IMI Rad 100 User manual

2023/05/11 11:42:19
[100372_81375_RAD100 Manual 1.4-2:9:21.02_Cover.pdf]

Operation Manual
Personal Radiation Detector
2023/05/11 11:42:18
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

IMI-International Medcom, Inc.
All rights reserved.
© 2015, 2016, 2017,2018,2019, 2020, 2021
Manual Revision 1.4, February 9, 2021
Thank You for Purchasing this Instrument from IMI
We trust it will provide you with many years of
useful service. Please contact us if we can
answer any questions or provide assistance in
your radiation detection projects.
Please remember to use caution when handling
or working around radiation sources and
radioactive materials.
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

Contents
1 Introduction ..........................................................................1
How the Rad 100 Detects Radiation.......................................1
Precautions............................................................................2
2 Features ................................................................................3
The Display............................................................................4
The Switches .........................................................................5
The Detector .........................................................................6
The Input/Output Ports ..........................................................6
3 Operation..............................................................................7
Units of Measurement ...........................................................7
Starting the Rad 100..............................................................7
Operating in the Dose and Count Rate Modes.......................7
Operating in Total/Timer Mode ..............................................8
Operating Ranges and Response Times................................10
The Utility Menu..................................................................12
Interfacing to an External Device..........................................13
4 Common Procedures ...........................................................14
Establishing the Background Count .....................................14
Environmental Area Monitoring ...........................................15
Checking an Object .............................................................15
5 Maintenance .......................................................................16
Calibration ..........................................................................16
Troubleshooting and Service ................................................19
6 Basics of Radiation and Its Measurement .............................21
Ionizing Radiation................................................................21
Measuring Radiation............................................................23
Radiation Measurement Units..............................................24
Higher Than Normal Readings .............................................24
Appendix: Technical Specifications ...........................................26
Limited Warranty .....................................................................28
2023/05/11 11:42:18
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

Rad 100 1
1 Introduction
The Rad 100 is a health and safety instrument that measures alpha,
beta, gamma, and X-ray radiation. Its applications include:
• Monitoring possible radiation exposure while working with
radionuclides
• Ensuring compliance with regulatory standards
• Checking for leakage from X-ray machines and other sources
• Screening for environmental contamination or environmental sources
of radioactivity
• Connecting to a computer or data logger to record and tabulate your
data
How the Rad 100 Detects Radiation
The Rad 100 uses a Geiger-Mueller tube to detect radiation.
The Geiger tube generates a pulse of electrical current each time
radiation passes through the tube and causes ionization. Each pulse
is electronically detected and registers as a count. The Rad 100
displays the counts in the mode you choose: microsieverts per
hour (µSv/hr), counts(CPM), or total counts. If conventional
units (mR/hr) is preferred you can easily convert units displayed
in the Utility Menu.
The count or dose rate displayed by the Rad 100 updates every 3
seconds and fluctuates due to the random nature of radioactivity. Use
the Total mode feature on the instrument to get a highly accurate,
unfluctuating reading by taking a measuremement for a longer timed
period. For more information, see “Operating in Total/Timer Mode”
in Chapter 3.
2023/05/11 11:42:18
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

2
Rad 100
Precautions
To keep the Rad 100 ingood condition, handle itwith care and
observe the following precautions:
• Do not contaminate the Rad 100 by touching it to radioactive
surfaces or materials.
• Do not leave the Rad 100 in temperatures over 122° F (50° C) or
in direct sunlight for extended periods of time.
• Do not get the Rad 100 wet. Water can damage the circuitry
and the coating of the mica surface of the Geiger tube.
•Do not put the Rad 100 in a microwave oven. It cannot measure
microwaves, and you may damage it or the oven.
• If you expect to not use the Rad 100 for longer than a few months,
remove the battery to avoid damage from battery corrosion.
• Change the battery when the battery indicator appears on
the display.
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

Rad 100
3
2 Features
information on how to use the Rad 100, see Chapter3, “Operation.”
The instrument counts ionizing events and displays the results on
the liquidcrystal display (LCD) (4). You control which unit of
measurement is shown by using the Mode switch.
When the Rad 100 is operating, the red count light (1) flashes
each time a count (an ionizing event) is detected.
1Count
Light
2Cal/Probe
Input Port
3Output Port
4LCD
5Mode
Switch
6On/O/
Audio
Switch
End Panel
7+, –, and
Set Buttons
8Alpha
Window
The Rad 100 measures alpha, beta, gamma, and X-radiation.
This chapter briefly describes the Rad 100's functions. For more
2023/05/11 11:42:18
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

4
Rad 100
The Display
Several indicators on the LCD show information about the mode setting,
the current function, and the battery condition.
• e numeric display (A) shows the current radiation level in the unit
specied by the mode switch setting.
• A small battery (B) appears to the le of the numeric display to indicate
low battery voltage.
•An hourglass (C) appears during a timed count.
•TOTAL (D) appears when the Rad 100 is in Total/Timer mode.
•X1000 (E) appears when the radiation level ishigh. Multiply
reading by 1,000 when this symbol is present.
• AVG (F)appears when the Rad 100 is showing the average reading
for a timed count.
•CAL (G) appears while you are calibrating the Rad 100.
•SET (H) appears when you are setting the Timer,the calibration
factor, or working in the Utility Menu (the numeric display shows the
setting being adjusted instead of the current radiation level).
The current unit of measurement (I)—CPM, CPS, mR/hr, or µSv/hr—is
displayed to the right of the numeric display.
•
MENU (J) appears when you are in the Utility Menu.
RANGE:Full (K) appears when the radiation level goes beyond the
range that can be displayed.
1Count
Light
2Calibration
Input Port
3Output Port
4LCD
5Mode
Switch
6On/Off/
Audio
Switch
End Panel
7+, –, and
Set Buttons
8Alpha
Window
D Total Mode
C Timer
B Low Battery
Indicator
A Numeric
Display
H Timer or
Calibration
Set Mode
I Units of
Measurement
J Menu
K Range Full
E X1000
Mode
G Calibration
Mode
F Average
•
•
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

Rad 100 5
The Switches
The Rad 100 has two switches on the front and three buttons on the
end panel. Each switch has three settings, which are described below.
Mode Switch (5)
Dose Rate. e numeric display shows the current radiation level
in the selected unit of measurement. In SI units it shows the current
radiation level in microsieverts per hour, from .000 to 1100. In con-
ventional units, it shows milliroentgens per hour from .000 to 110.
Count Rate. The display shows the current radiation level in
counts per minute from 0 to 350,000 . When X1000 is shown,
multiply the numeric reading by 1,000 to get the complete reading.
Total/Timer. e display shows the accumulated total of counts
starting when the switch is turned to this position, from 0 to
9,999,000. When X1000 is shown, multiply the numeric reading
by 1,000 to get the complete reading.
On/Off/Audio Switch (6)
Audio. The Rad 100 is on, and it makes a clicking sound for
each radiation event detected.
On. The Rad 100 is operating, but audio is off.
Off. The Rad 100 is not operating.
+, –, and SET Buttons (7)
These buttons are used for setting the timer. Theyare also used
for calibration and for using the Utility Menu. For more
information, see “Taking a Timed Count,”“The Utility Menu” in
Chapter 3 and “Calibration” in Chapter 5.
2023/05/11 11:42:18
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

6
Rad 100
The Detector
The Rad 100 uses a Geiger tube to detect radiation. Alpha radiation
does not penetrate most solid materials, so this Geiger tube has a thin
disk of mica, which alpha radiation can penetrate, on its end. The
screened opening at the top of the Rad 100 is called the alpha window
(8). It allows alpha and low-energy beta and gamma radiation to
penetrate the mica end of the tube.
CAUTION: The mica end surface of the Geiger tube can be
broken by direct impact. Be careful not to let anything
penetrate the screen.
The Input/Output Ports
There are two ports on the left side of the Rad 100.
The cal/probe input port (2) is used for calibrating electronically using a
pulse generator or an external IMI probe.For more information, see
“Calibrating Electronically” in Chapter 5.
The output port (3)below the calibration input port allows you to
interface the Rad 100 to GeigerLink™, a USB interface for collecting,
displaying and sharing radiation data, the Mineralab Radiation
Network and GeigerGraph USB cable and software, and other data
loggers and systems . This can also be used to connect to external
pulse counters, earphones, or other devicesusing a 3.5 mm stereo
plug. For more information, see “Interfacing to an External Device”
in Chapter 3.
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

Rad 100 7
3 Operation
The guidelines in this chapter describe how to use the Rad 100.
Units of Measurement
The Rad 100 is designed both for users of SI units (microsieverts per
hour and counts perminute) and for users of conventional units
(milliroentgens per hour and counts per minute). The default is
microsieverts per hour and counts per minute. To switch between units
of measurement, use the Utility Menu. See “The Utility Menu” in this
chapter.
Starting the Rad 100
Each instrument is delivered with a high quality alkaline battery
installed in the battery compartment.
Note: On 9 volt models, when replacing the battery, place the battery
wires along the side of the battery and not under it.
To start the Rad 100, set the top switch to the mode you want, and set
the bottom switch to On or Audio.The Rad 100 then does a brief
system check, displaying all the indicators and numbers.
After the system check, the radiation level is displayed in the
selected mode. Ninety seconds after you start the Rad 100, ashort
beep indicates that enough information has been collected to ensure
statis tical validity.
When using the Rad 100, always be sure there is no obstruction be tween
the detector window and the source you are surveying or monitoring .
Operating in the Dose and Count Rate Modes
When the mode switch is set t o Dose Rate or Count Rate, the numeric
display is updated every three seconds. At low count rates, changes in
the radiation level displayed can take up to 90 seconds to stabilize. See
“Operating Ranges and Response Times” in this chapter for more
information.
Count Rate (CPM) and timed total counts are the most direct
methods of measurement; Dose Rate (µSv/hr or mR/hr) measurements
2023/05/11 11:42:18
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

8
Rad 100
are calculated using a conversion factor optimized for Cesium-137, so this
mode is less accurate for other radionuclides unless you have calibrated
the instrument for a specific radionuclide using an appropriate source.
It is more appropriate to measure alpha and beta activity using Count
Rate rather than using Dose Rate. Conversion for alpha and beta
emitters is calculated differently, and the Rad 100’s Dose Rate reading
may not be accurate.
The most immediate indicators of the radiation level are the LCD and
the audio beep. It takes three seconds before an increase is shown on
the numeric display in Dose Rate mode.
Operating in Total/Timer Mode
When the mode switch is set to Total/Timer, the Rad 100 starts totaling
the counts it registers, and the numeric display is updated every second.
Taking a Timed Count
A timed total count is useful for determining the average counts per minute
over a period of time. The number of counts detected by the Rad 100
varies from minute to minute due to the random nature of radioactivity.
When a count is taken over a longer period, the average count per minute
is more accurate, and any small increase is more significant.
Taking an average allows you to detect low-level contamination or dif-
ferences in background radiation due to altitude or soil mineral content,
and can be useful for educational purposes. For example, if one 10-minute
average is one count higher than another 10-minute average, the increase
may be due to normal variation. But over 12 hours, a one count increase
over the 12-hour background average is statistically signicant.
The Rad 100 can give you a total count for a timed period of from
one minute to 40 hours. Follow these steps:
1.
With the Rad 100 operating, set the Mode switch t o Total/Timer.
e display shows TOTAL.
2. Press the Set button twice in quick succession. e display shows SET,
the hourglass, and the most recent timing period used. e rst time
you use the timer, the setting is 24:00, which means 24 hours.
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

Rad 100 9
3. Use the + and – buttons to set the timing period. e timed period can be
for 1 to 10 minutes in one-minute increments, for 10 minutes to 2 hours
in ten-minute increments, or for 2 to 40 hours in one-hour increments.
4.
Press the Set button again to start the timed count. The Rad 100
beeps three times and starts counting. e hourglass indicator ashes
during the timed period.
During the counting period, if you want to see how much time re-
mains, press and hold down the Set button. e display counts down
in hours and minutes to zero. For example, if the display says 00:21,
21 minutes remain.
5. At the end of the timed period, the Rad 100 beeps three times,
and repeats the beeping several times. e number displayed is the
total count.
6. To display the average count and dose rates for the timed period, press
and hold the Set button. e display alternates between the average
count rate and the average dose rate every 3 seconds, and shows AVG
above the numeric display.
7. Press the Set button twice to return to normal operation.
Aer you start a timed count, the timer mode is active in the background
even when the Mode switch is set to Dose Rate or Count Rate. For
example, during and aer the timed period, you can switch back and
forth between Total/Timer and Dose Rate; when the timed period is
over, the total is displayed whenever you switch back to Total/Timer.
e hourglass indicator is shown on the display in any mode setting; it
is blinking while the timer is totaling counts.
Taking a Total Count
e timer can take timed counts of up to 40 hours. In certain situations,
you may want to take a total count without the timer; for example, taking
a count for longer than 40 hours. Follow these steps:
1. Place the Rad 100 in the location where you plan to take the count.
2. Note the time.
3. Immediately when you note the time, set the mode switch to Total/
Timer.
2023/05/11 11:42:18
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

10
Rad 100
4. At the end of the time period, note the time and the total on the
numeric display.
5. Subtract the starting time from the ending time to determine the
exact number of minutes in the timing period.
6. To get the average count, divide the total reading by the number of
minutes in the timing period.
Operating Ranges and Response Times
In some modes, when radiation levels increase over certain preset levels,
the Rad 100 uses autoranging, automatically changing to the X1000
scale. Whenever X1000 is shown above the numeric display, multiply
the displayed reading by 1000 to determine the radiation level. The
following table shows the radiation levels the Rad 100 measures in each
mode and how they are displayed.
Mode Regular Range x1000 Range
μSv/hr .000–1100 N/A
mR/hr .000–110 N/A
CPM 0–9999 10,000–350,000
(displayed as 10.00–350 with x1000 indicator)
CPS 0–3500 N/A
Total/Timer 0–9999 10,000–9,999,000
(displayed as 10.00–9999 with x1000 indicator)
Maximum Level
When the maximum level for the current mode is reached, the Rad 100
beeps for three seconds, pauses for three seconds, and repeats that pattern.
The display shows RANGE:Full. The beeping pattern and the Range
Full icon continue until the level decreases or the Rad 100 is turned off.
Display Update and Response Time
In Total/Timer mode, the numeric display is updated each second. In the dose
and count rate modes, the numeric display is updated every three seconds.
When the radiation level is less than 1,000 CPM, the reading in the dose
and count rate modes is based on the radiation detected in the immediately
previous 90 seconds. In order to give a quicker response to changes, when
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

Rad 100 11
the radiation level exceeds 1,000 CPM in any 90-second period, the reading
is based on the previous 6 seconds, and when it exceeds 6,000 CPM, the
reading is based on the previous 3 seconds, as shown in the following
table. This automatic change in response time is called auto-averaging.
Radiation Level Basis for Reading
(after first 90 seconds)
<1000 CPM or <8.3 μSv/hr or <.83 mR/
hr (<17 CPS) 90 seconds
1000–6000 CPM or 8.3–50 μSv/hr or .83–5 mR/
hr (17–100 CPS) 6 seconds
>6000 CPM or >50 μSv/hr or >5 mR/
hr (>100 CPS) 3 seconds
Note: You can set the response time to 3 seconds at all radiation levels
using the Utility Menu; see “e Utility Menu” in this chapter.
2023/05/11 11:42:18
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

12
Rad 100
The Utility Menu
The Utility Menu allows you to change the default settings for several
operating parameters. When a setting is changed, it remains in effect
after the Rad 100 is turned off and until you change it again.
• To activate the Utility Menu, hold down the +button on the end panel
while you turn on the Rad 100. The word MENU appears at the
bottom right of the numeric display, and the display shows 1for menu
option 1.
• To scroll through the menu, push the plus (+) and minus (–) buttons.
• To select an option, push the Set button.
• Once an option is selected, use the + and – buttons to scroll among
the settings.
• Aer you choose the setting you want, select option 0 to exit the Utility
Menu.
e options are:
0Resume normal operation.
1Auto Averaging. on (the default) selects Auto averaging; oFF selects
3-second (fast response) averaging at all radiation levels.
2Units of measurement. CPM µSv/hr (the default) selects counts per
minute and microsieverts per hour; CPM mR/hr selects counts
per minute and milliroentgens per hour; CPS µSv/hr selects counts per
second and microsieverts per hour.
3Cal 100 Reset. Automatically resets the calibration factor to 100.
4, 5, 6 Reserved for future options.
7Cal Factor Adjust. Displays the current calibration factor, which
you can then adjust to the new factor you want. See “Calibration” in
Chapter 5.
8Factory Default Reset. Automatically resets items 1, 2, and 3 to Auto
averaging, CPM and µSv/hr, anda Calibration Factor of 100 .
9Revision #. Displays the firmware version number.
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

Rad 100 13
Interfacing to an External Device
The lower output jack on the left side of the Rad 100 is a dual
min iature jack that provides an audible click for use with a headset, or
a data output that can beused to drive external devices. You can use it
to record the counts on a computer, data logger, or accumulating
counter. Use a 3.5 mm stereo plug to access this port.
The outputs provide a positive pulse (6 to 9 volt peak, 1 kOhm
impedance) each time the Geiger tube detects a count. At the ring of
the plug, the pulse is approximately 1millisecond wide and is
well suited for headsets, chart recorders and inputs to audio
amplifiers.The tip signal is approximately 80 microseconds
wide and is suitable for high-speed counting and RS-232 and
USB adaptors.
GeigerLink and other adapters for USB or serial ports and
accompanying software is available from IMI, Mineralab and others.
For 4.5V logic compatible output, externally connect a1kOhm
resistor from the output to ground. A standard stereo or mono
headphone can be plugged directly into the jack. For some types of
headphones, external volume control may be needed.
GeigerLink by IMI, GeigerGraph and Radiation Network by
Mineralab and other third party data collection and sharing
solutions are available for use with the Rad 100. Visit IMI at http://
medcom.com for more information.
2023/05/11 11:42:18
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]

14
Rad 100
4 Common Procedures
e following sections give guidelines for several commonly-used pro -
cedures. With any procedure, the user must determine the suitability
of the instrument or procedure for that application.
Establishing the Background Count
Normal background radiation levels vary at different locations, according
to altitude and other factors, such as types of minerals in the ground.
Levels vary at different distances from the ground, and may differ even
in different areas of the same room. To accurately interpret the readings
you get on the Rad 100, it is a good idea to establish the normal back -
ground radiation level for each area you plan to monitor. You can do this
with a timed count. Use the following steps to get a ten-minute average.
1.
With the Rad 100 operating, set the Mode switch t o Total/Timer.
2. Press the Set button twice in quick succession.
3. e display shows the current timer period and SET. Unless you have
previously changed it, the display reads 24:00, which means 24 hours.
Use the + and – buttons to change the timer period to ten minutes.
4. Press the Set button on the end panel. The Rad 100 beeps three
times and starts counting.
During the timed count, if you want to see how much of the ten
minutes remains, hold down the Set button. e display counts down
from ten minutes to zero. For example, if the display says 00:03, seven
minutes have elapsed and three minutes remain.
5. At the end of the ten minutes, the Rad 100 beeps three times,
and repeats the beeping several times. Note the total reading.
6. To nd the average count and dose rates, hold down the Set button.
A ten-minute average is moderately accurate. You can repeat it several
times to nd how close the averages are. To establish a more accurate
average, take a one-hour timed count. In some locations, you may want
to take a longer count (for example, 12 hours). If you need to
determine whether there is contamination, take averages in several
locations and compare the averages.
[100372_RAD100 Manual_Inside Pages, Modified May 8 2023.pdf]