Ludlum Measurements 23 User manual

MODEL 23 AND 23-1
ELECTRONIC PERSONAL DOSIMETER
August 2017

MODEL 23 AND 23-1
ELECTRONIC PERSONAL DOSIMETER
August 2017

ii

Ludlum Measurements, Inc. August 2017
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]

Ludlum Measurements, Inc. August 2017

Ludlum Measurements, Inc. August 2017
Table of Contents
Introduction 1
Getting Started 2
Packing and Repacking 2-1
Battery Installation 2-1
Preparing the Instrument for Use 2-3
Operating the Instrument 2-3
Specifications 3
Description of Controls and Functions 4
Parts and Features 4-1
Display 4-2
Alarm 4-4
Safety Considerations 5
Environmental Conditions for Normal Use 5-1
Precautions 5-1
Cleaning Instructions 5-2
Recycling 6

Model23&23-1 TechnicalManual Section1
Ludlum Measurements, Inc. Page 1-1 August 2017
Introduction
he Model 23 EPDi is an electronic personal dosimeter, which
measures personal dose equivalent from external radiation sources. It
is ideal for the measurement and general monitoring of gamma and X-
ray radiation in medical and laboratory environments, as well as any
controlled or restricted area where personal radiation monitoring is required or
desired.
The Model 23-1 is identical to the Model 23, except that it measures in Sv/h
instead of R/hr.
The compact and lightweight body of the instrument (55.9 g {2 oz}) makes it
ideal for personal use. It can be compared to the size of an ink pen.
This instrument is sensitive to a wide range of energies from 35 keV to 3 MeV.
Dose, dose equivalent rate, and alarm values are easily seen on the four-digit
LCD screen. Each preset alarm threshold is displayed on the screen. When the
dose or dose rate reaches the preset alarm thresholds, the alarm activates.
Users who have multiple EPDi units, there is an optional reader/software kit
that can be used to quickly take data directly from the EPDi Dosimeter via
infrared communication to the user’s PC. The optional software also allows the
user to set or change alarm set points quickly.
Since the Model 23 has energy characteristics corresponding to 1 cm dose
equivalent, by placing it close to the body it is able to measure 1 cm dose
equivalent.
Notice!
The Model 23 Dosimeter may not measure pulsed radiation
accurately. Point the “body side” (noted on the dosimeter) or
display side towards the body or area to be measured. A dot next
to the gamma symbol on the instrument indicates the center
point of the unit.
Section
1
T

Model23&23-1 TechnicalManual Section2
Ludlum Measurements, Inc. Page 2-1 August 2017
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 between instruments.
To return an instrument for repair or calibration, provide sufficient packing
material to prevent damage during shipment and appropriate labeling.
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.
Battery Installation
Replace the battery with the following procedure:
1. Press and hold the power switch (color: red) for approximately two
seconds until the Model 23 turns off.
2. Remove the battery door.
3. Extract the used battery using miniature pliers or something similar
and insert the new battery with the negative (-) side facing upward.
4. Replace the battery cover.
Section
2
Insert the battery with the
negative (-) side facing upward.

Model23 &23-1 TechnicalManual Section2
Ludlum Measurements, Inc. Page 2-2 August 2017
Caution:
Always turn off the Model 23 EPDi before replacing the
battery. Be sure to observe proper polarity when replacing the
battery. This product operates on the CR2450 battery (3.0 V)
only (Part # 21-8639). Only use the battery specified.
Note:
When a low-battery indicator appears, take readings within
one minute before replacing the battery. To save battery life,
the power saving mode should be used.
Warning:
Do not throw the dosimeter or batteries into a fire. This
could result in personal injury.

Model23&23-1 TechnicalManual Section2
Ludlum Measurements, Inc. Page 2-3 August 2017
Preparing the Instrument for Use
To start the Model 23 EPDi, press and hold the power switch (color: red)
for approximately two seconds.
When the measurement screen appears, the red LED lamp lights for one
second and one short beep sounds, indicating that the Model 23 is in the
measurement mode.
Operating the Instrument
Point the “body side” (display side) of the Model 23 towards your body and
insert the Model 23 into your pocket, securing it with the clip as shown
below.
Green LED lamp flashes.
ALM Batt: RED LED lamp flashes.
Replace the used battery with new one.
ALM E06: Red LED lamp flashes. Contact our
representative or agency.
ALM E11: Red LED lamp flahes.
Restart the Model 23 by following the procedure:
Press and hold the power switch for
approximately two seconds until the Model
23 turns off.
Pres and hold the power swith for
approximately two seconds until the Model
23 turns on.
To turn off the Model 23, press and
hold the power switch for
approximately two seconds.

Model23&23-1 TechnicalManual Section3
Ludlum Measurements, Inc. Page 3-1 August 2017
Specifications
0
Detector: silicon semiconductor
Measurement Range: 0.001 mSv/h to 999.9 mSv/h (0.0001 R/hr to
99.9 R/hr)
Radiation Detected: gamma and X-Ray (35 keV to 3 MeV)
Display: 4-digit liquid crystal display, with dose rate, low battery, overlow
Accuracy: within 10% from 0.01 to 999.9 mSv (1.0 mrem to 99.99 rem)
(137Cs)
Linearity: within 10% (to 100 mSv/h)
Alarm Output: low, medium, high user-settable volume, and OFF. When
reaching or exceeding the present values –the alarm activates, red LED
lamp flashes, and vibrator activates.
Alarm Volume: approximately 60 dB
Sensitivity: approximately 2 cpm per µSv/h (20cpm/mR/hr)
Data Logging: 600 records (optional IR reader required for data
transmission to PC). When the Model 23 is turned off, the accumulative
dose data is automatically deleted.
Default Settings:
Dose alarm threshold: regular alarm 0.5 mSv; pre-alarm 0.3 mSv
Dose rate alarm threshold: regular alarm 4 mSv/h; pre-alarm 2 mSv/h
Overflow: The message “over” appears.
Temperature Range: -10 to 40 ˚C (14 to 104 ˚F)
Operating Humidity: ≤90% (non-condensing)
Section
3

Model23&23-1 TechnicalManual Section3
Ludlum Measurements, Inc. Page 3-2 August 2017
Shock Resistant: operates properly after a vertical drop test from 20 cm
Power: one each coin-type lithium battery (CR2450)
Battery Life: typically one month at 8 hours per day in non-alarm status
Size: 12 x 30 x 112.8 mm (0.5 x 1.2 x 4.4 in.) (H x W x D) without clip
Weight: 55.9 g (2 oz)

Model23&23-1 TechnicalManual Section4
Ludlum Measurements, Inc. Page 4-1 August 2017
Description of Controls and
Functions
Parts and Features
Strap Hole LED lamp Selection Buttons Power Switch
Buzzer Display
Infrared Communication Window Battery Cover
Clip
Section
4

Model23&23-1 TechnicalManual Section4
Ludlum Measurements, Inc. Page 4-2 August 2017
Display
Display at the end of normal operation
Display at the time of abnormal operation
See chart on following page for more examples.
Indicates that the Model 23 is operating in the measurement mode.
Alarm indications:
ALM DOSE (dose)
ALM RATE (dose rate)
ALM TIME (measurement time)
ALM BATT (battery replacement)
ALM E06 (faulty counting circuit)
ALM 11 (setup error)
ALM E12 (data recrording error)

Model23&23-1 TechnicalManual Section4
Ludlum Measurements, Inc. Page 4-3 August 2017

Model23&23-1 TechnicalManual Section4
Ludlum Measurements, Inc. Page 4-4 August 2017
Alarm
ALM DOSE
ALM RATE
When the dose or the dose rate of
gamma rays reaches preset values,
the pre-alarm activates
Five 0.1-second beeps
sound every second.
ALM DOSE
ALM RATE
When the dose or dose rate of
gamma rays reaches preset values,
the regular alarm activates.
1 1-minute beep, then a 1-
second beep and a 1-
second pause. This repeats
for the time previously set.
Red flashes every
two seconds
ALM BATT
Activates when battery voltage is
low.
Alarm for “ALM BATT”
is prioritized over “ALM
DOSE” or “ALM
RATE.” A 2-minute beep,
then a 2-second beep (3
times)
ALM TIME
Activates when the operating time
exceeds the set time.
A 1-minute beep, then a 1-
second beep and a 1-
second pause. This repeats
for the time previously set.
Red flashes every
two seconds
ALM E06
Activates when the counting circuit
shorts out due to disconnection or
condensation.
A 1-minute beep, then a 1-
second beep and a 1-
second pause. This repeats
for the time previously set.
Red flashes every
two seconds
Over
(Overflow)
Activates when the accumulative
dose has reached 10 Sv (1000 R) or
when the dose rate is equal to or
greater than 10 Sv/h (1000 R/hr),
the alarm activates.
A 1-minute beep, then a 1-
second beep and a 1-
second pause. This repeats
for the time previously set.
Red flashes every
two seconds
ALM E11
Activates when the measurement
circuit is abnormal.
A 2-minute beep, then a 2-
second beep (repeats 3
times)

Model23&23-1 TechnicalManual Section5
Ludlum Measurements, Inc. Page 5-1 August 2017
Safety Considerations
Environmental Conditions for Normal Use
No maximum altitude
Temperature range of -10 to 40 ˚C (14 to 104 ˚C)
Maximum relative humidity of less than 90% (non-condensing)
Pollution Degree 2 (as defined by IEC 664)
JIS Waterproof Grade 1: water resistant under normal living conditions
Notice!
The Model 23 Dosimeter may not measure pulsed radiation
accurately. Also, do not use it as a survey meter.
Warning:
To prevent short-outs, protect exposed terminals with insulating
tape prior to disposal. Failure to do so may cause excessive heat
generation, rupturing, or combustion, leading to personal injury or
fire. Do not throw the dosimeter or batteries into a fire. Do not
disassemble the dosimeter.
Preacautions
Do not drop or subject to impact. Shock resistant after a vertical drop test
from 20 cm.
Keep the dosimeter in a plastic bag for protection against organic solvents, water
droplets, moisture, dust, and contamination.
Section
5

Model23&23-1 TechnicalManual Section5
Ludlum Measurements, Inc. Page 5-2 August 2017
Dosimeter should always be handled with clean, dry hands.
Do not place the dosimeter with metallic items in pocket.
Do not use the dosimeter in an environment with high-frequency noise and
magnetic flux density equal to or greater than 200 gauss.
Pay careful attention when using it near the following devices:
Cell phones
PHS handsets
High-power transceivers (or similar devices)
Microwave ovens
Radars
Welding machinges
Any other spark-discharging or high-intensity, radio-wave emitting
devices.
Caution!
Keep at least 5 cm away from PHS handsets and cell phones.
Failure to do this may result in false operation.
Caution!
Do not force open the clip, as it may be damaged.
Cleaning Instructions
The Model 23 Dosimeter may be cleaned externally with a dry cloth if
contaminated with dirt.
Caution!
The operator or responsible body is cautioned that the protection
provided by the equipment may be impaired if the equipment is
used in a manner not specified by Ludlum Measurements, Inc.

Model23&23-1 TechnicalManual Section6
Ludlum Measurements, Inc. Page 6-1 August 2017
Recycling
udlum Measurements, Inc. supports the recycling of the electronics
products it produces for the purpose of protecting the environment
and to comply with all regional, national, and international agencies
that promote economically and environmentally sustainable
recycling systems. To this end, Ludlum Measurements, Inc. strives to supply
the consumer of its goods with information regarding reuse and recycling of
the many different types of materials used in its products. With many
different agencies - public and private - involved in this pursuit, it becomes
evident that a myriad of methods can be used in the process of recycling.
Therefore, Ludlum Measurements, Inc. does not suggest one particular
method over another, but simply desires to inform its consumers of the
range of recyclable materials present in its products, so that the user will
have flexibility in following all local and federal laws.
The following types of recyclable materials are present in Ludlum
Measurements, Inc. electronics products, and should be recycled separately.
The list is not all-inclusive, nor does it suggest that all materials are present in
each piece of equipment:
Batteries
Glass
Aluminum and Stainless Steel
Circuit Boards
Plastics
Liquid Crystal Display (LCD)
Section
6
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