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Thermo EPD Mk2, Technical Handbook

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Thermo EPD Mk2 Technical Handbook Download Page 66

         

         

 

 

                                                                                  

EPD/HB/40521/000 

 

ISSUE 5 

          EPD TECHNICAL HANDBOOK

 

 

 

Page 56 

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 
that the EPD detected a checksum error in the dose data.  Checksum failures are 
corrected by retrieving the last stored dose from secure store (EEPROM).  During 
the correction process up to 15 minutes of dose may be lost. 
 

4.6.8 

Dose And Dose Rate Alarm Processing 

The EPD performs alarm processing as described in this section.  The occurrence of 
a dose or dose-rate alarm is recorded by the following internal flags.  These flags 
make it easy for applications s/w to determine over the IR communications link 
whether an alarm has occurred during an issue period.  The flags are therefore 
normally cleared over the IR communications link at the start of an issue period: 

 

♦

 

Three Dose alarm flags indicate that a dose has exceeded the corresponding 
dose alarm thresholds.  There are 1

st

 and 2

nd

 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.  There are 1

st

 and 2

nd

 dose rate alarms for Hp(10)/h 

and a single dose rate alarm for Hp(0.07)/h.   The dose-rate flags are not 
cleared automatically when the dose-rate falls below the reset threshold. 

 

The 2

nd

 alarm threshold (dose or dose rate) always has a higher priority than the 1

st

 

alarm threshold.  The 1

st

 alarm threshold can be considered as a warning value and 

the 2

nd

 alarm threshold as a critical value.  Therefore, the 2

nd

 alarm threshold should 

always be set to the higher value.  

 

Dose rate alarms can be configured to work with hysteresis.  That is, the Hp(10)/h 1st 
and 2nd dose alarms and the Hp(0.07)/h dose rate alarm are each provided with 
separate ON and OFF thresholds.  When the dose rate equals or exceeds the alarm 
ON threshold the EPD will set an alarm flag and the sounder will sound and the LED 
flash (if enabled).  The alarm is self-cancelling when the dose rate falls below the 
alarm OFF threshold, but the alarm flag remains set. 
 

Summary of Contents for EPD Mk2

Page 1: ...ron 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: ...1202 782779 International 44 1202 782779 01202 782374 International 44 1202 782374 01202 782780 International 44 1202 782780 Fax 01202 782335 International 44 1202 782335 USA Sales Office Thermo Electron Corporation 105C Hembree Park Drive Roswell GA 30076 U S A Tel 770 521 4502 Fax 770 521 4535 ISSUE STATE Pages Issue Type Part ID File ID All 5 ESERS EPD HB 40521 HB40521_iss_5 doc ...

Page 3: ...Rate Alarms 20 3 2 4 Over Range Indication 21 3 2 5 Alarm Muting 22 3 3 BUTTON OPERATION AND DISPLAY SELECTION 23 3 4 LCD DISPLAY LOCK ON FACILITY 24 3 5 DISPLAY OPTIONS AND 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 ...

Page 4: ...5 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 EPD FAULTS AND RECOVERY ACTIONS 61 5 1 OVERV...

Page 5: ...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 CHARAC...

Page 6: ......

Page 7: ...ture for personal dose Hp 10 H07 EPD LCD nomenclature for personal dose Hp 0 07 H 10 h EPD LCD nomenclature for dose rate Hp 0 07 h H 07 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 ...

Page 8: ...al 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 wr...

Page 9: ...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 aff...

Page 10: ...EPD HB 40521 000 ISSUE 5 EPD TECHNICAL HANDBOOK Page xii ...

Page 11: ...a 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 annun...

Page 12: ...ns 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...

Page 13: ... 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 Do...

Page 14: ...EPD HB 40521 000 ISSUE 5 EPD TECHNICAL HANDBOOK Page 4 This page is intentionally blank ...

Page 15: ...nd 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 initialisation sequence 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 ...

Page 16: ...rm 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...

Page 17: ...e 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 br...

Page 18: ...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 atte...

Page 19: ...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 a...

Page 20: ...y 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...

Page 21: ...ds Wearing the EPD on the outside of protective clothing has the major advantage that the user can read the EPD s LCD display and operate the button as required Typically the EPD should be worn on the chest or the waist The type of outer protective clothing will determine how the EPD is attached i e the EPD clip or lanyard For example if the protective clothing has no breast pocket or the use of a...

Page 22: ...TECHNICAL HANDBOOK Page 12 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 ...

Page 23: ...own in Figure 3 4 Default settings and other display controls are changed using a suitable IR communications link and software e g EasyEPD2 For example the display can be configured to display values in either Sieverts or rems The EPD is provided with many different displays in order to provide a powerful stand alone facility for users not having direct access to communications software such as Ea...

Page 24: ... 5 EPD TECHNICAL HANDBOOK Page 14 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 ...

Page 25: ...EPD HB 40521 000 ISSUE 5 EPD TECHNICAL HANDBOOK Page 15 ...

Page 26: ...ion for example for office or hospital environments Alarms are acknowledged by pressing the button long press This action will extinguish the alarm LED and mute the sounder It is possible to disable the mute function via the EPD IR communications link see section 3 2 5 Note that certain operations and events will automatically mute the audible alarm for a short period because of the high electrica...

Page 27: ... alarm event recognised by the EPD see Table 3 3 Note that alarm duration is set in increments of 4 seconds Assuming an alarm is not acknowledged then following this period the alarm is replaced by a single beep every 30 seconds This feature avoids wasting battery power The timeout can be disabled if desired and the alarm output is not then so curtailed Alarm Feature Configuration Options Alarm So...

Page 28: ...Alarms are prioritised as defined in Table 3 3 Priority 1 being the highest priority An active alarm can be superseded by the following events A higher priority alarm is activated the new alarm starts The user mutes alarms with a long button press all mute able alarms are muted Alarms are cleared via the communications links A self cancelling condition de activates the alarm e g falling dose rate ...

Page 29: ...____________ High Loud 4 Hp 0 07 Dose Alarm Continuous Single Tone ____________ High Loud 5 Hp 10 Dose Alarm 1 Continuous Single Tone ____________ High Loud 6 Hp 10 h Dose Rate Alarm 2 Continuous Single Tone ____________ High Loud 7 Hp 0 07 h Dose Rate Alarm Intermittent Single Fast Tone _ _ _ _ _ _ High Loud 8 Hp 10 h Dose Rate Alarm 1 Intermittent Single Fast Tone _ _ _ _ _ _ High Loud 9 Battery...

Page 30: ...d The four most significant digits of the alarm thresholds can be viewed on the EPD LCD and changed using the function button see Section 3 5 8 3 2 3 Dose Rate Alarms Dose rate 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 The dose rate alarms can be made...

Page 31: ...rm will also cause the LCD display to flash every second Notes 1 The over range alarm condition is latched and the LCD will continue to flash even after a temporary dose rate over range condition has cleared The over range conditions are recorded in the EPD EEPROM and must be cleared over the IR communications link before the display will stop flashing 2 The over range alarm can be muted if enable...

Page 32: ...ng when the dose rate falls below the alarm off threshold level Similarly dose alarms are self muting if the dose is cleared or the thresholds suitably increased over the IR communications link Note that if the display backlight is enabled a short press of the button turns the back light on and temporarily silences any active alarm This is because the EPD unit battery cannot supply sufficient curr...

Page 33: ...d from the sequence Some displays are usefully disabled if their retention might confuse the wearers of the EPD Other displays should be disabled if their retention might cause an operational risk for example the ability to zero dose or adjust alarm thresholds Such display configuration is easily done using the EasyEPD2 software package A batch write facility is available in EasyEPD2 to enable the...

Page 34: ...n will only appear for approximately two seconds To accept the lock on facility press the button when the colon appears If the lock on facility is not required allow the selected display to time out To deselect the lock on facility press the button The display will move on to the next display selection but will thereafter revert to the default display after time out The seconds count down timer lo...

Page 35: ...wer Saving 6 Peaks Rate High 7 Test 8 Clear Peak H10 Dose Rate Peak H07 Dose Rate H10 and H07 Dose Clear Clr 9 Dose Alarm Thresholds 1st H10 Dose Alarm 2nd H10 Dose Alarm H07 Dose Alarm 1st H10 Dose Rate Alarm ON 2nd H10 Dose Rate Alarm ON H07 Dose Rate Alarm ON 10 Dose Rate Alarm ON Thresholds Rate On 11 Dose Rate Alarm Off Thresholds Rate Off 12 Sound Settings 1st H10 Dose Rate Alarm Off 2nd H10...

Page 36: ... the button within the display default time out 3 5 1 Displaying Hp 10 Dose Dose Rate and User ID To display Hp 10 doses press and hold the button until this top level display appears Three sub displays are available in the following sub display order Hp 10 Dose Hp 10 h Dose Rate User ID Digits Hp 10 Dose Display Short press the button to display the current dose This dose parameter is used for ta...

Page 37: ...ntion a non issued EPD is given a User ID FFFFFFFFFFFF Typically a User ID will have fewer than 12 digits but it must be an integer between 1 and 999999999999 For example a User ID 9012 will be shown on the LCD display as follows First Display Second Display Third Display In systems using 8 or fewer digits for the User ID it is usual to disable and thereby remove the unused displays e g the first ...

Page 38: ... inaccurate ADS User ID Digits An additional User ID is provided called Approved Dosimetry Service ADS User ID This is password protected and is used by ADS systems for permanent issue EPDs The ADS User ID may be displayed in a similar fashion to the User ID Short press the button again to display each of the remaining ADS User ID digit displays A non issued EPD may have an ADS User ID FFFFFFFFFFF...

Page 39: ...al Hp 10 dose Display Range Hp 10 0µSv to 16Sv auto ranging Hp 0 07 Total Dose Short press the button again to display the total Hp 0 07 dose Display Range Hp 0 07 0µSv to 16Sv auto ranging Each display represents a record of the total dose received by the EPD over multiple tasks e g per day per week etc 3 5 4 Starting Stopping The Seconds Count Down Timer To start stop the seconds count down time...

Page 40: ... available Double press the button to start the digits counting down to zero The display is in units of minutes and seconds The maximum count down time available is 99 minutes 59 seconds The count down function continues when the display reverts to the default display after the display timeout period However it is useful to lock on to this display as described in section 3 4 Stopping the Timer To ...

Page 41: ...ing radiation To return to operating mode press and hold the button The display will revert to the default display Note ON OFF control via the button may be inhibited by the appropriate setting of the EPD internal configuration via the IR communications link 3 5 6 Displaying Peaks Rate High To display peaks high rate press and hold the button until this top level display appears Two sub displays a...

Page 42: ...nce test the heart beat activity indicator flashes once per second The confidence test can be stopped at any time by pressing the button Note During the EPD confidence test a brief detector test is performed during which dose accumulation is momentarily inhibited Double press the button The EPD will commence its confidence test routine as follows 1 The all segment display is displayed for approxim...

Page 43: ...low 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 Upon completion of the confidence test the unit reverts to the default display If the confidence test is unsuccessful a letter F followed by three digits is displayed Note the failure codes and r...

Page 44: ... doses have now been cleared 3 5 9 Displaying Setting Dose Alarm Thresholds To display and or set dose alarm thresholds press and hold the button until this top level display appears Three sub displays are available in the following sub display order 1st Hp 10 Dose Alarm 2 nd Hp 10 Dose Alarm Hp 0 07 Dose Alarm The EPD can be used as a personal alarming dosemeter with alarm thresholds for accumula...

Page 45: ...d double press the button The display will change to the following with the digits flashing Alarm Set Limits 10µSv to 1Sv Pressing the button will increase the alarm threshold in the following steps 10µSv 50µSv 100µSv 500µSv 1mSv 5mSv 10mSv 50mSv 100mSv 500mSv 1 0Sv When the required threshold is reached double press the button to confirm the value and the flashing display will stop If you start t...

Page 46: ... Hp 0 07 h Dose Rate Alarm OFF The EPD can perform the role of a personal alarming EPD with alarm thresholds for dose rate There are two Hp 10 h dose rate alarms and a single Hp 0 07 h dose rate alarm that can de displayed The 2 nd Hp 10 h dose alarm has the higher priority and should always be set to a higher value than the 1st Hp 10 h alarm The alarm thresholds can be modified by the user if req...

Page 47: ...splay will change to the following and the digits will flash Alarm Set Limits 10µSv h to 1Sv h Pressing the button will increase the alarm threshold in the following steps 10µSv h 50µSv h 100µSv h 500µSv h 1mSv h 5mSv h 10mSv h 50mSv h 100mSv h 500mSv h 1 0Sv h When the required threshold is reached double pressing the button to confirm the value and the flashing display will stop If you start to ...

Page 48: ...s are available in the following sub display order Button Beep Enable Disable Chirp Dose Adjustment Internal Counters Display Note This option will not enable disable the alarm sounder Enabling disabling the sounder under alarm conditions can only be set via the IR communications link see Section 3 2 4 Button Beep Enable Disable The EPD can be configured to beep every time the button is pressed Th...

Page 49: ...chirp at every preset increment in Hp 10 h penetrating deep dose This increment can be set between 0 01µSv and 100µSv or disabled by setting the increment to 0 Short press the button to display the current dose per chirp An increment set to 1µSv is shown opposite With a chirp sensitivity of 1µSv chirp and a dose rate of 10mSv h the sounder will average 2 8 chirps every second To change the chirp r...

Page 50: ...rn to the previous chirp sensitivity To switch off the dose chirp double press the button when 0 0 µSv is displayed If the ESC screen is displayed and the button is not pressed after default time out the display will return to dose chirp adjustment display Again if the button is not pressed the display will return to the top level default screen after a further time out period Internal Counters Di...

Page 51: ...EPD HB 40521 000 ISSUE 5 EPD TECHNICAL HANDBOOK Page 41 This page intentionally blank ...

Page 52: ......

Page 53: ...in Appendix A to this handbook Sensitivity to X and γ radiation β particles Multiple PIN diode detectors 4 channel parametric algorithm processing Direct readout of personal dose equivalents Hp 10 penetrating deep whole body and Hp 0 07 superficial shallow skin Neutron response 2 Meets relevant parts of BS EN ISO61526 for dose equivalent monitors unless otherwise specified Dose display and storage...

Page 54: ...l between 1 to 60 minutes 15 minutes recommended Alarm sounder 98 dB A to 101 dB A at 20 cm loud mode 75 dB A to 85 dB A at 20cm quiet mode with multiple modes 4 2 2 Battery Management The EPD circuitry is designed to operate at 3 6V DC The EPD can be powered by either a 3 6V Lithium Thionyl Chloride LTC Sulphurous Oxychloride SOCL2 battery or a standard 1 5V AA Alkaline type battery If a 1 5V Alk...

Page 55: ...gular intervals between 1 and 60 minutes This time interval is factory preset to 15 minutes and can be adjusted via the IR communications link 15 minutes is the preferred interval 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 overnight In the power saving mode the LCD will display OFF i e the EPD is off see also Secti...

Page 56: ... outer case assembly and lid The inner liner houses the EPD s electronic components The outer case consisting of a moulded front and back fits around the inner liner and is fused together to provide physical protection The lid which is fitted to the top of the outer case has a tight tolerance and is locked in place as an integral part of the EPD assembly The outer case and lid are designed not to ...

Page 57: ...EPD HB 40521 000 ISSUE 5 EPD TECHNICAL HANDBOOK Page 47 Figure 4 1 EPD Dimensions ...

Page 58: ...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 EMI EMC Exceeds MIL STD 461D RS103 see Appendix B 4 4 2 Brief Environmental Description The EPD is designed for use in the following environments Office and Laboratory environment Industrial environments Hospitals Military environments including dockyards and shipping...

Page 59: ...arameters operational control and general functionality can be set During the read write process the EPD can be configured for any or all of the display selections shown in Figure 3 4 to be made available to the user as required Only limited functions can be configured via the EPD button On the front of the EPD there is an IR communications link for reading and writing data Communication with the ...

Page 60: ...ser time to remove the EPD from the IR field The EPD continues to measure radiation during communication Communication via the EPD s IR communications link will allow access to the following EPD functions and displays Default Display User Identification Dose and Dose Rate Alarms and Alarm Thresholds Counts Dose Quality Control of the EPD Status Scratch Pad Timed Events Dose Profile Special Total D...

Page 61: ... Hp 0 07 Can be reset after each controlled area entry day month etc by health physics staff or dose management system according to local procedures Total Dose Store Separate total dose store Special Total Dose Store 12 entries e g for automatic recording of end of month dose etc Event Log 23 entries for time recording of alarms etc for incident assessments ADS Dose Store Approved Dosimetry Servic...

Page 62: ...play as specified by the customer User selected displays have a time out period which can be set between 10 to 99 seconds This time out is the period of time that any display selected by the user will stay active before reverting to the default display The time out period may be adjusted via the IR communications link The default display can be changed to any of the displays shown in Figure 3 4 ag...

Page 63: ...valent to 1 64µSv and for Beta dose one count is approximately 1 6µSv To avoid statistical inaccuracies doses should only be displayed in micro sieverts or 0 1 rem but when summing a number of doses the full resolution should be used to minimize rounding errors Dose Rate This is the current dose rate as calculated by the EPD It may be viewed on the display or read via the IR communications link Do...

Page 64: ... rate calculated by the EPD since this value was last cleared is termed the peak dose rate The peak dose rates and the times at which these peak rates occur are recorded and can be displayed on the LCD or read over the IR communications link Note Peak dose rate times are stored to 1 second resolution 4 6 6 Counts The EPD has four internal counters HG Hard Gamma SG Soft Gamma FB Full Beta BC Beta C...

Page 65: ... is greater than approximately 4mSv h the counts caused by the shock will be small relative to the radiation counts and therefore all counts are used in the calculation of dose Shock Time is the time period over which shock processing has taken place Continuous Shock detection for greater than 45 seconds will cause an abuse alarm see Abuse Warning iii Dose Over range The dose over range flag indic...

Page 66: ...the IR communications link at the start of an issue period Three Dose alarm flags indicate that a dose has exceeded the corresponding dose alarm thresholds There are 1st and 2nd 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 There are 1st and 2nd dose rate alarms for Hp 10 h and a single do...

Page 67: ...retains information regarding its status EPD status can only be read via the IR communications link Status information provided is EPD Run Times EPD State Alarms Warnings Faults Event history 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 The OFF time is the numb...

Page 68: ...vent Logged An event possibly but not necessarily a fault has been logged in the EPD s event store 2 Connection Failed Communication with the EPD failed 3 Cal Factors Bad The EPD calibration factors failed a CRC check and cannot be recovered from secure store 4 EEPROM Fail An un recoverable EPD secure store failure occurred 5 Bad Sectors The number of bad EPD secure store sectors There is a maximu...

Page 69: ...o 127 µSv or less Note A dose profile interval of zero seconds turns off the dose profile function Dose profile can only be read via the IR communications link Dose profile may be synchronised to a particular time in the future e g hourly logging on the hour Note The EPD has no concept of real time but maintains a one second tick that is valid as long as the EPD is powered and not reset 4 6 11 Eve...

Page 70: ...1 on 224 Hp10 Dose Alarm 1 off 205 Hp10 Rate Alarm 2 on 225 Hp10 Rate Alarm 2 off 206 Hp07 Rate Alarm on 226 Hp07 Rate Alarm off 207 Hp10 Rate Alarm 1 on 227 Hp10 Rate Alarm 1 off 208 Battery Alarm on 228 Battery Alarm off 209 Return for read Alarm on 229 Return for read Alarm off 210 Count Down Alarm on 230 Count Down Alarm off 211 Abuse Alarm on 231 Abuse Alarm off Other Events Code Text as disp...

Page 71: ...at 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 Fault indication via sounder alarm Led LCD 2 Internal logging of fault conditions 3 Blank display and other uncontrolled faults 4 Communications Error over the IR link 5 LCD Display error codes 6 Recovery Procedures ...

Page 72: ...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 The fault alarm can also be set to self mute after a timeout period in order to preserve battery life If this happens the unit will give a short beep every 30 seconds thereafter An EPD conveys faults to the user by a number of displays e g Initialisa...

Page 73: ...er of bad EPD secure store sectors There is a maximum of nine spare sectors 6 Detector Test Fail The EPD detector test was run and the number of counts received were less than required to pass the test 7 Detector Threshold Fail The EPD detector thresholds failed to load successfully 8 Radio Fail Reserved for future use 9 Other Fault A fault occurred causing the EPD to reset 10 Disabled The EPD is ...

Page 74: ...AL HANDBOOK Page 64 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 ...

Page 75: ...move old andInsert new battery and restart unit see section 2 1 2 Communicate with the EPD via the IR communications link to access stored data Remove and replace battery cap see Section 2 1 2 Use a recommended battery Static Screen Heart Beat indication not flashing 1 second timer error Attempt to communicate with the EPD via the IR communications link Replace battery and restart unit see section...

Page 76: ...nder if required Faulty LED No visual alarm during Confidence Test LED fails to operate in alarm condition Hardware fault LED Disabled Contact supplier Enable LED if required Faulty Display Missing or additional segments on LCD display Hardware fault Confirm fault by running a CONFIDENCE TEST Contact supplier Table 5 1 Blank LCD other faults ...

Page 77: ...data and to recover normal operation where possible 5 6 Communications Error LCD A series of triple dashes appearing on the LCD display indicates a communications error This condition usually occurs when a data write operation fails to complete The typical cause is that the EPD unit is removed from the IR field before a critical write operation has completed for example an Issue of the EPD to a pe...

Page 78: ... 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 The system software then checks the status of the EPD completes any necessary data write operations advises the user what to do and clears the alarm The display then retur...

Page 79: ...he 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 They are divided into blocks according to the software module that generates them Epd Action This describes what the EPD does in addition to attempting to display the fault and record the fault inthe event history store ...

Page 80: ...lay fault code or indication Fxxx 2 Internal faults logged in the EPD Status Faults record 3 Contents of internal Event History store 4 Dose and peak dose rate time data if a spurious dose fault is suspected 5 Dose profile data if a spurious dose fault is suspected Where possible the data should be obtained as screen dumps from EasyEPD2 and attached to the completed Fault Log Form Appendix D If a ...

Page 81: ...plier if recurs Only runs from self test typically every 15 minutes Other problems may well occur before this time 014 Control Module Stack Overflow Reset ditto Only runs from self test typically every 15 minutes Other problems may well occur before this time 015 Control Module Asic Fault Halt Return to supplier This test performs a read write test on the digital ASIC Unrecoverable other knock on ...

Page 82: ...aulty Reset unit Return to supplier if recurs 035 Service Module Seconds Timer Array overflow Reset Reset unit Return to supplier if recurs This indicates a software fault 036 Service Module Fine Timer Array overflow Reset Reset unit Return to supplier if recurs This indicates a software fault 037 Service Module Long Timer Array overflow Reset Reset unit Return to supplier if recurs This indicates...

Page 83: ...Return to supplier This fault is unlikely to occur Sector Access Table is corrupted or EEPROM read failed 063 EEPROM could not read from the sector access table area Return to supplier Executes a Deferred Log Fault with RECOVERED option with the given fault code but only if the EEPROM fail bit is not set If the EEPROM fail bit is set the fault is ignored to stop the error store being flooded with ...

Page 84: ...ss clock is written with new value or incremented at wrong rate 085 Count too large HG or SG 300 000 or FB or BC 26 000 Reset Ditto This fault can occur by inputting a very large number of counts only possible under test conditions or severe interference 086 Detector threshold load failed Reset into comms mode only counts processing disabled Reset unit Return to supplier if recurs Texas chip or as...

Page 85: ... data is read back from the EEPROM For the ADS and Dose data the QF bits are also set This is done by reading the data from EEPROM setting the bit calculating the new checksum restoring the data to EEPROM and then doing a reset The correct values will then be restored on program restart Reset unit Return to supplier if recurs Indicates corruption of data in RAM Up to 15 mins of dose could be lost ...

Page 86: ...EPD HB 40521 000 ISSUE 5 EPD TECHNICAL HANDBOOK Page 76 This page is intentionally blank ...

Page 87: ...n However where expressly requested by customers in their purchase order EPDs may be supplied with the calibration factors in the unlocked sate This is to enable such customers to modify the calibration of these EPDs In such cases the customers attention is drawn to the following Disclaimer DISCLAIMER The EPDs within this shipment have been calibrated using the factors as defined on the supplied C...

Page 88: ...nvert the counts accumulated on the four detector channels into dose equivalents These constants are HGSens10 SGSens10 HGSens07 SGSens07 FBSens07 BCSens07 Detector Thresholds Detector thresholds discriminate between radiation pulses received by the EPDs detectors These thresholds are set as course and fine values measured as Hard Gamma HG Soft Gamma SG Full Beta FB Beta Compensating BC EPD calibra...

Page 89: ...t The following are recommended replacement batteries Saft Lithium 3 6 V LS 14500 Sonnenschien Lithium 3 6 V SL 760 Duracell Procell Alkaline 1 5 V MN 1500 Other AA batteries may be suitable however the user is advised that 1 The length of the battery including the battery anode pip should be in the range of 49 0 mm to 51 0 mm 2 The diameter of the battery should be in the range of 13 9 mm to 14 6...

Page 90: ...der any circumstances used in excess of 70 C and never exposed to temperatures in excess of 100 C opened punctured crushed or tampered with 3 Batteries in storage should be kept in an isolated dry well ventilated cool environment and kept out of direct sunlight Storage temperatures should be below 30 C 4 Batteries are susceptible to fire and abuse Some manufacturers provide batteries with a safety...

Page 91: ...endation and Local National regulations 7 If LTC batteries are to be transported by aircraft the batteries must be in their correct packaging 6 2 4 Replacing the EPD Battery 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 require...

Page 92: ...lanyard plate The lanyard plate slots into a recess in the EPD case see Figure 6 1 Retaining lugs secure the lanyard plate in position Figure 6 1 EPD Case Clip Assembly Recess The lanyard plate may not be fitted with the spring clip again depending on customer requirements see Figure 6 3 This makes the unit more comfortable to wear with the lanyard when the clip is not required If the EPD is shipp...

Page 93: ...e lanyard plate spring clip removed is shown in Figure 6 3 Note the tang on the lanyard plate it is not necessary to remove the spring clip from the lanyard plate in order to gain access to the tang Figure 6 3 EPD With Lanyard Plate But ton Pre ss see Han dbo ok Long Next Men u or Mute Alarm Shor t Next Disp lay or Lock on Doub le Start or Sele ct PHO TON ENE RGY 0 01 5 10 MeV STO RED DOS E 1usV 1...

Page 94: ...emoving The EPD Lanyard Plate Clip Assembly 6 3 2 Replacing The EPD Lanyard Plate Clip Assembly Set the lanyard plate into the recess on the rear of the EPD body This will be found to be much easier if the clip and lanyard plate is kept slightly open using a suitable small separator The plate should sit with its lugs in the lug recesses Push the plate towards the top of the EPD LCD end ensuring th...

Page 95: ...ld be shaken or blown out of the sounder aperture to restore the alarm noise level 6 4 2 Radiological Cleaning 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 If radioactive deposits are present the unit should be decontaminated by carefully w...

Page 96: ...e 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 ...

Page 97: ...MeV Ref Cs 137 30 1 5MeV to 6MeV Ref Cs 137 50 6MeV to 10MeV Ref Cs 137 Photon Hp 0 07 30 20keV to 6MeV Ref Cs 137 50 6MeV to 10MeV Ref Cs 137 Beta Hp 0 07 30 250keV to 1 5MeV average beta energy ref Sr 90 Angular response Hp 10 Cs 137 20 up to 75 Hp 10 Am 241 50 up to 75 Hp 0 07 Sr 90 30 up to 55 Accuracy Hp 10 Cs 137 10 Hp 0 07 Sr 90 20 Dose rate linearity Hp 10 Cs 137 10 0 5Sv h 20 0 5Sv h to 1...

Page 98: ...EPD HB 40521 000 ISSUE 5 EPD TECHNICAL HANDBOOK Page 88 Typical EPD Mk2 Energy Response Kr Sr Y 0 0 2 0 4 0 6 0 8 1 1 2 1 4 10 100 1000 10000 Photon Energy keV Response Hp 10 Hp 0 07 ...

Page 99: ...30Hz 100KHz See Chart 1 Note 1 Electrostatic Discharge EN61000 4 2 ESD N A 8KV Radiated Electric Field Emissions EN 50081 1 N A 30MHz 1 Ghz 30dB below Limit Radiated Susceptibility E Field High Field Spot Frequencies CW N A 100kHz 40 Ghz See Chart 2 Note 2 Radiated Susceptibility E Field High Field Spot Frequencies CW with 1kHz 1 µS square wave N A 500MHz 40 Ghz See Chart 3 Note 2 Notes 1 The limi...

Page 100: ...1 000 ISSUE 5 EPD TECHNICAL HANDBOOK Page 90 Chart 1 1 10 100 1000 10000 10 100 1000 10000 100000 Frequency Hz Amps Metre Chart 1 The tested Mk2 EPDs were not susceptible to H field radiation below the above graph ...

Page 101: ...NDBOOK Page 91 Chart 2 0 200 400 600 800 1000 1200 1400 0 1 1 10 100 1000 10000 100000 Frequency MHz Volts Metre Chart 2 The tested Mk2 EPDs were not susceptible to E field radiation below the above spot frequencies 100kHz 100GHz carrier wave ...

Page 102: ...ECHNICAL HANDBOOK Page 92 Chart 3 0 500 1000 1500 2000 2500 0 1 1 10 100 Frequency GHz Volts Metre Chart 3 The tested Mk2 EPDs were not susceptible to E field radiation below the above spot frequencies 0 1GHz 100GHz pulsed 1kHz 1µS ...

Page 103: ...EPD HB 40521 000 ISSUE 5 EPD TECHNICAL HANDBOOK Page 93 This page is intentionally blank ...

Page 104: ......

Page 105: ...cap with coin and security options Environmental and EMC seal Sounder Output Alarms 98 dB A to 101 dB A Quiet setting 80 dB A to 85 dB A at 20cm Configuration per alarm High low tone loud quiet off volume control in seven combinations of continuous or fast slow intermittent User mute enable disable control Dose Chirp Real time chirp function with programmable sensitivity 0 01 µSv chirp to 100 µSv ...

Page 106: ...rge non volatile store for dosemeter control parameters dose data storage dose profile system scratchpad etc 10 year data retention Issue Return Issue and return times of circa 1 second EPD communications time only Incident assessment Internal event alarm historical log 23 entries for time recording of alarms etc Peak dose rate recording Dose Profile Interval programmable from two seconds to 35 ho...

Page 107: ...may be permanently issued by ADS but also used on an access control system by the same wearer ADS Store Dose and supporting data is accumulated in an additional password protected ADS store System Integration Facilities Messaging Interface A powerful and efficient messaging interface allows fast and secure data transfer and speedy issue and return times Data is protected by 16 bit crc Issue and Re...

Page 108: ... system applications This is especially useful for non networked reader stations and can be used to store wearer access data interim dose readings worker access permissions etc Teledosimetry Virtually all data accesses and transfers available over the normal IR link are also available over the teledosimetry interface Operational issues During critical data writes e g issues and returns the EPD can...

Page 109: ...EPD HB 40521 000 ISSUE 5 EPD TECHNICAL HANDBOOK Page 99 APPENDIX D EPD FAULT LOG FORM SEE OVER ...

Page 110: ...EPD HB 40521 000 ISSUE 5 EPD TECHNICAL HANDBOOK Page 100 This page intentionally blank ...

Page 111: ...ault occurred Fault type e g Display fault Code Customer fault reference EPD returned to supplier Date battery installed Do IR communications still work EPD Status Faults attached Event History attached Dose Profile attached Extracted from EasyEPD2 DESCRIPTION OF FAULT DETAIL OF ACTIONS TAKEN TO RECTIFY FAULT Did fault recur after battery replacement or EPD Reset CONDITIONS PRIOR TO FAULT Environm...

Page 112: ...EPD FAULT LOG FORM HB40521 ...

Page 113: ...tery 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 Button 1 2 Button Operation 23 C Calibration 77 Case material 46 Cleaning 85 Clearing Dose Displays 34 Clip 46 Communicating with the EPD 49 Confidence Test 10 Running the Confidence Test 33 CONTENTS v CRC Failure 56 D Decontamination 85 Default Di...

Page 114: ...Rate 53 Dose Rate Alarms 20 Dose Store 59 E EEPROM 2 EEPROM storage 1 electrolyte leakage 80 Environmental Characteristics 48 Event History Store 59 F Fault Codes 71 Faults 61 G gamma radiation 2 General maintenance 3 Getting Started 5 Glossary ix I Infrared IR communication 1 infrared communications interface 3 Infra red Interface 49 Introduction 1 Issue Document iv Issuing an EPD 10 L LCD displa...

Page 115: ...erating Instructions 13 Operating Temperature 48 Over Range 21 Overview 1 P Pocket Clip Lanyard 82 Power 1 R Rem 3 Run Time 57 S Secure Memory 2 Sieverts 3 Silicon Diode detectors 1 2 Start up Sequence 9 T TECHNICAL DESCRIPTION 43 thresholds 36 U USA Sales Office iv W Warning 80 Wearing an EPD 11 Weight 1 46 X X rays 2 ...

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