 to 20000 cps and press START button on BOI.

During spectrum accumulation the LCD will display a graph of accumulated spectra in progress, and time (Figure 6.8 (1) that passes from the accumulation start. Displayed spectrum is renewed every 10 seconds.

1) 2)

Figure 6.8

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BDG3 accumulates spectrum by 1.024 channels. Channel capacity is 65536. It is necessary to accumulate not less than 104 pulses in the maximum count channel to get a good quality spectrum. Besides, you can visually determine the time of spectrum accumulation by the graph on LCD — if you can see clearly distinguishable peaks on the graph, you can stop the spectrum accumulation and start processing of the spectrum.

The following is available in the scintillation spectrum registration mode, Figure 6.8 (2): "Marker auto" automatic marker positioning; "Scale" (measuring scale) – change the displayed spectrum; "Scale" (bar) – select a type of displayed scale (linear/logarithmic).

Figure 6.9

The following is available after accumulation is finished: − "Identify" – starts process of identification by accumulated spectrum; − "Save" – saves accumulated spectrum; − "Restart" – starts accumulation of a new spectrum (BDG3 will reset statistics); − "Back" – returns to the accumulation process.

6.4.3 Radionuclide matter composition identification mode

To enter the radionuclide matter composition identification mode: select "Identify γ", Figure

6.10 (1) menu option.

1) 2) 3)

Figure 6.10

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BDG3 will enter the “Identify” radionuclide matter composition identification mode. LCD will display average count rate of photon radiation impulses being registered. Graphical scale of gamma channel load will be displayed on the LCD simultaneously with digital count rate indication. Move BDG3 as close to the tested object as necessary so that the count rate by detection unit is from 100 to 20000 cps, Figure 6.10 (2). To start spectrum accumulation and identification: press "Identify".

If gamma channel load is sufficient (within range 200-20000 pulses/sec (cps)), the instrument will take about 150-300 sec to display the identification result in the upper LCD area. If gamma channel load is less or more than stated one, then the instrument will take more time to identify.

When instrument accumulates statistical data enough for radionuclide matter composition identification attempt, the identification results will be immediately displayed in the upper BOI LCD area, Figure 6.10 (3).

Identification mode menu enables the following functions, Figure 6.11: "Absorber" thickness of a shielding agent; "Type" – absorber material type; "Matrix" – thickness of the material in which the source is spaced along the line connecting the source center and BDG3; "Library" – radionuclides library.

Figure 6.11

6.4.4 Photon radiation sources search mode BDG3 with BOI can be used to search for the photon radiation sources. The “OVL” message

is displayed on the BOI LCD if pulses count rate range exceeds upper measurement limit when BDG3 works in the search mode.

To search for gamma-sources: connect BDG3 to BOI, according to BOI-РМ1403 Operation Manual, and select a gamma-radiation sources search mode – "Search ".

BDG3 enters the search mode after the "Search " menu option is selected, Figure 6.3 (1). A current value of average count rate of impulses per second (cps) coming from BDG3 is being calculated in the search mode Calculated value is indicated in the center of BOI LCD. Statistical error of average count rate of gamma radiation in percents is displayed under indicated measurement units on LCD, Figure 6.12 (1).

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1) 2)

Figure 6.12 Current count rate value is compared to the operation threshold (calculated in the calibration

mode). If current count rate value exceeds threshold value, then alarms will be activated (sound and light). At that frequency of coming signals is constant or increases since the operation threshold is exceeded more and more (i.e. gamma-radiation source is getting closer and closer).

Detection threshold can be changed by setting new n-coefficient within 1.0-9.9 range. The lower the n coefficient value is, the less the threshold value is and the higher the BDG3 sensitivity in the search mode is. But at that false alarm probability increases.

N o t e – Automatic calibration will be started after n coefficient is changed. Gamma radiation sources search mode enables the following, Figure 6.12 (2): – "Reset statistics" start DER and count rate measurement; – "Calibration" – recalibrate BDG3. After it BDG3 will automatically enter the Search

mode; − "Sound On" sound alarm on/off; − "G threshold" set detection threshold; − "Detector" – information on BDG3.

6.4.4.1 Detection of gamma-radiation sources To detect gamma-radiation sources (further – radiation sources (RS)) place BDG3 so that the

graduation direction (see Figure 4.2) coincides with the direction to the tested object. The closer the effective center of the instrument detector is placed to the object under examination (luggage, person, container, vehicle, etc.) and the slower it moves alongside the object, the higher the RS detection rate will be.

Use light alarms and watch BOI LCD indication to detect RS in noisy environments (instrument sound (audio) signals might not be heard)).

BDG3 sensitivity and false operation rate depends on: - set n coefficient; - background level calculated by BDG3 in the calibration mode. Since natural radiation background level fluctuations can be significant, calibrate to

background level just before starting detection of gamma sources. Note, that the instrument during misoperation emits nonsystematic light and sound alarms.

Such alarms can be easily differed form the signals emitted by the instrument when RS are detected (the signals are characterized by constant repetition rate. The rate increases when RS gets closer to the instrument.

Start RS localization when RS is detected or there is some indication of possible RS presence.

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6.4.4.2 Localization of gamma-radiation sources To localize RS: place the instrument near the tested object at a distance of no more than 10

cm. Move the instrument alongside the object no faster than 10 m/s. The closer RS is, the faster the signals repetition rate is.

Sound (audio) signals accompanied by a blinking blue LED are heard when sound (audio) alarm function is switched on.

When frequency of light and sound (audio) alarms becomes extreme (right up to continuous light and sound signal), further localization procedure is possible only after the instrument is calibrated to new background level.

To do this, keep the same distance to the object (if possible), and select the “Calibration” line to start the calibration to current background level. Before it the BDOI LCD can display a message warning that the calibration could take some time. If so, the user has to decide whether to continue the calibration or cancel it. You can localize RS after the calibration to new gamma-background value is finished.

6.4.5 PC communication mode BDG3 enables information exchange with a PC running under WINDOWS OS. See the

“Help” file of the program to see the operation sequence for the PC communication mode by the USB interface. Do the following to enable BDG3-PC communication:

- install special software (it is supplied on CD disk) to the user PC; - connect BDG3 and PC by the cable № 3; - start the software; - PC will take control over BDG3. See the “Help” file or program comments for information on working with software.

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7 Using BDG3 with BDOI

7.1.1 BDG3 is connected to BDOI by means of the cable №2 by the RS-485 interface or to the

PC by the USB interface. 7.1.2 Connect BDG3 to BDOI BDG3 is connected to BDOI by means of the cable №2. Switch BDOI on. To switch BDOI on/off: press the ON/OFF button on the BDOI body (Figure 7.1, pos.11). BDG3 will be automatically energized after BDOI is switched on. At that a LED will light on

the BDG3 end surface (Figure 4.1(1)).

Figure 7.1 – External view of BDOI

1 – sound alarm – enables sound of set DER, DE thresholds are exceeded; 2 –"ALARM" LED; 3 –"BAT" LED; 4 – GPS receiver; 5 – color LCD 3.5” (89 mm); 6 – keypad keys; 7 –Wi-Fi antenna; 8 – fastening for removable clip, bracket; 9 –GPRS, GSM antenna; 10 – RESET button – restart BDOI OS; 11 – ON/OFF button – switch BDOI On/Off; 12 – battery compartment; 13 – pin to connect external detection units (RS485 interface); 14 – pin to connect to a PC and charge accumulators (USB interface); 15 – fastening for removable clip, bracket. External view of the BDOI keypad and functional purposes of the buttons are given in the

Figure 7.2.

7.1 Switch BDG3 On/Off

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1, 2 – , (<<,>>) – Fast switching between ultimate menu items or parameters;

3 – (MENU/SELECT) – enter selected BDOI operation mode or highlighted parameter in the MENU;

4 – (MODE/BACK/OK) – open the list of the BDOI operation modes. Exits or returns to the previous operation mode or parameter.

Navigation joystick keys:

5 – (UP), 6 – (DOWN) – Vertical cursor controlled scrolling navigation through menu lines;

7 – (LEFFT), 8 – (RIGHT) – Horizontal cursor controlled navigation; 9 – (ENTER) – Press this key to run EXECUTE command, and switch to the

highlighted parameter or a required program.

Figure 7.2 – External view and functional purposes of the BDOI keypad keys

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After test and calibration are finished, a connected BDG3 will be displayed in the BDOI menu in the "BDG3 Detector [CsI]" line, Figure 7.3 (2). If BDG3 is connected though the BDOI LCD doesn’t display "BDG3 Detector [CsI]" line, then select the “Find detectors” line in the window indicating BDOI operation modes, Figure 7.3 (1).

To enter the indication mode of BDG3 operation modes: select the "BDG3 Detector [CsI]" line. A menu will be opened listing BDG3 operation modes, Figure 7.3 (3).

1) 2) 3)

Figure 7.3

Use keypad keys to control BDOI (Figure 7.2). BDG3 is switched on and ready for operation. BDG3 is switched off after the cable is disconnected from BDOI or after BDOI is switched

off. To switch BDOI off: press ON/OFF button and wait. BDOI will switch off.

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7.2 Operation modes

The operation modes of BDG3 are as follows: - photon radiation DER measurement; - search for the photon radiation sources; - registration, accumulation of photon radiation scintillation spectra; - identification of the radionuclide matter composition; - programming of operation modes.

Use BDOI cursor keys to select the line, and use SELECT key to enter the operation mode. BDG3 enters test mode each time after it is connected to BDOI. The BDOI LCD indicates a

decreasing linear scale showing a time left to the test end, Figure 7.4 (1). BDG3 will automatically start calibration to gamma-background value after test is finished,

Figure 7.4 (2). Analogue scale indicates time passed from the calibration start in relative units. The scale will be totally filled when the calibration is finished. BDG3 will enter the search mode of the photon radiation sources after calibration is finished.

1) 2)

Figure 7.4 7.2.1 Measurement mode of photon radiation DER

BDG3 enters the measurement mode of photon radiation DER if the “Measurement mode”

menu item is selected in the "BDG3 detector [CsI]" window, Figure 7.3. BDOI LCD indicates in the “Measurement mode” DER measurement mode continuously

measured photon radiation DER values in µSv/h, mSv/h, Sv/h or µR/h, mR/h, R/h, Figure 7.5 (1). A statistical average square error of average DER value (further - statistical error) is displayed

in percents with 0.95 probability under indicated measurement units on LCD. Read the DER value when statistical error gets 10% or less. The less statistic error, the more accurate measurement result will be.

Level of the measured DER is also displayed graphically on analogue scale. Quantity of lighting analog scale segments corresponds to the measured DER value according to the set DER threshold value.

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1) 2)

Figure 7.5

When set DER threshold is exceeded, the analogue scale will be filled completely, and audio

alarm (monotonous single signals being repeated every 3 s) will be activated. The BDOI LCD indicates a ”Threshold exceeded” message informing on exceeded DER, and measured DER value will be indicated in red blinking digits. DER threshold exceeded event will be recorded to the BDOI non-volatile memory.

When DER measurement range is exceeded (overload), BDG3 emits sound alarm and indicates the "OVL" message on the LCD.

DER measurement mode enables the following, Figure 7.5 (2): – "Reset statistics" start of DER and count rate measurement; − "Save to history" saving measurement result into BDOI memory; − "Sound On/Off" sound alarm on/off; − "Thresholds" detection threshold setting.

7.2.2 Scintillation spectrum registration mode BDG3 enters the scintillation spectra registration mode after the "Spectrum

accumulation"/"Continue accumulation" (Figure 7.6) menu option is selected in the "BDG3 detector [CsI]" operation modes window.

"Spectrum accumulation" – statistics reset and new spectrum accumulation start "Continue accumulation" continues accumulation of the last accumulated spectrum (even

if it is saved and processed).

1) 2) 3)

Figure 7.6

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N o t e to check the spectrometric channel calibration: take reference spectrum from

reference source under the same conditions that will be applied when taking spectra from tested object. Sources of OSGI-3-2 152Eu, 228Th type with 50 -100 kBq activity can be used as reference sources. To take the reference spectrum: place a reference source as close to the geometrical (effective) center as possible and do the following procedure. Take the reference source away from BDG3 when the reference spectrum accumulation is over, and the spectrum is saved into BDG3 memory.

LCD will display average count rate of the registered photon radiation impulses. An analogue scale displaying relative value of the measured count rate is shown over the

digital count rate indication on the LCD, Figure 7.7.

1) 2) 3)

Figure 7.7

A pink scale, Figure 7.7 (1), means that average count rate of gamma-channel is too low:

"Low count rate" (below 200 cps). Too low gamma-channel load results in distorted spectrum. A green scale, Figure 7.7 (2), means that average count rate of gamma-channel corresponds to

optimal load (from 200 to 20000 cps). Optimal gamma-channel load results in reliable and undistorted spectrum.

A red scale, Figure 7.7 (3), means that average count rate of gamma-channel is too high: "High Count Rate" (more than 20000 cps). Too high gamma-channel load results in distorted spectrum.

Move BDG3 as close to the tested object as necessary so that the count rate by detection unit is from 200 to 20000 cps and press START button on BDOI.

During spectrum accumulation the LCD will display a graph of accumulated spectra in progress, and time (Figure 7.8 (1) that passes from the accumulation start. Displayed spectrum is renewed every 10 seconds.

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1) 2)

Figure 7.8

BDG3 accumulates spectrum by 1.024 channels. Channel capacity is 65536. It is necessary to accumulate not less than 104 pulses in the maximum count channel to get a good quality spectrum. Besides, you can visually determine the time of spectrum accumulation by the graph on LCD - if you can see clearly distinguishable peaks on the graph, you can stop the spectrum accumulation and start processing of the spectrum.

The following is available in the scintillation spectrum registration mode, Figure 7.8 (2): "Reset statistics" Manual statistics reset enables reset of measurement data buffer

accumulated by BDG3. BDG3 starts new spectrum accumulation after statistics are cleared; "Identify" Starts process of radionuclide matter composition identification by

accumulated spectrum. Identified radionuclides are classified into groups: 1) special nuclear radionuclides; 2) medical; 3) industrial; 4) natural;

"View Library" view a library of nuclides; "Options" change/view an identification report format settings and graphical

representation of the spectrum on BDOI LCD; "Set absorber". Enter protection parameters to get more reliable identification results

of radionuclide mater composition: o "Thickness, mm" – set material thickness value in mm; o "Material" – set material;

"Save as…" saving accumulated spectrum; "Send to NPNET" By user command the following data will be sent to the Web-

server: accumulated spectrum file with geographical coordinates (latitude/longitude) of BDG3, current date and time;

"Spectrum info" view reference information on the spectrum; "Peak info" view information on the spectrum peak in the marker position.

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Figure 7.9 The following information is indicated in the lower part of the BDOI LCD (Figure 7.9): set marker movement speed over the spectrum (х2/х4/х8/х16/х32); channel number (or energy in keV), where the marker is set; Quantity of impulses in this channel; spectrum accumulation time.

7.2.3 Identification mode of radionuclide matter composition

To enter the identification mode of radionuclide matter composition: select "Quick identify",

Figure 7.10 (1) in the "BDG3 detector [CsI]" operation modes window.

1) 2) 3)

Figure 7.10

BDG3 will enter the “Quick identify” radionuclide matter composition identification mode.

LCD will display average count rate of photon radiation impulses being registered. Graphical scale of gamma channel load will be displayed on the LCD simultaneously with digital count rate indication. Move BDG3 as close to the tested object as necessary so that the count rate by detection unit is from

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100 to 20000 cps (it corresponds to indication of the scale in its green area, Figure 7.10 (2). Press “OK” button on BDOI to start spectrum accumulation and identification.

If gamma channel load is sufficient (within range 200-20000 pulses/sec (cps)), it will take about 150-300 sec to display the identification result in the upper LCD area. If gamma channel load is less or more than stated one, then the instrument will take more time to identify.

The lower part of LCD displays an increasing image of the spectrum being accumulated and analogue scale of time passed from the spectrum accumulation start, Figure 7.10 (3) during spectrum accumulation. Displayed spectrum is being renewed every 10 sec. At that BDG3 each time (during this 10 sec period) tries to identify on the basis of the statistics accumulated during this time. When there will be accumulated statistical data enough for radionuclide matter composition identification attempt, the identification results will be immediately displayed in the upper BDOI LCD area, Figure 7.10 (3).

The scintillation spectra registration mode enables the following: "Reset statistics" at that current accumulated spectrum will ne reset and

accumulation will be started anew; "View library" – viewing the nuclides library; "Set absorber". Enter protection parameters to get more reliable identification results

of radionuclide mater composition: o "Thickness, mm" – set material thickness value in mm; o "Material" – set material.

7.2.4 Search mode of the photon radiation sources BDG3 with BDOI can be used to search for the photon radiation sources. If count rate

exceeds upper detection limit when BDG3 is working in the search mode, then BDOI LCD will indicate an “OVL” message.

To do search for gamma-radiation sources: connect BDG3 to BDOI, according to the BDOI-РМ1403 Operation manual, and select the search mode of gamma-radiation sources – "Search mode".

BDG3 enters the search mode when the “Search mode" menu item, Figure 7.3 is selected in the "BDG3 detector [CsI]" operation modes window. Current value of the average count rate (cps) coming from BDG3 is being calculated in the search mode. Calculated value is indicated in the "Count rate" line. Statistical error of average count rate of gamma radiation in percents is displayed under indicated measurement units, Figure 7.11 (1).

Current measured DER value of photon radiation is indicated in the “Measurement” line in µSv/h, mSv/h, Sv/h or µR/h, mR/h, R/h, Figure 7.11 (1).

1) 2)

Figure 7.11

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Current count rate value is compared to the operation threshold (calculated in the calibration mode). If current count rate value exceeds threshold value, then alarms will be activated (sound and light). At that frequency of coming signals is constant or increases since the operation threshold is exceeded more and more (i.e. gamma-radiation source is getting closer and closer).

Detection threshold can be changed by setting new n-coefficient within 1.0 - 9.9 range. The lower the n coefficient value is, the less the threshold value is and the higher the BDG3 sensitivity in the search mode is. But at that false alarm probability increases.

Gamma radiation sources search mode enables the following, Figure 7.11 (2): – "Reset statistics" start DER and count rate measurement; – "Calibration" – recalibrate BDG3, after that BDG3 will automatically enter the search

mode; − "Save to history" save measurement result into BDOI memory; − "Sound On/Off" sound alarm on/off; − "Thresholds" set detection threshold;

7.2.4.1 Detection of gamma-radiation sources To detect gamma-radiation sources (further – radiation sources (RS)) place BDG3 so that the

graduation direction (see Figure 4.2) coincides with the direction to the tested object. The closer the effective center of the instrument detector is placed to the object under examination (luggage, person, container, vehicle, etc.) and the slower it moves alongside the object, the higher the RS detection rate will be.

Use light alarms and watch BDOI LCD indication to detect RS in noisy environments (instrument sound (audio) signals might not be heard)).

BDG3 sensitivity and false operation rate depends on: - set n coefficient; - background level calculated by BDG3 in the calibration mode. Since natural radiation background level fluctuations can be significant, calibrate to

background level just before starting detection of gamma sources. Note, that the instrument during misoperation emits nonsystematic light and sound alarms.

Such alarms can be easily differed form the signals emitted by the instrument when RS are detected (the signals are characterized by constant repetition rate. The rate increases when RS gets closer to the instrument.

Start RS localization when RS is detected or there is some indication of possible RS presence. 7.2.4.2 Localization of gamma-radiation sources To localize RS: place the instrument near the tested object at a distance of no more than 10

cm. Move the instrument alongside the object no faster than 10 m/s. The closer RS is, the faster the signals repetition rate is.

Activated sound alarm is accompanied by blinking blue LED. When frequency of light and sound (audio) alarms becomes extreme (right up to continuous

light and sound signal), further localization procedure is possible only after the instrument is calibrated to new background level.

To do this, keep the same distance to the object (if possible), and select the “Calibration” line to start the calibration to current background level. Before it the BDOI LCD can display a message warning that the calibration could take some time. If so, the user has to decide whether to continue the calibration or cancel it. You can localize RS after the calibration to new gamma-background value is finished.

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7.2.5 PC communication mode BDG3 enables information exchange with a PC running under WINDOWS OS. See the

“Help” file of the program to see the operation sequence for the PC communication mode by the USB interface. Do the following to enable BDG3-PC communication:

- install special software (it is supplied on CD disk) to the user PC; - connect BDG3 and PC by the cable № 3; - start the software; - PC will take control over BDG3. See the “Help” file or program comments for information on working with software. 7.2.6 Mode of BDG3 operation settings

“Instrument settings” mode −> "BDG3 detector [CsI]", Figure 7.12 (2), enables the user to

view or change BDG3 operation settings. "Thresholds" tab, Figure 7.12 (3): − set the n coefficient. This coefficient determines operation threshold (minimum detection

level of gamma radiation) of gamma channel. Operation threshold of gamma channel can be changed by setting a new n coefficient by gamma channel. Setting range of n coefficient is 1 - 9.9, 0.1 discreteness;

− set DER thresholds, mSv/h – when instrument detects set DER value in the DER measurement mode, it will display a warning message: "Threshold is exceeded". DER threshold setting range corresponds to DER measurement range (Table 3.1). Enter DER threshold value which is equivalent to "mSv/h" measurement unit.

“Energy Calibration" tab, Figure 7.12 (4): − А, В, dFWHM, К1 and К2 coefficients coefficients values are calculated and recorded

into BDG3 by representatives of Polimaster for every temperature individually. The coefficients are used by BDG3 for calibration.

Attention! Wrong energy parameters will lead to BDG3 disfunction. “FWHM Calibration” tab, Figure 7.12 (5): − "FWHM – First point" – Width at half-height of first calibration point in keV.

Recommended initial value is 38.0 (for 122 keV energy); − "Energy – First point" – First calibration point energy. Recommended energy value is

122 keV; − "FWHM – Second point" – Width at half-height of second calibration point in keV.

Recommended initial value is 58.0 (for 662 keV energy); − "Energy – Second point" – Second calibration point energy. Recommended energy

value is 662 keV. "AutoCalibration" tab, Figure 7.12 (6): − " Name" – select spectrometric reference gamma radiation source for autocalibration; − " FWHM coeff" – coefficient of peak half-width. The coefficient corrects estimated peak

half-width at autocalibration. It enables increase of peak half-width if its value is more than 1, or decrease it if coefficient value is less than 1;

First point Min. – channel number of first peak start boundary; Max. – channel number of first peak decrease boundary;

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Energy – energy value of the line for the first calibration peak. Energy values of lines corresponding to calibration peaks within the set limits can be found in the nuclides library for the given calibration source;

Second point Min. – channel number of second peak start boundary; Max. – channel number of second peak decrease boundary; Energy – energy value of the line for the second calibration peak. Energy values of

lines corresponding to calibration peaks within the set limits can be found in the nuclides library for the given calibration source;

Third point Min. – channel number of third peak start boundary; Max. – channel number of third peak decrease boundary; Energy – energy value of the line for the third calibration peak. Energy values of lines

corresponding to calibration peaks within the set limits can be found in the nuclides library for the given calibration source.

1) 2) 3)

4) 5) 6)

Figure 7.12

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8 TECHNICAL MAINTANANCE Technical maintenance represents preventive maintenance. Technical maintenance includes the following: external examination, dust and dirt removal

and deactivation if the BDG3 body is contaminated with radioactive substances. Deactivate BDG3 by wiping it with a soft cloth wetted with ethyl alcohol (GOST 18300-87). Alcohol volume 40 ml is required.

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9 TROUBLESHOOTING A list of possible problems and troubleshooting is given in the Table 8.1. Table 9.1

Typical malfunctions Possible reasons Troubleshooting

1) The “MODE” green LED doesn’t light after connection to PC or BDOI/BOI

Cable is faulty BDOI/BOI or PC is/are switched off

Change the cable Switch BDOI/BOI or PC on

2) Sound alarm doesn’t work

Sound is off Sound alarm is faulty

Switch sound on in the mode of communication with PC or BDOI/BOI; Repaired by the manufacturer.

3) The detector cannot be seen after connection to PC or BDOI Cable is faulty Change the cable

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10 Utilization BDG3 poses no hazard to human life and health. It is environment friendly. Hence it must be

utilized according to local state norms and rules. There is no information on precious metals content in BDG3 since their clear weight (mass)

doesn’t exceed values stated in standards of manufacturing country (GOST 2.608-78).