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Ludlum Model 19A

MicroR Radiation Survey Meter

Introduction

● High Sensitivity Gamma Radiation MicroR Meter

● 0 to 5000 µR/hr Range

● Internal 1 x 1 in. NaI(Tl) Scintillation Detector

● Logarithmic Analog Meter

● Audio and Visual Alarming

● Splash-proof Protection for Outdoor Use

● Rugged

The Ludlum Model 19A is a highly sensitive gamma radiation MicroR survey meter with alarming capability employing an internally housed 1.0 in. diameter by 1.0 in. thick (2.5 x 2.5 cm) NaI detector. The display is an analog logarithmic meter scale with a range of 0-500 µR/hr (0-5 µSv/h), so switching between scales is not necessary as on many other instruments. The front panel controls include a three-position rotary switch for Off, Battery Check, and On, an Audio On/Off switch, and an Alarm Reset button. A red alarm light is mounted on the front panel and is accompanied by an audio signal. The alarm circuit is adjustable over the entire scale range. The cast aluminum 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 Model 19A is a complete turn-key system and includes two "D" cell batteries.

Specifications

PART NUMBER: 48-2117

APPLICATION: low level (μR) gamma radiation survey

RADIATION DETECTOR: 1 x 1 in. (2.5 x 2.5 cm) (Dia x L) NaI(Tl) scintillator
SENSITIVITY: approximately 175 cpm/μR/hr (17,500 cpm/µSv/h) (¹³⁷Cs gamma)
RESPONSE: dependent on number of counts present (typically not greater than 7 s from 10% to 90% of final reading)
ENERGY RESPONSE: energy dependent
LINEARITY: reading ±10% of true value
METER FACE: 0-500 μR/hr dual colored logarithmic scale, BAT TEST
METER: 2.5 in. (6.4 cm) arc, 1 mA analog type
ALARM RANGE: 0 to off-scale
ALARM: indicated by red lamp and audible tone (alarm audio overrides the audio ON/OFF switch)
CONTROLS:

Rotary Knob Selector: Instrument Off, Battery Check, Instrument On

Audio: ON/OFF switch, built-in unimorph speaker, greater than 60 dB at 2 ft (0.6 m)

Alarm Reset: pushbutton reset alarm

Calibration Controls: accessible from front of instrument (protective cover provided)

POWER: 2 each "D" cell batteries (housed in externally accessible sealed compartment)

BATTERY LIFE: typically 600 hours with alkaline batteries (battery check on meter)
CONSTRUCTION: cast and drawn aluminum with beige polyurethane enamel paint
WORKING ENVIRONMENT: splash-proof shields for outdoor use
TEMPERATURE RANGE: -4 to 122 °F (-20 to 50 °C), may be certified from -40 to 150 °F (-40 to 65 °C)
SIZE: 7.8 x 3.5 x 8.5 in. (19.8 x 8.9 x 21.6 cm) (H x W x L), with handle
WEIGHT: 4.5 lb (2.1 kg), including batteries