Thermo EPD Mk2 Release Note

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ELECTRONIC PERSONAL
DOSEMETER
(EPD Mk2)
TECHNICAL HANDBOOK
DATE OF ISSUE: APRIL 2004 CHANGE REFERENCE: Thermo Electron Corp. Revision
©Thermo Electron Corporation. All rights reserved.
The information contained herein is the property of Thermo Electron Corporation and is supplied
without liability for errors or omissions. No part may be reproduced or used except as authorised
by contract or other written permission. The copyright and the forgoing restriction on reproduction
or use extend to all the media in which this information may be embodied.

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MANUFACTURERS DETAILS
Manufacturer's Address
Thermo Electron Corporation
Sopers Lane
Poole
Dorset
United Kingdom
BH17 7ER
Tel. [phone] International: [phone]
[phone] International: + 44 1202 782374
[phone] International: + 44 1202 782780
Fax. [phone] International: + 44 1202 782335
USA Sales Office
Thermo Electron Corporation
105C Hembree Park Drive
Roswell
GA 30076
U.S.A.
Tel. [phone]
Fax. [phone]
ISSUE STATE
Pages Issue Type Part ID File ID
All 5 ESERS EPD/HB/40521 HB40521_iss_5.doc

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CONTENTS Page
GLOSSARY................................................................................................................................................................IX
CAUTIONS.................................................................................................................................................................XI
SECTION 1...................................................................................................................................................................1
INTRODUCTION........................................................................................................................................................1
1.1 GENERAL ..................................................................................................................................................1
1.2 EPDMAJOR CHARACTERISTICS.........................................................................................................1
1.3 BRIEF FUNCTIONAL DESCRIPTION........................................................................................................2
SECTION 2...................................................................................................................................................................5
GETTING STARTED..................................................................................................................................................5
2.1 SETTING-UP..............................................................................................................................................5
2.1.1 Unpacking The EPD......................................................................................................................6
2.1.2 The EPD Battery .............................................................................................................................6
2.1.3 Start-up Sequence..........................................................................................................................9
2.1.4 EPD Confidence Test..................................................................................................................10
2.1.5 Issuing an EPD..............................................................................................................................10
2.1.6 Wearing an EPD............................................................................................................................11
OPERATINGINSTRUCTIONS ..............................................................................................................................13
3.1 LCD DISPLAY AND BACKLIGHT .........................................................................................................13
3.2 AUDIBLE AND VISIBLE ALARMS.........................................................................................................16
3.2.1 Alarm features................................................................................................................................16
3.2.2 Dose Alarms...................................................................................................................................20
3.2.3 Dose Rate Alarms.........................................................................................................................20
3.2.4 Over-Range Indication.................................................................................................................21
3.2.5 Alarm Muting...................................................................................................................................22
3.3 BUTTON OPERATION AND DISPLAYSELECTION..............................................................................23
3.4 LCD DISPLAY LOCK-ON FACILITY....................................................................................................24
3.5 DISPLAY OPTIONSAND BUTTON FUNCTIONS..................................................................................26
3.5.1 Displaying Hp (10) Dose, Dose Rate and User ID..............................................................26
3.5.2 Displaying Hp(0.07) Doses, Dose Rate and ADS User ID ...............................................27
3.5.3 Displaying Total Dose..................................................................................................................29
3.5.4 Starting/Stopping The Seconds Count Down Timer...........................................................29
3.5.5 Turning the EPD off......................................................................................................................30
3.5.6 Displaying Peaks (Rate High)...................................................................................................31
3.5.7 EPD Confidence Test..................................................................................................................32
3.5.8 Clearing Dose Displays ...............................................................................................................34
3.5.9 Displaying/Setting Dose Alarm Thresholds...........................................................................34
3.5.10 Displaying/Setting Dose Rate Alarm On/Off Thresholds.............................................36
3.5.11 Setting The Sounder...............................................................................................................38
SECTION 4.................................................................................................................................................................43
TECHNICAL DESCRIPTION.................................................................................................................................43
4.1 GENERAL ................................................................................................................................................43
4.2.1 Electrical Characteristics............................................................................................................44

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4.2.2 Battery Management....................................................................................................................44
4.3 MECHANICALDESCRIPTION................................................................................................................46
4.3.1 Mechanical Characteristics And Dimensions.......................................................................46
4.3.2 Brief Mechanical Description.....................................................................................................46
4.4 ENVIRONMENTAL DESCRIPTION .........................................................................................................48
4.4.1 Environmental Characteristics..................................................................................................48
4.4.2 Brief Environmental Description ...............................................................................................48
4.5 INFRA-RED INTERFACE..........................................................................................................................49
4.5.1 Communicating With The EPD.................................................................................................49
4.6 EPDINTERNAL PROCESSING&FACILITIES.....................................................................................51
4.6.1 Memory Characteristics:.............................................................................................................51
4.6.2 Alarm Characteristics:.................................................................................................................52
4.6.3 Default Display...............................................................................................................................52
4.6.4 User Identification.........................................................................................................................52
4.6.5 Dose and Dose Rate....................................................................................................................53
Dose..................................................................................................................................................................53
Dose Rate........................................................................................................................................................53
4.6.6 Counts..............................................................................................................................................54
4.6.7 Dose Quality Flags.......................................................................................................................55
(i) Reset Count..............................................................................................................................................55
(ii) Shock Time Seconds...........................................................................................................................55
(iii) Dose Over-range...................................................................................................................................55
(iv) Dose Rate Over-range.........................................................................................................................55
(v) Counter Over-range ...............................................................................................................................55
(vi) Abuse Warning......................................................................................................................................56
(vii) CRC Failure...........................................................................................................................................56
4.6.8 Dose And Dose Rate Alarm Processing................................................................................56
4.6.9 EPD Operating Status.................................................................................................................57
EPD ‘Run’ and Off times.............................................................................................................................57
EPD State.......................................................................................................................................................57
Alarms ..............................................................................................................................................................58
Faults................................................................................................................................................................58
4.6.10 Dose Profile...............................................................................................................................59
4.6.11 Event History Store.................................................................................................................59
SECTION 5.................................................................................................................................................................61
EPDFAULTS ANDRECOVERY ACTIONS........................................................................................................61
5.1 OVERVIEW ..............................................................................................................................................61
5.2 VISUAL AND AUDIBLE FAULT INDICATION................................................................................... 62
5.3 INTERNAL LOGGING OFFAULT CONDITIONS ....................................................................................63
5.3.1 EPD Status Faults Record.........................................................................................................63
5.3.2 Event History store.......................................................................................................................63
5.4 BLANK LCDDISPLAYAND OTHER FAULTS.....................................................................................65
5.5 INITIALISATION ERROR (LCD---- )................................................................................................... 67
5.6 COMMUNICATIONS ERROR (LCD ==== ).......................................................................................67
5.7 LCD DISPLAY ERROR CODES............................................................................................................. 69
5.8 RECOVERYPROCEDURES.....................................................................................................................70
5.8.1 Logging Faults / Extracting Data..............................................................................................70
5.8.2 Clearing faults ................................................................................................................................70
SECTION 6.................................................................................................................................................................77
MAINTENANCE........................................................................................................................................................77
6.1 CALIBRATION.........................................................................................................................................77

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6.2 THE EPDBATTERY...............................................................................................................................79
6.2.1 Replacement Batteries ................................................................................................................79
6.2.2 Battery Leakage............................................................................................................................79
6.2.3 Lithium Thionyl Chloride Battery Warning..............................................................................80
6.2.4 Replacing the EPD Battery........................................................................................................81
6.3 EPDCLIP ASSEMBLY..........................................................................................................................82
6.3.1 Removing the EPD Lanyard Plate/Clip Assembly..............................................................83
6.3.2 Replacing The EPD Lanyard Plate/Clip Assembly.............................................................84
6.4 CLEANING...............................................................................................................................................85
6.4.1 General Cleaning...........................................................................................................................85
6.4.2 Radiological Cleaning...................................................................................................................85
6.4.3 Cleaning after a Battery Leakage.............................................................................................85
6.4.4 Periodic Cleaning ..........................................................................................................................86
APPENDIX A..............................................................................................................................................................87
RADIOLOGICAL SPECIFICATIONS..................................................................................................................87
APPENDIX B..............................................................................................................................................................89
ELECTROMAGNETIC COMPATIBILITY...........................................................................................................89
APPENDIX C..............................................................................................................................................................95
SUMMARY OF GENERAL PHYSICAL & FUNCTIONAL CHARACTERISTICS ....................................95
APPENDIX D..............................................................................................................................................................99
EPD FAULT LOG FORM.........................................................................................................................................99

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GLOSSARY
/h Per hour
°C Degrees Celsius
ADS Approved Dosimetry Service (or System)
CRC Cyclic Redundancy Check. Error checking code.
dB(A) Decibels -‘A’ weighted scale (sound intensity)
DC Direct Current
DDE Deep Dose Equivalent (alternative nomenclature for Hp(10))
Dose The accumulated dose to which alarm thresholds apply, intended for
tactical dose monitoring (eg. per day, per week, per shift etc)
Double-press Pressing the button twice in quick succession
EEPROM Electrically Erasable Programmable Read Only Memory
EPD Electronic Personal Dosemeter
EPDS Electronic Personal Dosimetry System
eV Electron Volt
Gy Gray, SI unit of dose
HEX Hexadecimal
H10 EPD LCD nomenclature for personal dose (Hp(10))
H07 EPD LCD nomenclature for personal dose (Hp(0.07))
H10/h EPD LCD nomenclature for dose rate (Hp(0.07)/h)
H07/h EPD LCD nomenclature for dose rate (Hp(10)/h)
Hp(10) Personal dose equivalent at a depth of 10mm of tissue (‘penetrating’,
‘deep’ or ‘whole body’ dose).
Hp(0.07) Personal dose equivalent at a depth of 0.07 mm of tissue (‘superficial’,
‘shallow’ or ‘skin’ dose).
Hp(10)/h Hp(10) dose rate
Hp(0.07)/hHp(0.07) dose rate
ICRU International Commission on Radiation Units
ID Identification
IR Infra-red
IrDA Infra-red Data Association
keV Kilo Electron Volt
LCD Liquid Crystal Display
LED LightEmittingDiode
Long Press Pressing and holding the button
LTC Lithium Thionyl Chloride (Sulphurous Oxychloride, SOCl2)
MeV MegaElectron Volt
mmetre/milli
mm millimetre
nm nanometre
NRPB National Radiological Protection Board -the statutory authority for
radiological protection in the UK
PCB Printed Circuit Board

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Glossary (continued)
SDE Shallow Dose Equivalent (alternative nomenclature for Hp(0.07))
ppm Parts per million
RAM Random Access Memory
rem A unit of dose equivalent, equal to 10mSv
RFI Radio Frequency Interference
Short-press A short press and release of the button
Sv Sievert, SI unit of dose equivalent
TTesla
TLD Thermoluminescent Dosemeter
Total Dose Intended to be a secure record of the total accumulated dose received
since Dosemeter issue-alarms do not apply to total dose.
User ID A numeric code of up to 12 digits that may be written to the EPD to
define the current user or wearer. By convention a value of
FFFFFFFFFFFF is written to EPDs not currently issued to a wearer.
User Name A character string of up to 22 characters that may be written to the EPD
and used as a second or supplementary Wearer Identity
(Supplementary to user ID ).
Wearer ID Alternative terminology for the User ID.
Wearer Name Alternative terminology for the User Name.

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WARNINGS
Radioactive Contamination
DURING OPERATIONAL USE THE EPD MAY BECOMEEXPOSED TO RADIOACTIVE
CONTAMINATION. THE EPD MUST BE SUBJECT TO ALL RELEVANT
DECONTAMINATION PROCEDURES LAID DOWN BY THE RADIOLOGICAL PROTECTION
AUTHORITY.
Lithium Thionyl Chloride Batteries
LITHIUM THIONYL CHLORIDE* (LTC) BATTERIES ARE POTENTIALLY DANGEROUS.
THEY MAY LEAK TOXIC SUBSTANCES THAT CAN BE HARMFUL. READ AND TAKE
NOTE OF THE MANUFACTURERS WARNINGS ON THE BATTERY CASE. READ ALSO
THE DETAILED LTC BATTERY WARNINGS IN THIS HANDBOOK.
* Sulphurous Oxychloride, SOCL2
Cautions
EPD batteries
Batteries are susceptible to fire and abuse. Some manufacturers provide batteries with a
safety vent, which allows a controlled release of electrolyte if fire and abuse conditions prevail.
If the EPD has been damaged in a manner that could affect the battery, care must be exercised
during battery removal. The battery may have vented into the EPD case and caused the EPD
to become pressurised.
EPD Battery Cap
Take care when removing the EPD battery cap, the battery cap may spring free with
unexpectedforce.

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SECTION 1
INTRODUCTION
This handbook is for the Thermo Electron Electronic Personal Dosemeter (EPD) -
EPD Mk2. The EPD Mk2 is lighter and slimmer than the original Thermo Electron
EPD and has new micro-circuitry, case design and software. The EPD Mk2 also has
a number of enhanced dosimetry features and user functions. To simplify
nomenclature the term EPD has been used throughout this handbook. The term EPD
should be read to signify the EPD Mk2.
1.1 General
The EPD is a personal radiation monitor that detects and measures beta and gamma
radiation. Radiation that is detected by the EPD is processed to give an indication of
penetrating dose, superficial dose and the dose rates. This information is displayed
to the user via an LCD display on the top of the EPD.
The EPD contains three silicon diode detectors. Each detector feeds a chain of
dedicated amplifiers and counter circuits to measure soft gamma, hard gamma and
beta radiation. The outputs from each detector chain are processed to calculate and
display penetrating and superficial dose and dose rate. Other functions include:
EEPROM storage of detected radiation, annunciation of alarm conditions (LED and
sounder), Infra-red (IR) communication and a user interface comprising an LCD
display and button. Each of the above functions is described in detail in this
handbook.
1.2 EPD Major Characteristics
Major Characteristics relating to the EPD are listed in Table 1.1.
Table 1.1 -EPD Major Characteristics
Item Characteristic
Power One AA battery, either a standard Alkaline (1.5 V) battery or
high energy Lithium Thionyl Chloride (LTC) (3.6 V).
Weight 95 gms (including LTC battery and clip).
Dimensions 86 x 62 x 18.5 mm (excluding clip).
Alarmsounder 98-101 dB.

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The new EPD also has the following major features:
♦Improvedimmunityto radio frequency interference (RFI).
♦Display Backlight.
♦EPD communication via an infra-red interface up to a range of approximately
1 metre.
♦Improved dose profile facility.
♦Real-time dose chirp (adjustable).
♦Password protected dose store for ADS functions.
♦Extended systems integration facilities.
♦Count down timer and alarm.
Appendix C is asummary of the general physical & functional characteristics of the EPD.
1.3 Brief Functional Description
The EPD is a highly sophisticated device sensitive to gamma and X-rays (photons),
and beta radiation (energetic electrons) in the following energy range:
gamma, X-rays :15 keV to 10 MeV
Beta radiation: 250 keV to 1.5 MeV (mean energy)
A full list of radiological characteristics and specifications can be found in Appendix A
to this Handbook.
Radiation detected by the three silicon diode detectors is combined to give the
following dose equivalents (as defined by ICRU Document 47):
(i) Hp(10) personal dose equivalent at a depth of 10mm of tissue (‘penetrating’,
‘deep’ or ‘whole body’ dose).
(ii) Hp(0.07) personal dose equivalent at a depth of 0.07 mm of tissue
(‘superficial’, ‘shallow’ or ‘skin’ dose).
The EPD calculates both the accumulated dose and the dose rate for Hp(10) and
Hp(0.07). These, and other data, are stored in an internal store (EEPROM) within the
EPD. A buttonin the EPD case allows the user to retrieve this data from store, select
a range of displays, acknowledge alarms and perform user control functions. Data is

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displayed to the user on a LCD display on the top of the EPD (see Figure 2.1). To
minimise the loss of data from battery or other failure, data is saved to secure
memorywithin the EPD every 15 minutes.
Data is written to and read from the EPD via an integral infra-red communications
interface. The Thermo Electron supplied EasyEPD2 program reads and writes data
to the EPD via the Infra-red communications link and displays the data in a PC
window. Thermo Electron also produces a range of Access Control Systems for use
with the EPD.
Dose is accumulated separately in the EPD in three stores: Dose,Total Dose and
ADS Dose. The use of several stores allows dose to be recorded over differing
periods, for example the Dose store may be used for each job or task performed (
and reset after each ), whilst the Total Dose records the total or aggregate dose from
all the jobs or tasks performed. ADS Dose is a password-protected dose store
intended for ‘legal dosimetry’ applications. Note that audible alarms are given if either
the accumulated dose or dose rates exceed programmable threshold levels. Dose
alarms are raised against the Dose store only.
The EPD is a sealed unit and is splash-proof. The unit will withstand short periods of
immersion in water but is not designed for prolonged immersion under pressure.
General maintenanceis confined to:
♦Removing/replacing the EPD battery,
♦Removing/replacing the EPD clip assembly,
♦Clearing fault conditions (where possible),
♦Checking the functionality and calibration of the EPD,
♦Keeping the unit clean.
Note:
1. This manual deals with Sieverts (Sv) throughout. To convert to rem multiply all
values by 100.

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SECTION 2
GETTING STARTED
This section describes the general procedures that must be carried out to ensure that
the EPD is set-up correctly and is functionally operational.
2.1 Setting-up
The EPD requires very little setting-up. Setting-up is primarily confined to:
1. Unpacking the EPD,
2. Inserting the battery,
3. Checking the initialisationsequence,
4. Checking the default settings,
5. Performing a confidence test.
A general view of the EPD is shown in Figure 2.1. External features are described in
Table 2.1.
Figure 2.1 -External View Of The EPD

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Feature Description
Battery Compartment Houses an Alkaline AA battery (1.5 V) or a Lithium
Thionyl Chloride (LTC) AA battery (3.6 V).
Infra-red Interface Infra-red communications interface to the EPD.
Button User interface for EPD control, alarm acknowledgement
and LCD display selection.
Sounder Provides an audible indication of an EPD alarm.
Beta Window Allows beta particles to pass through the case to the
Beta detector.
LCD Display Displays EPD parameters and/or functionality as
selected by the button.
Alarm LED Provides a visual indication of an EPD alarm.
Clip Assembly Provides a means of attaching the EPD to clothing, or
for attaching a lanyard as an alternative means of
wearing the EPD.
Table 2.1 -EPD External Features
2.1.1 Unpacking The EPD
There are no special unpacking instructions. Depending on customer requirements
the EPD may, or may not, be shipped with a battery and/or a clip assembly.
Alternatively, the EPD may be shipped with just a lanyard plate and lanyard (see
Section 6.3). The battery, if supplied, may be a LTC orAlkaline type.
2.1.2 The EPD Battery
WARNING
LITHIUM THIONYL CHLORIDE* (LTC) BATTERIES ARE POTENTIALLY
DANGEROUS. THEY MAY LEAK TOXIC SUBSTANCES THAT CAN BE
HARMFUL. READ AND TAKE NOTE OF THE MANUFACTURER’S WARNINGS
ON THE BATTERY CASE. READ ALSO THE DETAILED LTC BATTERY
WARNINGS ON PAGE 6.2 OF THIS HANDBOOK.
* Sulphurous Oxychloride, SOCl2)

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General Precautions and Instructions
Always fit new undamaged batteries of the correct type (see section 6.2). A time
interval of at least 10 seconds must elapse between removal and replacement of the
EPD battery (this allows the internal circuits of the EPD to power-down).
The EPD is fitted with either a security-type (tamper-proof) battery cap or a coin-
release battery cap, depending on customer requirements (see Figure 2.2). The
security-type battery cap restricts unauthorised removal of the cap and requires a
special tool. The coin type battery cap should be rotated using a small coin circa 20
mm diameter and 2 mm thick.
Figure 2.2 -Battery Cap Types and Special Tool
The battery cap also provides the return path for the EPD’s power supply.
Therefore, during fitment of either type of battery cap the EPD will begin its start-up
sequence (see Section 2.1.3). If the battery cap is not fitted cleanly and contact is
temporarily broken, the software initialisation process may not be successful. Under
these circumstances it is essential that the battery cap is removed and that a time
interval of at least 10 seconds elapses before any attempt is made to refit the battery
cap.
Inserting/Replacing The EPD Battery
Caution:
Take care when removing the EPD battery cap, the cap may spring free with
unexpectedforce.

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To set up the EPD for operational use the battery must be inserted/replaced in
accordance with the following procedure:
(i) Read and observe the General Precautions and Instructions at the beginning
of this section. If necessary remove the battery cap from the case as
described in (ii) and (iii) below.
(ii) If the battery cap is of thesecurity type, locate the two pips of the special tool
into the two conical recesses in the battery cap. If the battery cap is of the
coin type, locate the coin in the groove in the battery cap.
(iii) Maintain steady pressure on the special tool or coin so as to keep it fully
engaged in the battery cap and rotate the battery cap through approximately
85°in a counter-clockwise direction (to remove cap, see Figure 2.3). If a
battery is already fitted, the cap will normally release from the case under the
action of the battery cap compression spring.
Note: Do not attempt to rotate the cap beyond the design point
(approximately 85 degrees) or beyond the point where the
resistance of the end-stop is felt.
Figure 2.3 -Battery Cap Removal
(iv) Remove the existing battery (if fitted). Insert a new (or replacement) battery
into the battery compartment as shown in Figure 2.4.
Note:The battery must be inserted anode (+)first.

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Figure 2.4 -Inserting The EPDBattery
(v) To fit the battery cap, first locate it against the special tool or coin, as
appropriate) and align the battery cap tangs with the recesses in the EPD
body. Push the battery cap into the battery compartment opening, ensuring
that:
a) the body of the battery cap, which houses the (-) electrode contact
plate, is fully engaged within the battery compartment,
b) the cap sits flush with the body of the EPD.
(vi) Using the special tool or coin, as required, maintain pressure on the battery
cap (against its compression spring), and rotate the battery cap in a clockwise
direction, through approximately 85°, to its end-stop. Rotate the cap slowly to
the point where the resistance of the end stop is felt. Avoid use of excessive
force.
2.1.3 Start-up Sequence
When a battery is inserted into the EPD, fitment of the battery cap will automatically
initiate the start-up sequence. The start-up sequence is as follows:
1. ‘8888’ is shown on the display for approximately three seconds;
2. internal software initialisation, which checks the state of the EPD (such as
the internal bus, internal memory, each detector amplifier and counter
chain, etc.);

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3. confidence test sequence, see section 2.1.4 below.
If the confidence tests pass, the EPD default display will appear. The EPD default
display is preset at the factory to show Hp(10) (the penetrating or deep dose) or to
another default display as specified by the customer.
If a fault code is displayed, or the start-up sequence repeats, try a fresh battery. If
problems persist, refer to section 5.
2.1.4 EPD Confidence Test
The EPD has an built-in confidence test facility. This runs automatically at startup
following battery change. When enabled, this test can also be run at any time during
operational use as a check that the EPD is functioning correctly. The confidence test
is selected by scrolling through the EPD LCD displays to the CONFIDENCE TEST
menu (see Section 3.5.7). Throughout the confidence test the heart-beat (activity)
indicator flashes once per second. The confidence test can be stopped at any time
by pressing the button.
The confidence test sequence is as follows. This test sequence is automatic and
should be visually confirmed as each step initiated:
1. All segments of the display are activated for approximately 5 seconds. This
allows the user to check that all segments are functional (see Figure 3.2).
2. The alarm will sound and the LED will flash for approximately 2 seconds. This
indicates that the sounder and LED are functional.
3. The all-segment display will disappear. The alarm will continue to sound and
the LED will continue to flash, at an increased rate, for approximately 6
seconds. This indicates that all LCD segments can be turned off, and that the
tone frequencies are functional.
4. The all-segment display will reappear for approximately 5 seconds and the
LED will slow flash.
5. The all-segment display will disappear and the default display will appear. This
indicates that the confidence test has been successfully completed and that
the EPD is ready for operational use.
2.1.5 Issuing an EPD
In order to issue an EPD (i.e. assign it to a person) the EPD should be configured
with a numerical User ID and optionally with a User Name. There is a similar, but