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Thermo EPD Mk2 Technical Handbook

Electronic personal dosemeter
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EPD/HB/40521/000
ELECTRONIC PERSONAL
DOSEMETER
(EPD Mk2)
T
H
ECHNICAL
ANDBOOK
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.
ISSUE 5
EPD TECHNICAL HANDBOOK
Page (iii)

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Summary of Contents for Thermo EPD Mk2

  • Page 1 © 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.
  • Page 2 EPD/HB/40521/000 MANUFACTURERS DETAILS Manufacturer's Address Thermo Electron Corporation Sopers Lane Poole Dorset United Kingdom BH17 7ER Tel. (01202) 782779 International: + 44 1202 782779 (01202) 782374 International: + 44 1202 782374 (01202) 782780 International: + 44 1202 782780 Fax. (01202) 782335...

  • Page 3: Table Of Contents

    EPD/HB/40521/000 CONTENTS Page GLOSSARY................................IX CAUTIONS.................................XI SECTION 1...................................1 INTRODUCTION................................1 ..............................1 ENERAL EPD M ......................1 AJOR HARACTERISTICS ......................2 RIEF UNCTIONAL ESCRIPTION SECTION 2...................................5 GETTING STARTED ..............................5 ..............................5 ETTING 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...
  • Page 4 EPD/HB/40521/000 4.2.2 Battery Management ........................44 ........................ 46 ECHANICAL ESCRIPTION 4.3.1 Mechanical Characteristics And Dimensions...............46 4.3.2 Brief Mechanical Description .....................46 ......................48 NVIRONMENTAL ESCRIPTION 4.4.1 Environmental Characteristics....................48 4.4.2 Brief Environmental Description ....................48 .......................... 49 NFRA NTERFACE 4.5.1 Communicating With The EPD....................49 EPD I &...
  • Page 5 EPD/HB/40521/000 EPD B ..........................79 ATTERY 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 EPD C .......................... 82 SSEMBLY 6.3.1 Removing the EPD Lanyard Plate/Clip Assembly ..............83 6.3.2 Replacing The EPD Lanyard Plate/Clip Assembly.............84 ...............................

  • Page 7: Glossary

    EPD/HB/40521/000 GLOSSARY Per hour °C Degrees Celsius Approved Dosimetry Service (or System) Cyclic Redundancy Check. Error checking code. dB(A) Decibels - ‘A’ weighted scale (sound intensity) Direct Current Deep Dose Equivalent (alternative nomenclature for H p (10)) Dose The accumulated dose to which alarm thresholds apply, intended for tactical dose monitoring (eg.
  • Page 8 EPD/HB/40521/000 Glossary (continued) Shallow Dose Equivalent (alternative nomenclature for H p (0.07)) Parts per million Random Access Memory A unit of dose equivalent, equal to 10mSv Radio Frequency Interference Short-press A short press and release of the button Sievert, SI unit of dose equivalent Tesla Thermoluminescent Dosemeter Total Dose...

  • Page 9: Cautions

    EPD/HB/40521/000 WARNINGS Radioactive Contamination DURING OPERATIONAL USE THE EPD MAY BECOME EXPOSED TO RADIOACTIVE CONTAMINATION. MUST SUBJECT 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.
  • Page 10 EPD/HB/40521/000 ISSUE 5 EPD TECHNICAL HANDBOOK Page (xii)

  • Page 11: Section 1

    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.

  • Page 12: Brief Functional Description

    EPD/HB/40521/000 The new EPD also has the following major features: ♦ Improved immunity to 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. ♦...
  • Page 13 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.
  • Page 14 EPD/HB/40521/000 This page is intentionally blank ISSUE 5 EPD TECHNICAL HANDBOOK Page 4...

  • Page 15: Section 2

    EPD/HB/40521/000 SECTION 2 GETTING STARTED This section describes the general procedures that m ust be carried out to ensure that the EPD is set-up correctly and is functionally operational. Setting-up The EPD requires very little setting -up. Setting -up is primarily confined to: Unpacking the EPD, Inserting the battery, Checking the initialisation sequence,...

  • Page 16: Unpacking The Epd

    EPD/HB/40521/000 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.
  • Page 17 EPD/HB/40521/000 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).
  • Page 18 EPD/HB/40521/000 To set up the EPD for operational use the battery must be inserted/replaced in accordance with the following procedure: 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.

  • Page 19: Start-Up Sequence

    EPD/HB/40521/000 Figure 2.4 - Inserting The EPD Battery 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: the body of the battery cap, which houses the ( ) electrode contact...

  • Page 20: Epd Confidence Test

    EPD/HB/40521/000 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.

  • Page 21: Wearing An Epd

    EPD/HB/40521/000 separate, configuration for Approved Dosimetry Service (ADS). The User Name and numerical ID can only be configured via the IR communications link. Controlled and ADS User IDs can be viewed via the EPD’s LCD display. Detailed instructions to display User IDs are given in Section 3.5. 2.1.6 Wearing an EPD The EPD should be worn under the direction of the health physicist.
  • Page 22 EPD/HB/40521/000 WARNING DURING OPERATIONAL USE THE EPD MAY BECOME EXPOSED TO RADIOACTIVE CONTAMINATION. THE EPD MUST BE SUBJECT TO ALL RELEVANT DECONTAMINATION PROCEDURES LAID DOWN BY THE RADIOLOGICAL PROTECTION AUTHORITY. ISSUE 5 EPD TECHNICAL HANDBOOK Page 12...

  • Page 23: Operating Instructions

    ‘stand -alone’ facility for users not having direct access to communications software such as EasyEPD2. However for many users the sheer number of displays available may lead to confusion and Thermo Electron has therefore provided a facility for unwanted or unnecessary displays to be disabled. Backlight Operation The EPD is equipped with a display backlight to enable the display to be read in the dark.
  • Page 24 EPD/HB/40521/000 backlight effect is not apparent and the user may assume that a button press operation has somehow been ‘lost’. ♦ The backlight activation causes a temporary alarm muting effect, see section 3.2.5. ISSUE 5 EPD TECHNICAL HANDBOOK Page 14...
  • Page 25 EPD/HB/40521/000 ISSUE 5 EPD TECHNICAL HANDBOOK Page 15...

  • Page 26: Audible And Visible Alarms

    EPD/HB/40521/000 Figure 3.2 - LCD Display Segments Audible And Visible Alarms 3.2.1 Alarm features Overview The EPD contains a sounder and alarm LED (see Figure 3.1), which are activated together when certain alarm conditions occur. Alarms are also indicated in various ways on the LCD. Under alarm conditions the LED illuminates red and the sounder sounds at 4 kHz or 2 kHz with an intensity Figure 3.1 - Alarm LED...
  • Page 27 EPD/HB/40521/000 Alarm Configuration The EPD is able to initiate alarms for a number of different operational conditions. The nature of any alarm is shown on the LCD display by an alarm flag (see Figure 3.2) or, in the case of an over-range alarm, by a flashing LCD display. Faults are shown as a letter ‘F’...
  • Page 28 Loud and High frequency. The different alarm events identified by the EPD are listed in Table 3.3. This table also shows the default alarm configurations set by Thermo Electron at manufacture. The following alarms are regenerated after a reset (e.g. battery change): •...
  • Page 29 EPD/HB/40521/000 In general therefore the higher priority alarms should not be configured with either a short duration, or with LED or sounder disabled, unless the lower priority alarms are also configured this way. Priority Alarm/Event Alarm Tone Frequency Volume EPD Failure Alarm. Intermittent Single Slow Tone High Loud...

  • Page 30: Dose Alarms

    EPD/HB/40521/000 3.2.2 Dose Alarms Dose alarms are checked and updated every second, except at low dose rates where this period increases to a maximum of 14 seconds. Alarms can be adjusted or inhibited via the IR communications link. Dose alarms are calculated against a preset alarm threshold set in the EPD. When the dose equals or exceeds the dose threshold the LED will illuminate, the sounder will activate and the appropriate alarm flag on the LCD will be displayed.

  • Page 31: Over-Range Indication

    EPD/HB/40521/000 Figure 3.3 - Dose Rate Alarm Example The four most significant digits of the alarm ‘Off’ and the alarm 'On' thresholds can be viewed on the EPD LCD and, if user has authority to modify the thresholds, changed using the function button (see Section 3.5.9). 3.2.4 Over-Range Indication If a dose rate exceeds 1Sv/h, or if a dose store increments above 1.0Sv, an over-...

  • Page 32: Alarm Muting

    EPD/HB/40521/000 3.2.5 Alarm Muting Alarm conditions cause the sounder to be activated and the alarm LED to illuminate, subject to these facilities being enabled for the alarm. The appropriate LCD alarm flag is always activated. The user can silence ( mute ) the alarm by pressing and holding the button, provided mute is enabled on the alarm.

  • Page 33: Button Operation And Display Selection

    EPD/HB/40521/000 Button Operation and Display Selection The EPD will display a range of data to the user. The data displayed is selected by use of the button. The full range of displays is arranged on a two dimensional grid, as shown in Figure 3.4. There are a number of menus, each having a top-level display.

  • Page 34: Lcd Display Lock-On Facility

    Any new display selected using the button remains visible for a set period of time, (Thermo Electron default time-out is 10 seconds), before returning to the default display. Some display selections (marked * in Figure 3.4) can be ‘locked-on’, i.e. the return to the default display is suspended.
  • Page 35 EPD/HB/40521/000 Top-Level Display Sub-Displays Display:0 Menu Button Operation: Short- Next display or lock-on Blank User ID digits User ID digits User ID digits H10 Dose HP10 H10 Dose 5,6,7,8 1,2,3,4 9,10,11,12 H10 Doses Rate * ADS User ID ADS User ID ADS User ID H07 Dose HP07...

  • Page 36: Display Options And Button Functions

    EPD/HB/40521/000 Display Options and Button Functions The following sections describe typical displays that a user may see within each of the menus shown in Figure 3.4. This description assumes that all displays are enabled. The user may have access to any (or none) of the displays, depending on how the EPD has been configured.

  • Page 37: Displaying Hp(0.07) Doses, Dose Rate And Ads User Id

    EPD/HB/40521/000 Display Range: 0µSv/h to >4Sv/h (auto ranging) Note: Over-range (> 1.0 Sv/h) is indicated with a flashing LCD display. This condition is latched to warn the user that the dose value may be inaccurate. User ID Digits Short-press the button again to display the user identity number (User ID). This is a 12-digit number that is shown on three separate displays - the High 4 digits, the Middle 4 digits and the Low 4 digits.
  • Page 38 EPD/HB/40521/000 is used for tactical dose monitoring (e.g. per task etc.). Display Range: 0µSv to >16Sv (auto ranging). Note: Over-range (> 1.0 Sv) is indicated with a flashing LCD display. Hp(0.07)/h Dose Rate Display Short-press the button again to display the current Hp(0.07)/h dose rate.

  • Page 39: Displaying Total Dose

    EPD/HB/40521/000 3.5.3 Displaying Total Dose To display total dose, press and hold the button until this top-level display appears: Two sub -displays are available (in the following sub-display order): ♦ Hp(10) Total Dose ♦ Hp(0.07) Total Dose Hp(10) Total Dose Short-press the button to display the total Hp(10) dose.

  • Page 40: Turning The Epd Off

    EPD/HB/40521/000 ♦ Count-down Time MM:SS ♦ Reset (rSt) The count-down timer is a useful facility for activities where actions need to be completed within known time periods. The User may start, stop and reset the count down timer using the button. When the timer expires the appropriate alarm is sounded.

  • Page 41: Displaying Peaks (Rate High)

    EPD/HB/40521/000 To turn the unit off, press and hold the button until the word ‘On’ appears: Only one sub -display is available: ♦ On/Off This function enables the EPD to be placed in sleep or OFF mode. In OFF mode power consumption is reduced considerably and the EPD stops measuring radiation.

  • Page 42: Epd Confidence Test

    EPD/HB/40521/000 Short-press the button to display the Peak Hp(10)/h Dose Rate: Peak Hp(0.07)/h Dose Rate Short-press the button again to display Peak Hp(0.07)/h Dose Rate: Note: Peaks can only be cleared via the IR communications link. 3.5.7 EPD Confidence Test To perform the EPD confidence test, press and hold the button until this top-level display appears:...
  • Page 43 EPD/HB/40521/000 seconds. This indicates that the LCD segments can be turned off, and that the tone frequencies are functional. The all-segment display will reappear for approximately 5 seconds and the LED will slow flash. 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.

  • Page 44: Clearing Dose Displays

    EPD/HB/40521/000 3.5.8 Clearing Dose Displays To clear dose displays, press and hold the button until this top-level display appears: Only one sub -display is available ♦ Clr? This mode is used to clear the Hp(10) and Hp(0.07) doses. Note: The total doses are not cleared. Press the button once to select the display shown opposite.
  • Page 45 EPD/HB/40521/000 There are two Hp(10) alarm thresholds and a single Hp(0.07) alarm threshold that can be displayed and modified. The 2 Hp(10) dose alarm has the higher priority and should always be set to a higher value than the 1 Hp(10) alarm.

  • Page 46: Displaying/Setting Dose Rate Alarm On/Off Thresholds

    EPD/HB/40521/000 3.5.10 Displaying/Setting Dose Rate Alarm On/Off Thresholds To display and/or set dose rate alarm ON thresholds, press and hold the button until this top-level display appears: Three sub-displays are available (in the following sub -display order): ♦ Hp(10)/h Dose Rate Alarm ON ♦...
  • Page 47 EPD/HB/40521/000 Other values for the dose rate alarm thresholds may be set via the IR communications link. Note: To avoid false alarms due to counting statistics it is recommended that the Hp(0.07)/h dose rate alarm is not set to less than 100µSv/h Example 1 H p (10)/h dose rate on alarm threshold display set at a default...

  • Page 48: Setting The Sounder

    EPD/HB/40521/000 Notes: The ‘On’ threshold must always be greater than or equal to the ‘Off’ threshold. If an attempt is made to set the ‘On’ threshold below the ‘Off’ threshold the ‘Off’ threshold will be set automatically to the same value as the ‘On’ threshold. If an attempt is made to set the ‘Off’...
  • Page 49 EPD/HB/40521/000 Short-press the button to display the button beep enable/disable window. To configure the beep feature 'off' or 'on' double -press the button while the EPD is displaying the following displays. Button Beep Enabled Button Beep Disabled Dose Chirp Adjustment The EPD can be configured to give a warning chirp at every preset increment in Sv and Hp(10)/h, penetrating (deep) dose.
  • Page 50 EPD/HB/40521/000 Pressing the button will increase the dose per chirp in the following increments: 0.0µSv, 0.01µSv, 0.05µSv, 0.1 µSv, 0.5µSv, 1.0µSv, 5µSv, 10µSv, 50µSv, 100µSv. When the required sensitivity is reached “double-pressing” the button will confirm the value and the flashing display will stop. If you start to change the sensitivity, and change your mind, the option can be aborted.
  • Page 51 EPD/HB/40521/000 This page intentionally blank ISSUE 5 EPD TECHNICAL HANDBOOK Page 41...

  • Page 53: Section 4

    EPD/HB/40521/000 SECTION 4 TECHNICAL DESCRIPTION This section provides a technical description of the EPD and contains a summary of the EPD’s radiological features together with a summary of the EPD’s electrical, mechanical and environmental characteristics. General The EPD is of rugged construction and is suitable for most conditions that can reasonably be expected in industrial environments.

  • Page 54: Electrical Characteristics

    EPD/HB/40521/000 Electrical Description 4.2.1 Electrical Characteristics Power Supply: One AA Lithium Thionyl Chloride (LTC) battery 3.6 V), giving typically 5 months continuous operation at an average dose rate <5µSv/h with the alarm sounding <5 hours total during battery life. One standard AA Alk aline battery (1.5 V), giving typically 55 days continuous operation at an average dose <5µSv/h with the alarm sounding <2 hours total during battery life.
  • Page 55 EPD/HB/40521/000 (ii) As the battery voltage under load continues to fall, the low battery alarm flag is activated to indicate when a minimum of 10 hours battery life is remaining. Different thresholds are automatically selected for LTC or alkaline batteries. (iii) As the battery voltage under load finally falls below tolerance the EPD resets (blank display).

  • Page 56: Mechanical Description

    EPD/HB/40521/000 Mechanical Description 4.3.1 Mechanical Characteristics And Dimensions Display and function control: Single button on the front of the EPD (recessed to prevent inadvertent operation). Case material : High impact Polycarbonate/ABS blend. Clip : High impact plastic clip assembly comprising: ♦...
  • Page 57 EPD/HB/40521/000 Figure 4.1 - EPD Dimensions ISSUE 5 EPD TECHNICAL HANDBOOK Page 47...

  • Page 58: Environmental Description

    EPD/HB/40521/000 Environmental Description 4.4.1 Environmental Characteristics Operating Temperature : -10°C to +40°C. Storage: -25°C to +70°C. Humidity: 20% to 90% RH non condensing. Protection: IP55. Total protection against dust and against low pressure jets of water from all directions. Vibration: IEC 1526 2g, 15 min, 10 - 33 Hz Shock: 1.5 m drop on each surface onto concrete.

  • Page 59: Infra-Red Interface

    On the front of the EPD there is an IR communications link for reading and writing data. Communication with the EPD is usually via an IR adapter, which is connected to a host PC. EasyEPD2 is a Thermo Electron PC-based software product for maintaining, configuring and reading EPDs. The IR communication range is up to 1m, over an angle of ±30°...
  • Page 60 EPD/HB/40521/000 the EPD reverts to normal display. There is also an inhibit timer that prevents an EPD from re-establishing communications immediately after communications are completed. This gives the user time to remove the EPD from the IR field. The EPD continues to measure radiati on during communication.

  • Page 61: Epd Internal Processing & Facilities

    EPD/HB/40521/000 EPD Internal Processing & Facilities This section describes the internal processing performed by the EPD and the facilities provided over the IR communications link. 4.6.1 Memory Characteristics: Memory Retention: 10-year data retention. Dose Profile History: Settable interval from two seconds to 35 hours. Stores transitions of Hp(10) and Hp(0.07) at a resolution of 1µSv.

  • Page 62: Alarm Characteristics

    EPD/HB/40521/000 4.6.2 Alarm Characteristics: Alarms: 2 each Hp(10) dose and dose rate alarms 1 each Hp(0.07) dose and dose rate alarms Dose and Dose Rate Alarms: 0µSv to 16Sv and 0µSv/h to 16µSv/h resolution V 1/64µSv and 1µSv/h Recommended minimum settings to avoid false alarm 7µSv/h Hp(10)/h and 100µSv/h Hp(0.07)/h Alarm Types:...

  • Page 63: Dose And Dose Rate

    EPD/HB/40521/000 4.6.5 Dose and Dose Rate The EPD calculates dose and dose rate. Dose is accumulated in 3 stores: Dose, Total Dose and ADS Dose. Dose rate is the current rate calculated by the EPD. Dose The EPD displays Hp(10) (penetrating or deep) dose and Hp(0.07) (superficial or shallow) dose.

  • Page 64: Counts

    EPD/HB/40521/000 seconds below 1mSv/h. Due to limitations in the processing and memory available, this time constant cannot be reduced when rapid changes are observed, and the Hp(0.07)/h dose rate is approximated as the sum of Hp(10)/h and the beta dose rate. This approximation means that at low gamma energies (below 50 keV) the Hp(0.07)/h dose rate typically under-responds by up to 25% in comparison to the Hp(0.07) dose response.

  • Page 65: Dose Quality Flags

    EPD/HB/40521/000 4.6.7 Dose Quality Flags There are 7 dose quality flags set within the EPD. Dose quality can only be read and cleared via the IR communications link. They are normally cleared at the start of an Issue period. The dose quality flags are as follows: (i) Reset Count The reset count flag is a count of the number of times the unit has been reset, either removing and re-fitting the battery,...

  • Page 66: (Vi) Abuse Warning

    EPD/HB/40521/000 the unit has either been exposed to some kind of extreme interference or has developed a fault. (vi) Abuse Warning The abuse warning indicates that an abuse alarm has been activated. An abuse alarm is activated if mechanical shocks are detected continuously for greater than 45 seconds (see Shock Time Seconds) (vii) CRC Failure The CRC failure flag is set as a result of an integrity check on a set of data indicating...

  • Page 67: Epd Operating Status

    EPD/HB/40521/000 Alarm thresholds are set via the IR communications link, or by the button if the user is granted authority (see Figure 3.4), to any value in the following ranges: & 2 Hp(10)/h 0µSv/h to 16.777215 Sv/h Hp(0.07)/h 0µSv/h to 16.777215 Sv/h &...

  • Page 68: Alarms

    EPD/HB/40521/000 Detectors State. This is the current state of the EPD’s operating mode, i.e. ON or OFF. Alarms The EPD retains a record defining which of the following alarms has occurred. The record is normally cleared by system software at the start of an issue period: 3 Dose Alarm Flags As section 4.6.8 3 Dose Rate Alarm Flags.

  • Page 69: Dose Profile

    EPD/HB/40521/000 Disabled. The EPD is not calculating dose. 4.6.10 Dose Profile The EPD stores Hp(10) and Hp(0.07) dose to a resolution of 1µSv in non-volatile store so that a profile of the dose over time can be recreated. The interval between stores is set-up via the IR communications link.
  • Page 70 EPD/HB/40521/000 Events On Events Off Code Text as displayed by Code Text as displayed by EasyEPD2 EasyEPD2 Failure Alarm on Failure Alarm off Over Range Alarm on Over Range Alarm off Hp10 Dose Alarm 2 on Hp10 Dose Alarm 2 off Hp07 Dose Alarm on Hp07 Dose Alarm off Hp10 Dose Alarm 1 on...

  • Page 71: Section 5

    EPD/HB/40521/000 SECTION 5 EPD FAULTS and RECOVERY ACTIONS Overview This section identifies the fault conditions that can occur and describes the recovery procedure (if any) to be taken to restore the EPD to operational use. The section is organised as follows: 1.

  • Page 72: Visual And Audible Fault Indication

    EPD/HB/40521/000 Visual and Audible Fault Indication An EPD failure is usually indicated by a visual and audible alarm. In most instances the EPD will display an error code on the LCD and the LED will flash. The default audible alarm is as follows: Alarm rate: ___ ___ ___ ___ slow intermittent rate If alarm mute is enabled for the fault alarm the sounder can be silenced and the alarm Led extinguished by the action of pressing and holding the button.

  • Page 73: Internal Logging Of Fault Conditions

    EPD/HB/40521/000 Internal Logging of Fault Conditions 5.3.1 EPD Status Faults Record The EPD logs data to an internal data record in EEPROM, to indicate that faults have occurred. These faults are as follows: Event Logged. An event (dose alarm or a fault) has been logged in the EPD’s event history store.
  • Page 74 EPD/HB/40521/000 Note: The date/time data field wraps round after 194 days of operation. After this time previous event-associated day/date(s) cannot be considered as accurate. In addition elapsed time during loss of power is not recorded. ISSUE 5 EPD TECHNICAL HANDBOOK Page 64...

  • Page 75: Blank Lcd Display And Other Faults

    EPD/HB/40521/000 Blank LCD Display and Other Faults It may also be possible for the EPD to fail without producing or displaying an error code, or causing an alarm, for example due to failure of the micro-controller or digital circuit. A list of such faults and the recommended course of action is given in the table below.
  • Page 76 EPD/HB/40521/000 Confidence Test ♦ Enable sounder if required Sound fails to operate in Sounder Disabled alarm condition ♦ Contact supplier. Faulty LED Hardware fault No visual alarm during Confidence Test ♦ Enable LED if required LED Disabled LED fails to operate in alarm condition ♦...

  • Page 77: Initialisation Error ( Lcd

    EPD/HB/40521/000 Initialisation Error ( LCD ---- ) A series of single dashes appearing on the LCD display indicates an initialisation error following a reset or battery change: Initialisation errors typically refer to corruptions to data in the EPD’s non volatile memory (EEPROM).
  • Page 78 EPD/HB/40521/000 An EPD will only raise this condition if it is first triggered by the system software, in effect a message is passed to the EPD saying: “raise an alarm if the following write operations don’t complete successfully within ‘N’ seconds.” If the condition does occur then it is necessary to train the users not to remove the EPD from the IR field until indicated ( i.e.

  • Page 79: Lcd Display Error Codes

    EPD/HB/40521/000 LCD Display Error Codes Faults that exhibit a known condition are normally indicated on the EPD LCD as ‘F’ followed by a 3-digit error. The error code number is also logged in the Event History store, with date/time data. As an example the following shows fault F095: A list of EPD error codes is given in Table 5.2.

  • Page 80: Recovery Procedures

    Fault Log Form ( Appendix D ). If a faulty unit is to be r e turned to Thermo Electron it must be returned in a fully decontaminated and reasonably clean condition. The battery must be removed but kept with the unit.
  • Page 81 EPD/HB/40521/000 If the unit is to be restored to operational use, clear down all faults on display and in the Fault Status Record, using EasyEPD2. This is to ensure that any subsequent faults are detected. Control Module Code Text as displayed by Recommended Remarks EasyEPD2...
  • Page 82 EPD/HB/40521/000 Services Module Code Text as displayed by Recommended Remarks EasyEPD2 Action Customer Action Service Module stCalData Reset unit. Return to CRC faulty supplier if recurs. Service Module Reset unit. Return to stRateThres CRC faulty supplier if recurs. Service Module Reset unit.
  • Page 83 EPD/HB/40521/000 EEPROM Module Code Text as displayed by Recommended Remarks EasyEPD2 Action Customer Action EEPROM no more spare Write Return to supplier All 9 spare sectors have been sectors available aband used. This fault is unlikely to oned. occur in normal operation. Tests have shown that the EEPROMs are very resilient ( >...
  • Page 84 EPD/HB/40521/000 Counts Module Code Text as displayed by EPD Action Recommended Remarks EasyEPD2 Customer Action Unexpected Texas chip Reset unit. No Longer Used reset (Battery Low but no Return to Batt Low Status) supplier if recurs. Consecutive Drop (more No Longer Used than 45 seconds) Counts not latched yet Reset into...
  • Page 85 EPD/HB/40521/000 Code Text as displayed by EPD Action Recommended Remarks EasyEPD2 Customer Action Hard Gamma detector fail* None- continues Reset unit. Only the first normal processing Return to detector to fail is supplier if logged. recurs. Soft Gamma detector fail* None- continues -ditto- -ditto-...
  • Page 86 EPD/HB/40521/000 This page is intentionally blank ISSUE 5 EPD TECHNICAL HANDBOOK Page 76...

  • Page 87: Section 6

    Electron has no control over any subsequent adjustments made by the end user to these factors. Thermo Electron can therefore not warrant the calibration of these EPDs once they have left the factory. As such, Thermo Electron accepts no liability for the accuracy of the radiological response of these EPDs.
  • Page 88 A change in EPD calibration is usually indicative of a fault in the EPD and, due to the complexity of achieving calibration over the full energy range, it is recommended that any EPDs that fail calibration checks are returned to Thermo Electron for repair, recalibration or replacement.

  • Page 89: The Epd Battery

    EPD/HB/40521/000 The EPD Battery The EPD can use either a Lithium Thionyl Chloride (LTC) 3.6 V battery or a standard 1.5 V AA battery (see Section 4.2). A battery change is within the scope of any competent user. However, care must be taken when replacing the EPD battery (see Section 6.2.3).

  • Page 90: Lithium Thionyl Chloride Battery Warning

    EPD/HB/40521/000 going to be left non-operational for any length of time to avoid the possibility that leakage may occur and damage the EPD. 6.2.3 Lithium Thionyl Chloride Battery Warning Lithium Thionyl Chloride (LTC) (Sulphurous Oxychloride, SOCl ) batteries are potentially dangerous and can be harmful. The following warnings are to be observed when inserting/replacing the EPD battery.

  • Page 91: Replacing The Epd Battery

    EPD/HB/40521/000 the battery should be removed from the EPD using protective clothing, gloves, and goggles. (ii) the battery should be placed in a self-sealing polythene bag (or equivalent) and disposed of in the correct manner (see below). (iii) Wash with copious amounts of water any areas that come into contact with the electrolyte, especially the skin.

  • Page 92: Epd Clip Assembly

    EPD/HB/40521/000 EPD Clip Assembly Depending on customer requirements, the EPD may (or may not) be fitted with a clip assembly. The clip assembly comprises a lanyard plate and a spring clip, which allows the user to attach the EPD to an outer garment (see Section 2.1.6). The clip assembly is attached to the EPD by the lanyard plate.

  • Page 93: Removing The Epd Lanyard Plate/Clip Assembly

    EPD/HB/40521/000 Figure 6.2 - EPD With Clip Assembly 6.3.1 Removing the EPD Lanyard Plate/Clip Assembly To remove the lanyard plate/clip assembly, proceed as follows: If the spring clip is fitted to the lanyard plate, open the jaws of the clip by pushing downwards (see Figure 6.2) to give access to the lanyard plate.

  • Page 94: Replacing The Epd Lanyard Plate/Clip Assembly

    EPD/HB/40521/000 Insert a screwdriver, with a blade width of 3 to 4 mm, under the lanyard plate tang and apply downward leverage on the screwdriver (see Figure 6.4). At the same time, push the lanyard plate towards the bottom of the EPD so as to disengage the lanyard plate from the retaining lugs.

  • Page 95: Cleaning

    EPD/HB/40521/000 Cleaning The EPD is a sealed unit and has protection against dust and low pressure jets of water from all directions. The unit will not withstand prolonged immersion under pressure. Cleaning should be carried out if the unit requires general cleaning, if the EPD battery has leaked or if the unit has come into contact with radioactive contamination.

  • Page 96: Periodic Cleaning

    EPD/HB/40521/000 the leakage the EPD should be considered as unusable and the manufacturer contacted for advice. 6.4.4 Periodic Cleaning The EPD should be cleaned by wiping it over periodically with a cloth lightly dampened with a solution of water and up to 5% of a neutral water-based detergent. ISSUE 5 EPD TECHNICAL HANDBOOK Page 86...

  • Page 97: Radiological Specifications

    EPD/HB/40521/000 APPENDIX A RADIOLOGICAL SPECIFICATIONS The following specifications quoted apply under standard conditions of 20°C. Energy response ♦ Photon Hp(10) ±50% 15keV to 17keV (Ref. Cs-137) ±20% 17keV to 1.5MeV (Ref. Cs-137) ±30% 1.5MeV to 6MeV (Ref. Cs-137) ±50% 6MeV to 10MeV (Ref. Cs-137) ♦...
  • Page 98 EPD/HB/40521/000 Typical EPD Mk2 Energy Response Sr/Y Hp(10) Hp(0.07) 1000 10000 Photon Energy (keV) ISSUE 5 EPD TECHNICAL HANDBOOK Page 88...

  • Page 99: Electromagnetic Compatibility

    EPD/HB/40521/000 APPENDIX B ELECTROMAGNETIC COMPATIBILITY Standard Test The EPD was tested to the following specification with no failures: Test Type Specification Test Frequency Range Level Notes Radiated Mil Std 416D RS103 10kHz – 40 GHz 200V/m Susceptibility E- Field Radiated Def Stan 59-41 DRS02 14kHz –...
  • Page 100 EPD/HB/40521/000 Chart 1 10000 1000 1000 10000 100000 Frequency (Hz) Chart 1. The tested Mk2 EPDs were not susceptible to H-field radiation below the above graph. ISSUE 5 EPD TECHNICAL HANDBOOK Page 90...
  • Page 101 EPD/HB/40521/000 Chart 2 1400 1200 1000 1000 10000 100000 Frequency (MHz) Chart 2. The tested Mk2 EPDs were not susceptible to E-field radiation below the above spot frequencies (100kHz-100GHz carrier wave). ISSUE 5 EPD TECHNICAL HANDBOOK Page 91...
  • Page 102 EPD/HB/40521/000 Chart 3 2500 2000 1500 1000 Frequency (GHz) Chart 3. The tested Mk2 EPDs were not susceptible to E-field radiation below the above spot frequencies (0.1GHz - 100GHz pulsed 1kHz 1µS) ISSUE 5 EPD TECHNICAL HANDBOOK Page 92...
  • Page 103 EPD/HB/40521/000 This page is intentionally blank ISSUE 5 EPD TECHNICAL HANDBOOK Page 93...

  • Page 105: Summary Of General Physical & Functional Characteristics

    EPD/HB/40521/000 APPENDIX C SUMMARY OF GENERAL PHYSICAL & FUNCTIONAL CHARACTERISTICS Feature Characteristic 1.5V Alkaline AA or 3.6V Lithium Thionyl Chloride Battery Type (LTC) AA batteries. ( Observe Manufacturers warnings. ) Dimensions Diameter : 13.9 to 14.6 mm, Length : 49.0 to 51.0 mm. Typical Life 5 months (LTC), 55 days (Alkaline), continuous...
  • Page 106 IR communication to front of unit, range up to 1m. use standard IrDA adapters ( physical level 1 ) with ions & Internal Thermo Electron supplied DLL and application s/w as Data required ( EasyEPD2, Access Control s/w etc. ).
  • Page 107 ( Cyclic Redundancy Check ). Calibration. EPDs normally supplied with Calibration factors in the ‘locked’ state and only changeable by Thermo Electron. On request Thermo Electron will supply units with calibration factors unlocked. Dose Data User ‘dose’ readings also include detector counts and verification associated ‘quality’...
  • Page 108 EPD/HB/40521/000 essential ). Controls Various controls are possible over the communications interface to configure displays, sounder operation, detector and self test, clear dose and detector counts, analyse and clear faults, set alarm thresholds and alarm characteristics, turn the EPD On or Off, enable and disable controls via the button, adjust the dose profile and special store operation.

  • Page 109: Epd Fault Log Form

    EPD/HB/40521/000 APPENDIX D EPD FAULT LOG FORM SEE OVER ISSUE 5 EPD TECHNICAL HANDBOOK Page 99...
  • Page 110 EPD/HB/40521/000 This page intentionally blank. ISSUE 5 EPD TECHNICAL HANDBOOK Page 100...
  • Page 111 Owning Organisation: Site or Location: REPORT NO.: Related / Repeated Report Nos.: Raised By: Date: Contact / Telephone dd/mm/yyyy EPD Supplier ( Thermo Electron or Form Returned to: Distributor ): BATTERY Type (Alkaline or LTC): Manufacturer: Supplied by: EPD Serial No.s: Date/Time fault occurred: Fault type, e.g.
  • Page 112 EPD FAULT LOG FORM HB40521...
  • Page 113 EPD/HB/40521/000 INDEX Abuse Warning .................................56 Alarm Characteristics ..............................52 Configuration................................17 features..................................16 hysteresis ................................20 Muting ..................................22 Priorities ................................18 Sounder Volume..............................44 Tones ..................................19 Alkaline battery ................................44 Backlight..................................13 battery Replacement................................81 Battery..................................79 Warning ................................xi Battery cap ..................................7 Battery cap special tool............................7 Battery Management ..............................44 Battery storage .................................80 Beep (button)- enabling/disabling........................38 Beta radiation................................2...
  • Page 114 EPD/HB/40521/000 Display Selections..............................25 ADS User ID ................................27 Count Down Timer..............................30 Counters Display..............................40 Hp (10) Dose, Dose Rate............................26 Hp(0.07) Doses, Dose Rate..........................27 Peak Dose Rates..............................32 Total Dose................................30 User ID..................................26 Dose Alarm Thresholds ............................34 Dose Alarms................................20 Dose Chirp Adjustment ............................39 Dose Quality................................55 Dose Rate..................................53 Dose Rate Alarms ..............................20 Dose Store.................................59...
  • Page 115 EPD/HB/40521/000 Non-faulty Blocks..............................57 Off mode ..................................31 Off Mode Off times .................................57 Operating Instructions ..............................13 Operating Temperature............................48 Over-Range ................................21 Overview..................................1 Pocket Clip/Lanyard..............................82 Power.....................................1 Rem ....................................3 Run Time ..................................57 Secure Memory................................2 Sieverts..................................3 Silicon Diode detectors ............................1, 2 Start-up Sequence..............................9 TECHNICAL DESCRIPTION............................43 thresholds...................................36 USA Sales Office..............................iv Warning..................................80...

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