Fluke 35040 manual Introduction, Features

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General Information

Introduction 1

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, 60Co, and brachytherapy equipment. The instrument can be used for calibration, government compliance testing, installation and set-up of new equipment, and troubleshooting.

The Model 35040 Therapy Dosimeter is a reference grade instrument that exceeds calibration laboratories’ 1993 recommendations for linearity, long-term stability, and zero drift. The instrument uses calibrated ion chambers to simultaneously measure and display dose and dose rate in the user specified radiological units. At the user’s discretion, the reading may be corrected for air density by user entered ambient temperature and barometric pressure readings.

•The highly regulated, precision electronic bias is continuously monitored. The bias voltage may be selected from the front panel.

•The Model 35040 Therapy Dosimeter provides a timer for performing timed charge and dose measurements. A typical application of the timer is for measuring brachytherapy sources. The instrument supplies four timed measurement quantities, which may be added to any of the measurement displays with the Customization software

•Triaxial ion chamber input connectors are furnished on both the front and rear of the instrument to make it easier to set up and use.

•For the first time in a therapy dosimeter, the effective exposure time for 60Co source is determined from a single exposure.

1.2 Features

•Low leakage current in the instrument.

•All front panel settings are stored at power down and recalled at power up.

•A wide variety of measurements are available simultaneously; including charge, dose, current, dose rate, accumulated charge, accumulated dose, and effective exposure time.

•Timer for performing timed charge, predicted time charge and corresponding dose measurements.

•The user may select one of 32 ion chamber calibration factors for direct readout of dose or dose rate units.

•Dose measurement values may be displayed in units of Roentgens, rads, Sieverts, or Grays. Dose rate measurement values may be displayed in dose units per second, minute or hour. For brachytherapy applications, the instrument may be configured to read in Curies, becquerles, or kerma.

•The user may enter ambient temperature and pressure for air density correction of dose and dose rate measurements. Air density correction may be turned on or off from the front panel.

•The user may select the dose rate time divisor from the front panel.

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Contents Therapy Dosimeter 35040Fluke Biomedical Table of Contents Addendum Features of Firmware Version 27JAN00 or Later Troubleshooting and ServiceSample Customization Reports Iii Blank Introduction FeaturesIntroduction Safety Symbols And Terms Before You Start Safety PrecautionsOperators Manual Manual Addenda SpecificationsFactory Calibration Error Source ± %rdg Maximum ErrorCurrent Measurements Full Scale Range Display Resolution Noise ± countsFull Scale Range Display Resolution Timed Charge MeasurementsEffective Exposure Time Measurements SpecificationsGeneral Measurements High Performance Power Supply and Battery Charger Unpacking and Inspection 35040 Functional Description Hardware Block Diagram of the Model 35040 Therapy DosimeterSerial Communications Port Power SupplyFront Panel MicroControllerMultiplexer and A/D Converter Basic Operating EquationsElectrometer Bias SupplyQAccumprevious Quantity Description Units CommentsQExposure QAccumLeakage Measurements Charge and Current Measurements= time of electrometer conversion s Timed Charge and Dose Exposure Charge and DoseExposure Current and Rate Setting ThresholdsPredicted Timed Charge and Dose Accumulated Charge and DoseDoseRate = I a × Iccf Units/C × Adcf × RateMultiplier s Exposure Time⎝ P Air Density Correction FactorMm Hg = inch Hg x Units Display Minimum Maximum Standard Resolution ErrorIntroduction SetupSetup Front Panel FamiliarizationRear Panel Familiarization Powering The SystemIon Chamber Connector Power-Up Self-Test and Display MessagesGeneral Considerations Basic Measurement TechniquesMaking Non-Timed Exposure Measurements Timer Use Timer Setup3Making Timed Exposure Measurements Using Other Ion Chambers Battery CareFront Panel Controls PowerBattery Care Operation InstructionsPowering Up the Model 35040 Therapy Dosimeter Using the Test Function Button Powering Down the Model 35040 Therapy DosimeterOperation Instructions QScaleFactor=1.0000 IScaleFactor=1.0000 5Automatic Leakage Compensation 12. The Test Function Screen Showing the Timer SettingsCalibrated by Keithley RMD Nov 15 17. The Test Function Screen Showing the Timer Settings 6Timer SetupUsing the AIR Density Button Using the Detector Select ButtonUsing the Bias Select Button Using the Units Select ButtonSet 300.0 V 100% Central Electrde Pos IC Bias 300.0 V CEP Overranging Conditions Using the RESET/MEASURE ButtonOverrange Conditions Reset ErrorCondition Values Overranged Annunciator Condition Reset Error With Automatic Leakage Compensation EnabledAnnunciators AnnunciatorsCondition Overranged Measurement Measurement Indicators and ConditionsIndicator Measurement Condition ? left of valueStarting the Customization Software Installing/Uninstalling Customization SoftwareCustomization Connection to the ComputerMenu Items and Controls DownloadingCOM Port Drop Down List Close or File Close Ion ChambersFile Save AS and File Print Edit Special Items OK and Cancel36. The Special Items Menu Calibration Temperature has focus Download and CancelMeasurement Displays Display Line Operators Manual Available Display LinesChanging a Line on a Display Using the APPEND, DELETE, and Insert ButtonsDisplay Line Group Selection Selecting an Item and Placing It38. The Timer Intervals Form Timer Intervals39. The Bias Settings Form Bias SettingsExamples Deleting a Display Changing the Pressure UnitsCustomizing a Measurement Display Appending a DisplayErrors Troubleshooting Troubleshooting and ServiceSymptom LoBias annunciator displayed Symptom Display does not light up when Power is pressedSymptom ??Bias annunciator displayed Symptom HiBias annunciator displayedDo not make Symptom Internal Reset Error displayedSymptom Configuration Error displayed Bit Description ActionMeasurements. Return Symptom Current Overrange DisplayedSymptom Dashes displayed instead of digits Symptom Bias voltage measurement changes by one digitExample 299.9 to Display Will Not Light Hours? Is the battery voltage greater than 5.9 volts? Low BatteryGo to Bias ErrorLine Model 35040 Therapy Dosimeter Fuse Replacement Line Fuse ReplacementCleaning The Instrument Interface Connector CleaningReplaceable Parts Information Replaceable Parts Information Warranty InformationReplaceable Parts List Recalibration, Repair Information & Technical AssistanceBlank Sample Documents Sample Customization Reports35040 Appendix Sample Customization Reports 35040 Appendix Sample Customization Reports Blank Overview Introduction New FeaturesTimed Measurements Specifications Update New Features B SetupTimer Use Procedure Timer Setup ProcedureMaking Timed Exposure Measurements Setup B RESET/MEASUREAutomatic Leakage Compensation ADC ALCOperation Instructions B Start NA pA Stop Thres CurrentDecimal Places Timer SetupTable B-2. Measurement Indicators and Conditions Annunciators, Indicators, and Overrange ConditionsTable B-1. Annunciators Condition Overranged Measurement1 Table B-3. Overrange ConditionsTheory of Operation Theory Of OperationConfiguration Error Service Required Error Number Measurement Menu Main MenuMeasurement Displays Figure B-9 shows the Measurement Displays dialog box Table B-4. Available Display Lines Figure B-10. The Timer Intervals dialog box Page Fluke Biomedical
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