35040 Therapy Dosimeter Operators Manual February 2005 Manual No. 37870 Rev. 10 ©2004, 2005 Fluke Corporation, All rights reserved. Printed in U.S.A.
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.
Table of Contents Section 1: General Information................................................................................... 1-1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Introduction ............................................................................................................................ 1-1 Features ................................................................................................................................. 1-1 Before you Start - Safety Precautions.......................
3.9.12 3.9.13 3.9.14 3.9.15 3.9.16 3.10 3.10.1 3.10.2 3.10.3 3.10.4 3.10.5 3.10.6 3.10.7 3.10.8 3.10.9 3.10.10 3.10.11 3.10.12 3.10.13 Using the Reset/Measure Button .................................................................................. 3-17 Overrange Conditions.................................................................................................... 3-17 Reset Error ....................................................................................................................
Appendix B: Addendum Features of Firmware Version “27JAN00” or Later.............B-1 B.4.5 B.4.6 B.5 B.6 B.7 B.7.1 B.7.2 Reset Error (with Automatic Leakage Compensation Enabled)...................................... B-8 Annuciators, Indicators, and Overrange Conditions........................................................ B-9 Theory of Operation ............................................................................................................. B-11 Troubleshooting .............................
(Blank page)
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.
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. • Highly regulated, stable, electronic ion chamber bias supply. • The level of the internal electronic bias supply is continuously monitored. Annunciators appear on the display if an abnormal bias voltage level is detected.
General Information Safety Symbols and Terms 1 CAUTION The 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. Be sure to note these changes and incorporate them into the manual. 1.6 Specifications Charge Measurements Range, Resolution and Repeatability: Full Scale Range Display Resolution 200.
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. This program is available to the AAPM accredited calibration laboratories (or equivalent) and may be used to adjust the current and charge scale factors from their nominal factory setting of 1.000.
General Information Specifications 1.0000 μA 1 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.
35040 Operators Manual Observed Charge Error ≤ [ Period 5 × 0.10%] + 0.10% and Observed Current Error ≤ [ Period × 0.10%] + 0.15% 5 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. Add an additional ± 0.05%rdg for operation during and immediately following battery charging at the high rate. Add an additional ± 0.
General Information Specifications 1 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.
35040 Operators Manual - CD, 35040 Standard Customization (37870CD) - 9-pin connector adaptor (37616) - 7 foot RJ-45 Cable (105-260) 1-8
Theory of Operation Introduction 2 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, 60Co, 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. 2.
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. The charger has three charging stages.
Theory of Operation Functional Description 2 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. 2.2.
35040 Operators Manual Table 2-1.
Theory of Operation Basic Operating Equations 2 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.
35040 Operators Manual Charge X X X QOffset 0 TOffset TStart Time Start of Exposure - Charge samples in Leakage. X - 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.
Theory of Operation Basic Operating Equations 2 Q1 represents the next sample of charge at time T1 following the activation of the timer. Q2 corresponds to the interpolated charge at time T2, where T2 is an integral number of seconds that is restricted to times within the range: T1 < T2 ≤ (T1 + Timer Interval Setting). Predicted Timed Charge and Dose This measurement extrapolates the timed charge (QTimed) at the elapsed time (TElapsed) that should be accumulated at completion of the timer interval (i.e.
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. Since the start threshold determines the minimum dose rate, it may be necessary to lower the thresholds for some exposures.
Theory of Operation Basic Operating Equations X X X 2 X X X X Charge Q X X X X 1.33s T 1.33s 0 TOffset T2 T1 Time Start of Exposure Detected End 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 ⎛ 760 mmHg ⎞ ⎛ T ⎞ ADCF = ⎜ ⎟ ⎟×⎜ P ⎝ ⎠ ⎝T c ⎠ The air density correction factor is used to correct dose and dose rate measurements for a vented ion chamber.
35040 Operators Manual Table 2-2. Air Density Adjustment Ranges and Resolutions Units Display Minimum Maximum Standard Resolution inches of mercury inHg 20.55 31.30 29.90 0.05 % Error* 0.12 millimeters of mercury mmHg 522 795 760 1.0 0.10 altitude in feet ft -1200 10,000 0 25 0.07 altitude in meters m -360 3050 0 10 0.09 millibars mbar 697 1060 1013 1.0 0.07 hectoPascals hPa 697 1060 1013 1.0 0.07 Units Display Minimum Maximum Fahrenheit F 32.0 122.
Operation Setup 3 Section 3 Operation 3.1 Setup Introduction This section contains set-up and connection procedures for the Model 35040 Therapy Dosimeter. The instrument is factory calibrated to measure charge (Coulombs) and current (Amperes). It is recommended that the user customize the Model 35040 Therapy Dosimeter prior to its first use. This customization may involve selecting the desired ion chamber calibration factor, temperature units, pressure units, and bias voltages.
35040 Operators Manual 3.3 Rear Panel Familiarization ION CHAMBER INPUT ! TRIAX COMPUTER 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. AC Line Power Receptacle: The AC line input range is 100 - 240 VAC (47 - 63 Hz).
Operation Powering the System 3 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. 3.
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. The central pin and inner shield shell of the triaxial connector are operated at the bias voltage above the outer shell and instrument case. Although the bias potential is energy and current limited, care should be taken to avoid unnecessary and possibly hazardous shocks.
Operation Basic Measurement Techniques 3 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. • Make the exposure.
35040 Operators Manual NOTE Use the predicted timed charge or 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 to expire before investigating the cause of the discrepancy.
Operation Battery Care 3 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. Please note that the display examples shown here correspond to a particular customization set-up.
35040 Operators Manual and bias voltages, automatic leakage compensation settings, and timer settings.
Operation Operation Instructions 3 NOTE When attempting to turn the instrument on, firmly press the POWER button and hold for 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. Figure 3-6.
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. ADC Batt: 6.8 V +0.10 A Leakage: 0.001 pA IC Bias: 300.0 V CEP Figure 3-8.
Operation Operation Instructions ADC Start Thres: Stop Thres: Current: Figure 3-11. 3 ALC 1.0 pA 0.9 pA 0.0 pA 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. ADC ALC Interval: 60 s Count: UP Decimal Places: 0 Figure 3-12.
35040 Operators Manual With the automatic leakage compensation settings displayed (Figure 3-14), press the TEST FUNCTION button. The "f" 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 "f" cursor to the next field or exit Edit mode.
Operation Operation Instructions 3 3.9.6Timer 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 "f" cursor will appear to the left of the timer interval setting. Use the UP and DOWN arrow buttons to select a value from the user customizable list. Refer to Section 3-10 for details on programming the timer intervals.
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. The “f” cursor points to the first description string of the selected chamber.
Operation Operation Instructions OFF 22.5 C 3 760 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. Electrical units (coulombs and amperes) are, by definition, insensitive to the mass of air in the ion chamber. 3.9.
35040 Operators Manual ADC 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 ADC Set: 0.0 V 0% Bias Off IC Bias: 0.0 V OFF Figure 3-24. The Bias Select Screen With the Bias Turned Off ADC Set: -150.0 V -50% Central Electrde Neg IC Bias:-150.0 V CEN Figure 3-25. The Bias Select Screen With the Bias Set to a Negative Voltage In the example of Figures 3-23 to 3-25, the maximum voltage setting is 300.0 V. Thus, 300.
Operation Operation Instructions 3 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. Press the UP arrow to display the next Measurement screen.
35040 Operators Manual ADC OVER nC OVER pA OVER min OVER s ADC Current Overrange Reduce exposure and Press RESET/MEASURE Figure 3-28. The Measurement Screen With the Charge and Current Limits Exceeded After the First 60 Seconds 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. Table 3-1. Overrange Conditions Condition charge > 2.
Operation Operation Instructions 3 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.
35040 Operators Manual ADC LoBias Tmr 39.995 nC 659.8 pA 59.891 s Figure 3-32. ALC 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.
Operation Customization 3 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.
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.
Operation Customization 3 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.
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. Refer to Figure 3-35. The following description of the Parameter Editor may be followed when editing, appending, or inserting ion chamber parameters. Figure 3-35.
Operation Customization 3 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.
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.
Operation Customization 3 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. You may choose what appears on the other three lines. Figure 3-37 shows the Measurement Displays Form. Figure 3-37.
35040 Operators Manual Table 3-4.
Operation Customization 3 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. With the mouse, place the mouse cursor on the item. Press and hold the left key down.
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.
Operation Customization 3 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. The instrument automatically skips any settings that have a value of zero (0). 3.10.
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. Editing an Ion Chamber To change an ion chamber’s parameters, first select Ion Chambers from the menu. 1. Click twice on the ion chamber you want to modify. 2.
Operation Customization 3 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. This example changes the Pressure Units to millibars. 1. Click on the DOWN arrow symbol of the Pressure Units Drop List. 2. Click on millibars. 3.
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. The new Display contains two Blank Lines and a Charge measurement as a default. All the Displays behind Display 3 move down in order.
Troubleshooting and Service Introduction 4 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. Failure to do so may result in an electrical shock.
35040 Operators Manual The decision trees of the second part are presented in text format. To use the decision tree, start with statement number 1. The text may state one or more actions to be completed followed by a question. Choose the most appropriate answer. Use the number after the answer to find the next statement. Eventually, you will come to a statement that has an action and no question. This may refer you to another section or provide a conclusion to the problem.
Troubleshooting and Service Troubleshooting 4 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. Symptom: “Internal Reset Error” displayed.
35040 Operators Manual 7 8 9 Explanation: Additional operator settings are invalid. Timer interval customization settings are invalid. Additional calibration settings are invalid. Select the proper settings from the front panel. Reinstall settings using the Customization software. Do NOT make measurements. Return instrument for repair. The instrument detects whether the stored parameters are valid at power-up. If the parameters are invalid, it will affect one or more of the measurements.
Troubleshooting and Service Troubleshooting 4 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.
35040 Operators Manual 4.3 Display Will Not Light 1. Is the instrument connected to line voltage? 2. Disconnect the line cord. Check the fuse. (See Section 4.6.) Is the fuse filament intact? 3. Attach known operational appliance to outlet. Does the appliance work? 4. Connect instrument to AC line. Press the Power button. Did the display light up? 5. Is the battery current between +0.10 A and +3.00 A? 6. 7. The fault has been cleared. The battery is charging.
Troubleshooting and Service Low Battery 4 4.4 Low Battery 1. 2. 3. Is the instrument connected to line voltage? Is the instrument connected to line voltage? Turn the instrument off. Wait a few seconds. Turn the instrument on. A sequence of screens will appear. On the last screen, the battery voltage and current are displayed. Is the battery current between +0.10 A and +3.00 A? The battery is charging. Has the instrument been plugged in for more than 8 hours? 4. Is the battery voltage greater than 5.
35040 Operators Manual 4.5 Bias Error 1. Is "??Bias" displayed? 2. Has the instrument been on for more than one minute? 3. Turn off the power. Wait 10 seconds. Turn on the power. Wait 1 minute. Is "??Bias" displayed? 4. PROBLEM: Electrometer fault. See Section 4.10. 5. 6. 7. Change the bias voltage to a different setting and then change back. Wait about 10 seconds. Is the error on the display? Change the bias voltage to 0.0 V. Disconnect all triax cables. Cap the connectors.
Troubleshooting and Service Line Fuse Replacement 4 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. Model 35040 Therapy Dosimeter Fuse Replacement 2. Remove the fuse drawer. With your fingernails, squeeze together the two ends of the fuse drawer and pull it out of its slot. 3. Replace the fuses with P/N 38476.
35040 Operators Manual NOTE If fuses continue to fail - return the instrument for repair. 4.7 Interface Connector Cleaning WARNING Select 0.0 V bias setting AND turn off the Model 35040 Therapy Dosimeter prior to cleaning the interface connectors. Failure to do so may result in an electrical shock. The presence of dust or lint at the interface connectors can produce leakage currents that may have a detrimental affect upon the accuracy of radiation measurements.
Troubleshooting and Service Replaceable Parts Information Table 4-1. Replaceable Parts List Description Part Number AC Line Cord (USA) CO-19 AC Line Cord (Europe CEE 7/7) 86512060 AC Line Cord (UK & Ireland) 86583000 AC Line Cord (Denmark) 86536041 AC Line Cord (Italy) 86531031 AC Line Cord (Switzerland) 86515050 Carrying Case 37777 Customization Kit 37886 DB-9 Female Connector 37616 7 foot RJ-45 Cable 105-260 Customization Software Disk 3.
35040 Operators Manual (Blank Page)
Appendix Sample Customization Reports A 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”.
35040 Operators Manual A-2
Appendix Sample Customization Reports A A-3
35040 Operators Manual A-4
Appendix Sample Customization Reports A A-5
35040 Operators Manual (Blank page)
Appendix Features of Firmware Version “27JAN00” or Later B 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.
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. • Section B.4.4, Timer Setup, provides details on the timer configuration. • Section B.5, THEORY OF OPERATION, specifies how the instrument performs timed measurements.
Appendix New Features 1.000 μA 0.001 μA B 1 Average Current Measurements Range and Resolution: Full Scale Range 200.00 pA Display Resolution 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 Seconds 59.99 s Hours/Minutes/Seconds 59.99 s 19,999.9 s 5 h 33 min 19.9 s Display Resolution 0.01 s 0.
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. • Make the exposure. When the instrument senses that the exposure is over, it displays and holds the exposure measurements and then resets the electrometer (refer to Section B.4.
Appendix Setup B 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 to expire before investigating the cause of the discrepancy. NOTE To differentiate the predicted and non-predicted timed measurements, the instrument alternates the display of time with a “PREDICT” indicator on the predicted timed measurement lines. B.
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. ADC Start Thres: Stop Thres: Current: Figure B-1. ALC 1.0 pA 0.9 pA 0.
Appendix Operation Instructions B 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. The " " cursor will appear to the left of the ALC annunciator.
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. Use the UP and DOWN arrow buttons to select a value from the user customizable list. Refer to Section B.7 for details on programming the timer intervals.
Appendix Operation Instructions B 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.
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 accumulated charge > 1.0000 C Overranged Measurement1 charge average current accumulated charge effective exposure time accumulated charge current > 1.000 μA current current > 1.200 μA time > 19,999.9 s all non-leakage Condition charge > 19.
Appendix Theory of Operation B B.5 Theory Of Operation Basic Operating Equations Quantity QTimed Description Timed Charge Units C QTimed_Predicted Predicted Timed Charge C Comments The electrical charge delivered during the timer interval. The total amount of timed charge that should be accumulated at the completion of the timer interval, based on the observed delivery rate.
35040 Operators Manual B.6 Troubleshooting This section outlines steps that the operator may take to identify and correct problems. Symptom: "Configuration Error" displayed. ADC Configuration Error Service Required Error Number : 16 Cause: The instrument has lost the calibration or customization data. Action: Convert the configuration error number to a binary value using a program such as the Windows® Calculator and use the table below to determine the extent of the problem.
Appendix Operation Instructions B ADC 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. The instrument can accept an input current up to 3 mA without damage to the instrument. B.
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,” “Amps, Coulombs, Volts,” “Dose, Rate,” and “Time.
Appendix Customization B Table B-4. Available Display Lines Display Line Group (on the Rotating Rack) Configuration Amps, Coulombs, Volts Dose, Rate Time Title (on the Rotating Rack) Blank Line Appearance (on a Measurement Display) Air Density Setting ADCF = -.--- Temperature Pressure --.- C Bias Setting Set: >+---.- V +---% Firmware Revision FW Rev: 15OCT92 A Time Interval Setting Interval: ---- s IC Calibration Factor ICCF=1.
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. Select CANCEL or press ESC to discard any changes and return to the Measurement menu.
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.
