Ludlum Model 44-9 Detector Overview

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Questions and Answers

Which part is primarily responsible for detecting radiation in the Model 44-9?

PROTECTIVE SCREEN

SNAP-IN FRONT COVER

HANDLE GRIP

GM TUBE (correct)

Which component serves as the grip for handling the detector?

PENCIL CLIP

HANDLE GRIP (correct)

GM TUBE

DETECTOR BODY

What type of detector is the Ludlum Model 44-9 classified as?

Alpha and X-ray detector

Alpha, Beta, and Gamma detector (correct)

Radiation shielding device

Thermal imaging camera

What is the primary function of the Ludlum Model 44-9 GM Detector?

To detect alpha, beta, and gamma radiation Signup and view all the answers

What is the recommended operating voltage for the Ludlum Model 44-9 Detector?

900 Vdc Signup and view all the answers

What is the consequence of using an instrument input sensitivity lower than 30 mV?

The detector may double pulse, counting a single pulse multiple times. Signup and view all the answers

What type of window does the Ludlum Model 44-9 Detector have?

Thin mica window Signup and view all the answers

What additional feature does the pancake shape of the Ludlum Model 44-9 provide?

Easier handling for surveys and personnel monitoring Signup and view all the answers

How does the Ludlum Model 44-9 Detector respond in the 60 keV to 100 keV energy range?

It over-responds by a factor of 6. Signup and view all the answers

What is the typical efficiency of the Model 44-9 detector for detecting 90Sr/90Y isotopes?

22% Signup and view all the answers

What is the window area of the Model 44-9 detector classified as active?

15.51 cm2 Signup and view all the answers

What is the dead time specification for the Model 44-9 detector?

80 µs Signup and view all the answers

At what operating voltage does the Model 44-9 detector function?

900 Vdc Signup and view all the answers

What is the typical sensitivity of the Model 44-9 detector in terms of cpm per mR/hr?

3300 cpm Signup and view all the answers

What is the proper high voltage setting for the detector?

900 volts Signup and view all the answers

What is the typical background reading for the detector when connected to the instrument?

25-50 cpm Signup and view all the answers

What should be verified after exposing the detector to a check source?

The instrument must indicate within 20% of the check source reading. Signup and view all the answers

What precaution should be taken when cleaning the detector?

Disconnect the detector cable before cleaning. Signup and view all the answers

What should you avoid doing with the mica window of the tube?

Touching it directly. Signup and view all the answers

What is a sign that the detector may be malfunctioning?

The result is significantly different from the last calibration reading. Signup and view all the answers

Study Notes

Overview of Ludlum Model 44-9

The Ludlum Model 44-9 is a GM (Geiger-Mueller) Detector designed to identify alpha, beta, and gamma radiation.
Known for its pancake shape, making it user-friendly for surveying and personnel monitoring.
Operates within a voltage range of 850-1000 volts, with a recommended voltage of approximately 900 Vdc.

Warranty and Repairs

Covered by a 12-month warranty against defects in workmanship, materials, and design.
Calibration is guaranteed within specified accuracy limits at the time of shipment.
Exclusions: replacement of photomultiplier tubes, G-M tubes, proportional tubes, and scintillation crystals damaged due to misuse.
For returns, include necessary information and a completed Instrument Return Form.

Specifications

Efficiency varies: approximately 5% for 14C, 22% for 90Sr/90Y, 19% for 99Tc, and more.
Typical sensitivity is 3300 cpm per mR/h for 137Cs gamma radiation.
Active window area is 15.51 cm² with a mica window thickness of 1.7 ± 0.3 mg/cm².
Background reading is typically 60 cpm with a dead time around 80 µs.

Operating Procedures

To connect, securely attach the cable from the detector to the measurement instrument.
Proper background reading should be checked after connection, aiming for 25-50 cpm at 8-15 µR/h.
Ensure detector's reading matches within 20% of the check source after calibration.
Instrumental failures may necessitate further inspection or maintenance.

Tube Replacement

Instructions include removing the back plate, loosening set screws, and carefully replacing the GM tube.
The mica window is delicate; touching may lead to malfunction, requiring extra caution.
Recalibrate the instrument after replacing the tube to ensure accurate functionality.

Cleaning Instructions

Clean the detector externally with a damp cloth using only water; immersion is not allowed.
Turn off instrument electronics prior to cleaning and disconnect cables.

Parts List

Complete assembly is referenced under part number 47-1539.
Parts include: Detector Body (2002-109), GM Tube (01-5008), and various screws and connectors.

Additional Features

Enhanced efficiency and energy response influenced by detector design.
Detector weight is approximately 0.5 kg, and it operates in temperatures ranging from -15 to 50 °C, with certification possible for broader ranges.
Caution advised during air transport due to potential altitude effects on GM tube integrity.

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Description

This quiz focuses on the Ludlum Model 44-9 Alpha, Beta, and Gamma Detector. It includes information on its features, specifications, and warranty details as of January 2018. Test your knowledge on the functionalities of this radiation detection equipment.