LUDLUM Model 3 General Purpose Ratemeter

This general purpose, handheld analog ratemeter supports operating two separate radiation detectors. A switch allows the user to select between the internally mounted GM detector with an exposure range of 0–20 mSv/h (0–2000 mR/hr) or an external GM or scintillator detector of choice (see table below).

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 five-decade range and instrument shut-off, an audio on/off switch, a fast/slow response switch, a high voltage display button, and a battery test button.
 
The analog meter face comes in a variety of options to support the measurement units and ranges for the additional external detector selected. A one meter (39 in.) straight type detector cable with "C" style connector is included in the price of the instrument.

The Ludlum Model 3 Survey Meter is the industry standard of radiation survey meters. The meter has a rugged design and microprocessor electronics. With proper care, the Ludlum Model 3 will last decades. It operates on two " D" cells for approximately 2000 hours. The Ludlum Model 3 has adjustable high voltage to 1500 volts and includes external calibration controls. The four counting ranges are x0.1, x1, x10, x100. ( Dual scale, mR/ hr & cpm available on special request.) Typical Counting Range is from 0 - 200 mR/ hr, or 0 - 500, 000 cpm. The Ludlum Model 3 is supplied as shown with built-in speaker, strain relief cable, probe clip-on handle, two " D" cell batteries and standard factory calibration. Model 44-3 or 44-2 gamma scintillator probes and many others can also be used with this meter.

INDICATED USE: General purpose survey
COMPATIBLE DETECTORS: G-M, scintillation
METER DIAL: 0 - 2 mR/ hr, or 0 - 5k cpm, BAT TEST ( others available) 
MULTIPLIERS: X0.1, X1, X10, X100
LINEARITY: Reading within ± 10% of true value with detector connected
CONNECTOR: Series " C" ( others available) 
AUDIO: Built in unimorph speaker with ON/ OFF switch ( greater than 60 dB at 2 feet) 
CALIBRATION CONTROLS: Accessible from front of instrument ( protective cover provided) 
HIGH VOLTAGE: Adjustable from 200 - 1500 volts
THRESHOLD: 30 mV ± 10 mV
RESPONSE: Toggle switch for FAST ( 4 seconds) or SLOW ( 22 seconds) from 10% to 90% of final reading RESET: Push-button to zero meter
POWER: 2 each " D" cell batteries ( housed in sealed compartment that is externally accessible) 
BATTERY LIFE: Typically greater than 2000 hours with alkaline batteries ( battery condition can be checked on meter) 
METER: 2.5" ( 6.4 cm) arc, 1 mA analog type
CONSTRUCTION: Cast and drawn aluminum with beige polyurethane enamel paint
TEMPERATURE RANGE: -4° F( -20° C) to 122° F( 50° C) 
May be certified for operation from -40° F( -40° C) to 150° F( 65° C) 
SIZE: 6.5" ( 16.5 cm) H X 3.5" ( 8.9 cm) W X 8.5" ( 21.6 cm) L
WEIGHT: 3.5 lbs. ( 1.6 kg) including batteries