Ludlum Measurements 334AB User manual

LUDLUM MODEL 334AB
ALPHA/BETA PARTICULATE MONITOR
January 2021

Model 334AB Operations
Manual

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

STATEMENT OF WARRANTY
Ludlum Measurements, Inc. warrants the products covered in this manual to
be free of defects due to workmanship, material, and design for a period of
twelve months from the date of delivery. The calibration of a product is
warranted to be within its specified accuracy limits at the time of shipment. In
the event of instrument failure, notify Ludlum Measurements to determine if
repair, recalibration, or replacement is required.
This warranty excludes the replacement of photomultiplier tubes, G-M and
proportional tubes, and scintillation crystals which are broken due to excessive
physical abuse or used for purposes other than intended.
There are no warranties, express or implied, including without limitation any
implied warranty of merchantability or fitness, which extend beyond the
description of the face there of. If the product does not perform as warranted
herein, purchaser’s sole remedy shall be repair or replacement, at the option of
Ludlum Measurements. In no event will Ludlum Measurements be liable for
damages, lost revenue, lost wages, or any other incidental or consequential
damages, arising from the purchase, use, or inability to use product.
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. Your cooperation will expedite the return of your
equipment.
LUDLUM MEASUREMENTS, INC.
ATTN: REPAIR DEPARTMENT
501 OAK STREET
SWEETWATER, TX 79556

X-Scale is a registered trademark of Intel Corporation.
GETTING STARTED...................................................................................................... 1
GENERAL DESCRIPTION .................................................................................................... 1
UNPACKING AND REPACKING ........................................................................................... 1
PARTS OF THE MODEL 334AB........................................................................................... 2
UNDERSTANDING THE DETECTOR HEAD ........................................................................... 3
TURNING THE UNIT ON..................................................................................................... 4
Charging the Batteries................................................................................................... 4
Power Button Functions................................................................................................ 5
STARTING THE PROGRAM.................................................................................................. 5
Response Check............................................................................................................. 5
Understanding the Display............................................................................................ 6
How to Change the Filter.............................................................................................. 7
Password Security ......................................................................................................... 7
Setting the Clock............................................................................................................ 8
CALIBRATION................................................................................................................ 9
CALIBRATION OVERVIEW.................................................................................................. 9
CALIBRATION EXPIRATION.............................................................................................. 10
SOURCE REQUIREMENTS ................................................................................................. 11
ALPHA ENERGY CALIBRATION........................................................................................ 11
Performing the Calibration......................................................................................... 12
ALPHA EFFICIENCY CALIBRATION .................................................................................. 15
BETA EFFICIENCY CALIBRATION..................................................................................... 16
Summary...................................................................................................................... 16
Reset the Background Count ....................................................................................... 16
Understanding the 2-Channel Board Adjustments...................................................... 17
Adjusting the Beta Background Threshold.................................................................. 18
Adjusting the Gamma Background Threshold............................................................. 19
Verifying the Background Count................................................................................. 19
Beta Efficiency Calibration......................................................................................... 20
Response Check........................................................................................................... 20
FLOW CALIBRATION........................................................................................................ 21
Setting Up the Apparatus............................................................................................. 20
Performing the Calibration......................................................................................... 20
CONFIGURATION........................................................................................................ 25
INSTRUMENT PROPERTIES ............................................................................................... 25
INSTRUMENT OPTIONS .................................................................................................... 26
General Tab................................................................................................................. 27
Logging Tab................................................................................................................. 28
Beta Tab....................................................................................................................... 29
Alarm Settings.............................................................................................................. 30
Table of Contents

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
RESPONSE CHECK ROUTINE ............................................................................................ 38
Source Requirements................................................................................................... 38
Running the Response Check....................................................................................... 39
NORMAL MEASUREMENT OPERATION............................................................................. 40
Minimum-Detectable Levels & Window Times ........................................................... 40
Display: Meter/Spectrum/Log ..................................................................................... 40
Operational Duration.................................................................................................. 41
MEASUREMENT CALCULATIONS ......................................................................... 43
ACUTE &CHRONIC MOVING-WINDOWS......................................................................... 43
BETA MEASUREMENT CALCULATIONS............................................................................ 44
ALPHA MEASUREMENT CALCULATIONS ......................................................................... 46
MINIMUM DETECTABLE MEASUREMENT CALCULATIONS............................................... 47
RADON MODE CONSIDERATIONS .................................................................................... 48
RETRIEVING & ANALYZING THE DATA............................................................. 50
ENDING A DOSE MEASUREMENT..................................................................................... 50
PC SYNCING SOFTWARE ................................................................................................. 50
CONNECTING TO A PC OVER USB................................................................................... 51
CONNECTING TO A PC OVER A NETWORK ....................................................................... 52
GRAPHING DATA IN EXCEL –MANUALLY ....................................................................... 55
GRAPHING DATA IN EXCEL –WITH TEMPLATES .............................................................. 55
Spectrum Chart............................................................................................................ 55
Chronic & Acute Charts.............................................................................................. 56
RADNET OPERATION ................................................................................................ 59
ASCII OPERATION...................................................................................................... 61
STATUS CONDITIONS................................................................................................ 63
NETWORK FILE ACCESS.......................................................................................... 65
Troubleshooting........................................................................................................... 65
Remote Administration................................................................................................ 66
Technical References................................................................................................... 67

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......................................................................................................... 73

Model 334AB Operations Manual
Ludlum Measurements, Inc. 1 January 2021
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).
Measurements are taken in both fast-responding (acute) and high-sensitivity (chronic) assessments
and report in English or SI units.
The instrument stores acquired data in comma-separated-variable (.csv) format. Data may be
saved in the instrument’s internal memory or written to an SD card for later retrieval.
The Model 334AB features an integrated LCD and touchscreen that displays information on
instrument status and readings during operation. The estimated dose and instrument status is
displayed at all times. A window below may be switched from showing historical readings and
battery status, or to display the current spectrum.
Unpacking and Repacking
Remove the calibration certificate and place it in a secure location. Remove the instrument and
ensure that all of the items listed on the packing list are in the carton. Check individual item serial
numbers and ensure calibration certificates match between instruments.
To return an instrument for repair and calibration, provide sufficient packing material to prevent
damaged during shipment. Every returned instrument must be accompanied by an Instrument
Return Form, which can be downloaded from the Ludlum website at www.ludlums.com. Find
the form by clicking the “Support” tab and selecting “Repair and Calibration” from the drop-
down menu. Then choose the appropriate Repair and Calibration division where you will find a
link to the form.
SECTION
1

Model 334AB Operations Manual
Ludlum Measurements, Inc. 2 January 2021
Parts of the Model 334AB
The Model 334AB consists of a fiberglass NEMA enclosure containing the SabreMCA™
electronics, battery and pump assemblies. A detector head, mounted to the right side of the
case, contains the detector, preamp, and a filter holder. A light stack containing an audible
alarm and red light is mounted to the top of the case.
On the front, the Model 334AB contains a 5.5-inch touch-screen display. The display is most
easily operated using a stylus. There are three buttons located below the touch-screen
display, which allow the user to toggle displayed units and isotope/channel, as well as an
alarm acknowledge to silence and clear an alarm.
On the right side below the detector head, there is a red
power button, mini USB port, charging port and LED
charging indicator, along with other ports needed for
additional options.
The Model 334AB includes an annunciator (alarm
light/audible alarm) that is used when radiological alarms
have been enabled. The annunciator has an adjustable
volume setting. To adjust the volume, twist the top of the
light stack, mechanically limiting its sound. To make the alarm louder, twist counter-
clockwise, allowing more sound from the horn. 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.

Model 334AB Operations Manual
Ludlum Measurements, Inc. 3 January 2021
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.
The detector head has several components that function together to be able to accurately
detect the decay of radioactive particulates. The following is a brief summary:
The detector is mounted to the side of the case inside a cavity, covered by a
removable filter holder. The detector is delicate and should not be touched.
The filter holder captures a 37 mm filter with a threaded ring and mounts it inside
the cavity, opposite the detector face.
Between the detector face and the filter is a small gap of air that creates a flow
path by extending circularly around the outside of the Detector Head.
Air-borne particulates are suctioned into the Head via the air flow path,
through the radial gap and are captured on the filter.
The air flow continues past the filter, through the side holes, and into the case,
where it is pumped out the bottom of the case.
As particulates on the filter decay, the emitted alpha and/or beta particles hit
the face of the detector and are recorded by the 334AB.
Following is a series of diagrams that illustrates the progression of particulates and their decay.

Model 334AB Operations Manual
Ludlum Measurements, Inc. 4 January 2021
Turning the Unit On
A red switch located on the side of unit below the detector head turns on the power to the
Model 334AB. After pressing the switch, the Model 334AB application will execute
automatically. In general, a cold startup takes about 20 seconds. If it does not, the unit needs
to be charged.
Charging the Batteries
Upon receiving a new unit, or when preparing a unit that has been shut down for a length of
time, the Lithium-Ion battery must be fully charged. The battery can be charged by plugging
the AC Adapter into a wall socket (115/220 VAC only) and plugging the power connector
into the jack at the lower right side of the case. A Red/Green LED next to the connector
indicates the charging state. When the LED is Red, the battery is being charged. When the
LED is Green, the battery is charged and the charger may be removed. The charging time is
approximately 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. So after the battery is fully discharged, all
that is needed is to reconnect the unit to AC power and allow the battery to charge again.
Depending on user settings, measurement records can either be stored on the SD card or in
the My Documents folder.The default save location for log data is the My Documents
folder, but in the event of a full battery discharge, these files would not be restored. Only
files saved on the SD card will be retained if the instrument is turned off or the battery dies.

Model 334AB Operations Manual
Ludlum Measurements, Inc. 5 January 2021
NOTE: Two charge cycles may be required for completely discharged batteries.Simply
unplug and re-plug the power connector to start a new charge cycle.
Power Button Functions
To turn the instrument off, press and hold the power button for 4 seconds; or until the
display goes blank and the pump turns off. Be aware that this clears all measurement files in
My Documents. In most cases, standby mode will be sufficient for most storage situations,
and a charge of at least 50% should last the weekend. Full shutdown should be used for
shipping or storage longer than several days.
Starting the Program
Under normal circumstances, the Model 334AB program will start automatically when the
instrument is turned on, and remains in the program when the instrument is shut off. If
there is a need to exit the program, it can be restarted from the desktop screen by double-
tapping the icon labeled ‘Ludlum 334AB’ using the stylus.
Once the Model 334AB program is running, you will not be able to perform any other
Windows CE operations like setting the clock, running other applications, or changing
display or network settings. To close the Model 334AB program, tap File –Close in the
menu.
Response Check
Unless it is disabled on startup, the Response Check dialog is the first screen to be displayed
after starting the 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. The home screen is then displayed.

Model 334AB Operations Manual
Ludlum Measurements, Inc. 6 January 2021
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.
The Menu bar across the top of the screen provides access to the various settings and other
information. They will appear differently depending on whether the password security
feature is enabled. These menu items and their sub-menus will be covered in detail in other
sections of the manual.
The Meter displays the status and current data of the selected channel. In Beta-Only mode,
only the beta and flow channels are displayed. In Alpha-Beta mode, it will display up to two
alpha isotopes of interest and the short-lived radon daughters: Po-212, Po-214 and Po-218.
The first line indicates the channel name with a suffix character to denote the type of
reading, Acute (/A) or Chronic (/C), which is followed by a status, usually normal. The
second line reports the current reading with the default unit.
The Log entry display in the lower half of the screen shows the readings for the beta
channel and alpha channels (optional), logged once a minute. Each standard log entry lists
the chronic reading, the minimum detectable dose, the highest acute reading of that minute,
and the battery charge level. Other log entries are listed as they occur. Possible log entry
status conditions are high alarm, low battery, flow rate failure, and other types of failures.
The Spectrum can also be viewed in the lower portion of the screen, in addition to the log
entry display, by tapping View—Spectrum…in the menu. The spectrum is displayed as a bar
graph made up of the detected counts. Each count is assigned to one of 256 channels,
increasing in energy along the non-visible X-axis. The Y-axis is a non-visible scale of counts
that compresses to fit the entire spectrum in view. The red line represents the mathematical
peak-fit curve that best matches the actual data. After several hours, three peaks will have
formed on the right end of the spectrum and illustrate the counts associated with the three
radon daughters.
The meter displays the various isotopes and variables being measured. To toggle the current
channel displayed, press the Channel button on the front of the unit. Repeated presses of
the Channel button will cycle through the channels, switching between acute and chronic
information before cycling to the next channel.
Menu
Meter
Log &
Spectrum

Model 334AB Operations Manual
Ludlum Measurements, Inc. 7 January 2021
Changing the units displayed on the meter is done by hitting the Units button. This will
toggle through units of activity and concentration (e.g. pCi, cps, DAC-Hr, DAC). Each
Channel has its own set of four units, while Flow and Gamma (optional) channels only have
one unit each.
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).
Replace the filter by removing the Filter Holder from the Detector Head, unscrewing the
ring that captures the filter, and discarding or storing the filter appropriately. With the Back
or Pump Side facing up, lay a new filter into the retaining ring and screw it back onto the
Filter Holder. It should be snug enough to create a good seal with the O-rings. The back side
should not be visible. Insert the Filter Holder back into the Detector Head cavity. From the
menu, tap Monitor —Reset Instrument to start a new count that does not include data from the
old filter. Always reset the instrument after a filter change.
Password Security
The Model 334AB supports password security to prevent unauthorized users from changing
the instrument configuration or calibration. By default, password security is turned off and
all menus and functions are accessible. Password security may be enabled by checking Use
Password Security from the File—Properties…menu. The Properties dialog is explained
fully in Section 3: Configuration. Tap File—Login… from the menu to enter a password.
Security Levels and Default Passwords:
Logged Out User level allows access to the View menu item only
Configuration level allows access to the View and Monitor menu items- config
Calibration level allows full access to the View, Monitor and Calibrate menu items - calib

Model 334AB Operations Manual
Ludlum Measurements, Inc. 8 January 2021
When logged in to the calibration level, the user is able to change the password(s) by tapping
File—Security Options… to open the Authorization Level Passwords dialog. Be sure to
record the new passwords in a safe place, as a forgotten password would require factory
support to reset.
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. The Model 334AB program will sense this condition and allow the
operator to manually set the clock during startup. To access the Date/Time properties
dialog, double-tap the time displayed in the lower right of the desktop.

Model 334AB Operations Manual
Ludlum Measurements, Inc. 9 January 2021
Calibration
To maintain accurate measurements of dose and concentration, the unit must be calibrated
periodically. Separate Alpha, Beta, and Flow calibrations are required for complete calibration.
The purpose of alpha calibration is to ensure that the peak-fitting algorithm knows where in the
spectrum to expect the radon peaks. This ensures that proper radon background subtraction of
the beta channel is performed. If the radon peaks appear too far from the expected locations, the
peak-fitting algorithm will fail (POOR FIT status), and the unit will fail to alarm properly.
The purpose of beta calibration is to ensure that the unit is measuring beta counts with the highest
possible counting efficiency and low noise. 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. Calibrations
should be performed in this order, for both Beta-only and Alpha/Beta configurations: Alpha
Energy Alpha Efficiency Beta Efficiency. Flow calibration can be performed at any
time.
NOTE: Ludlum instruments are shipped already calibrated at the factory elevation of
5100 feet. Because they are elevation-dependent, for any elevation difference greater than
1000 feet, both the Alpha Energy Calibration and Flow Calibration should be repeated at
the customer site before the instrument is put into service.
Calibration Overview
When performing a calibration, the Alpha energy calibration step should always be
performed before doing the alpha or beta efficiency calibrations.
SECTION
2

Model 334AB Operations Manual
Ludlum Measurements, Inc. 10 January 2021
Flow Calibration consists of:
Setting up an apparatus: Flow Calibration Aid, Flowmeter, & flow restriction device
Defining 3 flow rates and entering the measured flow of each in LPM
Validating the calibration with a 4th flow rate, which gives an error percentage
Alpha Energy Calibration consists of:
Roughing in the position of the IoI peak with a source and adjusting the Offset
Running the unit overnight to accumulate a radon decay product spectrum
Setting the peak marker positions of the Po-212, Po-214 and Po-218 radon daughter
peaks along with the IoI peak marker.
Alpha Efficiency Calibration consists of:
Determining the counting efficiency to an alpha calibration source.
Beta Efficiency Calibration consists of:
Adjusting threshold potentiometers on a PCB inside the case for desired beta and guard
detector background
Acquiring a 10-minute background count for background subtraction
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:
A user-defined number of days since the last calibration have elapsed. Default is 365 days.
[An option allows calibration expiration on the last day of the month following the
specified days.]
The unit has exceeded the user-defined number of hours of pump run-time since the last
calibration. Default is 8800 hours.
When the calibration expires, the Model 334AB display will indicate OUT OF CAL.

Model 334AB Operations Manual
Ludlum Measurements, Inc. 11 January 2021
Source Requirements
When performing any of the alpha and beta calibrations, a calibration source is used. Calibration
sources should be electroplated on stainless steel disks no larger than 32 mm (1.26 in.) in
diameter, have an active area restricted to the center 25 mm (1 in.) diameter, and have an activity
between 10,000 and 150,000 DPM.
NOTE: It is vital that the active surface of the source is the same distance from the
detector face as the surface of a filter would be. Poor-fitting source holders and sources
that are too large or have a bezel would severely impact calibration.
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.
Calibration I nstructions
Alpha Energy Calibration
To begin the alpha energy calibration, tap Calibrate—Alpha Energy…on the menu. The
Alpha Energy Calibration dialog will be displayed showing the alpha energy calibration
settings and a window of the spectrum, if it has been collected.
The horizontal axis represents the possible energies, assigned to channels 0 to 255. The
vertical scale accumulates counts in each channel and adjusts automatically to display the
highest peak.
Several vertical red lines are scattered along the alpha spectrum. The number of lines
depends on the operating configuration of the Model 334AB. These lines indicate the
position of the alpha peaks, and can be adjusted by dragging to match up with the peak
location. The numbers at the top of each red line correspond to the channel number of the
peak location.

Model 334AB Operations Manual
Ludlum Measurements, Inc. 12 January 2021
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. In Beta-only mode, only the 3 markers for the radon peaks and one
marker for the alpha source are used.
Configuration Settings
The three fields on the top of the Alpha Energy dialog each correspond to one of the three
configuration settings. The parameters for Gain, Threshold, and Offset determine the view
of the alpha spectrum on the display. These configuration settings affect the location, width,
spacing, and offset of alpha peaks on the spectrum. The threshold and gain should not have
to be adjusted from factory settings, so only the offset may need to be changed based on
the elevation of the instrument’s location.
The instrument is initially calibrated at 5100 feet. Alpha calibration is altitude dependent, so
it is important that this is taken note of. The values for these three settings are stored
permanently on the SabreMCA board, and changing any of them will save the new values
over the old values. The user can read the following descriptions of the three parameters to
get a better understanding of how the Alpha spectrum is displayed:
Gain—(Range 1 to 31) This value controls the amplitude of pulses coming from the
detector. Increasing the gain broadens isotope peaks, shifts them to the right, and
spreads individual peaks further apart. As the Gain is increased, the peak(s) can be
shifted completely off the right end of the spectrum display. Also, as Gain is
increased, the noise amplitude will increase proportionally, requiring a compensating
increase in Threshold level. Gain should not normally be changed from the factory setting.
Threshold—(Range 1 to 31) This value controls the amplitude threshold that
pulses must exceed to be measured. It should be set just above the level where the
amplifier noise is first observed. Default Threshold is 9. Less than 9 disables the threshold.
Offset—(Range 0 to 255, in 8-channel increments) Increases in this value shift the
256-channel spectrum the defined number of channels to the left. The Offset is
elevation-dependent and may need to be adjusted by the user in increments of 8.
Default Offset is set at factory calibration.
Performing the Calibration
Alpha energy calibration consists of aligning the peak markers with the corresponding
isotope peaks in the spectrum. This is most efficient when a mid-energy (e.g. 5 MeV) source
is verified to appear near channel 120, then resetting the spectrum and accumulating a radon
spectrum overnight. Once the spectrum is positioned, the peak markers may be aligned.
Observe the following steps for more detail.
Consideration for Radon Mode
The Model 330AB can be operated in “Radon Mode” by selecting PAEC as the primary IoI
(Iso1) where the radon/thoron progeny are used to determine the PAEC (potential alpha