Ludlum Measurements 44-2 User manual

LUDLUM MODEL 44-2
GAMMA SCINTILLATOR
February 2018
Serial Number PR361009 and Succeeding
Serial Numbers

LUDLUM MODEL 44-2
GAMMA SCINTILLATOR
February 2018
Serial Number PR361009 and Succeeding
Serial Numbers
LUDLUMMEASUREMENTS,INC.
501 OAK STREET, P.O.BOX810
SWEETWATER, TEXAS 79556
325-235-5494,FAX:[phone]

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. February 2018
Table of Contents
Introduction 1
Unpacking and Repacking 2
Specifications 3
Operating Procedures 4
Safety Considerations 5
Parts List, Drawings and Diagrams 6
Energy Response Curve 10

Model 44-2 Gamma Scintillator
Ludlum Measurements, Inc. Page 1 February 2018
Introduction
The Model 44-2 sodium iodide (NaI) gamma scintillator is
primarily used for detecting low levels of gamma radiation in
the range of 20 keV–1.5 MeV. It consists of a 2.54 x 2.54 cm (1
x 1 in.) (Dia. X thickness) NaI crystal coupled to a
photomultiplier tube and is housed in a 0.157 cm (0.062 in.)
thick aluminum housing. The front entrance window has a total
thickness of 2.3 mm (0.09 in.) of aluminum. The detector is
energy dependent, over-responding by a factor of 10 or greater
in the 100keV range and under-responding by a factor of 0.5
above 1 MeV when normalized to 137Cs.
The Model 44-2 will operate with any Ludlum instruments or
equivalent instruments that provide 500–1200 volts. The
recommended instrument input sensitivity is approximately 10
mV or higher.
Some common applications for this detector include
background radiation monitoring, low-level radiation detection,
and spectrum analysis when used in conjunction with a single-
or multi-channel analyzer.
Model 44-2
Note:
The detector does not contain any consumable materials.

Model 44-2 Gamma Scintillator
Ludlum Measurements, Inc. Page 2 February 2018
Note:
If the detector is used in a manner not intended by the
manufacturer, the detector may not function properly.
Unpacking and Repacking
Remove the calibration certificate or detector functional check
certificate and place it in a secure location. Remove the
detector(s) and accessories (if applicable) and ensure that all
items listed on the packing list are in the carton. If multiple
detectors are included, refer to the calibration certificates for
serial number (SN) matches.
To return an instrument or detector for repair or calibration,
provide sufficient packing material to prevent damage during
shipment, and affix appropriate warning labels to promote
careful handling.
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.

Model 44-2 Gamma Scintillator
Ludlum Measurements, Inc. Page 3 February 2018
Specifications
Compatible Instruments: general-purpose survey meters,
ratemeters and scalers
Sensitivity: typically 175 cpm per µR/hr (137 Cs gamma)
Dead Time: approximately 10 µs, typically limits linear range to
5 mR/hr (50 µSv/h) with non-corrected
measurements, or to 50 mR/hr (500 µSv/h) with
electronics equipped with dead time correction
Energy Response: energy dependent
Background: 1800 cpm
Operating Voltage: 500–1200 volts
Dynode String Resistance: 100 megohm
Connector: series ˝C˝(others available)
Scintillator: 2.5 x 2.5 cm (1 x 1 in.) Dia. x thickness)
Tube: 2.9 cm (1.1 in.) diameter magnetically shielded
photomultiplier
Efficiency (4 π): 125I is 7%; 57Co is 10%; 137Cs is 3%; 60Co is 3%
Construction: aluminum housing with beige powder-coat
finish
Temperature Range: -15 to 50 °C (5 to 122 °F); may be
certified for -40 to 65 °C (-40 to 150 °F)
Size: 5.1 x 18.5 cm (2 x 7.3 in.) (Dia. x L)
Weight: 0.5 kg (1 lb)