DURRIDGE RAD7 User manual

RAD7 RADON DETECTOR
User Manual
Owner__________________________
Serial #______________
SERVICE RECORD
Date Service
It is recommended that the unit be returned to DURRIDGE Company annually, for recalibration.
DURRIDGE Company Inc.
524 Boston Rd
Billerica, MA 01821
Tel: [phone]
Fax: [phone]
[email protected]
Revision 7.4.0. © 2015 DURRIDGE Company www.durridge.com
1

WARNING
Opening the cover of this instrument is likely to expose dangerous voltages.
Disconnect the instrument from all voltage sources while it is being opened.
Due to battery power, the instrument may still be dangerous.
Using this instrument in a manner not specified by the manufacturer may
impair the protection provided by the instrument.
2

TABLE OF CONTENTS
..................................................................................................INTRODUCTION 10
...........................................................................1. GETTING STARTED: 11
YOUR FIRST DAY WITH THE RAD7 11
.....................................................................................................1.1 Unpacking 11
RAD7 Packing List!11
...........................................................................1.2 General Safety Instructions 12
...............................................................................................................................1.2.1 Air Travel 13
................................................................................................1.3 Taking a Look 13
The RAD7 Professional Electronic Radon Detector!13
................................................................................1.4 Starting a Two-day Test 14
RAD7 Normal Configuration!14
.......................................................................................1.5 Starting a Sniff Test 16
RAD7 SNIFF Configuration!16
.........................................................2. BASICS OF RAD7 OPERATION 18
...................................................................................................2.1 Introduction 18
...........................................................................................................................2.1.1 The Key Pad 18
........................................................................................................................2.1.2 Command List 18
................................................................................................................2.2 Test 18
..............................................................................................................................2.2.1 Test Status 18
.........................................................................................................2.2.1a Quick Save-and-Restart 19
..........................................................................................................2.2.2 Test Start and Test Stop 20
.................................................................................................................................2.2.3 Test Save 20
...............................................................................................................................2.2.4 Test Clear 20
...............................................................................................................................2.2.5 Test Purge 20
.................................................................................................................................2.2.6 Test Lock 21
................................................................................................................................2.2.7 Test Sleep 21
................................................................................................................................2.2.8 Test Print 21
.................................................................................................................................2.2.9 Test Com 21
...............................................................................................................2.3 Data 21
..............................................................................................................................2.3.1 Data Read 21
..............................................................................................................................2.3.2 Data Print 22
...............................................................................................................................2.3.3 Data Com 22
........................................................................................................................2.3.4 Data Summary 23
...............................................................................................................................2.3.5 Data Free 23
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............................................................................................................................2.3.6 Data Delete 23
......................................................................................................................2.3.7 Data Renumber 24
..............................................................................................................................2.3.8 Data Erase 24
.............................................................................................................2.4 Setup 24
........................................................................................................................2.4.1 Setup Protocol 24
Table 2.4.1 Preset protocols!24
.............................................................................................................................2.4.2 Setup Cycle 24
..........................................................................................................................2.4.3 Setup Recycle 25
.............................................................................................................................2.4.4 Setup Mode 25
..........................................................................................................................2.4.5 Setup Thoron 25
............................................................................................................................2.4.6 Setup Pump 26
..............................................................................................................................2.4.7 Setup Tone 26
..........................................................................................................................2.4.8 Setup Format 26
.............................................................................................................................2.4.9 Setup Units 27
.........................................................................................................................2.4.10 Setup Savuser 27
............................................................................................................................2.4.11 Setup Clock 27
..........................................................................................................................2.4.12 Setup Review 28
...........................................................................................................2.5 Special 28
..........................................................................................................................2.5.1 Special Ident 28
........................................................................................................................2.5.2 Special SPrOn 28
........................................................................................................................2.5.3 Special SPrOff 28
......................................................................................................................2.5.4 Special SetBaud 28
.........................................................................................................................2.5.5 Special Status 28
...........................................................................................................................2.5.6 Special Start 28
............................................................................................................................2.5.7 Special Stop 28
....................................................................................................................2.5.8 Special Comspec 29
......................................................................................................................2.5.9 Special ComAll 29
........................................................................................................................2.5.10 Special SPrAll 29
.......................................................................................................................2.5.11 Special S-Load 29
.......................................................................................................................2.5.12 Special Version 29
........................................................................................................................2.5.13 Special Model 29
.........................................................................................................................2.5.14 Special Serial 29
...........................................................................................................................2.5.15 Special Beep 29
........................................................................................................................2.5.16 Special Relays 29
..............................................................................................2.6 Infrared Printer 29
Alpha Energy Spectrum!30
..................................................3. BASICS OF RAD7 TECHNOLOGY: 31
HOW IT WORKS 31
...................................................................................................3.1 Introduction 31
......................................................................................3.2 Radon Decay Chain 31
Radon and Thoron decay chains!32
................................................................................................................3.2.1 Radon-222 (Radon) 33
...............................................................................................................3.2.2 Radon-220 (Thoron) 33
....................................................................................3.3 Continuous Monitors 33
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..........................................................................................................3.4 Sniffers 34
...............................................................................................3.5 Working Level 34
...........................................................................3.6 RAD7 Solid-State Detector 35
................................................................................3.6.1 RAD7 Calibration and Data Correction 35
............................................................................................3.7 RAD7 Spectrum 36
.......................................................................................................3.8 Windows 37
.......................................................................................3.9 Isotope Equilibrium 38
.................................................................................3.10 Modes: Sniff and Auto 39
...................................................................................................3.11 Background 39
.............................................................................3.11.1 Short-lived Radon and Thoron Daughters 39
..............................................................................................................3.11.2 Adsorbed Radon Gas 40
.................................................................................................3.11.4 Long-lived Radon Daughters 40
........................................................3.11.5 Contamination by Radon, or Thoron, Producing Solids 40
.............................................................................................................3.11.6 Other Alpha Emitters 40
.....................................................................................................3.11.7 Beta and Gamma Emitters 41
...................................................................................3.12 Precision & Accuracy 41
.........................................................................................................................3.12.1 Dry operation 41
Table: 3.12 Typical RAD7 precision based on counting statistics only.!41
..............................................................................................................3.12.2 Humidity Correction 42
..................................................................................................3.12.3 Concentration Uncertainties 42
......................................................................................3.13 Spectrum Examples 44
...................................................................................................3.13.1 Operational Radon Spectra 44
.......................................................................................................................3.13.2 Thoron Spectra 45
..............................................................................................................3.13.3 Combination Spectra 46
..............................................................................................................3.13.4 Pathological Spectra 48
...............................................................................4. USING THE RAD7: 50
RADON AND THORON MEASUREMENT IN AIR 50
...................................................................................................4.1 Introduction 50
.................................................................................4.2 Continuous Monitoring 50
............................................................................................................................4.2.1 Preparation 50
...................................................................................................................................4.2.2 Purging 50
..........................................................................................................................4.2.3 Test Location 51
..........................................................................................................................4.2.4 Test Protocol 51
........................................................................................................4.2.5 To Print Or Not To Print 51
.....................................................................................................................4.2.6 Running the Test 52
.................................................................................................4.2.7 Security and Quality Control 52
...................................................................................................................4.2.8 Finishing the Run 52
...............................................................................................................4.2.9 Examining the Data 53
..................................................................................................4.2.10 Very Short Term Monitoring 53
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.........................................................................................................4.3 Sniffing 53
..............................................................................................................................4.3.1 Why Sniff? 53
.................................................................................................4.3.2 Locating Radon Entry Points 54
............................................................................................................................4.3.3 Preparation 54
...................................................................................................................................4.3.4 Purging 54
.....................................................................................................................4.3.5 Running the Test 54
.........................................................................................................4.3.6 Drilled Sampling Points 55
........................................................................................................................4.3.7 Spot Readings 55
..............................................................................................4.4 Grab Sampling 55
...........................................................................................................................4.4.1 Applicability 55
............................................................................................................................4.4.2 Preparation 55
..................................................................................................................................4.4.3 Protocol 56
..................................................................................................................4.4.4 Taking the Sample 56
..................................................................................................................................4.4.5 Analysis 56
....................................................................................4.5 Thoron Measurement 56
..................................................................................................................4.5.1 Thoron and Radon 56
..................................................................................................4.5.2 Thoron Measurement Issues 56
...............................................................................4.5.3 Calculation and Interference Correction 57
................................................................................4.5.4 Avoiding Longer Lived Decay Products 57
........................................................4.5.5 Decay Correction, Flow Rate, and Thoron Calibration 58
.....................................................................................................4.5.6 Calculating Sample Decay 58
...............................................................................4.5.7 Calculating Internal Cell Concentration 58
.........................................................................4.5.8 Internal Cell Thoron Sensitivity Calibration 58
.........................................................................................4.5.9 Setting up a Thoron Measurement 58
..........................................................................................................................4.5.10 Thoron Mode 59
Recommended RAD7 Thoron Configuration!59
..................................................................................4.6 Managing Background 60
......................................................................................4.7 Airflow Rate Limits 60
..........................................................................................................4.7.1 Maximum Airflow Rate 60
...........................................................................................................4.7.2 Minimum Airflow Rate 60
............................................................4.8 Harsh and Hazardous Environments 61
.....................................................................................................................4.8.1 Splashing Water 61
.................................................................................................................4.8.2 Dusty Environment 61
...................................................................................................................4.8.3 Radiation Hazard 61
...........................................................5. USING RAD7 ACCESSORIES: 62
TESTING FOR RADON IN THE GROUND AND WATER 62
...................................................................................................5.1 Introduction 62
..............................................................................................5.2 Radon in Water 62
.......................................................................................................5.2.1 The RAD H2O Accessory 62
The RAD H2O Accessory!62
The RAD AQUA Accessory!62
....................................................................................................5.2.2 The RAD AQUA Accessory 63
..............................................................................................5.2.3 The WATER PROBE Accessory 63
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........................................................................................5.3 Soil Gas Sampling 63
.............................................................................................................................5.3.1 Application 63
...............................................................................................5.3.2 The Soil Gas Probe Accessory 63
...................................................................................................5.3.3 Soil Gas Probe Preparation 63
.....................................................................................................................5.3.4 Running the Test 64
..............................................................................................................5.3.5 Interpreting the Data 64
...............................................................................5.4 Emission Measurements 64
.............................................................................................................................5.4.1 Application 64
......................................................................................................5.4.2 Open Loop Configuration 64
....................................................................................................5.4.3 Closed Loop Configuration 64
.......................................................................................................5.4.4 Very Low Emission Rates 65
.......................................................................................................................5.4.5 Bulk Emissions 65
....................................................................................................................5.4.6 Surface Emission 65
The Bulk Emission Chamber!65
The Surface Emission Chamber!66
.................................................................................5.5 Supporting Accessories 66
................................................................................................................................5.5.1 Overview 66
...............................................................................................................5.5.2 The Range Extender 66
The Range Extender!66
.........................................................................................................................5.5.3 The DRYSTIK 67
The DRYSTIK (Model ADS-3R)!67
......................................................................................6. PC Connectivity 68
................................................................................6.1 PC Connectivity Basics 68
..................................................................................6.1.1 Connecting the RAD7 to the Computer 68
Connecting the RAD7 to a computer using the StarTech USB to Serial Adaptor!69
Connecting the RAD7 to a computer using the KeySpan USB to Serial Adaptor!69
.....................................................................................6.2 CAPTURE Software 70
..........................................................................................................6.2.1 CAPTURE Installation 70
CAPTURE Software running in Windows 7!70
...................................................................................................................6.2.2 Feature Summary 71
......................................................................................................6.2.3 Downloading RAD7 Data 71
..........................................................................................................6.2.4 Graphing and Analysis 71
.................................................................................................6.2.5 Real-Time RAD7 Monitoring 71
...................................................................6.3 RAD7 Communication Protocol 72
...............................................................................................6.3.1 Communication Requirements 72
.......................................................................................................6.3.2 RAD7 Command Format 72
...............................................................................................................6.3.3 Parsing RAD7 Data 72
Table 6.3.3 RAD7 Data Record Content !73
..........................................................................................................6.3.4 Terminal Emulator Tips 74
..............................................................................6.4 Serial Port Specifications 74
.......................................................................................................6.4.1 Communication Protocol 74
Table 6.4.1a Serial Port Pin Assignments!74
Table 6.4.1b Communication Parameters!74
..................................................................................................6.4.2 Extending the RS-232 Range 74
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............................................................................................7. Maintenance 75
.......................................................................7.1 Accessories - Usage and Care 75
................................................................................................................................7.1.1 Desiccant 75
.........................................................................................................7.1.2 Laboratory Drying Unit 75
Table 7.1.2 Laboratory Drying Unit Life !75
..................................................................................................................7.1.3 Small Drying Tube 75
Table 7.1.3 Small Drying Tube Life!75
........................................................................................................7.1.4 Cascading Drying Tubes 76
.....................................................................................................................................7.1.5 Filters 76
.................................................................................................................................7.1.6 Batteries 76
............................................................................7.1.7 Real-time Clock and Non-volatile Memory 77
...............................................................................................................7.1.8 Printer and Adapter 77
...........................................................................................7.2 Operating ranges 77
Table 7.2 RAD7 Operating Ranges!77
........................................................................................7.3 Service and Repair 78
.............................................................................................................................7.3.1 Calibration 78
.....................................................................................................................................7.3.2 Repair 78
.................................................................................................................................7.3.3 Shipping 78
................................................................................................................................7.3.4 Upgrades 78
..............................................................................7.4 RAD7 Quality Assurance 79
................................................................................................................................7.4.1 Spectrum 79
............................................................................................................................7.4.2 Spill Factor 79
.........................................................................8. TROUBLESHOOTING 80
..........................................................................................................8.1 Display 80
.........................................................................................................................8.1.1 Blank Display 80
.......................................................................................................................8.1.2 Frozen Display 80
......................................................................................8.1.3 Incomplete Or Garbage Characters 80
........................................................................................................8.2 Readings 80
..............................................................................................................................8.2.1 No Counts 80
.........................................................................................8.2.2 Excessive Uncertainty In Reading 80
........................................................................................................8.2.3 Run/Cycle Number 0000 80
.................................................................................8.3 Relative Humidity high 80
.........................................................................................8.4 Water Catastrophe 81
......................................................................................8.5 Battery Voltage Low 81
......................................................8.6 Pathological Values and Error Messages 81
...............................................................Appendix 1: Wireless Infrared Printer 82
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..........................................................................A1.1 Infrared Printer Description 82
..................................................................................................................................A1.1.1 General 82
..................................................................................................................................A1.1.2 Features 82
..........................................................................................................................A1.1.3 Power Switch 82
......................................................................................................................A1.1.4 Indicator LEDs 82
..........................................................................................................................A1.1.5 Push Buttons 82
...................................................................................................................................A1.1.6 Sensors 82
Infrared Printer Component Locations and Functions!83
.............................................................................A1.2 Infrared Printer Operation 84
............................................................................................................................A1.2.1 Precautions 84
..................................................................................................................................A1.2.2 Self-Test 84
.............................................................................................................................A1.2.3 Setup Mode 84
Table A1.2.3 Sel and Feed Functions!84
....................................................................................................................A1.2.4 Using the Printer 85
Using the Infrared Printer!85
........................................................................A1.3 Infrared Printer Maintenance 85
................................................................................................................A1.3.1 Battery Installation 85
..................................................................................................................A1.3.2 Paper Installation 85
..............................................................................................................A1.3.3 Cleaning the Printer 86
........................................................................................................A1.3.4 Cleaning the Print Head 86
......................................................................A1.4 Infrared Printer Specifications 87
Table A1.4 Infrared Printer Specifications!87
.......................................................................Appendix 2: RAD7 Specifications 88
Table A2.1 Functional Specifications!88
Table A2.2 Technical Specifications!88
Table A2.3 Physical Specifications!89
9

INTRODUCTION
The RAD7 is a highly versatile instrument that can form the basis of a comprehensive radon measurement
system. It may be used in many different modes for different purposes. This manual adopts a progressive
approach, in which there is, first, a simple, step-by-step description of how to get readings for a) real-time
monitoring, and b) sniffing. Next comes a more detailed description of the many features of the
instrument and how to access them. The rest of the manual covers a whole range of topics, in somewhat
arbitrary order. We recommend that, as soon as possible, you read the entire text, just so that you will
have an idea of what there is. While you can start to make good measurements on the first day of
ownership of the RAD7, it can take years to master the subtleties of radon and thoron behavior, and to
appreciate the full capabilities of the instrument.
We have tried to make the manual easy to use, with a useful table of contents. Please let us know how
well we have succeeded. If there are some topics inadequately covered, please tell us. We will issue
updates from time to time.
Points of special note
The RAD7 is a rugged and long-lasting piece of equipment. There are many units still in daily use that
were sold ten years ago or more. However, it is a sophisticated, precision electronic device, and it is not
hermetically sealed, so please treat it with respect. Please do not allow water, other liquids or dirt to get
into the machine. If using it somewhere where it may get splashed, damaged, or exposed to rain, please
protect it. See Chapter 4.8.1.
The batteries are lead-acid technology, like a car’s. If left in a discharged state they will lose capacity.
After running the RAD7 on its batteries please recharge them as soon as possible (by plugging in the
unit). With careful use the batteries will last five years or more.
Finally, there is one security feature that is sometimes inadvertently set by an inexperienced, though
authorized, user; namely the key pad lockout. If the key pad ceases to function, and all you see is
DURRIDGE RAD7 on the display, just do the following: Hold down the [ENTER] and two arrow keys
until you hear a beep, release the three keys and immediately push [MENU]. You should then be rewarded
by >Test on the display. If the tone was set to OFF, then you will not hear the beep, so hold the three
keys down for three to four seconds, before releasing them and pushing [MENU], - try hold-down times a
little longer, or shorter, if, at first, you do not succeed.
DURRIDGE Company Inc.
524 Boston Rd, Billerica, MA 01821 USA
Tel: [phone] Fax: [phone]
Email: [email protected]
Web: www.durridge.com
European Representative:
Dr. Martyn J. Key
c/o Radiansa Consulting S.L.
Montcalm 20-22, 17006 Girona, Spain
Tel: [phone]
10

1. GETTING STARTED:
YOUR FIRST DAY WITH THE RAD7
1.1 Unpacking
First make sure you have everything you are
supposed to have. Take the materials out of the
packing boxes and see if you have all the items
shown in the diagram below, or on the packing list
enclosed with the shipment. If anything is
missing, please email DURRIDGE immediately
or call us at [phone].
RAD7 Packing List
RAD7 and Case Accessories
•RAD7 electronic radon detector
•12V adaptor w/ 4 plugs
• 12V cord for custom applications
•RAD7 Carrying Strap
•Keys for RAD7 case
RAD7 Printer Supplies
•Wireless infrared printer
•Battery Charger
•4 Rechargeable AA batteries
•6 Rolls printer paper
Drying Tubes and Desiccant
•Gas drying unit
•Opener tool for drying unit
•5 lbs desiccant
•4 drying tubes
RAD7 Filters
•5 RAD7 inlet filters
•1 Dust filter
(Continued on next page.)
Chapter 1 Getting Started
11

RAD7 Packing List (Continued)
Vinyl Tubing Set (3ft x 3)
•From sample to drying tube
•From drying tube to RAD7 inlet
•From RAD7 outlet to exhaust
USB/Serial Supplies
•Null modem cable
•USB Cable
•USB to serial adaptor
RAD7 Documentation Binder
•RAD7 User’s Manual
•Infrared Printer Manual
•Additional documentation
•DURRIDGE Software USB Stick
1.2 General Safety Instructions
For your own safety and the proper operation of
RAD7:
DO NOT spill liquids onto the machine.
DO NOT expose operating panel of machine to
rain or any other excess moisture.
DO NOT allow liquid to be sucked into inlet tube.
If you intend to use the instrument in a harsh
environment, give it some protection. Even just a
transparent plastic bag enclosing the RAD7 (but
not the air sampling tube) can protect it from
splashing mud and water. Allowing the dry air
from the RAD7 outlet to exhaust into the interior
of the bag will keep the RAD7 in a clean and dry
environment.
If liquid does get into the machine, please
disconnect the power cord, turn off the power
switch, and follow the instructions in Chapter
4.8.1, Harsh and Hazardous Environments:
Splashing Water. It will be necessary to return the
RAD7 to DURRIDGE for repair.
Do not use your RAD7 if the instrument is
damaged or malfunctioning. Please call, or email,
the DURRIDGE service department, who will
advise what to do about the problem.
Replace a frayed or damaged power cord
immediately. Electrical equipment may be
hazardous if misused. Keep away from children.
Do not open or attempt to repair the machine.
The detector has an internal high voltage supply
that can generate more than 2,500V.
Chapter 1 Getting Started
12

The batteries are Gates Monobloc type
0819-0012, 6V 2.5Ah. There are two installed in
the instrument. They are not user replaceable.
1.2.1 Air Travel
The RAD7 is safe to take on an airplane either as
carry-on or checked baggage. It is probably
easiest, and least likely to cause problems, if it is
put inside a suitcase, with clothes, and checked in.
Some airlines and some airline staff are concerned
about lead-technology batteries, such as those in
the RAD7. An MSDS sheet, issued by the battery
manufacturer, is enclosed with the manual in the
RAD7 documentation. A copy of that should be
carried and presented when requested, when
traveling with a RAD7 by air.
1.3 Taking a Look
The RAD7 Professional Electronic Radon Detector
Chapter 1 Getting Started
13

1.4 Starting a Two-day Test
You will need the RAD7 and power cord, the
Laboratory Drying Unit (the large tube of
desiccant, with a screw cap at one end), an inlet
filter (one of the six small filters supplied), the
piece of tubing with a 5/16” ID segment at one
end and a ⅛” ID segment at the other and the
printer.
On first starting up, you may need to set the clock
for your time zone (See Setup Clock, Chapter
2.4.11). Switch on the RAD7, push [MENU], then
push [➔]twice. You will see Setup on the
display. Push [ENTER], then push [➔]ten
times. You will see Setup Clock. Push [ENTER].
Use the arrow keys to adjust hours, minutes,
seconds, day, month and year, pushing [ENTER]
to confirm each setting. Now we are ready to
continue.
RAD7 Normal Configuration
a) Attach the filter to the tubing (push it into the
end with the insert).
b) Carefully remove both plastic caps from the
Drying Unit (you will need them later, to reseal
the unit). Attach the sleeved end of the tubing
to the tube fitting, on the Drying Unit, farthest
from the screw cap.
c) Attach the filter to the Inlet port of the RAD7.
The air sampling system is now set up for the
measurement. (See RAD7 Standard
Configuration diagram at left.)
d) Plug in the RAD7 and switch on.
e) Push [MENU], [ENTER], then push [➔]four
times. You should see on the LCD display:
Test Purge.
f) Push [ENTER]. The pump should start.
g) Set up the printer (insert paper and batteries -
see manual).
h) Place printer between green lines on face plate
(See photo, Chapter 1.3).
i) After purging for some time (normally, at least
five minutes), push [MENU], and [➔]two
times, you will see: Setup on the display.
j) Push [ENTER] twice, then push either arrow
key repeatedly until you see:
Protocol: 2-Day on the display. Push [ENTER].
k) With Setup on the display, push [ENTER], then
[➔]seven times, to see >Setup Format on
the display. Push [ENTER] then use arrow
keys to select Format: Short. Push
[ENTER].
l) Switch off the RAD7. Switch on the printer,
now switch the RAD7 back on. The printer will
print out something like the following:
DURRIDGE RAD7
Vers 2.5f 991128
Model 711
Serial 00512
Calib 21-MAY-13
Last used
Chapter 1 Getting Started
14

!FRI21-MAY-13!17:30
Current settings
!FRI21-MAY-13!19:09
Protocol: 2-Day
Cycle: 01:00
Recycle: 48
Mode: Auto
Thoron: Off
Pump: Auto
Tone: Geiger
Format: Short
Units: pCi/L C
m) Push [MENU], [ENTER], [➔]. You should
see on the LCD display: >Test Start
n) Push [ENTER]. The pump will start running.
On the LCD display you will see something like:
0101! ! Live! ! Sniff
00:59:37! ! ! 00001
You are now monitoring the radon level right
where you are. Every hour, the printer will print
out a reading something like this:
0102 2.69 " 0.73 p Sniff
!FRI21-MAY-13 19:41
!26.8 C RH: 7% B:7.06V
Where 0102 are the run (01) and cycle (02)
numbers, 2.69 is the measured radon
concentration, 0.73 is the two-sigma
STATISTICAL uncertainty, p indicates the units
(in this case pCi/L), and Sniff shows that, for this
reading, only the Po-218 decays are being
counted (after three hours, the mode changes
automatically to Normal). The second line is
clearly the date and time, while the third shows
the temperature and humidity inside the
measurement chamber, and the battery voltage.
Medium and Long format settings print more
information each cycle.
If you allow the RAD7 to complete a run, it will
print out a summary of the entire run, including:
1. Date and time
2. Machine serial number
3. Average value for the test
4. Bar chart of the individual readings, and
5. Cumulative alpha energy spectrum.
In the example shown it may be seen that the
average level was 3.71 pCi/L, or 137 Bq/m3.
To terminate the run early, you may switch off the
RAD7. The data collected, to the end of the last
completed cycle, is automatically stored in the
RAD7 memory, and available for later display,
printing or download to a PC. If you wish to store
the last, incomplete cycle data as well, use Test
Save before switching off the RAD7. When you
do this, the end-of-run printout does not take
place. The summary is stored in memory and
may be printed at any time, except that the
cumulative spectrum, which would have been
printed out at the end of the run, is lost.
End-of-Run Printout
Chapter 1 Getting Started
15

1.5 Starting a Sniff Test
Sniffing lets you make quick, qualitative surveys
of radon and thoron levels. It may be used to
search for radon entry points. There are some
advantages in sniffing for both thoron and radon
at the same time, (see Chapter 3.13.3), so that is
the procedure described here.
You will need the same equipment as for the 2-
day test, above, except that a small drying tube
should be used, instead of the laboratory drying
unit. Also, for portability, you may remove the
external power from the RAD7, and run the
RAD7 on its batteries.
If you have not already done so, set the clock, as
described above.
RAD7 SNIFF Configuration
a) Attach the filter to the tubing (push it into the
end with the ⅛” ID segment)
b) Carefully remove both plastic caps from the
small drying tube (you will need them later, to
reseal the unit). Attach the 5/16” ID end of the
tubing to one end of the tube.
c) Attach the filter to the Inlet port of the RAD7.
Make sure it is firmly fit onto the inlet. The air
sampling system is now set up for the
measurement. While testing, you can use the
small drying tube as a wand, to collect your air
sample from the location of interest.
d) Plug in the RAD7 and switch on.
e) Push [MENU], [ENTER], then push [➔]four
times. You should see on the LCD display:
Test Purge.
f) Push [ENTER]. The pump should start.
g) Set up the printer.
h) Place printer between green lines on the face
plate (See photo, Chapter 1.3).
i) After purging for a few minutes push [MENU],
and [➔]two times, you will see: >Setup on
the display.
j) Push [ENTER] twice, then push either arrow
key repeatedly until you see:
Protocol: Thoron on the display. Push
[ENTER]. (See Chapter 2.4.5 for difference
between Thoron and Sniff protocols).
k) With Setup on the display, push [ENTER], then
[➔]seven times, to see Setup Format on the
display. Push [ENTER] then use arrow keys to
select Format: Short. Push [ENTER].
l) Switch off the RAD7. Switch on the printer,
now switch the RAD7 back on. The printer will
print out something like the following:
Chapter 1 Getting Started
16

DURRIDGE RAD7
Vers 2.5f 991128
Model 711
Serial 00512
Calib 21-MAY-08
Last used
!WED23-MAY-08!17:30
Current settings
!FRI25-MAY-08!19:09
Protocol: Thoron
Cycle: 00:05
Recycle: 00
Mode: Sniff
Thoron: On
Pump: Auto
Tone: Geiger
Format: Short
Units: pCi/L C
!
m) Push [MENU], [ENTER], [➔]. You should
see on the LCD display: >Test Start
n) Push [ENTER]. The pump will start running.
On the LCD display you will see something like:
0201! ! Live! ! Sniff
00:04:37! ! ! 00001
You are now sniffing for thoron and radon. Every
five minutes, the printer will print out a reading
something like this:
0203!2.69 " 2.83!p Sniff
!!1.68"2.15!pThoron
!FRI21-MAY-99 19:41
!26.8°C RH: 7% B:7.06V
Where 0203 are the run (02) and cycle (03)
numbers, 2.69 is the measured radon
concentration, 2.83 is the two-sigma
STATISTICAL uncertainty, p indicates the units
(in this case pCi/L), and Sniff shows that, for this
reading, only the Po-218 decays are being
counted. The second line is the measured thoron
concentration and uncertainty. The third line is
now the date and time, while the fourth shows the
temperature and humidity inside the measurement
chamber, and the battery voltage. Medium and
Long format settings print more information each
cycle.
Note that the Po-218 has a 3-minute half life.
After moving to a new location, it will take about
15 minutes for the count rate to reach equilibrium
with the new radon concentration. So not until
after the third 5-minute cycle will the reading
indicate the new level. However, the thoron
daughter, Po-216, has a very short half life (150
ms), so the response of the RAD7 to thoron is
virtually instantaneous. For thoron, the first 5-
minute cycle is as good as any other.
Thoron will only be found very close to radon
entry points. That, together with its fast response,
makes thoron sniffing an excellent sleuth for
radon entry points.
To terminate the run any time, you may switch off
the RAD7. The data collected, of completed
cycles, is stored in the RAD7 memory, and
available for later display, printing or
downloading to a PC.
Chapter 1 Getting Started
17

2. BASICS OF RAD7 OPERATION
2.1 Introduction
2.1.1 The Key Pad
The RAD7 is operated through a four-key menu-
driven interface. These four keys allow you to
look at the commands, select one, and then do it.
Menu Key
Press [MENU] and you see the menu prompt (>)
and the word Test:
>Test
Arrow Keys
Press the forward and backward arrow keys to go
through the available options. To advance quickly
through the options, hold down the key so that it
"auto-repeats."
The arrow keys allow you to move right and left
through the various commands, looking for the
action you want.
Enter Key
When you have decided on a certain menu option,
you select it by pressing [ENTER]. The enter key
tells the RAD7 that you have made your selection.
You are telling it what you want it to do.
The enter key makes it happen.
2.1.2 Command List
The RAD7 command list has four command
groups: Test, Data, Setup and Special. The Test
group of commands controls the collection of new
radon data. The Data group retrieves data from
memory, outputs them, and gets rid of old,
unwanted data. The Setup group prepares the
RAD7 to operate according to your requirements.
The Special group is a set of commands that are
available when RADLINK, the remote control
software, is loaded.
2.2 Test
The Test group of commands controls the
collection of radon data and allows you to
manipulate the current test (test-in-progress). You
can start and stop data collection, save or clear the
current test, or print the current test as it stands.
(The Test commands do not allow access to stored
data. You have to go to Data for that.)
2.2.1 Test Status
To see the status display, enter the Test Status
command. Press [MENU], [ENTER], [ENTER]
On the LCD display, you will see:
0501! ! Idle! ! Sniff
00:30:00! ! ! 00000
On the upper left, you see the current run number/
cycle number (0501 - run 05, cycle 01.).
The middle shows the detector status (Idle or
Live), and the upper right gives the current test
mode (Sniff, Normal or Grab). (Note that in
AUTO mode, the indication will change from
Sniff to Normal after three hours of measurement.
Lower left shows the count-down timer (00:30:00
= 30 minutes) which counts down to zero when
the detector is Live (i.e., a test is in progress).
The lower right shows the total number of counts
since the beginning of the current cycle.
The arrow keys may now be used to access
additional status information.
Press [➔]once, and you will see something like
this:
Last reading:
0409!1.80 " 0.74!p
The lower left is the run number (2 digits) and
cycle number (2 digits) of the last completed
cycle stored to memory.
The lower right is the radon reading and two-
sigma statistical uncertainty, followed by "p",
Chapter 2 Basics of RAD7 Operation
18

indicating picoCuries/liter, or "b" for Becquerels/
cubic meter.
When a cycle ends, the information on this
display is updated. If there have been no readings
yet, the display will show
No readings yet.
Press [➔]once again, and now you will see
something like this:
24.8°C!RH:3%
B: 6.36V!P: 00mA
Top left is the internal temperature. (To change
from Celsius to Fahrenheit, see Chapter 2.4.9,
Setup Units.)
Top right shows the internal Relative Humidity
reading. When testing, maintain this value at 10%
or less, by using the desiccant.
Bottom left is the battery voltage. This should
range from about 6.00V to 7.10V. A discharged
battery (less than 6.00 ) should be recharged as
soon as possible. A fully charged battery will rest
at 6.40 to 6.50 V. During a recharge, the voltage
will eventually rise above 7.00 V. At no time
should this read higher than 7.20V. In the lower
right is the pump current. This number should
vary from 00mA (pump off) to 80mA. When the
pump is running with a light load, the current will
range from 40-70mA. When the pump is running
with a heavy load (clogged filter or blocked hose),
the current will go to 90mA or higher. Pump
currents above 90mA are considered a sign of
trouble. Try changing the filters and check for
blockage.
Press [➔]again, and you will see something like
this:
HV: 2218V, 10%
L: 02 S: 0.21V
This is a display of diagnostic values. Ordinarily
it will be of little interest to you.
The top line is the high voltage reading and duty
cycle. The range of normal values is from 2000
to 2500V, and from 8% to 18%.
The lower left corner is the leakage current. At
room temperature, this value will normally range
from 0 to 10. Higher temperatures ordinarily
cause this value to rise. Excessive leakage current
will result in "noise" in the lower energy end of
the spectrum, and will also cause broadening
of the alpha peaks.
The lower right corner is the signal voltage from
the analog circuit. This number should be
"stable"; that is, fluctuations should be no more
than " 0.05V from the average value.
Press [➔]yet again, and you will see something
like this:
w!| cpm!| +/- !| %tot
A!| 6.0!| 4.3!| 48.8
This is the display for the A window data. You
may press [➔]to advance to B, C, D, etc.
The RAD7 records 8 windows (A - H) every time
you make a measurement. They separate counts
due to daughters of radon and thoron, and the
background. Specific alpha particles end up in
specific windows.
W: The window letter.
cpm: The counts per minute observed in the
window.
+/-: The two-sigma statistical uncertainty of the
cpm value, also in units of cpm.
%tot: The number of counts in the window as a
percentage of the total counts in the spectrum.
This tells you quickly where the majority of the
counts are: In the 3-minute radon peak (window
A), or the long-lived radon peak (window C), etc.
As always, you press the [MENU] key to exit this
display and return to the start of the menu.
2.2.1a Quick Save-and-Restart
This function allows the user to end a sniff test,
store it to memory, and start up a new sniff test,
all using a single key. It operates only from the
SNIFF mode.
From the status display (showing the countdown
timer), press the [ENTER] key once. The display
will show:
Save and restart
Chapter 2 Basics of RAD7 Operation
19

? Yes
Press the [ENTER] key once more to confirm
your intention. To escape, push the [MENU] key
or push an arrow key to select “No” and push
[ENTER].
2.2.2 Test Start and Test Stop
To start testing (or "counting"), after you have
chosen the required setup, go to >Test Start
by pressing [MENU], [ENTER], [➔], and then
[ENTER]. The display will indicate that
counting has begun:
Start counting.
One second later, the Status display will appear
with the countdown timer in motion:
0501! ! Live! ! Sniff
00:29:37 !! !00001
When the countdown reaches zero, the RAD7 will
automatically calculate the radon concentration,
store (or "save") the counts to memory, and clear
the counters to begin a new cycle.
To interrupt the measurement, go to >Test Stop
by pressing [MENU], [ENTER], [➔], [ENTER].
The display will respond:
Stop counting.
After one second, the display will go back to the
top of the menu >Test.
You may wish to examine the Status display to
verify that the status is Idle.
To resume testing from exactly the same point in
the cycle where you stopped, select >Test
Start as described above.
Note that Stop does not terminate the run, it is a
pause. If you do not wish to resume testing from
the same point, you should select either >Test
Save or >Test Clear before continuing. This
will terminate the suspended test, store it to
memory (Save) or wipe it out (Clear), and clear
the counters to begin a new run.
2.2.3 Test Save
The >Test Save command suspends counting
and saves the suspended test (test-in-progress) to
memory as if it had reached completion. Test
Save completes the current run, so any subsequent
test data will be stored as a new run. The display
momentarily shows the run and cycle number in
the form of 0101 Saved. This command may be
accessed whether the status is Live or Idle. It
always leaves the status Idle.
You will find this command especially useful
when you wish to move the instrument to another
location without waiting for the countdown to
reach zero, but without losing that last incomplete
cycle. The calculated radon concentration from
the incomplete cycle is still good.
2.2.4 Test Clear
The >Test Clear command causes counting to
be suspended and the current run to be completed
without saving the last (suspended) incomplete
cycle. Subsequent test data will be stored as a
new run. You must answer Yes to the question
Are you sure? in order to activate this command.
This command may be accessed whether the
status is Live or Idle. It always leaves the status
Idle.
2.2.5 Test Purge
The >Test Purge command suspends counting
and begins purging the detector. The pump
begins running and the high voltage circuit turns
off in order to clear the sample chamber of radon
gas and daughters as quickly as possible. You
must provide clean, desiccated, radon-free air to
the inlet in order to push out any radon that was
previously sampled. Outdoor air is usually
adequate for this purpose.
As always, use the inlet filter and drying tube.
Ten minutes is usually sufficient for bringing the
background down after exposure to moderate
amounts of radon.
In order to dry out the RAD7 without using up
much desiccant, connect the hoses from the
RAD7 to the drying unit, as a loop. When the
pump runs, the same air will circulate repeatedly
through the desiccant. This procedure will
Chapter 2 Basics of RAD7 Operation
20