Fuji Electric NRF31 User manual

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User’s Manual
Electronic Personal Dosemeter
(For Gamma(X)-ray and neutron)
NRF31
Fuji Electric Co., Ltd.

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Introduction
Thank you for purchasing the Electronic Personal Dosimeter NRF31 (Hereinafter described as “the
Dosimeter”) by FUJI ELECTRIC CO., LTD. The User’s Manual is organized to provide descriptions of
parts, functions and operational instructions for optimal use. Please make sure that you read this manual
carefully before operation.
In the event of product malfunction, contact your Fuji Electric authorized customer service representative.
In order to ensure prompt service, please provide precise details of the problem and its evolution, along
with the model and serial number. A photo or drawing would enhance understanding and would be greatly
appreciated.
Do not repair or attempt to repair the Dosimeter through any unauthorized service providers. Such actions
may void the warranty by Fuji Electric Co., Ltd.

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HANDLING PRECAUTIONS
Please read the following handling precautions to ensure that you use the Product safely and avoid injury/
damages. Please read this User’s Manual carefully to understand all the precautions before using the
Product.
Measures of Precaution
Attention
・ The Dosimeter is a precision instrument; do not drop it or subject it to
impact.
・ Keep the Dosimeter in a plastic bag for protection when used in an
environment where chemical fumes, splashes /steam, full of dust and
wastes are present.
・ Handle the Dosimeter with clean, dry hands. If becomes tainted, clean it
with dry cloth.
・ Do not place the Dosimeter and metal objects in the same pocket. It may
cause the dosimeter breaking.
・ Avoid use where with high frequency noise. Pay attention when use near
the following devices:
1. Mobile phone
2. Premises/local wireless phone such as <PHS>
3. High power transceiver, or like kind
4. Microwave oven
5. Radar
6. Welding machine
7. Any other spark discharging or high intensity radio wave emitting
devices
Especially keep the Dosimeter at least 5cm away from any mobile/
wireless phones
・ When the battery level is critically low, read the displayed value within 10
minutes.
・ Use CR123A battery only. During replacement, align the battery
polarities correctly.
・ Prior to disposal of the used battery, protect exposed terminals with
insulating tape to prevent shorting that may cause possible heating,
rupture, or burning. Otherwise, injury or fire may result.
・ Do not throw the Dosimeter or battery into a fire. Do not disassemble
them.
・ Keep distance between the buzzer and ears to avoid the injury.
(Buzzer makes the sound over 85dB)
・ Do not use the Dosimeter as a survey meter.
・ If a hard impact operating on the dosimeter, it may have a crack to
the dosimeter. In this case, it may deteriorate the capabilities in a
waterproof and a resistance of radio wave.
・ Do not excessively open or pull the clip to avoid breakage.

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Contents
1. Overview ..............................................................................................................................................5
2. Product Overview.................................................................................................................................6
2.1 Product package ...........................................................................................................................6
2.2 Product type code ......................................................................................................................... 6
3. Precautions ..........................................................................................................................................7
3.1 Operational conditions................................................................................................................... 7
3.2 Other requirements .......................................................................................................................7
4. Descriptions of Parts and Functions.....................................................................................................8
4.1 Part names....................................................................................................................................8
4.2 Display function...........................................................................................................................10
4.3 Buzzer function ............................................................................................................................11
4.3.1 Audible signal........................................................................................................................11
4.3.2 Audible alarms ..................................................................................................................... 12
5. Battery Replacement..........................................................................................................................17
5.1 Battery replacement.................................................................................................................... 17
5.2 Attaching and removing a clip .....................................................................................................18
6. Operational Instructions......................................................................................................................19
6.1 When start to use........................................................................................................................ 19
6.2 During use................................................................................................................................... 21
6.3 After use...................................................................................................................................... 24
7. Care and Maintenance....................................................................................................................... 25
7.1 Check procedures....................................................................................................................... 25
7.2 Consumable supplies.................................................................................................................. 25
8. Specification.......................................................................................................................................26
8.1 General specification................................................................................................................... 26
8.2 Energy response......................................................................................................................... 27
8.2.1 Gamma(X)-ray ..................................................................................................................... 27
8.2.2 Neutron ................................................................................................................................ 27
8.3 Dose equivalent rate dependence............................................................................................... 28
8.4 Angular of incidence.................................................................................................................... 29
8.4.1 For 137Cs on phantom.........................................................................................................29
8.4.2 For 241Am (X-ray 56.2keV) on phantom ............................................................................... 29
8.4.3 For 137Cs in Free air.............................................................................................................30
8.4.4 For 241Am-Be on phantom....................................................................................................30
8.5 Ambient temperature................................................................................................................... 31
9. Appendix ............................................................................................................................................32
9.1 Troubleshooting Table................................................................................................................. 32
9.2 Disposal ......................................................................................................................................33

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1. Overview
The Electronic Personal Dosimeter NRF31 (hereinafter referred to as NRF31) is designed to
provide measurement of personal dose equivalent of external exposure to radiations (hereinafter
referred to as dose).
The Dosimeter NRF31 measures gamma dose and neutron dose, indicates each preset dose
threshold (alarm threshold) will be audibly alarmed if reached.
Using the Dosimeter Setting Device and a PC, you can write PC-edited values to / read
measurement data trend from the Dosimeter NRF31 via communication with the device.
If worn tight to the body, energy characteristic of the NRF31 series enables direct reading of dose
equivalent at the depth of 1cm (unit: Sv or rem, 1Sv is equivalent to 100 rem).
You can switch Sv and rem units through the Dosimeter Setting Device. Default setting of
NRF31021-□21YY and NRF31021-□22YY are Sv and rem, respectively.

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2. Product Overview
2.1 Product package
(1) The Dosimeter NRF31 1 (Clip included)
(2) Option
Battery (CR-123A) 1
Plug-pin 1
2.2 Product type code
1 2 3 4 5 6 7 8 9 10 11 12 13 14
N R F 3
1
－
Y
Y －
Radiation measured
1 Gamma(X)-ray and neutron
Transmission
0 Infrared
Battery
2 Primary cell
Modification number
1 Normal version
Indication plate
1 Japanese
2 English
Measurement
2 Cumulative dose + Dose rate
Unit
1 Sv
2 rem
Non-Standard specification
Blank Standard
A Other specifications

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3. Precautions
Attention
3.1 Operational conditions
Item Condition
Temperature range -20℃to ＋50℃
Relative humidity 90% or less (No condensation)
Storage temperature -20℃to +50℃
Reset of cumulative dose Reset through the Dosimeter Setting Device
Alarm volume Approximately 85dB @20 cm
Battery life Continuously 2880 hours (Using a new battery under normal temperature
and no alarm activity)
Impact resistance Impact from 150cm drop onto a hard wood surface
Dose threshold (default) Alarm 0.5mSv (50 mrem)
Pre-Alarm 0.25mSv (25 mrem)
Dose rate threshold (default) Alarm 700mSv/h (70000 mrem/h)
Pre-Alarm 70mSv/h (7000 mrem/h)
Overload indication ‘OVER’ is indicated
*1 Default of dose and dose late threshold of neutron are set to 9.999Sv and
9.999Sv/h, respectively. If these thresholds are used, please reset the
threshold properly via setting device.
3.2 Other requirements
(1) See User’s Manual “Dosimeter Setting Device” for information on parameter writing and data
reading via the device and a PC.
(2) If multiple dosimeters are used, dosimeter rack (*Option) is recommended. See Outline
Drawing “Dosimeter Rack” for information on the rack for storage dosimeters.
(3) Try to turn OFF & ON the dosimeter if you encounter technical problems. See the
“Troubleshooting Table” if not recovered.
(4) The dosimeter NRF31 cannot be reset by inserting the plug pin (*Option) if the reset-mode
setting of dosimeter is “OFF”. In this case, please reset the Dosimeter through the Dosimeter
Setting Device.

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4. Descriptions of Parts and Functions
4.1
4.14.1
4.1 Part names
4. Battery cap
9. Communication port
6. Point of
Calibration
1. Buzzer
8. Power ON/OFF Jack
5. Mode switch
7. Clip
2. LED (RED)
3. LCD
Top view
Bottom view
Front view Side view Rear view
10. Plug pin
(Option)
15mm
11. Label

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Functions
1. Buzzer: Sounds the alarm, buzzer sound check, low battery level.
2. LED: Red type Light Emitting Diode.
3. LCD: Liquid Crystal Display Indicator. Displays the dose, set dose value, operating time, etc.
and can read directly as 1cm dose and 0.07cm dose (unit: Sv or rem)
4. Battery Cap: Seals the battery compartment.
5. Mode Switch: Select desired display mode with this switch-- Accumulated Dose (mSv or mrem)
or Dose Rate (mSv/h or mrem/h)
6. Point of Calibration: Shows location of calibration point. (Sensor position)
7. Clip: To fix the dosimeter on the pocket or on the band.
8. Power on/off Jack: Switches power On and Off without and with a plug pin.
After 10 second from insert the plug-pin to the dosimeter, power turn off.
9. Communication Port (IR): The communication port with the setting device of an exclusive use.
10. Plug pin: For power on or off of the dosimeter. If some or many dosimeter are used, dosimeter
rack is recommended for storage.
11. Label: Type number, Serial number and the date of Manufacture are mentioned.
12. Maximum dose rate during use is transmitted to a dosimeter reader or a dosimeter setting
device.
13. Stores maximum 600 records of trend data and maximum 500 records of access data.

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4.2
4.24.2
4.2 Display function
LCD Indications
Normal mode
Alarm mode
Alarm Indicators
Accumulation time mode : Operating Time
Decreasing time mode : Remaining Time
Accumulated Dose or Dose Rate
Dose Type
Accumulated Dose or Dose Rate
Unit of Accumulated Dose
Or Dose Rate
Unit of accumulated Dose
or Dose Rate
Dose Type
Accumulation time mode : Operating Time
Decreasing time mode : Remaining Time

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4.3 Buzzer function
4.3.1 Audible signal
Audible signals sound under the following circumstances:
Signal beep Starts when: Beep pattern
ON/OFF The dosimeter is turned on.
The dosimeter is turned off. No sound
Contact to external
device
The dosimeter is set at the setting device or
a rack.
No sound
Data transmission Successful completion of data transmission No sound
Setting value In the dosimeter are changed
Using a setting device.
Data transmission failed No sound
Buzzer test Buzzer test
(See Sec.6.2 During use)
Beep
30msec
Beep
0.5 sec
Beep
0.5 sec
Beep
5sec

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4.3.2 Audible alarms
Alarm activations and beep patterns are as follows:
Alarm activation Alarm cause Beep pattern
Preset
accumulated
dose threshold is
reached
Accumulated dose has reached
the preset dose threshold.
(Pre-ALarm)
Alarm sound generates 50-
ms beeps at intervals
of 150 ms for 3 times in one second.*1
This repeats until exit operation by turning the
power off or communicating with external devices
*2
Note: In case of pre-alarm, LED
dose not light
on/blink.
Accumulated dose has reached
the preset dose threshold.
(ALarm)
Operating time
Or remaining time
Dose type
Accumulated dose
or dose rate
(blink)
Alarm Typ
e (blink)
Operating time
Or remaining time
Dose type
Accumulated dose
or dose rate
(blink)
Alarm Type (blink)
LED (blink)
●
50ms
150ms 550ms
50ms
50ms
150ms
1sec

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Preset dose rate
threshold is
reached
Dose rate has reached the
preset dose threshold.
(Pre-ALarm)
Alarm sound generates 150-
ms beeps at intervals
of 50 ms for 3 times in one second.*1
This repeats
until exit operation by turning the
power off, decreasing to 50 % of pre
set dose rate,
or communicating with external devices *2
Note: In case of pre-alarm, LED
dose not light
on/blink.
Dose rate has reached the
preset dose threshold.
(ALarm)
*1 If the preset dose and dose rate thresholds are simultaneously reached, the alarm sound
pattern is switched and repeated at intervals of one second.
*2 If the mode-switch is pressed in 3 second during preset alarm duration, the buzzer and LED
are inactivated. (This Alarm-Stop-Function can switch ON and OFF using a setting device.
Default setting is ON.)
Attention
If you press and hold the button until the audible/LCD alarm stops, any other
alarm is not available except for dose rate alarm.
As for accumulated dose alarm in this case, audible alarm does not activate
and only “AL” and “OVER” are blinking.
* One-second interval alarm sound does not activate in this case.
Operating time
Or remaining time
Dose type
Accumulated dose
or dose rate
(blink)
Alarm Type (blink)
150ms
50ms 450ms
150ms
150ms
1sec
50ms
Operating time
Or remaining time
Dose type
Accumulated dose
or dose rate
(blink)
Alarm Type (blink
)
LED (blink)
●

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Alarm activation
Alarm cause Beep pattern
Low battery level
When the battery voltage
became lower than 2.2V.
If this alarm and one of the above-mentioned
alarms activate simultaneously, the alarm sound
for low battery voltage activates first. The low
battery voltage alarm sounds 3 times with 2
seconds interval.
LED is NOT activated.
Exceed the
Operating time
Accumulated time
When the operating time
reaches the preset time
(In case of the setting is 9:30 )
The alarm begins with a 1 min-long beep, followed
by a 1 sec mute. After that, a 1 sec beep and a 1
sec mute are repeated. All beeps go on for preset
alarm duration. *2
LED is activated in 1 sec. interval.
Decrease time
When the remaining-time
reaches to zero.
Dose type
Operating time
Or remaining time
Accumulated dose
or dose rate
(blink)
Alarm Type (blink)
2sec
2sec 2sec
2sec
2sec
LED（blink）
●
Alarm Type
（blink
）
Operating time (blink)
Accumulated dose
or dose rate
LED（blink）
●
Remaining time (blink)
Accumulated dose
or dose rate
Alarm Type
（blink
）
preset alarm duration

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Detector function
error
E :06” will start blinking if an
error occurred with detection
circuit (e.g. an open circuit or
short –circuit with condensing).
The alarm begins with a 1 min-long beep, followed
by a 1 sec mute. After that, a 1 sec beep and a 1
sec mute are repeated. All beeps go on for
preset alarm duration. *2
LED is activated in 1 sec. interval.
*2 If the mode-switch is pressed in 3 second during preset alarm duration, the buzzer and LED
are inactivated. (This Alarm-Stop-Function can switch ON and OFF using a setting device.
Default setting is ON.)
Attention
If you press and hold the button until the audible/LCD alarm stops, Operating
time alarm activates without audible alarm.
* One-second interval alarm sound does not activate in this case.
Alarm Type (blink)
LED（blink）
●
preset alarm duration

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Alarm activation
Alarm cause Beep pattern
Overflow Accumulate dose reaches a
10Sv or
Dose rate reaches a 10Sv/h.
・Accumulate dose and dose rate (common)
The alarm begins with a 1 min-
long beep, followed
by a 1 sec mute. After that, a 1 sec
beep and a 1
sec mute are repeated. All beeps go on for
preset alarm duration. *3
LED is activated in 1 sec. interval.
*3 If the mode-switch is pressed in 3 second during preset alarm duration, the buzzer and LED
are inactivated. (This Alarm-Stop-Function can switch ON and OFF using a setting device.
Default setting is ON.)
Attention
If you press and hold the button until the audible/LCD alarm stops and then
dose rate alarm occurs, audible/LCD alarm for dose rate activates only when
the dose rate exceeds 10Sv/h.
As for accumulated dose alarm in this case, audible alarm does not activate
and only “AL” and “OVER” are blinking.
* One-second interval alarm sound does not activate in this case.
preset alarm duration
Alarm Type (blink)
LED（blink）
●
Al
arm Type (blink)

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5. Battery Replacement
5.1 Battery replacement
Follow these steps to replace the battery :
(1) Insert the plug pin (*Option) to
turn the dosimeter off.
(2) Unscrew the battery cap using a coin.
(3) Replace the battery.
Insert a new battery in the compartment correctly.
(4) Close the battery cap using a coin till the
O-ring is disappeared.
An O-ring is consumables, please change the O-ring every 2 years or the when of battery
replacement (recommend). The information of the O-ring purchase, please contact our agency.
Attention
1. When replacing battery, make sure to turn off the dosimeter
by inserting the
Plug pin.
2. During replacement, align the battery polarity correctly.
3. Use only CR123A battery in 3.0 V. *4
*4 The battery voltage is checked on electrodes of CR123A by using a ordinary voltmeter.
Becase of a load resistance in the dosimeter, in some cases, the measured voltage is higher
than the voltage during the operation.
Battery
(CR123A)
Plug pin
(Option)
Battery
cap
+
-

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5.2 Attaching and removing a clip
Follow these steps to replace the battery;
・Removing a clip
Pull up a clip as shown fig.2 with pushing the hook arrow pointing toward as shown fig.1
・Attaching a clip
Attach the circled area of a clip as shown below to the rear side of a dosimeter. Make sure to
insert a clip perfectly. If inserting incompletely, a clip comes away and a dosimeter might fall.
Fig.1
Fig.2

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6. Operational Instructions
6.1 When start to use
(1) Unscrew and remove the Plug pin (*Option). Confirm the power is ON (one beep) and LCD.
LCD
Check items Method of confirmation
Audible signal (1 beep) Confirm one beep after removing the plug pin.
Indicated dose value 0 µSv (0.0 mrem) or 0µSv/h (0.0 mrem/h)
Display of operating time Operating time or remaining time
[hour : min] or [hour.]
0 min. to 99 hr 59 min 100 hr to 9999 hr 59 min
LCD 〔Normal display〕
If Hp(10) is 0 µSv (0.0mrem).
Operating time is 2 min.
〔Abnormal display〕
Replace the battery if battery level
is low.
Please entry a new battery (CR123A)
into the dosimeter for the first time use.
(To see Sec. 5.1 battery replacement)

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(2) Select desired display mode with this switch--Accumulated Dose (Sv or rem) or Dose
Rate (Sv/h or rem/h). Display mode may be changed at any time by using the mode
switch.
(3) Clip the dosimeter onto the chest pocket as shown below.
Human Body
Pocket