Ludlum Measurements 334AB Operation Manual
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Ludlum Measurements 334AB Operation Manual

Alpha/beta particulate monitor
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LUDLUM MODEL 334AB
ALPHA/BETA PARTICULATE MONITOR
January 2021

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  • Page 1 LUDLUM MODEL 334AB ALPHA/BETA PARTICULATE MONITOR January 2021...
  • Page 2 Model 334AB Operations Manual...
  • Page 3 L U D L U M M E A S U R E M E N T S , I N C Model 334AB Operations Manual Documentation version 2.3 January 2021 Trademarks Ludlum, the Ludlum logo, and Model 334AB are trademarks of Ludlum Measurements, Inc. Microsoft, Windows CE, ActiveSync, Excel and the Windows logo are registered trademarks of Microsoft...
  • Page 5 RETURN OF GOODS TO MANUFACTURER If equipment needs to be returned to Ludlum Measurements, Inc. for repair or calibration, please send to the address below. All shipments should include documentation containing return shipping address, customer name, telephone number, description of service requested, and all other necessary information.

  • Page 6: Table Of Contents

    X-Scale is a registered trademark of Intel Corporation. GETTING STARTED ...................... 1 ....................1 ENERAL ESCRIPTION ................... 1 NPACKING AND EPACKING 334AB ................... 2 ARTS OF THE ODEL ................3 NDERSTANDING THE ETECTOR ..................... 4 URNING THE Charging the Batteries....................4 Power Button Functions ....................
  • Page 7 Isotope Tabs (with Alpha option) ..................31 Flow Tab ........................34 RadNet Tab (with WiFi or Ethernet option) ............... 35 ASCII Tab (with RS-232, Ethernet, or WiFi option) ............36 STARTING A DOSE MEASUREMENT ..............38 .................... 38 ESPONSE HECK OUTINE Source Requirements ....................
  • Page 8 EDITING THE ALPHA ISOTOPES DATABASE ............. 68 IODINE AND NOBLE GAS MONITORING ............. 70 Sensitivity to Iodine-131 ....................71 Configuring Iodine Monitoring ................... 71 When to Use a PTFE Filter Together with the Carbon-Impregnated Filter ....71 Filter Ordering ......................72 SPECIFICATIONS......................

  • Page 9: Getting Started

    Getting Started General Description The Model 334AB is a portable beta air monitor designed to function both as a workplace monitor and a Continuous Air Monitor (CAM). Spectral analysis is conducted via a 1024-channel analyzer that feeds data to the embedded processor. Factory configuration provides either beta particulate measurements, special nuclear materials (SNM) measurements or radon progeny measurements of potential alpha energy concentration (PAEC).

  • Page 10: Parts Of The Model 334Ab

    To make the alarm softer, twist the ring clockwise. In addition to the Model 334AB itself, the package it comes in contains an AC Adapter for charging the Model 334AB, a USB sync cable for exchanging data with a PC, a flow calibration aid, and a CD with software, certificates, and training videos.

  • Page 11: Understanding The Detector Head

    Model 334AB Operations Manual Understanding the Detector Head The Model 334AB has an integrated head that houses the detector. Optionally, it can house an additional guard detector for use in gamma background subtraction. Also, an In-Line Sample Head on an umbilical is available as an option.

  • Page 12: Turning The Unit On

    4 hours. Complete Battery Discharge The Model 334AB has persistent registry settings that are saved in non-volatile flash memory, thus keeping your program configuration settings intact if the battery is fully discharged. Also, the Model 334AB application will be stored in non-volatile memory and will be restored once power is returned to the unit.

  • Page 13: Power Button Functions

    Model 334AB program. The Response Check function will be covered later in this manual. For now, and until the Model 334AB is fully calibrated, tap the Skip button to bypass the Response Check or wait for 60 seconds for it to time out and then automatically continue.

  • Page 14: Understanding The Display

    Understanding the Display The basic display for the Model 334AB includes a Menu bar across the top, a Meter in the upper half of the screen, and a Log entry in the lower half that toggles to view the current Spectrum.

  • Page 15: How To Change The Filter

    How to Change the Filter After a Model 334AB has been monitoring for some time, the filter will become laden with dust and need to be replaced. Do this regularly; either by a specific schedule or when the flow rate declines and indicates Lo Flow (see Section 3 on configurations).

  • Page 16: Setting The Clock

    Setting the Clock The Model 334AB is configured with a real-time clock, which can be manually set or set automatically when connected via the USB port to a PC. The unit is factory calibrated to the correct customer time-zone before shipment. Whenever the battery and external power are disconnected from the main processor board during maintenance or repair, the clock will be reset to a default date.

  • Page 17: Calibration

    Flow calibration is also important, as it determines if the Model 334AB is converting the pump current into the measured flow rate correctly. The calibration functions are accessed from the Calibration item on the main menu. The four calibration functions are Flow, Alpha Energy, Alpha Efficiency and Beta Efficiency.

  • Page 18: Calibration Expiration

     Performing an efficiency calibration using a beta source. Calibration Expiration The Model 334AB program keeps track of the last time the alpha energy calibration was performed and will indicate that the unit is out of service if one of two conditions is met: ...

  • Page 19: Source Requirements

    Calibration source holders may be ordered which fit the Model 334AB detector head and hold a 32 mm source in the proper position for repeatable calibration geometry. It is also very important that the alpha calibration source matches the first isotope-of-interest (IoI 1), and the beta calibration source is similar in energy to the expected beta isotope.

  • Page 20: Performing The Calibration

    Model 334AB Operations Manual There are either zero, one, or two alpha isotopes-of-interest, plus the Po-218, Po-214, and Po-212 radon-progeny peaks. In radon mode, a peak marker for Po-210 may also appear. If operating in Alpha-Beta mode, the lower reference line(s) on the spectrum coincide with the isotope(s)-of-interest.
  • Page 21 Alpha Energy Calibration window open on the screen before leaving the Model 334AB to collect the radon spectrum. Leave the Model 334AB operating in a high- radon area for 8-24 hours so that a well-defined radon spectrum can be accumulated.
  • Page 22 Model 334AB Operations Manual You can always manually set the markers by lining up each of the red lines with their respective peak location. Tap on a line and drag it across the screen until they line up with the center of the peak.

  • Page 23: Alpha Efficiency Calibration

    This efficiency is used to produce accurate exposure and concentrations in units of measure meaningful to the user (e.g. DAC-h and mWL). It also makes sure that the Model 334AB is counting at an acceptable rate. To begin the Alpha Efficiency Calibration, select Calibrate—Alpha Efficiency… from the menu.

  • Page 24: Beta Efficiency Calibration

    Go to the menu at the top of the screen and tap on Calibrate—Beta Efficiency… First, remove the filter and return the filter holder to the radial head, so that the Model 334AB is operating under normal flow conditions but without a filter. Tap the Beta Reset button so the display Ludlum Measurements, Inc.

  • Page 25: Understanding The 2-Channel Board Adjustments

    Verifying the Background Count. Understanding the 2-Channel Board Adjustments The Model 334AB has four settings that control the 2-Channel board beta detection sensitivity; they are controlled by four manually adjustable potentiometers inside the unit.  R18 controls the V voltage used to bias the beta-sensitive detector.

  • Page 26: Adjusting The Beta Background Threshold

    To get to the potentiometers, first unscrew the large plastic screws that secure the Model 334AB lid to the base and open up the case. The 2-Channel board is located in the top half of the Model 334AB base, with the potentiometers mounted on blue casings.

  • Page 27: Adjusting The Gamma Background Threshold

    Model 334AB Operations Manual Adjusting the Gamma Background Threshold If the Model 334AB does not include the guard detector, then the count rate in the guard field will be disabled and will be zero counts per minute. This step may be skipped.

  • Page 28: Beta Efficiency Calibration

    Then tap Start Efficiency. The calibration will run for two minutes or until it has reached 10,000 counts, whichever is longer. After the beta source count is complete, the Model 334AB will display the 4-Pi beta efficiency. The efficiency should be in the range of 12-18%. For a low-energy beta source like Tc-99, an efficiency of 6-10% is typical.

  • Page 29: Flow Calibration

    Model 334AB Operations Manual Flow Calibration The Model 334AB sample flow rate is estimated by monitoring the internal pump’s electrical current. Flow calibration is necessary to ensure that the Model 334AB program is correctly monitoring and converting the pump current into a flow. This relationship is not linear. As a result, a three-point flow calibration is used, with validation at a fourth flow rate.

  • Page 30: Performing The Calibration

    Model 334AB Operations Manual NOTE: Ensure that the variable flow restriction does not completely cut off the airflow The pump is not designed to pull a high vacuum to the pump. , and low flow rates can damage the pump diaphragm. Do not allow the pump to run below 5 LPM for 7 LPM pumps (or 4 LPM for 6 LPM pumps) for more than a few minutes.
  • Page 31 Model 334AB Operations Manual The first step in the flow calibration is to reduce the flow rate by adjusting the flow restriction device to a low flow rate, at about 2 LPM below the unrestricted rate. Enter the actual value from the flowmeter in the dialogue under Measured Flow. Then hit Start Calibration.
  • Page 32 Model 334AB Operations Manual The flow calibration is now completed, and this example shows 0.4% error, which is acceptable. Tap Close and save the calibration settings. Remove the flow calibration aid from the detector head, which may be difficult because of the suction created. It is recommended that the pump is turned off temporarily for better leverage.

  • Page 33: Configuration

    Model 334AB Operations Manual SECTION Configuration The Model 334AB program provides several dialogs to allow configuration of the instrument operation. These dialogs are accessed through the File and Monitor menus. Each dialog and its settings are described below. Instrument Properties This dialog controls the operation of the of the user interface aspects of the program.

  • Page 34: Instrument Options

    Alarm Ack button on the face of the Model 334AB. When paired with the Use Password Security option, the user must have at least a config-level password in order to acknowledge and silence the alarm.

  • Page 35: General Tab

    Calibration Expiration Settings Calibration expires—This non-editable item displays the latest date on which the Model 334AB calibration will expire. The expiration could occur sooner if the maximum runtime hours are exceeded. End of Month—this checkbox allows expirations to be posted on the last day of the month following the actual expiration date.

  • Page 36: Logging Tab

    The Logging Interval settings control the data logging behavior of the Model 334AB. Several types of log files are created on the Model 334AB during operation. See Section 6: Retrieving and Analyzing the Data, for more information on the log files.

  • Page 37: Beta Tab

    Model 334AB Operations Manual Beta Tab This page defines the parameters concerning the measurement of and alarming on the net beta reading. It supports both a fixed beta background, and the use of a guard detector for real-time subtraction of gamma interference.

  • Page 38: Alarm Settings

    Default is 1.0. Guard Detector Present—This checkbox is selected if the Model 334AB is factory– configured with a guard detector. It is not user-editable.

  • Page 39: Isotope Tabs (With Alpha Option)

    Model 334AB Operations Manual Chronic Concen.—This setting determines the alarm set point for a chronic concentration alarm. Default is 1000 DAC. Acute Alarms Dose (DAC-h)—This setting determines the alarm set point for an acute dose alarm. Default is 80 DAC-h.
  • Page 40 Model 334AB Operations Manual NOTE: The Isotope field can also be used to select the PAEC (or Potential Alpha Energy Concentration) mode for monitoring radon Working Levels. NOTE: This field can also be used to select a Region-of-Interest (ROI_1) mode.
  • Page 41 Model 334AB Operations Manual Alarm Configuration Enable Alarms—this checkbox controls the checking for and annunciation of alarms for this isotope of interest. Left unchecked, all alarming will be disabled and no alarm checking will be performed! Default is checked, Alarming performed.

  • Page 42: Flow Tab

    It also offers a Fixed Flow setting for externally plumbed units. Low Limit—This setting defines the limit in liters per minute below which the Model 334AB will indicate a LO FLOW status. A low flow status can indicate a loaded or wet filter. Default is 6.0 LPM High Limit—This setting defines the limit in liters per minute above which the Model...

  • Page 43: Radnet Tab (With Wifi Or Ethernet Option)

    RadNet Tab (with WiFi or Ethernet option) This page contains the settings for RadNet Protocol broadcasts for Model 334AB units with the RadNet over WiFi, or RadNet over Ethernet option installed. This page will only appear for wireless- or Ethernet-enabled instruments.

  • Page 44: Ascii Tab (With Rs-232, Ethernet, Or Wifi Option)

    This page contains the settings for ASCII Communications Protocol broadcasts for Model 334AB units with an RS-232, Ethernet, or WiFi Option installed. The RS-232 and Ethernet options offer a RJ-9 or RJ-45 connector on the side panel respectively, while the WiFi option utilizes an internal antenna for broadcasting.
  • Page 45 Model 334AB Operations Manual Enable Beta Data—when checked, this setting includes beta data in the measurement packets. Default is checked Enable Alpha Data—when checked, this setting includes alpha data in the measurement packets. If unit is Beta-only, this setting is disabled. Default is checked Enable Short ASCII Format—when checked, ASCII broadcasts are stripped of extraneous...

  • Page 46: Starting A Dose Measurement

    Starting a Dose Measurement Response Check Routine Before starting a dose measurement, the Model 334AB should be tested using the Response Check routine to make sure that it is operating properly and in calibration. The purpose of the Response Check is to verify the following: ...

  • Page 47: Running The Response Check

    Model 334AB Operations Manual Running the Response Check After starting the Model 334AB program, the Response Check dialog is automatically initiated. It may also be initiated from the menu by tapping Monitor – Response Check…. There are four edit fields in the upper portion of the screen: Source—This list box selects the Alpha or Beta sources that can be used for the...

  • Page 48: Normal Measurement Operation

    The minimum-detectable levels of concentration and dose will be elevated until the Acute and Chronic Window times have elapsed, defaulted to 120 sec and 240 min respectively. Until the full window times have elapsed, the Model 334AB is using incomplete spectrum accumulations to calculate the dose and concentration and has elevated statistical fluctuations of the results.

  • Page 49: Operational Duration

    256-channel spectrum is displayed instead of the log entries. Return to the log entry view by tapping View—Log. In the event that a dose or concentration reading exceeds alarm limits, the Model 334AB will alarm visually and audibly, automatically display the channel of the chronic or acute reading that caused the alarm, and the status will be changed to High Alarm.
  • Page 50 Model 334AB Operations Manual NOTE: In order to preserve program and log data, the Model 334AB will automatically shut down when the battery life reaches 15%. Ludlum Measurements, Inc. January 2021...

  • Page 51: Measurement Calculations

    Model 334AB Operations Manual SECTION Measurement Calculations Acute & Chronic Moving-Windows In order to calculate a concentration, the counts for each counting channel are saved—along with the flow rate and volume—in a history array, so that the increase in counts over time can be used to determine the net count rate.

  • Page 52: Beta Measurement Calculations

    Because the counting efficiency for betas is dependent on the maximum isotope energy, the Model 334AB must be calibrated for the beta isotope-of-interest in order for the concentration and dose calculations to be accurate. Typically, it is calibrated to SrY-90, Cl- 36, or Tc-99.
  • Page 53 The Model 334AB program calculates dose according to the activity collected on the filter. Because the Model 334AB is typically used to continuously monitor the air in a facility, the concept of “worker dose” is dependent upon the portion of time the worker spends in the facility in comparison to the time the Model 334AB filter has been accumulating activity.

  • Page 54: Alpha Measurement Calculations

    Model 334AB Operations Manual Alpha Measurement Calculations For alpha-beta mode configurations, the curve fit function produces coefficients for each isotope that correspond to the counts under the peak. Like the beta channel behavior, alpha channels use a history array, so that the increase in counts over time can be used to determine the net count rate.

  • Page 55: Minimum Detectable Measurement Calculations

    In the Model 334AB, the minimum detectible concentration (MDC) is not directly related to the spectrum counts, but to the uncertainty in the peak fit.

  • Page 56: Radon Mode Considerations

    = Peak area variance for most recent Radon Mode Considerations The Model 334AB may be used to operate as a radon progeny monitor, measuring and alarming on PAEC (potential alpha energy concentration) levels of milli-Working Levels (mWL), and dose estimates in mWL-h. Alternatively, if configured for SI units, the instrument will display radon concentration in µJ/m³...
  • Page 57 Bi-212 before the ultimate energy yield of 13.69 MeV of Po-218 are summed. While its contribution is not included in the PAEC result, the Model 334AB does monitor for and report the concentration and dose estimate from Po-210.

  • Page 58: Retrieving & Analyzing The Data

    Retrieving & Analyzing the Data The log files stored on the Model 334AB on the SD Card or in the My Documents folder may be retrieved and analyzed on a PC, laptop, or workstation, either over the USB connection, or over the Ethernet/WiFi network connection.

  • Page 59: Connecting To Apc Over Usb

    Connecting to a PC over USB To connect to your Model 334AB, plug the USB sync cable from the computer to the mini-USB connection on the side of the unit. If the unit is turned on, the Model 334AB should automatically connect with the computer.

  • Page 60: Connecting To Apc Over A Network

    Connecting to a PC over a Network To connect to your Model 334AB over a WiFi or Ethernet network, you will need to know the network IP Address of the BPM from your IT staff who set up the instrument on the network.
  • Page 61 Model 334AB Operations Manual The Ludlum folder contains the log files on the Model 334AB SD Card. Each log file contains time stamps in the name of the file. They are formatted with YYYY being the year, MM being the month, and DD being the day of the file creation. Each file begins with a header line describing the individual fields.
  • Page 62 (°C) readings. It is deleted and a new log started when the Model 334AB application starts. Once the Model 334AB log data has been retrieved, you may disconnect the USB cable from the computer to the unit. Disconnecting the USB cable will not affect the operation of the unit nor the files copied or synced.

  • Page 63: Graphing Data In Excel - Manually

    Model 334AB Operations Manual Graphing Data in Excel – Manually Data can be imported in Microsoft Excel and then manually graphed by following these instructions. Alternatively, the data can be graphed using the Excel templates on your CD, as described in the next section.

  • Page 64: Chronic & Acute Charts

    Model 334AB Operations Manual Spectrum Animate Chart  Click the Spectrum Data tab to view the raw data. Click on any cell to begin  To import new data, select the Data menu tab and click Refresh (not Refresh All) ...
  • Page 65 Model 334AB Operations Manual  Because there are several data tabs, you can either select Refresh All from the first data tab and choose the files one after the other in order, or select Refresh from each tab and choose one file at a time.
  • Page 66 Model 334AB Operations Manual Beta Chronic Chart Beta Acute Chart Alpha Chronic Chart Alpha Acute Chart Ludlum Measurements, Inc. January 2021...

  • Page 67: Radnet Operation

    Model 334AB and relay those transmissions either via an Ethernet cable or via a second wireless link to the RadNet Client workstation. The concentration readings and spectrums from up to 50 Model 334AB units may be displayed on a single RadNet Client workstation.
  • Page 68 RadNet Client Workstation Configuration In order to communicate with the Model 334AB, the Model 334AB and client workstation must be configured with compatible IP Addresses in the same Class-C range. Choose addresses that do not conflict with each other.

  • Page 69: Ascii Operation

    ASCII log data. A wireless access point (WAP) is required to receive the transmissions from the Model 334AB and relay those transmissions either via an Ethernet cable to a network workstation, or via a second wireless link to the workstation.
  • Page 70 Model 334AB Operations Manual Configuration of Wireless Connections The Model 334AB with the Wireless ASCII Output option includes an 802.11b/g WiFi module and antenna. Configuration of this is covered in Section 8 on the WiFi RadNet Option. Standard Log Data Format The log data is reported in comma-delimited format.

  • Page 71: Status Conditions

    Model 334AB Operations Manual Appendix Status Conditions Status Description INITIALIZING Model 334AB program initialization (momentary status) NORMAL Operating normally, alarm levels below limit HIGH Dose or Concentration set point has been exceeded LO FLOW Flow rate is below Low Limit...
  • Page 72 Model 334AB Operations Manual OVERRANGE The detector is receiving too high a count rate to process. This is a failed condition. STANDBY Instrument is in a calibration dialog. Ludlum Measurements, Inc. January 2021...

  • Page 73: Network File Access

    Model 334AB Operations Manual Appendix Network File Access When enabled at the factory, the SabreBPM/Alert Ethernet and WiFi communications provide remote access of log files without using the USB Windows Mobile Device Center connection. File sharing has been enabled on the SabreBPM/Alert so that instruments accessible on the network can be accessed from Windows File Explorer.

  • Page 74: Remote Administration

    Virus/Firewall for a few minutes to see if the connection can be established. If so, then the AV/Firewall settings are causing the problem. Remote Administration The use of logon credentials and security on the Model 334AB can be administered through a web page. The Remoteadmin (Windows CE Remote Management Tool) allows you to ...

  • Page 75: Technical References

    Model 334AB Operations Manual Technical References There is a web interface on a PC connected to the SabreAlert to help set up shared folders and file sharing: https://developer.toradex.com/knowledge-base/webinterface On the SabreBPM/Alert you can enable authentication. [HKEY_LOCAL_MACHINE\Services\Smbserver\Shares] "UseAuthentication"=dword:1 "NoSecurity"=dword:0 https://stackoverflow.com/questions/39689835/smb-filesharing-on-windows-ce-6 Ludlum Measurements, Inc.

  • Page 76: Editing The Alpha Isotopes Database

    The alpha isotopes that appear in the drop-down lists for selection as the Iso 1 and Iso 2 isotopes-of-interest are taken from a comma-delimited text file on the FlashDisk/User folder on the Model 334AB. This file Isotopes.csv is user-editable from a text editor like the Windows Notepad, or from Microsoft Excel.
  • Page 77 Alarms—these four columns define the alarms in DAC and DAC-h. Typical default alarm levels are 200 DAC-h and 1000 DAC for the Acute and 20 DAC-h and 100 DAC for the Chronic. These values are updated from the Model 334AB application when changed under the Alarm Settings dialog.

  • Page 78: Iodine And Noble Gas Monitoring

    The Model 334AB can effectively monitor for I-131 or noble gasses when carbon- impregnated filters are used as the collection medium. In most cases a second Model 334AB is used in the upstream air-sampling path to remove most particulates (especially radon decay products)—and to monitor for any beta particulate isotopes.

  • Page 79: Sensitivity To Iodine-131

    Sr/Y-90. Configuring Iodine Monitoring The Model 334AB is made sensitive to Iodine in gaseous form by passing the gas through a carbon impregnated filter paper to absorb and retain I-131. This filter is placed in the sampling head in place of the normal particulate filter.

  • Page 80: Filter Ordering

    Model 334AB Operations Manual Filter Ordering  Standard Speclon™ PTFE membrane-type filters are available from Bladewerx, part Speclon 1.5 number BSP-FILT-15B037, 37 mm diameter 1.5 µm filter. When used with an external pump where the flow rate is in excess of 20 LPM, BSP-FILT- Speclon 5 50B037, 37 mm diameter 5 µm...

  • Page 81: Specifications

    Model 334AB Operations Manual Appendix Specifications Sampling Head and Flow  37 mm Filter holder masked to 25 mm collection diameter  Detector: Solid-state silicon 300-µm-depleted (450 mm² active area)  Pump: diaphragm-type, 7.0 LPM with no load Beta Data Analysis ...

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