Ludlum Measurements 44-2 User manual

LUDLUM MODEL 44-2
GAMMA SCINTILLATOR
March 2010
Serial Number PR134789 and Succeeding
Serial Numbers
LUDLUM MEASUREMENTS, INC.
501 OAK STREET, P.O. BOX 810
SWEETWATER, TEXAS 79556
325-235-5494, FAX: [phone]

Ludlum Measurements, Inc. March 2010
Table of Contents
Int roduction 1
U npa c k ing and Re pa c k ing 2
Spe c ific a t ions 3
Opera t ing Proc e dure s 4
Safet y Considera t ions 5
Pa rt s List , Dra w ings a nd Diagra m s 6
Ene rgy Re sponse Curve 10

Model 44-2 Gamma Scintillator
Ludlum Measurements, Inc. Page 1 March 2010
Introduction
The Model 44-2 sodium iodide (NaI) gamma scintillator is
primarily used for detecting low levels of gamma radiation in
the range of 60 keV–1.25 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 cm (0.90 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 March 2010
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. The following items and information should
also be included to ensure quick turnaround time of your
equipment.
•instrument(s) and related cable(s)
•brief description as to the reason for return
•description of service requested
•return shipping address
•customer name and telephone number

Model 44-2 Gamma Scintillator
Ludlum Measurements, Inc. Page 3 March 2010
Specifications
Com pa tible I nstrum e nt s: general-purpose survey meters,
ratemeters and scalers
Se nsitivit y: typically 175 cpm per µR/hr (137 Cs gamma)
Energy Response: energy dependent
Ba c kground: 1800 cpm
Ope ra t ing Voltage: 500–1200 volts
Dynode St ring Re sist anc e : 100 megohm
Conne ct or: series ˝C˝(others available)
Sc int illator: 2.5 x 2.5 cm (1 x 1 in.) Dia. x thickness)
Tube: 2.9 cm (1.1 in.) diameter magnetically shielded
photomultiplier
Const ruction: aluminum housing with beige powder-coat
finish
Tem perature Ra nge : -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)
We ight: 0.5 kg (1 lb)

Model 44-2 Gamma Scintillator
Ludlum Measurements, Inc. Page 4 March 2010
Operating Procedures
CONNECTING TO AN INSTRUMENT
Connect one end of the cable provided to the
detector by firmly pushing the connector
together while twisting clockwise one quarter
of a turn until latched. Repeat the process in
the same manner with the other end of the
cable and the instrument.
TESTING THE DETECTOR
1. Ensure the instrument high voltage (HV) is at the proper
setting for the detector.
2. Connect the detector to the instrument and check for a
proper background reading (typically 1.4-2.6 kcpm or 8-
15 µR/hr).
3. Expose the detector to a check source and verify that the
instrument indicates within 20% of the check source
reading from the last calibration. Alternatively, expose the
detector to a source of known value and verify that the
detector detects greater than or equal to the efficiency
listed in the specification section of this manual.
4. Instruments and detectors that meet these criteria are
ready for use. Failure to meet these criteria may indicate a
malfunction in the detector.

Model 44-2 Gamma Scintillator
Ludlum Measurements, Inc. Page 5 March 2010
Safety Considerations
ENVIRONMENTAL CONDITIONS FOR NORMAL USE
1. Indoor or outdoor use (in a dry environment)
2. No maximum altitude
3. Temperature range of -20 to 50 °C (5 to 122 °F); May be
certified for operation from -40 to 65 °C (-40 to 150
°F).
4. Maximum relative humidity of less than 95% (non-
condensing)
5. Pollution Degree 3 (as defined by IEC 664)
(Occurs when conductive pollution or dry nonconductive
pollution becomes conductive due to condensation. This is
typical of industrial or construction sites.)
CLEANING INSTRUCTIONS AND PRECAUTIONS
The detector may be cleaned externally with a damp cloth,
using only water as the wetting agent. Do not immerse the
instrument in any liquid. Observe the following precautions
when cleaning:
1. Turn the instrument electronics OFF.
2. Allow the instrument to sit for one minute.
3. Disconnect the detector cable before cleaning the
detector.

Model 44-2 Gamma Scintillator
Ludlum Measurements, Inc. Page 6 October 2007
Parts List, Drawings and Diagrams
Reference Description
Part Number
UNIT Completely Assembled
Model 44-2 Alpha-Beta-Gamma
Detector 47-1532
1 EA DETECTOR BODY 2002-084-01
1 EA END CAP 7002-505
1 EA 2.5 x 2.5 cm (1 x 1 in.) NaI CRYSTAL
40-5154
1 EA 2.9 cm (1.1 in.) TUBE SOCKET ASSY
4002-572
1 EA TUBE SHIELD 40-4006
1 EA CONNECTOR, UG 706/U 4478-011
1 EA EJ560-1.10 × .080 OPT PAD 01-5804
1 EA O-RING 16-8317
1 EA LUG 18-8766
4 EA SCREWS 17-8811
6 EA SPONGE 7002-505
2 EA XTAL SIDE SPONGE 7002-276
10 cm (4 in.) TEFLON WIRE 21-9362
10 cm (4 in.)# 26 WIRE WIRE 21-9558
Mode l 4 4-2 Gamm a Sc int illator

Model 44-2 Gamma Scintillator
Ludlum Measurements, Inc. Page 7 March 2010