Ludlum Measurements 26-2 User manual

LUDLUM MODEL 26-2 FRISKER
USER’S MANUAL
December 2016
Serial Number PF002406
and Succeeding Serial Numbers

Model
LUDLUM MODEL 26-2 FRISKER
USER’S MANUAL
December 2016
Serial Number PF002406
and Succeeding Serial Numbers

Model26-2Frisker User’s Manual

Model26-2Frisker User’s Manual
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]

Model26-2Frisker User’s Manual
Table of Contents
Introduction 1
Getting Started 2
Unpacking and Repacking 2-1
Battery Installation 2-2
Instrument Operational Test 2-3
Detector Failure Diagnostics 2-4
Detector Over Range 2-4
Instrument Use and Controls 2-5
Rate Mode Operation 2-6
Max Mode Operation 2-7
Timed Frisk Mode Operation 2-8
Specifications 3
Setup Mode 4
Setup Overview 4-1
Entering Setup Mode 4-2
Default Setup Values 4-3
Setup Mode Operation 4-3
Safety Considerations 5
Environmental Conditions for Normal Use 5-1
Warning Markings and Symbols 5-1
Cleaning and Maintenance Precautions 5-2
Revision History 6
Recycling 7

Model26-2Frisker User’s Manual Section1
Ludlum Measurements, Inc. Page 1-1 December 2016
Introduction
The Model 26-2 is an ergonomic, lightweight instrument intended for
contamination frisking. The instrument features a large backlit LCD
(liquid crystal display), LEDs which signify alarm and non-alarm
conditions, a piercing audio warning, and easy, intuitive use in a single-
handed platform. A comfortable wrist strap and lanyard are also
included for keeping the instrument close and secure. The unit body is
made of lightweight but durable plastic. It is intended for outdoor use
and can resist splashing water.
There is also a headphone option available (not included). The
instrument can be modified to include a standard 1/8 inch headphone
jack (part number 4498-538).
Three modes of operation are available for the Model 26-2; RATE,
MAX, and TIMED FRISK. RATE mode operation measures
contamination from background levels up to 1.99 kcps or 100.0 kcpm.
MAX mode is used to capture the highest count rate detected –useful
for finding peak contamination rate, or frisking when the display is not
visible. TIMED FRISK mode allows the user to perform a
contamination frisk for a predetermined time. The display will be
automatically backlit if light levels are low. The display backlight can
also be configured for ‘Continuous On’ operation. RATE and MAX
modes can be silent or may utilize a 'click' audio; the 'click' audio is
always on during TIMED FRISK mode. RATE and TIMED FRISK
modes feature non-latching continuous tone alarms for count rates
above alarm levels. The continuous tone alarms in MAX mode will
latch with the captured highest count rate, and will clear when the MAX
count is acknowledged and then reset. The RATE, MAX, and TIMED
FRISK modes can also be disabled, simplifying the unit even further
The Model 26-2 allows up to three count rate alarm settings, which are
automatically evaluated from lowest to highest values. Four LEDs show
the current alarm status; a green LED for no alarm, and three red
LEDs, which work in combination to signify the alarm level.
Section
1

Model26-2Frisker User’s Manual Section1
Ludlum Measurements, Inc. Page 1-2 December 2016
The Model 26-2 utilizes a standard 15 cm2(0.9 in2) Geiger-Mueller
"pancake" detector, which can detect alpha, beta, or gamma radiation.
Caution is needed with handling the instrument because of the thin
radiation detector's window.
Setup of the instrument is accomplished through the front-panel
buttons. The advanced user or administrator can set:
Response Rime
Auto-Response Rate (Fast or Slow)
Up to three Count Rate Alarm Levels
Frisk Time
Available Operational Modes
Setup can be disabled via the internal switch on the Model 26-2 in order
to protect settings.
The unit is operated with two AA batteries for operation from -40 to 65
°C (-40 to 150 °F). Battery life should be approximately 1000 hours
under normal usage. A low-battery indicator on the LCD warns when
less than 16 hours of battery life remain.

Model26-2Frisker User’s Manual Section2
Ludlum Measurements, Inc. Page 2-1 December 2016
Getting Started
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. The Model 26-2 serial number is located on a label on the
front of the unit.
To return an instrument for repair or calibration, provide sufficient packing
material to prevent damage during shipment. Be aware that the thin mica
window of the detector may be damaged (imploded) because of pressure
differentials if the unit is shipped by air. Protect the unit by putting it inside
a sealed can or other protective enclosure.
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
2

Model26-2Frisker User’s Manual Section2
Ludlum Measurements, Inc. Page 2-2 December 2016
1. Grab the ring on the screw.
2. Turn the ring one quarter turn
counter-clockwise.
3. Release and remove the battery cover.
4. Replace two each AA batteries.
5. Firmly insert the barb of the battery
cover completely into the body of the
Model 26-2.
6. Replace the cover and turn ring one
quarter of a turn clockwise to secure.
Battery Installation
A low-battery indicator appears at the bottom of the LCD when less than 16 hours of battery life remain.
When this indicator is present, follow these steps to replace the two standard AA batteries:
Warning: If this procedure
is not followed correctly,
and the barb is not inserted
into the body of the
instrument correctly, the
barb may break off.

Model26-2Frisker User’s Manual Section2
Ludlum Measurements, Inc. Page 2-3 December 2016
Instrument Operational Test
Turn the instrument ON by pressing the ON/ACK button for about a
second, and then releasing. The instrument should activate all the LCD
segments and the audio, and cycle through the LEDs. Observe the device
during this time. If any LCD segments are missing, or if audio or any LEDs
fail to work, the device is in need of repair. Please refer to Figure 1 below.
Figure 1: Startup display for Model 26-2, with all LCD segments shown.
It then displays the firmware version number before displaying the current
count rate, starting at 0 cpm (or 0.0 cps). Ensure that the low-battery
indicator is not present. If the low-battery indicator is present, replace the
batteries as soon as possible. Under extremely low-battery conditions, be
aware that the unit may not even turn on or may turn itself off abruptly.
A reference reading with a check source, 1 µCi (37 kBq) of 137Cs for
example, should be obtained at the time the instrument is received in the
field. Small check sources of radiation are available from Ludlum
Measurements. While exempt from many regulations because of their small
size, these sources are large enough to produce a response on this
instrument. The detector's position is indicated by the circular screen on the
back of the Model 26-2: the seam between the enclosure halves indicates the
approximate center of the detector. If this procedure is done routinely with
the same radiation source, instrument malfunction may be detected when
anomalous readings are observed. If at any time the instrument fails to read
within 20% of the reference reading when using the same check source, it
should be sent to a calibration facility for recalibration and/or repair.
Example log reading:
Check Source # Count Rate
Once this procedure has been completed, the instrument is ready for use.

Model26-2Frisker User’s Manual Section2
Ludlum Measurements, Inc. Page 2-4 December 2016
Detector Failure Diagnostic
Note that the Model 26-2 has its own diagnostic tests to ensure that the
detector is functioning correctly. The Model 26-2 can detect when the
radiation detector is malfunctioning and will flash the display to indicate a
fault. If the detector stops detecting radiation for 60 seconds, normally
through a puncture of the thin mica window, the Model 26-2 will flash a
zero reading. If this indication is observed, remove the unit from service and
have it evaluated by a qualified repair and calibration technician.
Figure 2: Detector Failure display (shown for cpm); will also flash.
Detector Over Range
If the unit has an internal malfunction that causes it to count high or
excessively, the unit flashes the maximum rate (either 1.99 kcps or 100.0
kcpm) as a warning. The user should ensure whether this is being caused by
a high radiation field or by internal malfunction.
Figure 2: Detector Over Range (shown for cpm); will also flash.

Model26-2Frisker User’s Manual Section2
Ludlum Measurements, Inc. Page 2-5 December 2016
Instrument Use and Controls
With only two front-panel buttons, the Ludlum Model 26-2 is simple and
easy to use with minimal training required. Default operation is RATE
mode, and the display shows the current count rate. Pressing the MODE
button will switch the instrument to MAX mode, which will display the
highest count rate detected. Pressing the MODE button again will switch it
to TIMED FRISK mode, which will display the Frisk timer. Note that
RATE, MAX, and TIMED FRISK modes can be locked out in the setup
process.
See the Model 26-2 front-panel drawing at the beginning of this
manual to reference the following controls:
ON/ACK button:Used to power the Model 26-2 ON and OFF, silence click
audio, reset MAX mode, start/reset the TIMED FRISK, and acknowledge
audio alarms.
Power On: Press for approximately one second and release (all LCD
segments will activate, and firmware version will be shown).
Power Off: Press for approximately five seconds (audio will beep
and LCD will clear).
Normal Operation: Will silence ‘click’ audio in RATE, MAX and
TIMED FRISK modes, reset MAX mode display, start Frisk Timer
in TIMED FRISK mode, and acknowledge/silence audio alarms in
all modes of operation.
MODE button: Used to advance between the three operating modes: RATE,
MAX, and TIMED FRISK. Will reset an active frisk in TIMED FRISK
mode. Note that RATE, MAX and/or TIMED FRISK modes may be
disabled from use by the administrator or calibrator.
ALARM STATUS LEDs: Used to indicate the current non-alarm/alarm
status, also used to signify TIMED FRISK status.
Green LED: Flashes at a medium pace during non-alarm conditions
in RATE and MAX modes, and while a frisk is active in TIMED
FRISK mode; will be steady on when a frisk is not active in TIMED
FRISK mode; will turn off during the first four seconds of
operation to signify the window for Setup Entry.

Model26-2Frisker User’s Manual Section2
Ludlum Measurements, Inc. Page 2-6 December 2016
Red LEDs: Flashes in patterns to indicate the alarm level in all
modes.
oLowest Alarm Level (Active if two or more alarms enabled)
oMiddle Alarm Level (Active if all three alarms enabled)
oHighest Alarm Level (Active if one or more alarms enabled)
RATE Mode Operation
In RATE mode the current count rate will be displayed.
Under a non-alarm condition, the green LED will be flashing; pressing the
On/Ack button will turn the ‘click’ audio on/off.
If an alarm condition is present, pressing the On/Ack button will
acknowledge and turn off the continuous tone alarm audio. A change from a
lower level alarm condition to a higher level alarm condition will re-trigger
the continuous tone alarm. Under an alarm condition, the ALARM display
indicator will remain on, and the appropriate red Alarm Status LEDs will be
active. Alarms are non-latching in RATE mode.
If other operational modes are available, pressing the MODE button will
move to the next available operational mode.
Figure 1: RATE mode display showing typical background radiation rate
and the low-battery icon. Green LED will be flashing.

Model26-2Frisker User’s Manual Section2
Ludlum Measurements, Inc. Page 2-7 December 2016
MAX Mode Operation
While in MAX mode, the highest detected count rate (since the last reset) is
displayed. The word MAX will be displayed when in MAX mode.
Under a non-alarm condition, the green LED will be flashing; pressing the
On/Ack button will turn the ‘click’ audio on/off. Pressing the On/Ack
button a second time will reset the display and enable the ‘click’ audio.
If an alarm condition is present, pressing the On/Ack button once will
acknowledge and turn off the continuous tone alarm audio (The ‘click’ audio
will remain as selected under non-alarm conditions). Pressing the On/Ack
button a second time will reset the display and clear the alarm condition. A
change from a lower level alarm condition to a higher level alarm condition
will re-trigger the continuous tone alarm. Under an alarm condition, the
ALARM display indicator will remain on, and the appropriate red Alarm
Status LEDs will be active. Alarms in MAX mode latch with the display.
If other operational modes are available, pressing the MODE button will
move to the next available operational mode.
Figure 2: MAX mode operation display with ALARM indicators for
Lowest Alarm Level. A single red LED will be flashing.

Model26-2Frisker User’s Manual Section2
Ludlum Measurements, Inc. Page 2-8 December 2016
TIMED FRISK Mode Operation
In TIMED FRISK mode, operation depends on the current state of the
Frisk Timer.
When the Frisk Timer is not actively counting down:
The display will alternate between showing the Frisk Time for four
seconds and the current count rate for one second. The green LED
will be steady ON.
Under a non-alarm condition, pressing the On/Ack button starts
the Timed Frisk.
If an alarm condition is present, pressing the On/Ack button will
acknowledge and turn off the continuous tone alarm audio. A
change from a lower-level alarm condition to a higher-level alarm
condition will re-trigger the continuous tone alarm. Under an alarm
condition, the ALARM display indicator will remain on, and the
appropriate red Alarm Status LEDs will be active. Alarms are non-
latching in TIMED FRISK mode.
If other operational modes are available, pressing the MODE
button will move to the next available operational mode.
When the Frisk Timer is active:
The display will alternate between showing the current count rate
for four seconds and the Frisk Time remaining for one second. The
green LED will alternate between ON and OFF.
Under a non-alarm condition, pressing the On/Ack button will turn
the ‘click’ audio on/off.
If an alarm condition is present, pressing the On/Ack button will
acknowledge and turn off the continuous tone alarm audio. A
change from a lower-level alarm condition to a higher-level alarm
condition will re-trigger the continuous tone alarm. Under an alarm
condition, the ALARM display indicator will remain on, and the
appropriate red Alarm Status LEDs will be active. Alarms are non-
latching in TIMED FRISK mode.
Pressing the MODE button will cancel the current Timed Frisk and
reset the Frisk Timer. If a Timed Frisk is canceled, a long audio tone
will sound.
Completion of a Timed Frisk will be indicated with two short audio
beeps.

Model26-2Frisker User’s Manual Section2
Ludlum Measurements, Inc. Page 2-9 December 2016
Figure 3: TIMED FRISK mode operation showing Frisk Timer of 3
minutes. Green LED will be steady ON.

Model26-2Frisker User’s Manual Section3
Ludlum Measurements, Inc. Page 3-1 December 2016
Specifications
0
Detector: pancake GM (Geiger-Mueller) detector, stainless steel screen
Linearity: ±10%
Window Area:Active: 15.51 cm² ( 2.4 in²); Open: 12.26 cm² (1.9 in²)
Window Protective Screen: 79% open
Efficiency (4п) Surface Plane:
Alpha: 11% for 239Pu
Beta: 18% for 99Tc; 32% for 32P; 2% for 14C; 22% for 90Sr/Y;
0.2 % for 125I
Gamma: 3300 cpm/mR/hr or 5.5 cps/μSv/hr (137Cs);
≤ 1% for 99mTc
Resolving Time: approximately 110 µsec as defined by IEC 60325
Alarms: up to three count rate alarm setpoints, adjustable over the display
range
Overload: high rate saturation protection, indicated by flashing display and
audio alarm, prevents false display of lower count rates
Zero Protection: after 60 seconds of no pulses from detector, unit will flash a
zero reading and the alarm audio will be triggered
LCD Display: 3½ digit LCD with large 12.7 mm (0.5 in.) digits, (k)cps,
(k)cpm, low-battery indicator, MAX, ALARM
Display Range: 0.1 cps to 1.99 kcps, or 1 cpm to 100.0 kcpm
Backlight: built-in ambient light sensor automatically activates low-power
LED backlight, unless internal dip switch 1 is set to continuous-on.
User Controls:
ON/OFF/Quiet –press to turn ON, tap to alternate between ‘click’
audio and QUIET, hold for OFF; press to start Timed Frisk
Section
3

Model26-2Frisker User’s Manual Section3
Ludlum Measurements, Inc. Page 3-2 December 2016
MODE –alternates between RATE (count rate), MAX ( captures peak
rate) and TIMED FRISK ( preset frisk time) modes; press to stop a
Timed Frisk
Click Audio: greater than 60 dB at 0.6 m (2 ft)
Power: two “AA” batteries
Battery Life: approximately 250 hours of operation (less if the backlight is
configured for continuous on), 16-hour low-battery warning
Construction: high-impact plastic with water-resistant rubber seals and
separate battery compartment
Environmental Rating: NEMA (National Electrical Manufacturers
Association) rating of 3 or IP (Ingress Protection) rating of 53
Distance from Surface Plane to Grill: 0.32 cm (one-eighth inch)
Size:4.6 x 6.9 x 27.2 cm (1.8 x 2.7 x 10.7 in.) (H x W x L)
Weight: 0.45 kg (1.0 lb)

Model26-2Frisker User’s Manual Section4
Ludlum Measurements, Inc. Page 4-1 December 2016
Setup Mode
Warning!
Only advanced users or administrators should consider changing
any of the parameters in the following section. Incorrect settings
could jeopardize the safety of users depending on this instrument.
Setup Overview
Your instrument has been shipped from Ludlum Measurements only after
passing electronic checkout, a 30-hour burn-in process, and a careful calibration
process. Calibration papers are supplied with each instrument shipped from
Ludlum Measurements.
Recalibration should be accomplished after maintenance or adjustments have
been performed on the instrument. Recalibration is not normally required
following instrument cleaning or battery replacement. Recalibration does not
require any special tools or software to perform.
Ludlum Measurements offers a full-service repair and calibration department.
Not only do we repair and calibrate our own instruments, we also service most
other manufacturers’ instruments. Calibration procedures are available upon
request for customers who choose to calibrate their own instruments.
Note:
Ludlum Measurements, Inc. recommends recalibration at intervals
no greater than one year, assuming that regular operational checks
are performed. Check the appropriate local, state, and federal
regulations to determine required recalibration intervals.
Section
4

Model26-2Frisker User’s Manual Section4
Ludlum Measurements, Inc. Page 4-2 December 2016
Entering Setup Mode
To enter setup mode, power down the Model 26-2, then turn the unit back ON.
When “0.0 cps” (or “0 cpm”) appears on the LCD, press the MODE button
three times (within four seconds) to enter Setup mode. The greed LED will
remain off during the four-second window for entry to Setup mode, and will
resume normal operation when the window has closed. Entry to Setup mode
can be confirmed when the numeric portion of the display is off and only the
rate units (either cps or cpm) are displayed. If you simply wish to view the
parameters, you may do so by not pressing any other buttons. The parameters
will change every four seconds when no buttons are pressed. The unit will
return automatically to normal mode after the last parameter is presented.
SETUP PROTECT: The Model 26-2 parameters can be protected from
unauthorized changes via the internal switch located on the Model 26-2 circuit
board. To change the switch, open the battery compartment and remove the
batteries from the Model 26-2. Next, loosen the four captive Phillips head
screws, which fasten the detector cover.
Now turn the Model 26-2 over so that the detector is facing up. Gently remove
the plastic case that covers the back of the instrument, paying careful attention
not to lose the protective screen that covers the detector itself. Remove the
protective screen, and gently lift the GM pancake detector and set it to the side.
The DIP (dual inline position) switch should now be visible below the detector
retainer.
To protect the Model 26-2 from changes in Setup mode, slide DIP Switch 2
(closest to the battery compartment) to the ON (right) position. If DIP Switch 2
is in the OFF (left) position, changes are allowed in Setup mode. Once the DIP
Switch is set as desired, gently replace the detector in the detector retainer. Place
the detector screen over the detector, and fit the plastic case on the back of the
instrument. Turn the instrument over and tighten the four Phillips head screws.
Install the batteries, and replace the battery cover. Note that with the DIP
Switch 2 in the ON position, Setup mode may be entered and parameters
viewed, but changes cannot be made.
DISPLAY BACKLIGHT ‘Continuous On’: The Model 26-2 display
backlight can be set to remain on continuously during operation. Follow the
steps above for SETUP PROTECT, but use DIP Switch 1 for display
backlight selection. Setting DIP Switch 1 to the ON (right) position will
configure the display backlight to remain on during operation. Set DIP Switch 1
to the OFF (left) position, and the display will be backlit only when light levels
are low.
NOTE: Setting the display backlight for continuous-on operation can result in
reduced battery life.