Ludlum Model 3 With 44-9 pancake-type detector

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This is Ludlum's best selling, general purpose, handheld analog ratemeter known for accuracy and long-lasting dependability. The analog meter comes in a variety of measurement ranges and units to support the external radiation detector selected.

The aluminum cast instrument housing with its separate battery compartment and accompanying metal handle offer an industrial robustness and quality that promote long-lasting protection and instrument life. The front-panel controls include a rotary switch for selecting the four-decade range, instrument shut-off, battery test, an audio on/off switch, a fast/slow response switch, and a count reset button.

Specifications

APPLICATION: alpha, beta, and gamma surveying
DETECTION RANGE: typically 0-200 mR/hr, or 0-500,000 cpm

COMPATIBLE DETECTORS: GM, scintillation

LINEARITY: reading within 10% of true value with detector connected
HIGH VOLTAGE: adjustable from 400-1500 Vdc
THRESHOLD: fixed at 40 mV Â± 10 mV

METER DIAL: 0-2 mR/hr, or 0-500 kcpm, BAT TEST
METER: 6.4 cm (2.5 in.) arc, 1 mA analog type

CONTROLS:

Rotary Selector: switches between instrument off, battery check, ranges: x0.1, x1, x10, x100
Response Switch: toggles between FAST (4 seconds) or SLOW (22 seconds) from 10% to 90% of final reading
Reset Pushbutton: to zero meter
Audio Switch: for audio on/off, built-in unimorph speaker, greater than 60 dB at 0.6 meters (2 ft)
Calibration Controls: accessible from front of instrument (protective cover provided)

CONSTRUCTION: cast and drawn aluminum with beige powder coat
CONNECTOR: series â€œCâ€
TEMPERATURE RANGE: -20 to 50 Â°C (-4 to 122 Â°F), may be certified for operation from -40 to 65 Â°C (-40 to 150 Â°F)
POWER: two each â€œDâ€ cell batteries (housed in externally accessible sealed compartment)
BATTERY LIFE: typically greater than 2000 hours with alkaline batteries (battery condition can be checked on meter)
SIZE: 16.5 x 8.9 x 21.6 cm (6.5 x 3.5 x 8.5 in.) (H x W x L), including handle
WEIGHT: 1.6 kg (3.5 lb), including batteries

The GM pancake-type detector in the Model 44-9 is arguably the most popular radiation detector used throughout the world. This detector is sensitive to alpha, beta, and gamma radiation, is enclosed within a rugged metal enclosure, and is conveniently shaped and sized for checking contamination on people and objects.

This detector operates between 85 to 1000 volts, and is compatible with any Ludlum instrument capable of supplying 900 Vdc and an input sensitivity of 30 mV or higher.

Specifications

INDICATED USE: alpha, beta, gamma survey; sample counting
DETECTOR: pancake-type, halogen-quenched GM
WINDOW: 1.7 + 0.3 mg/cmÂ² mica
WINDOW AREA: 15 cmÂ² (2.3 inÂ²) active, 12 cmÂ² (1.9 inÂ²) open
EFFICIENCY (4Ï€): 5%-¹⁴C; 22%-⁹⁰Sr/⁹⁰Y; 19%-⁹⁹Tc; 32%-³²P; 15%-²³⁹Pu, â‰¤ 1%-^99mTc
SENSITIVITY (¹³⁷Cs gamma): 3300 cpm/mR/hr
ENERGY RESPONSE: energy dependant
BACKGROUND: 60 cpm
DEAD TIME: 80 microseconds
OPERATING VOLTAGE: 900Vdc

CONNECTOR: series "C" (others available)

INPUT SENSITIVITY: â‰¥ -30 mV
CONSTRUCTION: aluminum housing with beige powder-coat finish

TEMPERATURE RANGE: -15 to 50 Â°C (5 to 122 Â°F), may be certified for operation from -40 to 65 Â°C (-40 to 150 Â°F)
SIZE: 4.6 x 6.9 x 27.2 cm (1.8 x 2.7 x 10.7 in.) (H x W x L)
WEIGHT: 0.5 kg (1 lb)