Ludlum Measurements 334A User manual

LUDLUM MODEL 334A
ALPHA AIR MONITOR
January 2021

Model 334A Operations Manual

L U D L U M M E A S U R E M E N T S , I N C
Model 334A Operations Manual
Documentation version 3.0
January 2021
NO WARRANTY. The technical documentation is being delivered to you AS-IS and Ludlum makes no warranty
as to its accuracy or use. Any use of the technical documentation or the information contained therein is at the risk
of the user. Documentation may contain technical or other inaccuracies or typographical errors. Ludlum reserves
the right to make changes without prior notice. No part of this publication may be copied without the express
written permission of Ludlum Measurements, Inc. 501 Oak Street, Sweetwater, Texas 79556
Trademarks
Ludlum, the Ludlum logo, and Model 334A are trademarks of Ludlum Measurements, Inc.
Microsoft, Windows CE, ActiveSync, Excel and the Windows logo are registered trademarks of Microsoft Corporation.
X-Scale is a registered trademark of Intel Corporation.

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
800-622-0828 325-235-5494
FAX [phone]

GETTING STARTED...................................................................................................... 1
GENERAL DESCRIPTION .................................................................................................... 1
UNPACKING AND REPACKING ........................................................................................... 1
PARTS OF THE MODEL 334A ............................................................................................. 2
UNDERSTANDING THE DETECTOR HEAD ........................................................................... 3
TURNING THE UNIT ON..................................................................................................... 4
Charging the Batteries................................................................................................... 4
Power Button Functions................................................................................................ 4
STARTING THE PROGRAM.................................................................................................. 5
Response Check............................................................................................................. 5
Understanding the Display............................................................................................ 5
How to Change the Filter.............................................................................................. 6
Password Security ......................................................................................................... 7
Setting the Clock............................................................................................................ 8
CALIBRATION................................................................................................................ 9
CALIBRATION OVERVIEW................................................................................................ 10
CALIBRATION EXPIRATION.............................................................................................. 10
SOURCE REQUIREMENTS ................................................................................................. 10
SET SOURCE PARAMETERS.............................................................................................. 11
Calibration Instructions .............................................................................................. 11
ALPHA ENERGY CALIBRATION........................................................................................ 11
Performing the Calibration......................................................................................... 13
ALPHA EFFICIENCY CALIBRATION .................................................................................. 15
AUTOMATIC ALPHA CALIBRATION ................................................................................. 16
Response Check........................................................................................................... 17
FLOW CALIBRATION........................................................................................................ 18
Setting Up the Apparatus............................................................................................. 18
Performing the Calibration......................................................................................... 19
CONFIGURATION........................................................................................................ 21
INSTRUMENT PROPERTIES ............................................................................................... 21
INSTRUMENT OPTIONS .................................................................................................... 22
General Tab................................................................................................................. 23
Logging Tab................................................................................................................. 24
Isotope Tabs................................................................................................................. 25
Alarm Settings.............................................................................................................. 27
Flow Tab...................................................................................................................... 28
RadNet Tab (with WiFi option) ....................................................................................... 29
ASCII Tab (with RS-232 or WiFi option).......................................................................... 30
STARTING A DOSE MEASUREMENT..................................................................... 31
Table of Contents

RESPONSE CHECK ROUTINE ............................................................................................ 31
Source Requirements................................................................................................... 31
Running the Response Check....................................................................................... 32
NORMAL MEASUREMENT OPERATION............................................................................. 33
Minimum-Detectable Levels & Window Times ........................................................... 33
Display: Meter/Spectrum/Log ..................................................................................... 33
Operational Duration.................................................................................................. 34
MEASUREMENT CALCULATIONS ......................................................................... 35
ACUTE &CHRONIC MOVING-WINDOWS......................................................................... 35
ALPHA MEASUREMENT CALCULATIONS ......................................................................... 35
MINIMUM DETECTABLE MEASUREMENT CALCULATIONS............................................... 37
RADON MODE CONSIDERATIONS .................................................................................... 39
RETRIEVING & ANALYZING THE DATA............................................................. 40
ENDING A DOSE MEASUREMENT..................................................................................... 40
PC SYNCING SOFTWARE ................................................................................................. 40
CONNECTING TO A PC..................................................................................................... 41
SYNCING LOG FILES........................................................................................................ 42
GRAPHING DATA IN EXCEL –MANUALLY....................................................................... 43
GRAPHING DATA IN EXCEL –WITH TEMPLATES.............................................................. 43
Spectrum Chart............................................................................................................ 44
Chronic & Acute Charts.............................................................................................. 45
RADNET OPERATION ................................................................................................ 46
ASCII OPERATION...................................................................................................... 48
STATUS CONDITIONS................................................................................................ 50
SPECIFICATIONS......................................................................................................... 51

Model 334A Operations Manual
Ludlum Measurements, Inc 1 January 2021
Getting Started
General Description
The Model 334A is a portable alpha air monitor designed to function both as a workplace
monitor and a Continuous Air Monitor (CAM) for measurements. Spectral analysis is conducted
via a 1024-channel analyzer that feeds data to the embedded processor. Factory configuration
provides either special nuclear materials (SNM) 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 334A features an integrated LCD and touchscreen that displays information on
instrument status and readings during operation. The estimated dose of the isotope(s) of interest
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 insure 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

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Parts of the Model 334A
The Model 334A consists of a fiberglass NEMA enclosure containing the 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 side of the case.
On the front, the Model 334A contains a 3.5-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 334A 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 bottom of the light stack, mechanically
limiting its sound. To make the alarm louder, twist to
the right, allowing more sound from the horn. To
make the alarm softer, twist the ring to the left.
In addition to the Model 334A itself, the package it comes in contains an AC Adapter for
charging the Model 334A, a USB sync cable for exchanging data with a PC, a flow
calibration aid, and a CD with software, certificates and training videos.

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Understanding the Detector Head
The Model 334A has an integrated head that houses the detector. 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 suctions a 37mm filter in place and mounts 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 Detector 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 tygon tubing, and into the
case, where it is pumped out the bottom of the case.
As particulates on the filter decay, the emitted alpha particles hit the face of
the detector and are recorded by the 334A.
Below is a series of diagrams that illustrates the progression of particulates and their decay.

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Turning the Unit On
A red switch located on the side of unit below the detector head turns on the power to the
Model 334A. After pressing the switch, the Model 334A 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 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 3 hours.
Complete Battery Discharge
The Model 334A 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 334A application will be stored on a non-volatile SD card 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 on
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 can withstand a full battery discharge.
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.
CAUTION: Verify instrument voltage input rating before connecting to a power converter.
If the wrong power converter is used, the instrument and/or power converter could be
damaged.
Power Button Functions
The unit can be put into standby/sleep mode at any time during operation by pressing the
power button. This ends all measurement processes, and turns off the pump and LCD.
From sleep mode, the unit can be turned back on by pressing the power button again.
For a full shutdown, press and hold the power button for 5 seconds. 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.

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Starting the Program
Under normal circumstances, the Model 334A program will start automatically when the
instrument is turned on, and remain in the program when the instrument is put to sleep and
resumed. If there is a need to exit the program, it can be restarted from the desktop screen
by double tapping the icon labeled ‘Ludlum 334A’ using a stylus. Once the Model 334A
program is running, you will not be able to perform any other Windows CE operations like
running other applications or changing display or network settings. To close the Model
334A program tap File –Close in the menu.
Response Check
The Response Check dialog is the first screen to be displayed after starting the Model 334A
program. The Response Check function will be covered later in this manual. For now and
until the Model 334A 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.
Understanding the Display
The basic display for the Model 334A 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.
Menu
Meter
Log &
Spectrum

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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 standard mode,
the unit displays up to two alpha isotopes of interest and the short-lived radon daughters:
Po-212, Po-214 and Po-218. Also the flow channel is displayed. In Radon-mode, the first
IoI will be replaced by the PAEC channel. 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 alpha channels,
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
info before cycling to the next channel.
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 the Flow channel only has one unit, LPM.
How to Change the Filter
After a Model 334A 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 and
discarding or storing the filter appropriately.
Lay the Back or Pump Side against the hole pattern on the Filter Holder.
If the pump is on, the filter will be suctioned to the Filter Holder and the back side
should not be visible.

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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 334A 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

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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 334A 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 334A 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.

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Calibration
To maintain accurate measurements of dose and concentration, the unit must be calibrated
periodically. Separate Alpha and Flow calibrations are required for complete calibration.
The purpose of alpha calibration is to insure that the peak-fitting algorithm knows where in the
spectrum to expect the radon peaks. This ensures that proper radon background subtraction 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.
Flow calibration is important, as it determines if the Model 334A is converting the pump current
into the measured flow rate correctly.
The calibration functions are accessed from the Calibration item on the main menu. Two types
of calibrations can be performed on the Model 334A. The first is called the “Automatic Alpha”
calibration, which is a source calibration check. The other type of calibration is the “Advanced”
calibration, which separates Alpha Energy and Alpha Efficiency calibrations. Advanced
Calibrations should be performed in this order: Alpha Energy Alpha Efficiency Flow
NOTE: Ludlum instruments are shipped already calibrated at the factory elevation of
5100 feet. Because they are elevation-dependent, both the Advanced Alpha Energy
Calibration and Flow Calibration should be repeated at the customer site, for elevation
differences of greater than 1000 feet, before the instrument is put into service.
For new instruments, the customer should perform the “advanced” alpha energy and efficiency
calibrations so that subsequent Automatic Alpha calibrations start from an accurate calibration
baseline.
SECTION
2

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Calibration Overview
When performing a manual calibration, the Alpha energy calibration step should always be
performed before doing the alpha efficiency calibrations.
Advanced Alpha Energy Calibration consists of:
Roughing in the position of the IoI peak with a source and adjusting the Offset
Running the unit for +8 hours to accumulate a radon daughter spectrum
Adjusting the peak marker positions of the Po-212, Po-214 and Po-218 radon
daughter peaks along with the IoI peak marker.
Advanced Alpha Efficiency Calibration consists of:
Determining the counting efficiency to an alpha calibration source.
Automatic Alpha Calibration consists of:
Using the Isotope of Interest source to run an Efficiency Calibration
Adjusting the peak marker for the IoI, which automatically adjusts the radon peaks
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
Calibration Expiration
The Model 334A 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.
The unit has exceeded the user-defined number of hours of run-time since the last
calibration. Default is 8800 hours.
When the calibration expires, the Model 334A display will indicate OUT OF CAL.
Source Requirements
When performing any of the alpha calibrations, a calibration source is used. Calibration sources
should be electroplated on stainless steel disks no larger than 32 mm (1.26”) in diameter, have an
active area restricted to the center 25 mm (1”), and have an activity between 10k and 150k DPM.
NOTE: It is vital that the 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 334A detector head and hold a
32mm 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).

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Set Source Parameters
For the alpha calibrations, the source type and activity must first be entered in the Calibration
Isotope Parameters dialog by tapping Calibrate—Set Alpha Source… Entering the calibration
isotope parameters separately enables the user to use a source isotope for the Automatic and
Advanced Alpha Calibration and for the Response Check. Enter parameters and tap ok.
Calibration I nstructions
Alpha Energy Calibration
To begin the alpha energy calibration, tap Calibrate—Advanced—Alpha Energy…on the menu.
The Alpha Energy Calibration dialog will be displayed showing the alpha energy calibration
settings and a window where the spectrum will appear with several red lines.
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 334A. 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.