LUDLUM 44-2 Gamma Scintillator User Manual

: June 4, 2024
: LUDLUM

Table of Contents

LUDLUM 44-2 Gamma Scintillator
Introduction
Unpacking and Repacking
Specifications
Operating Procedures
Safety Considerations
Parts List, Drawings and Diagrams
Documents / Resources
- Read User Manual Online (PDF format)
- Download This Manual (PDF format)

LUDLUM 44-2 Gamma Scintillator

LUDLUM-44-2-Gamma-Scintillator-product-image

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.

LUDLUM-44-2-Gamma-Scintillator-product-image

Note: The detector does not contain any consumable materials.
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 “Service Department” from the drop-down menu. Then choose the appropriate Service Department division where you will find a link to the form.

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 21 cm (2 x 8.25 in.) (Dia. x L)
Weight: 0.5 kg (1 lb)

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

Ensure the instrument high voltage (HV) is at the proper setting for the detector.
Connect the detector to the instrument and check for a proper background reading (typically 1.4-2.6 kcpm or 8-15 µR/hr).
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.
Instruments and detectors that meet these criteria are ready for use. Failure to meet these criteria may indicate a malfunction in the detector.

Safety Considerations

ENVIRONMENTAL CONDITIONS FOR NORMAL USE

Indoor or outdoor use (in a dry environment)
No maximum altitude
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).
Maximum relative humidity of less than 95% (non-condensing)
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: