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Model 42-31H

The Ludlum Model 42-31H Neutron Detector is designed to detect thermal and fast neutrons (0.025 eV to approximately 12 MeV). Neutrons are detected indirectly through nuclear reactions which result in energetically charged particles, such as alpha particles, which are often found associated with intense fields of gamma rays. Therefore, it is important to choose a method of neutron detection with the ability to discriminate against gamma rays in the detection and measurement processes.

The Model 42-31H is intended for use with portable counting instruments, and is fitted with a top bracket for convenient mounting. The instrument consists of a cadmium-loaded polyethylene sphere surrounding the 3He detector. A study has demonstrated that the 9-inch cadmium-loaded sphere has a response similar to that of a 10-inch diameter rem-responding sphere.

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Related Products

Headphone Jack

This modification for survey meters adds a headphone jack to the instrument body so headphones can be used to monitor click-per-event audio and audio alarms. Headphones are helpful when the instrument is being used in areas with high ambient noise levels or in areas where the audio would be distracting to others, such as in a medical or office environment.

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Shoulder Strap

This 1.8 m (6 ft) adjustable shoulder strap is a great way to keep your hands free while operating survey meters. The nylon strap with a wide rubber comfort pad can also be helpful for conveying some of the heavier instrument/detector combinations in the field. 

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Model 3-IS NORM Kit
  • Ready-to-Go Kit in Rugged Case
  • Intrinsically Safe Analog Survey Meter
  • Measures Alpha, Beta, and Gamma Contamination
  • Includes:
    • Model 3-IS Intrinsically Safe Survey Meter
    • Model 44-9 Alpha-Beta-Gamma Detector
    • Model 44-2 High Energy Gamma Detector
    • Check Source, Cable, Batteries, Transport & Storage Case

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Model 14C-MERK
Medical Environment Response Kit
  • Model 14C Survey Meter
  • Model 44-2 Gamma Scintillator Detector
  • Model 44-9 Alpha-Beta-Gamma GM Detector
  • Model 25 Series Personal Radiation Monitor
  • Check Source and Holder
  • Rugged Case

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Model 2241-3MERK
Medical Environment Response Kit
  • Model 2241-3 Scaler-Ratemeter
  • Model 44-2 Gamma Scintillator Detector
  • Model 44-9 Alpha-Beta-Gamma GM Detector
  • Model 44-142 Beta Scintillator Detector
  • Model 25 Series Personal Radiation Monitor
  • Check Source and Holder
  • Rugged Case

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Model 3001-MERK
Medical Environment Response Kit
  • Model 3001 Survey Meter
  • Model 44-2 Gamma Scintillator Detector
  • Model 44-9 Alpha-Beta-Gamma GM Detector
  • Model 44-142 Beta Scintillator Detector
  • Model 25 Series Personal Radiation Monitor
  • Check Source
  • Rugged Case

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Model 14C-RK
Emergency Response Kit
  • Model 14C Survey Meter
  • Model 44-2 Gamma Scintillator Detector
  • Model 44-9 Alpha-Beta-Gamma GM Detector
  • Check Source and Holder
  • Rugged Case

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Cables

Ludlum offers straight cables with either type C, BNC, SHV, MHV, or UHF connectors. Unless specified otherwise, Ludlum survey meters and detectors are shipped with “C” type connectors. When a meter and accompanying probe are ordered as a matched set, Ludlum automatically includes a 99 cm (39 in.) straight-type cable with “C” connectors at no additional charge. (Note: We no longer offer coiled cables.)

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Model 3002/FM Series
Alpha-Beta Floor Monitor
  • Alpha-Beta Scintillation Detectors
  • Active Window Area: 400 or 1080 cm2 (62 or 167.4 in2)
  • 22.4, 40.9, or 65.7 cm (8.8, 16.1, or 25.9 in.) Wide Detection Path
  • Adjustable Detector Height

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Model 42-38
WENDI-2 Wide Energy Neutron Detector
  • Detector Type:
    • 3He Tube
    • Moderator: 22.9 cm (9 in.) dia.
  • Sensitivity (241Am/Be): 450 cpm per mrem/hr
  • Detection Range: Thermal to 5 GeV

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Model 78-9
Stretch Scope Survey Meter
  • Digital Meter
  • Extends to 3.6 m (12 ft.)
  • Pancake GM Detector

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Model 78-6
Stretch Scope Survey Meter
  • Analog + Digital Meter
  • Extends to 3.6 m (12 ft.)
  • NaI(Tl) Scintillator Detector
  • Range: 0.01 to 50 µSv/h (1 to 5000 µR/hr)

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Model 79/2
Stretch Scope Survey Meter
  • Digital Meter
  • Extends to 4.5 m (14.75 ft.)
  • Internal Energy-Compensated GM
  • Range: 0.001 mSv/h to 0.04 Sv/h (0.1 mR/hr to 4 R/hr)

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Model 79/1
Stretch Scope Survey Meter
  • Digital Meter
  • Extends to 4.5 m (14.75 ft.)
  • CsI(Tl) Scintillator Detector
  • Range: 0.01 µSv/h to 500 µSv/h (1 µR/hr to 50 mR/hr)

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Model 79
Stretch Scope Survey Meter
  • Digital Meter
  • Extends to 4.5 m (14.75 ft.)
  • Energy-Compensated GM Detector
  • Range: 10 µSv/h to 10 Sv/h (1 mR/hr to 1000 R/hr)

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