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Thermo Electron EPD MK2 Technical Manual
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Thermo Electron EPD MK2 Technical Manual

Beta/gamma sensitive electronic personal dosemeter
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EPD/HB/40521/000
EPD MK2
Beta/Gamma Sensitive
Electronic Personal Dosemeter
Technical Manual
February 2004

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May 14, 2025

What is difference in the blue, orange, and gray EPD. We are using the ThermoScientific MK2.

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Summary of Contents for Thermo Electron EPD MK2

  • Page 1 EPD/HB/40521/000 EPD MK2 Beta/Gamma Sensitive Electronic Personal Dosemeter Technical Manual February 2004...
  • Page 3 © Thermo Electron Corporation 2004 ALL RIGHTS RESERVED. REPRODUCTION IN WHOLE OR IN PART OF ALL MATERIAL THIS PUBLICATION, INCLUDING DRAWINGS DIAGRAMS, IS FORBIDDEN. THIS INSTRUCTION MANUAL IS CONFIDENTIAL TO THERMO ELECTRON CORPORATION AND IS SUPPLIED FOR USE ONLY IN CONNECTION WITH THE OPERATION AND/OR...
  • Page 5 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 MANUFACTURERS DETAILS & ISSUE STATE MANUFACTURERS DETAILS Manufacturer's Address Thermo Electron Corporation Environmental Instruments Division Radiation Measurement & Protection Sopers Lane Poole Dorset United Kingdom BH17 7ER e-mail: service.epd.uk@thermo.com Tel. (01202) 782740 Fax. (01202) 782056...

  • Page 7: Table Of Contents

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 CONTENTS CONTENTS Page GLOSSARY ..........................VII WARNINGS AND CAUTIONS ....................IX SECTION 1........................... 1 INTRODUCTION.......................... 1 ........................1 ENERAL EPD M ..................2 AJOR HARACTERISTICS .................. 3 RIEF UNCTIONAL ESCRIPTION SECTION 2........................... 5 GETTING STARTED ........................5 ........................
  • Page 8 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 CONTENTS SECTION 4..........................41 TECHNICAL DESCRIPTION..................... 41 ........................41 ENERAL ..................42 LECTRICAL ESCRIPTION 4.2.1 Electrical Characteristics ..................42 4.2.2 Battery Management .................... 42 4.2.3 On / Off Operating Modes ..................44 ..................45 ECHANICAL ESCRIPTION 4.3.1 Mechanical Characteristics And Dimensions ............
  • Page 9 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 CONTENTS SECTION 5..........................63 EPD FAULTS AND RECOVERY ACTIONS ................63 ........................63 VERVIEW ..............64 ISUAL AND UDIBLE AULT NDICATION ..............65 NTERNAL OGGING OF AULT ONDITIONS 5.3.1 EPD Status Faults Record..................65 5.3.2 Event History store ....................

  • Page 11: Glossary

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 GLOSSARY 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 12 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 GLOSSARY Glossary (continued) The Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin. The national institute of natural and engineering sciences and the highest technical authority for metrology and physical safety engineering of the Federal Republic of Germany. Shallow Dose Equivalent (alternative nomenclature for H p (0.07)) Parts per million Random Access Memory A unit of dose equivalent, equal to 10mSv...

  • Page 13: Warnings And Cautions

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 WARNINGS AND CAUTIONS WARNINGS Radioactive Contamination DURING OPERATIONAL USE THE EPD MAY BECOME EXPOSED TO RADIOACTIVE CONTAMINATION. MUST SUBJECT RELEVANT DECONTAMINATION PROCEDURES LAID DOWN RADIOLOGICAL PROTECTION AUTHORITY. Lithium Thionyl Chloride Batteries LITHIUM THIONYL CHLORIDE* (LTC) BATTERIES ARE POTENTIALLY DANGEROUS. THEY MAY LEAK TOXIC SUBSTANCES THAT CAN BE HARMFUL.

  • Page 15: Section 1

    INTRODUCTION This handbook is for the Thermo Electron Corporation Electronic Personal Dosemeter (EPD), Beat/Gamma variant, Mks 2.0, 2.1, 2.2 & 2.3. The EPD Mk2 family is lighter and slimmer than the original Mk1 EPD and has new micro- circuitry, case design and software.

  • Page 16: Epd Major Characteristics

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 INTRODUCTION 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).

  • Page 17: Brief Functional Description

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 INTRODUCTION 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...
  • Page 18 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 INTRODUCTION ♦ 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: This manual deals with Sieverts (Sv) throughout. To convert to rem multiply all values by 100.

  • Page 19: Section 2

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 GETTING STARTED 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. 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 20: Unpacking The Epd

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 GETTING STARTED 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 control, alarm acknowledgement and LCD display selection. Sounder Provides an audible indication of an EPD alarm.
  • Page 21 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 GETTING STARTED 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 22 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 GETTING STARTED 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 23: Start-Up Sequence

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 GETTING STARTED 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.

  • Page 24: Epd Confidence Test

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 GETTING STARTED 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 25: Wearing An Epd

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 GETTING STARTED 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. For most operating conditions it is recommended that the EPD be worn on the outside of any protective clothing (see Figure 2.5).
  • Page 26 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 GETTING STARTED 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 Page 12 Thermo...

  • Page 27: Section 3

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS SECTION 3 OPERATING INSTRUCTIONS This section explains the essential functions performed by the EPD and describes operating instructions that will allow the user to display data, acknowledge alarms and operate the EPD. LCD Display and Backlight A custom-designed LCD display on the top of the EPD provides a visual interface for viewing dose and other EPD data.
  • Page 28 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS ♦ The backlight activation causes a temporary alarm muting effect, see section 3.2.5. ISSUE 5 Page 14 Thermo...
  • Page 29 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS Figure 3.2 - LCD Display Segments ISSUE 5 Thermo Page 15...

  • Page 30: Audible And Visible Alarms

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS 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 of between 98 to 101 dBA (4 kHz...
  • Page 31 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS 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.
  • Page 32 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS 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 at manufacture. The following alarms are regenerated after a reset (e.g. battery change): •...
  • Page 33 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS Priority Alarm/Event Alarm Tone Frequency Volume EPD Failure Alarm. Intermittent Single Slow Tone High Loud __ __ __ __ Over-range Alarm. Continuous Dual Fast Tone High/Low Loud _-_-_-_-_-_ Hp (10) Dose Alarm Continuous Single Tone High Loud ____________...

  • Page 34: Dose Alarms

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS 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.

  • Page 35: Over-Range Indication

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS 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).

  • Page 36: Alarm Muting

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS 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 37: Button Operation And Display Selection

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS 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.

  • Page 38: Lcd Display Lock-On Facility

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS LCD Display Lock-on Facility Any new display selected using the button remains visible for a set period of time, (Thermo 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 39 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS 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 H P 1 0 H10 Dose 5,6,7,8 1,2,3,4 9,10,11,12 H10 Doses Rate * ADS User ID...

  • Page 40: Display Options And Button Functions

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS 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.

  • Page 41: Displaying Hp(0.07) Doses, Dose Rate And Ads User Id

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS Note : Over-range (> 1.0 Sv/h) is indicated with a flashing LCD display, see section 3.2.4. 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).
  • Page 42 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS Hp(0.07) Dose Display Short-press the button to display the current dose. This dose parameter is used for tactical dose monitoring (e.g. per task etc.). Display Range: 0 µ Sv to >16Sv (auto ranging). Note : Over-range (>...
  • Page 43 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS In systems using 8 or fewer digits for the ADS User ID it is usual to disable and thereby remove the unused displays ( e.g. the first and second display in the above example). ISSUE 5 Thermo Page 29...

  • Page 44: Displaying Total Dose

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS 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...

  • Page 45: Turning The Epd Off

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS 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 46: Displaying Peaks (Rate High)

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS Assuming that the display shows On, double-press the button. The display will change to “OFF” (flashing). Double-press the button again to confirm the request. The display will change to the word “OFF” (not flashing), confirming that the unit is in OFF mode and not measuring radiation.
  • Page 47 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS To perform the EPD confidence test, press and hold the button until this top-level display appears: Only one sub-display is available: ♦ Test This test can be run at any time during operational use as a confidence check that the EPD is functioning correctly.

  • Page 48: Clearing Dose Displays

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS 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.
  • Page 49 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS and should always be set to a higher value than the 1 Hp(10) alarm. The accumulated dose alarm thresholds can be set using the button as follows: 10 µ Sv, 50 µ Sv, 100 µ Sv, 500 µ Sv, 1mSv, 5mSv, &...

  • Page 50: Displaying/Setting Dose Rate Alarm On/Off Thresholds

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS 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): ♦...
  • Page 51 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS 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 100 µ Sv/h Example 1 H p (10)/h dose rate on alarm threshold display set at a default value of 500 µ...

  • Page 52: Setting The Sounder

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS 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.
  • Page 53 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 OPERATING INSTRUCTIONS 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 Hp(10)/h, penetrating (deep) dose. This increment can be set between 0.01 µ µ...
  • Page 54 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 OPERATING INSTRUCTIONS If you start to change the sensitivity, and change your mind, the option can be aborted. Short-press the button until the following is displayed (letters flashing). Double-press the button to confirm you want to return to the previous chirp sensitivity.

  • Page 55: Section 4

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 TECHNICAL DESCRIPTION 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 56: Electrical Description

    The EPD software runs an internal battery condition test at regular intervals (between 1 and 60 minutes). This time interval is factory preset to 15 minutes and should not be adjusted except following consultation with Thermo Electron. EPDs prior to software version 11: If a 1.5V Alkaline battery is installed the EPD automatically switches-in a step-up...
  • Page 57 (Lithium battery)* * These thresholds should not normally require adjustment and any adjustment considered should first be agreed with Thermo Electron. The battery low alarm and LCD segment are activated when the battery voltage falls below the appropriate battery low threshold. The EPD will continue to run normally thereafter for a period of at least 10 hours, though this may be shortened by continuous audible alarm output.

  • Page 58: On / Off Operating Modes

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 TECHNICAL DESCRIPTION Additional information and warnings relating to the EPD battery are given in Section 6.2. 4.2.3 On / Off Operating Modes The EPD has an ON/OFF power saving facility, in which the detectors are turned off, which is intended for short-term storage (e.g.

  • Page 59: Mechanical Description

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 TECHNICAL DESCRIPTION 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 60 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 TECHNICAL DESCRIPTION Figure 4.1 - EPD Dimensions ISSUE 5 Page 46 Thermo...

  • Page 61: Environmental Description

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 TECHNICAL DESCRIPTION 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:...

  • Page 62: Infra-Red Interface

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 TECHNICAL DESCRIPTION Infra-red Interface The EPD contains an infra-red interface (see Figure 4.2) which can optically communicate (read and write) to PC-based hardware using a suitable infra-red communications program. This interface is compatible with IrDA level 1 protocol. Figure 4.2 - EPD Infra-Red Interface 4.5.1 Communicating With The EPD...

  • Page 63: Epd Configuration Via The Ir Communications Links

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 TECHNICAL DESCRIPTION communications are completed. This gives the user time to remove the EPD from the IR field. The EPD continues to measure radiation during communication. 4.5.2 EPD Configuration via the IR Communications Links Communication via the EPD’s IR communications link will allow access to the following EPD functions and displays: ♦...
  • Page 64 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 TECHNICAL DESCRIPTION 2) PTB APPROVED EPD The Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, is the national institute of natural and engineering sciences and the highest technical authority for metrology and physical safety engineering of the Federal Republic of Germany.

  • Page 65: Epd Internal Processing & Facilities

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 TECHNICAL DESCRIPTION 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.

  • Page 66: Alarm Characteristics

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 TECHNICAL DESCRIPTION 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...

  • Page 67: Dose And Dose Rate

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 TECHNICAL DESCRIPTION 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 68: Counts

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 TECHNICAL DESCRIPTION Averaging time constants used to calculate penetrating dose rate Hp(10)/h maximise at 60 seconds below 70uSv/h and therefore the statistical errors increase as the dose rate drops below 70uSv/h. Additional processing is used to provide faster response but with reduced accuracy when rapid changes in dose rate are observed.

  • Page 69: Dose Quality Flags

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 TECHNICAL DESCRIPTION 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 with the dose and detector counters at the start of an Issue period, e.g.

  • Page 70: (Iv) Dose Rate Over-Range

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 TECHNICAL DESCRIPTION (iv) Dose Rate Over-range The dose rate over-range flag indicates that the dose rate has exceeded 1Sv/h (100 rem/h) at some time in the past, (i.e. the recorded dose may be inaccurate, probably low, due to non-linearity at high dose rates).

  • Page 71: Epd Operating Status

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 TECHNICAL DESCRIPTION ♦ Three Dose alarm flags indicate that a dose has exceeded the corresponding dose alarm thresholds. There are 1 and 2 dose alarms for Hp(10) and a single dose alarm for Hp(0.07). ♦ Three Dose rate alarm flags indicate that a dose rate has exceeded the dose rate alarm thresholds.

  • Page 72: Epd 'Run' And Off Times

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 TECHNICAL DESCRIPTION EPD ‘Run’ and Off times The EPD contains an accurate clock (±30 ppm) and records the elapsed time, both for operating (Run Time) and in ‘OFF’ Mode. Times are recorded to a resolution of 1 second.
  • Page 73 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 TECHNICAL DESCRIPTION Bad Sectors . The number of bad EPD secure store sectors. There is a maximum of nine spare sectors. Detector Test Fail . The EPD detector test was run and the number of counts received were less than required to pass the test.

  • Page 74: Dose Profile

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 TECHNICAL DESCRIPTION 4.6.10 Dose Profile The EPD stores Hp(10) and Hp(0.07) dose to a resolution of 1 µ Sv 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 75: Event History Store

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 TECHNICAL DESCRIPTION 4.6.11 Event History Store The EPD logs up to 23 events in non-volatile store, together with a time stamp. These comprise alarm and fault events see tables 4.1 and 5.2. From software version 11, EPD ON and OFF events are also recorded (see Table 4.1). Note : The Event History time store wraps round after 194 days of operation.
  • Page 76 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 TECHNICAL DESCRIPTION This page intentionally blank ISSUE 5 Page 62 Thermo...

  • Page 77: Section 5

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 FAULTS AND RECOVERY ACTIONS 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 78: Visual And Audible Fault Indication

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 FAULTS AND RECOVERY ACTIONS 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...

  • Page 79: Internal Logging Of Fault Conditions

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 FAULTS AND RECOVERY ACTIONS 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 .

  • Page 80: Dose Quality Factors

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 FAULTS AND RECOVERY ACTIONS 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. 5.3.3 Dose Quality Factors A number of faults and events are counted and recorded in association...

  • Page 81: Blank Lcd Display And Other Faults

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 FAULTS AND RECOVERY ACTIONS 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.
  • Page 82 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 FAULTS AND RECOVERY ACTIONS ♦ Contact supplier. Hardware fault Faulty LED No visual alarm during Confidence Test ♦ Enable LED if required LED fails to operate in LED Disabled alarm condition ♦ Confirm fault by running a Faulty Display Hardware fault Missing or additional...

  • Page 83: Initialisation Error ( Lcd

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 FAULTS AND RECOVERY ACTIONS 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 84 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 FAULTS AND RECOVERY ACTIONS IR field until indicated ( i.e. by the system, through displays, Leds etc. ). However the EPD communications software is tolerant of short duration loss of connection. If the condition does occur it is normal for system software to clear the alarm and LCD display automatically when the EPD is re-presented to the IR media.

  • Page 85: Lcd Display Error Codes

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 FAULTS AND RECOVERY ACTIONS 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.

  • Page 86: Recovery Procedures

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 FAULTS AND RECOVERY ACTIONS Recovery Procedures 5.8.1 Logging Faults / Extracting Data All faults other than the communications error described in section 5.6 should be logged using the standard Form in the Appendices. This form may be used to log single or multiple faults.
  • Page 87 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 FAULTS AND RECOVERY ACTIONS Control Module Code Text as displayed by Recommended Remarks EasyEPD2 Action Customer Action Control Module Error - Comms Reset unit. Return More than 2 consecutive Critical only to supplier if recurs. resets.
  • Page 88 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 FAULTS AND RECOVERY ACTIONS 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.
  • Page 89 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 FAULTS AND RECOVERY ACTIONS 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 sectors available aband been used. This fault is oned.
  • Page 90 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 FAULTS AND RECOVERY ACTIONS 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 Return to no Batt Low Status) supplier if recurs.
  • Page 91 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 FAULTS AND RECOVERY ACTIONS 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.
  • Page 92 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 FAULTS AND RECOVERY ACTIONS This page intentionally left blank ISSUE 5 Page 78 Thermo...

  • Page 93: Section 6

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 MAINTENANCE SECTION 6 MAINTENANCE This section describes the maintenance that may be required for the EPD. Maintenance is limited to general cleaning, removing/replacing the EPD battery and removing/replacing the EPD clip assembly. Limited maintenance can also be carried to clear fault conditions and check the functionality of the EPD.
  • Page 94 These ‘gain’ adjustments are made using software facilities available via Thermo Electron but should only be considered in consultation with Thermo. Detector Thresholds . Detector thresholds discriminate between radiation pulses received by the EPDs detectors.
  • Page 95 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 MAINTENANCE 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 the manufacturer for repair or replacement.

  • Page 96: The Epd Battery

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 MAINTENANCE 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.
  • Page 97 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 MAINTENANCE 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. ISSUE 5 Thermo Page 83...

  • Page 98: Replacing The Epd Battery

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 MAINTENANCE WARNING Lithium Thionyl Chloride Batteries Lithium Thionyl Chloride battery contents are potentially toxic, flammable and explosive. Lithium Thionyl Chloride batteries should not be: ♦ short circuited or charged under any circumstances. ♦ used in excess of +70°C and never exposed to temperatures in excess of +100°C.
  • Page 99 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 MAINTENANCE The EPD is fitted with either a security type (tamper-proof) battery cap or a coin- release battery cap, depending on customer requirements. The security type battery cap helps to prevent unauthorised removal of the cap and requires a special tool (see Section 2, Figure 2.2).

  • Page 100: Epd Clip Assembly

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 MAINTENANCE 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 101: Removing The Epd Lanyard Plate/Clip Assembly

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 MAINTENANCE 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 102: Replacing The Epd Lanyard Plate/Clip Assembly

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 MAINTENANCE Insert a screwdriver, with a blade width of 3 to 4 mm, under the lanyard plate tang and apply gentle 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 103: Cleaning

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 MAINTENANCE 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 104: Periodic Cleaning

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 MAINTENANCE 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 Page 90 Thermo...

  • Page 105: Radiological Specifications

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 APPENDIX A 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.
  • Page 106 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 APPENDIX A Typical EPD Mk2 Energy Response Sr/Y Hp(10) Hp(0.07) 1000 10000 Photon Energy (keV) ISSUE 5 Page 92 Thermo...

  • Page 107: Electromagnetic Compatibility

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 APPENDIX B APPENDIX B ELECTROMAGNETIC COMPATIBILITY Standard Test The EPD was tested to the following specification with no failures: Test Type Specification Test Frequency Level Notes Range Radiated Mil Std 461D RS103 10kHz – 40 GHz 200V/m Susceptibility E- Field...
  • Page 108 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 APPENDIX B Chart 1 10000 1000 1000 10000 100000 F re que nc y ( H z) Chart 1. The tested Mk2 EPDs were not susceptible to H-field radiation below the above graph. Chart 2 1400 1200 1000...
  • Page 109 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 APPENDIX B 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 Thermo Page 95...
  • Page 110 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 APPENDIX B This page is intentionally blank ISSUE 5 Page 96 Thermo...

  • Page 111: Summary Of General Physical & Functional Characteristics

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 APPENDIX C APPENDIX C SUMMARY OF GENERAL PHYSICAL & FUNCTIONAL CHARACTERISTICS Feature Characteristic 1.5V Alkaline AA or 3.6V Lithium Thionyl Chloride Type Battery (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 112 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 APPENDIX C Feature Characteristic Drop 1.5m, each face to concrete. Button Sealed recessed prevent inadvertent operation. Tactile, with button beep facility (sounder). Teledosimetry May be attached to Thermo teledosimetry adapter using clip attachment features. Environmental Temperature -10°C to +40°C ( operating ),...
  • Page 113 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 APPENDIX C In built Detector Test Regular ‘flash LED’ detector test, also available on demand over the communications link, at time of Integrity issue. The test takes approximately 1 to 2 ms, during Checks which time normal dose measurement is inhibited. Non volatile Dose data copied to non-volatile store every 15 store.
  • Page 114 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 APPENDIX C on the EPD LCD in place of the wearer ID, see section 3.5.1. The character representation on a seven segment display is necessarily limited, see table below. Controls Various controls possible over communications interface to configure displays, sounder operation, detector and self test, clear dose and detector counts, analyse and clear faults, set...
  • Page 115 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 APPENDIX C #: Seven Segment Display representation of the character(s) to the left. WEARER NAME: EPD LCD LETTER REPRESENTATION ISSUE 5 Page 101 Thermo...

  • Page 116: Appendix D

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 APPENDIX D This page intentionally left blank ISSUE 5 Page 102 Thermo...

  • Page 117: Epd Fault Log Form

    ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 APPENDIX D APPENDIX D EPD FAULT LOG FORM SEE OVER ISSUE 5 Page 103 Thermo...
  • Page 118 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/ 000 APPENDIX D This page intentionally blank. ISSUE 5 Page 104 Thermo...
  • Page 119 EPD FAULT LOG FORM Owning Organisation: Site or Location: REPORT NO.: Related / Repeated Report Nos.: Raised By: Date: Contact / Telephone dd/mm/yyy EPD Supplier ( Thermo or Distributor ): Form Returned to: BATTERY Type (Alkaline or LTC): Manufacturer: Supplied by: EPD Serial No.s: Date/Time fault occurred: Fault type, e.g.
  • Page 120 EPD FAULT LOG FORM HB40521...
  • Page 121 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 Index INDEX Abuse Warning........................... 56 Alarm Characteristics ........................52 Configuration.......................... 17 features ..........................16 hysteresis ..........................20 Muting ............................ 22 Priorities ..........................18 Sounder Volume ........................42 Tones ............................. 19 Alkaline battery........................... 42 Backlight ............................. 13 Battery ............................
  • Page 122 ELECTRONIC PERSONAL DOSEMETER EPD/HB/40521/ 000 HANDBOOK Index Total Dose..........................30 User ID ........................... 27 Dose Alarm Thresholds......................34 Dose Alarms..........................20 Dose Chirp Adjustment ......................39 Dose Quality......................... 55, 66 Dose Rate ..........................53 Dose Rate Alarms ........................20 Dose Profile ..........................60 EEPROM ............................
  • Page 123 ELECTRONIC PERSONAL DOSEMETER HANDBOOK EPD/HB/40521/000 Index Over-Range..........................21 Overview............................1 Pocket Clip/Lanyard ........................86 Power ............................1 PTB Approved EPDs........................50 Recovery Procedures......................... 72 Rem .............................. 4 Run Time ............................ 58 Secure Memory ..........................3 Sieverts............................3 Silicon Diode detectors......................1, 3 Start-up Sequence ........................
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