Graetz GammaTwin User manual

Operaon Manual
for the
GRAETZ Dose Rate Meter
GammaTwin
Release: October 2017, Soware Version 1.4/1.5 Part Number 5641 9877
23.51
10.02

Soware Version 1.4/1.5
GammaTwinOperaon Manual
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GammaTwin
Soware Version 1.4/1.5
Operaon Manual
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1. Inhalt
1. Preface .................................................................... 5
2. Introducon ............................................................ 6
2.1 Possibilies of use ............................................... 6
2.2 Control and display ele men ts ............................. 8
3. Pung into operaon ............................................. 9
3.1 Before use ........................................................... 9
3.2 Switching ON/OFF ............................................... 9
3.3 Indicaon .......................................................... 10
3.3.1 „Twin“-indicaon .................................... 11
3.3.2 Dose indicaon ........................................ 12
3.3.3 Dose rate indicaon ................................ 13
3.4 Single-pulse indicaon and funconal control
signal ............................................................... 14
3.5 Display illuminaon .......................................... 14
3.6 Acknowledgement of acousc alarms .............. 15
4. Alarm messages .................................................... 16
4.1 Dose and dose rate alarm ................................. 16
4.2 Baery alarm .................................................... 17
5. The menu .............................................................. 17
5.1 Acvate the menu ............................................. 17
5.1.1 Menu operaon ....................................... 17
5.1.2 Dose and dose rate alarm thresholds ...... 18
5.1.3 Acouscs .................................................. 18
5.1.4 Dose ......................................................... 19

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5.1.5 Seng basic display ................................. 19
6. Possible defects .................................................... 20
6.1 Error messages .................................................. 20
6.2 Baeries discharged ......................................... 20
6.3 Other error messages ....................................... 21
6.4 Switching on ...................................................... 21
7. Disposal of disused devices .................................. 24
8. Technical data ....................................................... 25
9. Repair and maintenance ....................................... 31

GammaTwin
Soware Version 1.4/1.5
Operaon Manual
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1. Preface
To guarantee a faultless handling of the dose
rate meter GRAETZ GammaTwin, please read
the following operaon manual carefully.
Aer having inserted the baeries and swit-
ched on the instrument, the user can immedi-
ately start measurement of ionizing radiaon.
Please note: When applied in pulsed radiaon
elds the measuring results of the GammaTwin
are not reliable as measurements are based on
Geiger-Müller-tube technology. Thus, it is not
suitable for pulsed X-rays.

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2. Introduction
2.1 Possibilies of use
The GammaTwin is a very robust, reliable
and easy to operate PTB-approved dose rate
meter. It is used for the safe determinaon of
the current local dose rate as well as the accu-
mulated dose of photon radiaon. The measu-
rands are the ambient dose equivalent rate
Ḣ*(10) as well as the ambient dose equivalent
H*(10).
The ambient dose equivalent rate Ḣ*(10) as
well as the ambient dose equivalent H*(10) are
PTB-approved.

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The GammaTwin oers the following features:
9acvatable acousc single-pulse indica-
on
9acvatable acousc funcon control
94 dose and dose rate alarm thresholds
each
9alternavely either simultaneous or
separate indicaon of dose or dose rate
9automac and connuous storage of
the dose
9simple menu navigaon
9illuminable display
9measured peak value of dose rate since
switching on the GammaTwin

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2.2 Control and display elements
1 privileged direcon of irradiaon
and posion of reference point in
12 mm depth
2 LC- display
3 buon for ON/OFF and background
illuminaon
4 buon for menu and acousc
single-pulse indicaon
5 screw for baery compartment
6 sound source
1
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3. Putting into operation
3.1 Before use
Before starng the instrument the user has to
ensure that the GammaTwin is not damaged
and is correctly equipped with two baeries of
the type AAA 1,5 V (polarity acc. to the corres-
ponding label). For perfect contacng, please
ghten the screw of the baery compartment
by means of a coin. Remove the protecve foil
from the display.
3.2 Switching ON/OFF
The GammaTwin is turned on by briey press-
ing the -buon. The instrument passes a self-
test, in which the user may control the alarm
signal and all segments of the display. Further-
more, the serial number, the soware version
as well as the check sum of the soware are
displayed. The PTB-approved version of the
rmware and the corresponding check sum are
indicated in chapter 8 (technical data). If there
is no error, the GammaTwin is directly starng
operaon.

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When pressing the buon for more than 2
seconds during operaon, the instrument is
switched o and the following safety check will
appear:
All acve sengs and the acousc single pulse
indicaon will be stored. An acvated acousc
alarm or acousc error messages have to be
acknowledged before switching o the Gam-
maTwin.
3.3 Indicaon
The user can either select the separate indica-
on of dose and dose rate or the simultaneous
indicaon („Twin“-indicaon). The dual „Twin“-
indicaon is preset by GRAETZ.

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3.3.1 „Twin“-indicaon
Displayed elements:
• bargraph (analog/logarithmic
indicaon of the dose rate)
• dose rate
• dose
• acvated dose rate alarm threshold
(DRA)
• acvated dose alarm threshold (DA)
• funcon control
(ashing once per second)
• loudspeaker symbol (when acousc
single-pulse indicaon is acvated)
• baery symbol

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3.3.2 Dose indicaon
Displayed elements:
• bargraph (shows the dose in per-
centages of the acvated alarm
threshold)
• dose
• acve alarm thresholds (DRA/DA – as
shown above)
• funcon control (ashing once per
second)
• loudspeaker symbol (when acousc
single-pulse indicaon is acvated)
• baery symbol

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Operaon Manual
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3.3.3 Dose rate indicaon
Displayed elements:
• bargraph (analog/logarithmic
indicaon of the dose rate)
• dose rate
• measured peak value since switching
on the GammaTwin
• acve alarm thresholds (DRA/DA – as
shown above)
• funcon control (ashing once per
second)
• loudspeaker symbol (when acousc
single-pulse indicaon is acvated)
• baery symbol

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3.4 Single-pulse indicaon and funconal
control signal
By briey pressing the buon the acousc
single-pulse indicaon is acvated respecvely
deacvated. When acvated, the loudspeaker
symbol is displayed and each GM-tube pulse
triggers a brief sound.
This seng can be changed in the menu
„Acouscs“, where it is possible to reduce the
pulse rate of the background radiaon in such
a way that only the tweneth GM-tube pulse
will trigger a sound. Addionally, a funconal
control signal sounds approx. every two min-
utes, indicang the GammaTwin is correctly
working. This signal can be combined with both
acousc single-pulse indicaons.
3.5 Display illuminaon
During operaon the display illuminaon can
be turned on by pressing the buon .
By briey pressing the key once again, the illu-
minaon is turned o. For saving the baeries
energy, the illuminaon automacally turns o
aer approx. 10 seconds.

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During menu operaon it is not possible to
switch illuminaon on or o, because then the
corresponding buon has another funcon.
Thus, the illuminaon has to be acvated be-
fore menu operaon. Illuminaon will switch
o when leaving the menu.
3.6 Acknowledgement of acousc alarms
Triggered alarms or error messages can be ac-
knowledged by briey pressing the buon .
Then, the acousc alarm signal is switched o,
but the opcal warning remains sll acve.
In case of serious errors, the GammaTwin auto-
macally switches o aer acknowledgement
(see chapter 6).

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4. Alarm messages
4.1 Dose and dose rate alarm
When an acvated alarm threshold is exceed-
ed, the display is blinking.
In case of an exceeded dose alarm threshold,
the display switches to the dose indicaon
and in case of an exceeded dose rate alarm
threshold to the dose rate indicaon. If both,
the dose and the dose rate alarm threshold are
exceeded, the „Twin“-indicaon is displayed.
In case of a dose rate alarm short constant
acousc warning signals will be triggered. If the
acousc alarm has been acvated in the menu,
the warning signal sounds every second.
Such an alarm can be acknowledged by means
of the -key. Thus, the acousc alarm is swit-
ched o and the menu returns to the selec-
ted standard display. But, the triggered alarm
threshold is sll blinking.
The acousc alarm will be re-triggered as soon
as the measured value falls below an already
acknowledged dose rate alarm threshold and is
then exceeded again.

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Soware Version 1.4/1.5
Operaon Manual
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4.2 Baery alarm
The GammaTwin regularly checks the charge of
the baeries. The displayed baery symbol in-
dicates the residual capacity. When this signal
starts blinking, the baeries have to be repla-
ced as soon as possible (please also see chapter
6.2).
5. The menu
5.1 Acvate the menu
The GammaTwin’s menu is acvated by press-
ing the buon for at least 2 seconds. If for 30
seconds no key is pressed during menu opera-
on, the instrument automacally returns to
the preset standard display. Sengs changed
within a menu point will be taken over and
stored.
5.1.1 Menu operaon
There are ve dierent menu points the user
can scroll through by means of the -buon.

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5.1.2 Dose and dose rate alarm thresholds
In these both menus the acvated alarm
threshold is marked by a hook. By using the
buon it is possible to scroll through the single
alarm thresholds. With the -buon the inver-
se shown alarm threshold is chosen (black line,
white gures) and acvated. By pressing this
-buon again, the next menu point is selected.
5.1.3 Acouscs
By using the -buon it is possible to scroll
through the lines. With the -buon the inver-
se shown opon can be selected. This selecon
is marked by a hook. By pushing the buon

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in the line „accept“, the seng is taken over
and the GammaTwin changes to the next menu
point.
5.1.4 Dose
In this menu the user can irrevocably clear the
accumulated dose by pressing the buon . By
using the buon it is possible to scroll to the
next menu point without clearing the dose.
5.1.5 Seng basic display
Here, the user sets the indicaon which will ap-
pear when starng the GammaTwin and when
leaving the menu.

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The acvated basic seng is marked by a hook.
By means of the -buon, it is possible to
scroll through the display indicaons. With the
buon the inverse shown line can be selec-
ted and taken over as standard display. For lea-
ving the menu, the buon has to be pressed
again.
6. Possible defects
6.1 Error messages
Each me being switched on, the GammaTwin
passes a self-test. Addionally, all important
funcons are connuously controlled during
operaon. In case of an error, the user will be
informed by a corresponding error message.
6.2 Baeries discharged
If baery voltage falls below 1.8 volt, opera-
on of the GammaTwin cannot be connued.
By pressing the buon the instrument swit-
ches o. Remove and dispose the baeries im-
mediately, even if there are no new baeries
available.