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Fluke 35040 Operator's Manual

Fluke 35040 Operator's Manual

Therapy dosimeter
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35040
Therapy Dosimeter
Operators Manual
February 2005
Manual No. 37870 Rev. 10
©2004, 2005 Fluke Corporation, All rights reserved. Printed in U.S.A.
All product names are trademarks of their respective companies

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  • Page 1 35040 Therapy Dosimeter Operators Manual February 2005 Manual No. 37870 Rev. 10 ©2004, 2005 Fluke Corporation, All rights reserved. Printed in U.S.A. All product names are trademarks of their respective companies...
  • Page 2 Fluke Biomedical Radiation Management Services 6045 Cochran Road Cleveland, Ohio 44139 440.498.2564 120 Andrews Road Hicksville, New York 11801 516.870.0100 www.flukebiomedical.com/rms...

  • Page 3: Table Of Contents

    Table of Contents Section 1: General Information................... 1-1 Introduction ..........................1-1 Features ..........................1-1 Before you Start - Safety Precautions..................1-2 Safety Symbols and Terms....................1-2 Manual Addenda ........................1-3 Specifications ......................... 1-3 Unpacking and Inspection...................... 1-7 Section 2: Theory Of Operation .................. 2-1 Introduction ..........................
  • Page 4 3.9.12 Using the Reset/Measure Button .................. 3-17 3.9.13 Overrange Conditions....................3-17 3.9.14 Reset Error ........................3-18 3.9.15 Reset Error (With Automatic Leakage Compensation Enabled) ........3-19 3.9.16 Annunciators........................3-19 3.10 Customization ........................3-21 3.10.1 Introduction........................3-21 3.10.2 Installing/Uninstalling Customization Software.............. 3-21 3.10.3 Connection to the Computer..................
  • Page 5 Appendix B: Addendum Features of Firmware Version “27JAN00” or Later.....B-1 B.4.5 Reset Error (with Automatic Leakage Compensation Enabled)........B-8 B.4.6 Annuciators, Indicators, and Overrange Conditions............B-9 Theory of Operation ......................B-11 Troubleshooting ........................B-12 Customization ........................B-13 B.7.1 The Main Menu......................B-13 B.7.2 The Measurement Menu ....................
  • Page 6 (Blank page)

  • Page 7: General Information

    General Information Introduction Section 1 General Information 1.1 Introduction The Model 35040 Therapy Dosimeter is designed for calibration dosimetry of therapeutic radiation treatment machines including high-energy accelerators, Co, and brachytherapy equipment. The instrument can be used for calibration, government compliance testing, installation and set-up of new equipment, and troubleshooting.

  • Page 8: Before You Start - Safety Precautions

    35040 Operators Manual • The ion chamber bias voltage may be set to one of 11 user-customized settings. The display indicates the polarity of the central electrode and the actual measured output voltage generated by the ion chamber bias supply. •...

  • Page 9: Manual Addenda

    General Information Safety Symbols and Terms CAUTION heading used in this manual explains hazards that could damage the instrument. Such damage may invalidate the warranty. 1.5 Manual Addenda Any improvements or changes concerning the instrument or manual will be explained in an addendum included with the manual.
  • Page 10 35040 Operators Manual Measurement Accuracy: Charge measurement accuracy is warranted to be better than ± (0.20%rdg + 2 counts) over the operating temperature range of 18°C to 28°C for 1 year. Field Calibration: Field calibrations may be performed via a restricted distribution MS-DOS Calibration program.
  • Page 11 General Information Specifications 1.0000 μA 0.0001 μA Measurement Method: Average current measurement is derived by monitoring the charge integrated over the time interval beginning 1.33 seconds after the detection of the start of the exposure, and ending 1.33 seconds prior to the detection of the end of the exposure. Dividing the charge integrated over this interval by duration of the time interval yields the average current value.
  • Page 12 35040 Operators Manual ≤ Period × Observed Charge Error 0.10%] 0.10% ≤ Period × Observed Current Error 0.10%] 0.15% where “Period” is the time interval in years between calibrations. Gain Temperature Stability: The maximum temperature effect is less than ± 0.05%rdg for both charge and current measurements over operating range of 18°C to 28°C.

  • Page 13: Unpacking And Inspection

    General Information Specifications command, or exposure detection). The automatic power down feature applies only when the instrument is operating from battery power. In addition, all front panel settings are saved as part of the automatic power down sequence. Internal Electronic High Voltage Ion Chamber Bias Supply Voltage Range: A maximum of 11 output level settings in the range of -500 V to +500 V may be programmed during user customization.
  • Page 14 35040 Operators Manual - CD, 35040 Standard Customization (37870CD) - 9-pin connector adaptor (37616) - 7 foot RJ-45 Cable (105-260)

  • Page 15: Theory Of Operation

    Theory of Operation Introduction Section 2 Theory of Operation 2.1 Introduction The Model 35040 Therapy Dosimeter is a radiation measurement instrument intended for use in calibration procedures for high-energy accelerators, Co, and brachytherapy. Basic theory of operation of the instrument is explained in the following paragraphs. For information on radiation dosimetry and ion chamber measurement theory, the reader should refer to one of the standard radiological physics texts.

  • Page 16: Power Supply

    35040 Operators Manual 2.2.1 Power Supply During operation, the instrument may be powered by line voltage in the range of 100 to 240 VAC or from the internal 6 volt sealed lead acid battery for up to 8 hours. The power supply consists of a high performance charger that continuously charges the battery whenever the instrument is plugged in.

  • Page 17: Electrometer

    Theory of Operation Functional Description 2.2.5 Electrometer The electrometer is a single range, resettable, integrating amplifier. The high speed solid state reset is activated either by the operator pressing the RESET/MEASURE button or automatically when the instrument detects the end of an exposure. Errors resulting from temperature drift of the components and from dielectric absorption are dynamically corrected by the controlling firmware.
  • Page 18 35040 Operators Manual Table 2-1. Description of Quantities Quantity Description Units Comments Air Density Calculated by instrument and depends on front panel ADCF Correction None Temperature and Pressure settings. Factor Electrical charge delivered to readout in response to Charge during QExposure radiation incident upon detector since the last exposure...
  • Page 19 Theory of Operation Basic Operating Equations Charge and Current Measurements The instrument’s electrometer charge and current measurements are factory calibrated to a United States National Institute for Standards and Technology (NIST) traceable standard. Governing regulatory agencies or best of practice protocols may require that the instrument be calibrated by an independent calibration agency.
  • Page 20 35040 Operators Manual Charge QOffset Time TStart TOffset Start of Exposure - Charge samples in Leakage. - Samples discarded. - Charge samples in exposure. - Extrapolated charge due to leakage current Figure 2-2. Leakage Current and Start of Exposure When automatic exposure detection is disabled (start and stop threshold set to 0.0 pA), there is no correction for extrapolated charge due to leakage current.

  • Page 21: Setting Thresholds

    Theory of Operation Basic Operating Equations represents the next sample of charge at time T following the activation of the timer. Q corresponds to the interpolated charge at time T , where T is an integral number of seconds that is restricted to times ≤...

  • Page 22: Exposure Time

    35040 Operators Manual or dielectric absorption. The start and stop thresholds are set independently, but the stop threshold must be less than the start threshold. The thresholds are settable in 0.1 pA increments from 0.0 pA to 9.9 pA. In some test setups, it may be necessary to raise the thresholds to reliably detect an exposure in the presence of a relatively large leakage current.

  • Page 23: Air Density Correction Factor

    Theory of Operation Basic Operating Equations X X X Charge 1.33s 1.33s TOffset Time End of Exposure Detected Start of Exposure Detected - Sampled charge data points in average current. - Charge data points for leakage. Figure 2-3. Average Current and Exposure Time 2.3.3 Air Density Correction Factor ⎛...
  • Page 24 35040 Operators Manual Table 2-2. Air Density Adjustment Ranges and Resolutions % Error * Units Display Minimum Maximum Standard Resolution inches of mercury inHg 20.55 31.30 29.90 0.05 0.12 millimeters of mercury mmHg 0.10 altitude in feet -1200 10,000 0.07 altitude in meters -360 3050...

  • Page 25: Operation

    Figure 3-1. The Model 35040 Therapy Dosimeter Front Panel Triaxial Ion Chamber Input: This input accepts the current line of ion chambers from Fluke Biomedical, various 0.6 cc, 0.3 cc, and 0.1 cc therapy ion chambers from other manufacturers, and Brachytherapy well chambers.

  • Page 26: Rear Panel Familiarization

    35040 Operators Manual 3.3 Rear Panel Familiarization ION CHAMBER INPUT COMPUTER TRIAX INTERFACE RS-232 100-240V 50/60 Hz 50VA Figure 3-2. The Model 35040 Therapy Dosimeter Rear Panel RS-232 Receptacle (RJ-45 Style): The RS-232 Computer Interface is used for computer controlled factory test, for calibration, for customization, and for remote control/data acquisition.

  • Page 27: Power-Up Self-Test And Display Messages

    Operation Powering the System The Model 35040 Therapy Dosimeter operates on battery power for eight hours after a full charge. The dosimeter can be recharged quickly, usually in two to three hours, even during instrument operation. A low battery annunciator is displayed when 30 minutes or less of operation remains. When the battery pack is fully discharged, the instrument automatically shuts off and will not operate until AC line power is connected.

  • Page 28: Basic Measurement Techniques

    35040 Operators Manual WARNING Mating and unmating to this connector (or to the other end of a cable already connected to it) should be done only when the bias is set to 0 volts, or when the instrument power is turned off. central pin and inner shield shell of the triaxial connector are operated at the bias voltage above the outer shell and instrument case.

  • Page 29: Making Timed Exposure Measurements

    Operation Basic Measurement Techniques Procedure: • The annunciator line on the Measurement screen displays "WAIT System Not RDY" while the instrument is acquiring the minimum number of samples required for leakage compensation. Wait for this message to disappear. • Wait for the leakage current to return to the nominal value. •...

  • Page 30: Using Other Ion Chambers

    35040 Operators Manual NOTE predicted timed charge dose measurement to diagnose a problem at the onset of a timed measurement for sources that deliver at a constant exposure rate. If the predicted timed measurement is drastically different from the expected value, there is no reason to wait for the complete timer interval...

  • Page 31: Operation Instructions

    Operation Battery Care instrument will not be available for use. Depending upon the level of discharge, this period of unavailability may be on the order of days, and in extreme cases the battery will be permanently damaged. 3.9 Operation Instructions This section contains detailed instructions on the front panel operation of the Model 35040 Therapy Dosimeter.

  • Page 32: Powering Up The Model 35040 Therapy Dosimeter

    35040 Operators Manual bias voltages, automatic leakage compensation settings, and timer settings. • When the Test Function screen is displayed, pressing the TEST FUNCTION button displays a cursor that allows modification of the following settings: - Enabling or disabling automatic leakage compensation or setting of the start and stop exposure current thresholds - Selecting the timer interval, count mode, and decimal places - Specifying the effective exposure time presentation...

  • Page 33: Powering Down The Model 35040 Therapy Dosimeter

    Operation Operation Instructions NOTE When attempting to turn the instrument on, firmly press POWER button hold approximately one second. Always allow several seconds between retries. During this self-test period, the Model 35040 Therapy Dosimeter displays a sequence of screens. The first screen to appear after pressing the POWER button is the Pixel Test screen shown in Figure 3-6.
  • Page 34 35040 Operators Manual Figure 3-8 shows the ion chamber bias voltage (IC Bias), the system leakage current (Leakage), and the battery voltage and current. The bias voltage shown is 300.0 volts. The central electrode is positive (CEP). The leakage current is 0.001 picoamps. The battery current is a small positive number, thus the battery is charging and is almost fully charged.

  • Page 35: Automatic Leakage Compensation

    Operation Operation Instructions Start Thres: 1.0 pA Stop Thres: 0.9 pA Current: 0.0 pA Figure 3-11. The Test Function Screen Showing the Automatic Leakage Compensation Settings Figure 3-12 displays the settings for the timer interval, count mode, and decimal places. Refer to Section 3.9.6 for details.
  • Page 36 35040 Operators Manual With the automatic leakage compensation settings displayed (Figure 3-14), press the TEST FUNCTION button. The " " cursor will appear to the left of the ALC annunciator. Use the UP and DOWN arrow buttons to toggle the setting between on (ALC) and off (OFF). With automatic leakage compensation enabled, press the TEST FUNCTION button to advance the "...

  • Page 37: Timer Setup

    Operation Operation Instructions 3.9.6 Timer Setup The Test Function screen provides for configuring the timer interval, count mode, and decimal places (see Figure 3-17). With the timer settings displayed, press the TEST FUNCTION button. The " " cursor will appear to the left of the timer interval setting.

  • Page 38: Using The Detector Select Button

    35040 Operators Manual 3.9.8 Using the DETECTOR SELECT Button Pressing the DETECTOR SELECT button displays the Detector Select screen, see Figure 3-18. This screen displays information about the selected ion chamber calibration factor. An ion chamber consists of two text lines and an ion chamber calibration factor (ICCF) with units. All ion chambers are entered and can be modified via the Customization Software.

  • Page 39: Operation

    Operation Operation Instructions 22.5 C 760 mmHg ADCF = 1.000 Figure 3-20. The Air Density Screen With Air Density Corrections Disabled Air density correction is only applied to dose or dose rate measurements such as, Roentgens, rads, Grays, Sieverts, etc. These measures are dependent on correctly compensating for the mass of air in the ion chamber.
  • Page 40 35040 Operators Manual Set: 300.0 V 100% Central Electrde Pos IC Bias: 300.0 V CEP Figure 3-23. The Bias Select Screen With the Bias Set to a Positive Voltage Set: 0.0 V Bias Off IC Bias: 0.0 V OFF Figure 3-24. The Bias Select Screen With the Bias Turned Off Set: -150.0 V...

  • Page 41: Using The Reset/Measure Button

    Operation Operation Instructions 3.9.12 Using the RESET/MEASURE Button The RESET/MEASURE button has dual functionality. If no Measurement screen is displayed, pressing the RESET / MEASURE button displays one. When a Measurement Screen is displayed, pressing the RESET/MEASURE button zeroes all measurement readings and causes the Model 35040 Therapy Dosimeter to restart the measurement process.

  • Page 42: Overrange Conditions

    35040 Operators Manual OVER nC OVER pA OVER min OVER s Figure 3-28. The Measurement Screen With the Charge and Current Limits Exceeded After the First 60 Seconds Current Overrange Reduce exposure and Press RESET/MEASURE Figure 3-29. The Measurement Overrange Screen Table 3-1 specifies the conditions that cause the Model 35040 Therapy Dosimeter to display the overrange indicator for a measurement.

  • Page 43: Reset Error (With Automatic Leakage Compensation Enabled)

    Operation Operation Instructions A reset error will not occur for ion chambers calibrated in dose rate units (i.e. Brachytherapy chambers) since the measurement is primarily concerned with amps or dose rate. 3.9.15 Reset Error (With Automatic Leakage Compensation Enabled) The following discussion is only applicable when automatic leakage compensation is enabled and the ion chamber is calibrated in Coulombs.
  • Page 44 35040 Operators Manual LoBias Tmr 39.995 nC 659.8 pA 59.891 s Figure 3-32. Annunciator positions Table 3-2 lists the indicators the instrument uses to signal that a measurement quantity has not been compensated for leakage or is not available due to the specified condition. Table 3-2.

  • Page 45: Customization

    Operation Customization 3.10 Customization 3.10.1 Introduction The Model 35040 Therapy Dosimeter is shipped with valid settings allowing you to make measurements immediately. Should the need arise to change or modify any of the items described below, the Customization software provides for customizing the Model 35040 Therapy Dosimeter to meet your needs.

  • Page 46: Downloading

    35040 Operators Manual 35040 Customization Software, verify that COM PORT indicator is green, and click on the UPLOAD button. We recommend that you print a copy of the customization report (Print) as your first step in the customization process. This report contains all of the customization values and thus serves as a guide for returning to the original settings should an operator keyboard error occur during the process.

  • Page 47: Ion Chambers

    Operation Customization CONNECT Select CONNECT to force an initialization the computer’s serial port for use with the 35040 Customization Software. Normally initialization is done automatically at the start of the 35040 Customization Software or by selecting the serial port from the Com Port drop down list. UPLOAD Select UPLOAD to request the Dosimeter to send a listing of all the Customization Settings.
  • Page 48 35040 Operators Manual Figure 3-34. The Ion Chambers Form EDIT To modify existing ion chamber parameters, click twice with the mouse on a title within the Ion Chamber List Box. A form titled “Program Ion Chamber” appears with the parameters of the selected Ion Chamber and two buttons: OK and CANCEL.

  • Page 49: Special Items

    Operation Customization OK and CANCEL When you complete your editing of ion chamber parameters, you may use OK or CANCEL to exit the Parameter Editor. If you select CANCEL, all modifications are discarded and the original parameter settings of the ion chamber remain. If you select OK, the ion chamber parameters (modified or not) are sent to the instrument where they are stored for use during measurement modes.
  • Page 50 35040 Operators Manual Figure 3-36. The Special Items Menu (Calibration Temperature has focus) To modify the Power Down Interval or Optional Text, click on the desired text box and type in the new text from the keyboard. To select the Calibration Temperature, or different Temperature or Pressure Units, click on the DOWN arrow key and select another item from the drop down list by clicking on it.

  • Page 51: Measurement Displays

    Operation Customization 3.10.9 Measurement Displays The Model 35040 Therapy Dosimeter can contain up to sixteen (16) measurement displays, which are viewed from the Measurement Displays Form. With this form you may customize the appearance of any of the measurement displays. All screens must show an Annunciators Status Line (see Section 3.9.13) on the first line of the display.
  • Page 52 35040 Operators Manual Table 3-4. Available Display Lines Display Line Appearance Group Title (on a Measurement Display) Configuration Blank Line Air Density Setting ADCF = -.--- Temperature Pressure --.- C ---- hPa Bias Setting Set: >+---.- V +---% Firmware Revision FW Rev: 15OCT92 A Time Interval Setting...
  • Page 53 Operation Customization Display Line Group Selection Click on the Group’s DOWN arrow key and select another group from the drop down list by clicking on it. Each group on the drop down list will bring up a different Display Line List. Refer to Table 3-4. Selecting an Item and Placing It Use the mouse to move an item from the Display Line List to a Display.

  • Page 54: Timer Intervals

    35040 Operators Manual NOTE Upon completing the insertion, the Customization software tells the Model 35040 Therapy Dosimeter to insert the Display you specified. Initially, the inserted Display has two Blank Lines and a Charge measurement. 3.10.10 Timer Intervals The Model 35040 Therapy Dosimeter can contain up to twenty (20) timer interval settings, which are programmed from the Timer Intervals Form.

  • Page 55: Bias Settings

    Operation Customization The Model 35040 Therapy Dosimeter displays the timer intervals in the same order they are entered. That is, it does not sort the timer interval settings. The UP arrow key displays the timer interval settings in an increasing interval number order (e.g., Interval 1, Interval 2 … Interval 20), while the DOWN arrow key presents the timer interval settings in a decreasing order.

  • Page 56: Examples

    35040 Operators Manual When you press Bias Select on the Model 35040 Therapy Dosimeter front panel, the UP & DOWN keys allow you to select the bias settings in the order you entered them in the Bias Settings dialog box. 3.10.12 Examples The following examples describe many functions of the Customization program.
  • Page 57 Operation Customization 1. Clicking on the Power Down Interval places the input focus there. 2. Keyboard: Enter 15 into the Edit Box. 2. Click on DOWNLOAD. The Customization software downloads the new Power Down Interval to the model 35040 Therapy Dosimeter. Changing the Pressure Units To change the Pressure Units, select Special Items from the Main menu.

  • Page 58: Errors

    35040 Operators Manual 2. The Customization software prompts you to enter a Display number ahead of which to insert a new Display. Type 3 and press ENTER. The Customization software inserts a new Display ahead of Display 3. The Customization software downloads the insert operation to the instrument.

  • Page 59: Troubleshooting And Service

    Troubleshooting and Service Introduction Section 4 Troubleshooting and Service NOTE The Model 35040 Therapy Dosimeter contains no internal operator serviceable parts. Disassembly of the unit could result in electrical shock. Always select 0 volts bias or turn off the Model 35040 Therapy Dosimeter prior to connecting or disconnecting the ion chamber.
  • Page 60 When “PROBLEM”: is the first part of the action, the problem has been identified. The exact wording of the phrase should be used when reporting the problem to Fluke Biomedical’s Repair Coordinator. Let’s walk through a likely problem. The instrument is running from the battery. The phrase “LoBat” is blinking on the top line of the display.
  • Page 61 Troubleshooting and Service Troubleshooting Explanation: The low battery annunciator is a reminder that while running on the battery, there is a finite amount of energy available. For the battery in this instrument and the energy consumption of the instrument, when the battery voltage drops below 5.9 volts there is less than 30 minutes of operating time left.
  • Page 62 35040 Operators Manual Additional operator settings Select the proper settings are invalid. from the front panel. Timer interval customization Reinstall settings using the settings are invalid. Customization software. Additional calibration Do NOT make settings are invalid. measurements. Return instrument for repair. Explanation: The instrument detects whether the stored parameters are valid at power-up.
  • Page 63 Troubleshooting and Service Troubleshooting Example: 299.9 to 300.0 Cause: Rounding error in measurement. Action: None. Explanation: The bias voltage is not actually changing. The control for the bias is in discrete steps. The measurement is also in discrete steps. The control program may select a setting that causes the measurement to be very near the transition between one measurement step and the next.

  • Page 64: Display Will Not Light

    35040 Operators Manual 4.3 Display Will Not Light Go to line: Is the instrument connected to line voltage? Disconnect the line cord. Check the fuse. (See Section 4.6.) Is the fuse filament intact? Attach known operational appliance to outlet. Does the appliance work? Connect instrument to AC line.

  • Page 65: Low Battery

    Instrument or line cord is faulty. Replace cord with known good cord or establish that the line cord is good. Is line cord good? PROBLEM: Battery charger inoperative. See Section 4.10. Outlet is faulty. See Section 4.9. Order proper line cord. PROBLEM: Low battery during trickle charge. Call Fluke Biomedical for Service.

  • Page 66: Bias Error

    35040 Operators Manual 4.5 Bias Error Go to line: Is "??Bias" displayed? Has the instrument been on for more than one minute? Turn off the power. Wait 10 seconds. Turn on the power. Wait 1 minute. Is "??Bias" displayed? PROBLEM: Electrometer fault. See Section 4.10. Change the bias voltage to a different setting and then change back.

  • Page 67: Line Fuse Replacement

    Troubleshooting and Service Line Fuse Replacement 4.6 Line Fuse Replacement NOTE Disconnect the Model 35040 Therapy Dosimeter from other equipment along with the AC line power and turn off power before continuing with this section. 1. Position the instrument on its display face. Figure 4-1.

  • Page 68: Interface Connector Cleaning

    5. Let the instrument dry completely before using. 4.9 Replaceable Parts Information Fluke Biomedical maintains a complete inventory of all normal replaceable parts (see Table 4-1). To place an order, or to obtain information concerning replaceable parts, contact Fluke Biomedical at 440.248.9300.

  • Page 69: Recalibration, Repair Information & Technical Assistance

    018-304 4.10 Recalibration, Repair Information & Technical Assistance If your instrument needs recalibration or repair, we request that you contact Fluke Biomedical at 440.248.9300. More information concerning the operation, application, or service of your instrument may be obtained from the applications engineer at the previously listed numbers.
  • Page 70 35040 Operators Manual (Blank Page)

  • Page 71: A.1 Sample Documents

    Appendix Sample Customization Reports Appendix A Sample Customization Reports A.1 Sample Documents This section contains sample documents that the Customization Software can produce. It produced these ® documents on a HP LaserJet All of them contain the header “35040 THERAPY DOSIMETER”.
  • Page 72 35040 Operators Manual...
  • Page 73 Appendix Sample Customization Reports...
  • Page 74 35040 Operators Manual...
  • Page 75 Appendix Sample Customization Reports...
  • Page 76 35040 Operators Manual (Blank page)

  • Page 77: Introduction

    Appendix Features of Firmware Version “27JAN00” or Later Appendix B Features of Firmware Version”27JAN00” or Later B.1 Introduction This addendum updates information provided in the Model 35040 Therapy Dosimeter Instruction Manual. Particularly, the instrument now supports a measurement timer and extended charge and current ranges. B.2 New Features B.2.1 Overview •...

  • Page 78: Specifications Update

    35040 Operators Manual Refer to the following sections for details on the timed measurements: • Section B.3.2, Making Timed Exposure Measurements, presents an overview on configuring and using the timer. • Section B.4.1, Front Panel Controls: RESET/MEASURE, discusses how to start and stop the timer as well as zero measurements.

  • Page 79: Setup

    Appendix New Features 1.000 μA 0.001 μA Average Current Measurements Range and Resolution: Full Scale Range Display Resolution 200.00 pA 0.01 pA 2.0000 nA 0.0001 nA 20.000 nA 0.001 nA 200.00 nA 0.01 nA 1.0000 μA 0.0001 μA Effective Exposure Time Measurements Range and Resolution: Full Scale Range Display Resolution...

  • Page 80: Making Timed Exposure Measurements

    35040 Operators Manual Procedure • The annunciator line on the Measurement screen displays "WAIT System Not RDY" while the instrument is acquiring the minimum number of samples required for leakage compensation. Wait for this message to disappear. • Wait for the leakage current to return to the nominal value. •...

  • Page 81: Operation Instructions

    Appendix Setup a timed measurement for sources that deliver at a constant exposure rate. If the predicted timed measurement is drastically different from the expected value, there is no reason to wait for the complete timer interval expire before investigating the cause of the discrepancy. NOTE To differentiate the predicted and non-predicted timed measurements, the instrument alternates the...

  • Page 82: Using The Test Function Button

    35040 Operators Manual B.4.2 Using the Test Function Button Figure B.1 shows the automatic leakage compensation settings, which consist of the ALC status, start and stop threshold currents, and the instantaneous current measurement. Refer to Section B.4.3 for details. Start Thres: 1.0 pA Stop Thres:...
  • Page 83 Appendix Operation Instructions the instrument will cease updating the exposure measurements when the current drops below the stop threshold and will return to measuring leakage. NOTE The instrument uses the start and stop threshold settings to sense when an exposure is in progress. With the automatic leakage compensation settings displayed (Figure B-4), press the TEST FUNCTION button.

  • Page 84: Timer Setup

    35040 Operators Manual B.4.4 Timer Setup The Test Function screen provides for configuring the timer interval, count mode, and decimal places (see Figure B-6). With the timer settings displayed, press the TEST FUNCTION button. The " " cursor will appear to the left of the timer interval setting.

  • Page 85: Annuciators, Indicators, And Overrange Conditions

    Appendix Operation Instructions B.4.6 Annunciators, Indicators, and Overrange Conditions Table B-1 specifies the annunciators that may appear on the top line of the display. Table B-1. Annunciators Annunciator Condition No bias measurement possible since the ??Bias electrometer is not ready Air density correction in use (only applicable to radiological measurements) Automatic leakage compensation enabled...
  • Page 86 35040 Operators Manual Table B-3 specifies the conditions that cause the Model 35040 Therapy Dosimeter to display an overrange indicator (OVER) for a measurement quantity. Table B-3. Overrange Conditions Condition Overranged Measurement charge > 19.999 mC charge average current accumulated charge effective exposure time accumulated charge >...

  • Page 87: Theory Of Operation

    Appendix Theory of Operation B.5 Theory Of Operation Basic Operating Equations Quantity Description Units Comments Timed Charge The electrical charge delivered during the timer Timed interval. Predicted The total amount of timed charge that should be Timed_Predicted Timed Charge accumulated at the completion of the timer interval, based on the observed delivery rate.

  • Page 88: Troubleshooting

    35040 Operators Manual B.6 Troubleshooting This section outlines steps that the operator may take to identify and correct problems. Symptom: "Configuration Error" displayed. Configuration Error Service Required Error Number : 16 Cause: The instrument has lost the calibration or customization data. ®...

  • Page 89: Customization

    Appendix Operation Instructions Current Overrange Reduce exposure and Press RESET/MEASURE Cause: The input current has exceeded the 1.200 uA limit. Action: Stop the exposure. Change the setup to reduce the current. Explanation: The instrument has a 1.000 uA limit on measurable current and will continue to measure charge for currents up to 1.200 uA.
  • Page 90 35040 Operators Manual Figure B-9 shows the Measurement Displays dialog box. Figure B-9. The Measurement Displays Dialog Box (shown with the rotating rack having focus) The display lines are grouped within the Rotating Rack according to their function. The groups consist of “Configuration,”...
  • Page 91 Appendix Customization Table B-4. Available Display Lines Display Line Group Title Appearance (on the Rotating Rack) (on the Rotating Rack) (on a Measurement Display) Configuration Blank Line Air Density Setting ADCF = -.--- Temperature Pressure --.- C ---- hPa Bias Setting Set: >+---.- V +---% Firmware Revision FW Rev:...
  • Page 92 35040 Operators Manual Figure B-10. The Timer Intervals dialog box Select a field by pressing TAB until it is highlighted, or click on it with the mouse. Enter an integral number of seconds for the timer interval setting. When you select OK, the Customization software sends the timer interval settings to the instrument and returns the program to the Measurement menu.
  • Page 94 Fluke Biomedical Radiation Management Services 6045 Cochran Road Cleveland, Ohio 44139 440.498.2564 120 Andrews Road Hicksville, New York 11801 516.870.0100 www.flukebiomedical.com/rms...

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