Tenmars TM-91N User manual

RADIATION METER
TM-91N
HB2TM91N0001
TENMARS ELECTRONICS CO., LTD

EN-2
CONTENTS
1. introduction .............................................3
2. Safety Precaution....................................4
3. Specification............................................6
4. Identifying parts.......................................7
5. Operation Procedure ..............................7
6. Battery Replacement ............................11
7. NOTICE ............................................... 12
8. Interaction of radiation with matter....... 13
9. End of life............................................. 15

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1. INTRODUCTION
This manual contains valuable information about
the nature of ionizing radiation that should be
understood by the user so that accurate
measurements can be made. Information on the
care of your Geiger counter is also included. If the
following instructions are followed, your radiation
monitor will give you many years of reliable
service.
The radiation meters are very sensitive pieces of
equipment. Although housed in a high –impact
case, the Geiger-Mueller tube that senses
radiation is fragile. If the unit is dropped, the G-M
tube may break. Exposure of the unit above 40℃
(100℉) may also cause the G-M tube to stop
functioning.
The electronic circuitry is sensitive to high
humidity(over 90%RH).

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2. SAFETY PRECAUTION
CAUTION
Take extremely care for the following
conditions while measuring
CAUTION
Please put the radiation monitor into a
plastic zipper bag before operating it
in a radiative contaminated area to
avoid radiative dust falling on the
monitor’s surface
Do not operate the meter under the
environment with explosive gas (material),
combustible gas (material) steam or filled
with dust.

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Do NOT put the unit in a very hot place(such
as a car, glove box, especially during
summer).
Do NOT allow the unit to get wet. However,
if it cannot be avoided, clean it with a towel
and allow unit to air-dry for several days(do
not place in an oven or microwave).
Do NOT back cover to bemoved only by
qualified service technician.internal
operating voltage is over 400VDC.
In order to avoid reading incorrect data,
please replace the battery immediately
when the symbol “ ” appears on the
LCD.
In order to avoid the damage caused by
contamination or static electricity, do not
touch the circuit board before you take any
adequate action.
Operating Environment: Indoors use. This
instrument has been designed for being
used in an environment of pollution degree 2.
Operation Altitude: Up to 2000M.
Operating Temperature & Humidity: 5℃~40
℃, 0%~ 80%RH.
Storage Temperature & Humidity: -10℃~
50℃, 0%~ 70%RH.

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3. SPECIFICATI
Display : 3 1/2 digits LCD with maximum
reading 1999.
Sampling :
10 second/ times(<20µSv/h).
1 second/ times(>20µSv/h)
unit selection :
µSv/h,µRem/h or mRem/h .
Measurement Range :
0.50µSv/h~1400µSv/h or
50µRem/h~140.0mRem/h
Alarm function : alarm set default
0.50µSv/h,can set 0~19.99µSv/h
Auto Power Off function : set time default
30 min, can set 0~60min;0 min disable auto
power off.
Low battery indication “”.
Power : 9V battery、NEDA 1604、IEC
6F22 or JIS 006P
Battery Life : About 50 hours(Alkaline
battery).
Over load display “OL”
Accuracy : ±20% (Cesium-137)
Energy dependency : 30KeV to 1.3 Mev
Weight : 220g.
Size : 143x74 x34 mm（LxWxH）

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4. IDENTIFYING PARTS
1. LCD display.
2. Setup function button.
3. Units and setup function down button.
4. Power ON / OFF button.
5. Unit and setup function up button.
5. OPERATION PROCEDURE
Press : All segment of the LCD
indicator is illuminated together with
BEEP signal for about two second. We
are now ready for testing.
Intermittent BEEP signal follows during
detection,auxliary radiation strength
sensing. The higher the repetition rate.

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Press : Select test unit µSv/h
Press : Select test unit µRem/h.
Press r more than 1 second to enter
setting alarm mode , the LCD display
“ALR”first the press the setting value, press
the ””or ””change the digit
value, Alarm the initial value 0.5µSv/h.
Press more than 1 second to enter
setting auto power-off(APO), the LCD
display “APO”first the setting value, press
the ””or ””change the digit
value, Auto power-off setting, the initial
value is 30 minutes.
Press more than 1 second to enter
setting buzzer ON or OFF ,the setting
default is always “ON”, the LCD display
“ON”or ”OFF”,press””or ””
change the ON or OFF.
Press more than 1 second to enter
setting calibration facfor, the LCD display
“CF”first the setting value,
press ””or ””change the digit
value, Calibration facfor the initial value
1.00.

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Press more than 1 second to exit
and return to measurment mode.
The Geiger-mueller tube is located behind
the slots in the upper edge of the case. The
surface of the tube is very thin .This allows
beta radiation to penetrate and to be
detected with greater efficiency. (Beta rays
and other types of radiation will be
discussed in the next section). This thin
surface is fragile and poking sharp objects
through the slots will damage the tube.
Your Geiger Counter is designed to be
sensitive to:
1. Gamma radiation (which includes X-rays).
2. Beta radiation.
Gamma radiation and X-rays can
penetrate the plastic case with
comparative ease.
Beta radiation can most efficently enter
the case through the slots. Although Beta
radiation is easily detected. It is difficult to
measure accurately. Therefore, when a
radioactive object is being searched for
Beta radiation, the open slots in the case
should be positioned in such a way that

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they are exposed to the object(see Figure
1).
(Figure 1)
If the unit shows a significantly higher
reading with increasing beep sound volume
in this position, you can be certain that the
object is emitting Beta radiation.
Now position the unit as shown in Figure 2.
In this position, where radiation cannot pass
directly through the slots (Beta radiation
travels in straight lines for the most part )
only gamma and X-ray radiation from the
object wil be detected.