Model 44-2 Sodium Iodide Gamma Scintillator

Model 44-2 Sodium Iodide Gamma Scintillator

• Primarily used for detecting low levels of gamma radiation in the range of 20 keV–1.5 MeV
• Consists of a 2.54 x 2.54 cm (1 x 1 in.) NaI crystal coupled to a photomultiplier tube
• Housed in a 0.157 cm (0.062 in.) thick aluminum housing with a front entrance window of 2.3 mm (0.09 in.) thick aluminum
• Energy dependent, over-responding by a factor of 10 or greater in the 100 keV range and under-responding by a factor of 0.5 above 1 MeV when normalized to 137Cs

Operating Conditions and Applications

• Operates with any Ludlum instruments or equivalent instruments that provide 500–1200 volts
• Recommended instrument input sensitivity is approximately 10 mV or higher
• Common applications include:
  • Background radiation monitoring
  • Low-level radiation detection
  • Spectrum analysis when used with a single or multi-channel analyzer

Specifications of the Instrument

• Compatible with general-purpose survey meters, ratemeters, and scalers

Sensitivity and Dead Time

• Typically 175 cpm per µR/hr for 137 Cs gamma
• Dead Time: approximately 10 µs
• Linear range limited to 5 mR/hr (50 µSv/h) without dead time correction
• Linear range extended to 50 mR/hr (500 µSv/h) with electronics equipped with dead time correction

Energy Response and Background

• Energy response is energy dependent
• Background measurement is 1800 cpm

Operating Conditions

• Operating Voltage: 500–1200 volts
• Dynode String Resistance: 100 megohm

Physical Properties

• Connector type: series ˝C˝ (others available)
• Scintillator size: 2.5 x 2.5 cm (1 x 1 in.) diameter and thickness
• Tube size: 2.9 cm (1.1 in.) diameter, magnetically shielded photomultiplier

Efficiency and Construction

• Efficiency (4 π): 7% for 125I, 10% for 57Co, 3% for 137Cs and 60Co
• Aluminum housing with beige powder-coat finish

Environmental Conditions

• Temperature Range: -15 to 50 °C (5 to 122 °F); optional certification for -40 to 65 °C (-40 to 150 °F)
• Size: 5.1 x 18.5 cm (2 x 7.3 in.) diameter and length
• Weight: 0.5 kg (1 lb)