Ludlum Model 177-61

   Radiation Alarm Ratemeter

Features

• 4 Decade Range

• Linear Analog Scale Readout

• Adjustable Alarms

• 50 Hour Rechargeable Battery

• Supports G-M, Proportional, and Scintillation Type Radiation Detectors

• Total Counting Range from 0 - 500,000 cpm

Introduction

The Ludlum Model 177-61 is a rugged benchtop radiation ratemeter with alarming capability. These units are very popular for frisking operations at stations where line power is available but can also be used in portable applications for up to 50 hours using the internal rechargeable battery. The 177-61 supports G-M, proportional and scintillation type radiation detectors and displays the results on a linear readout analog meter. The audio alarm is adjustable from 0 through 150% of full scale and is factory set to latching. Reconfiguration to non-latching can be accommodated via a minor internal change. Front panel controls include a 4 position rotary switch for selecting each detector decade, alarm set control, audio volume adjust, fast/slow response switch, power on/off switch and push buttons for count reset, battery test, high voltage test and alarm test. The back panel contains the power cord connection and a 9 pin type "D" plug that supports, rapid battery charging, 6 - 9.6 volts power output, alarm output, pulse output, and a recorder output.

Specifications

PART NUMBER: 48-1382

INDICATED USE: Multi-purpose radiation monitoring; frisking
COMPATIBLE RADIATION DETECTORS: G-M, proportional, scintillation
METER FACE: 0 - 500 cpm, 0 - 2.5 kV, BAT TEST (see picture below)
MULTIPLIERS: X1, X10, X100, X1k
LINEARITY: Reading within plus or minus 10% of true value with detector connected
CONNECTOR: Series "C" (others available)
AUDIO: Built in unimorph speaker with volume control (greater than 60 dB at 2 feet full volume)
ALARM: Indicated by a red lamp and full volume audible tone
DATA OUT: 9 pin series "D" connector allowing for external connections of the following items: battery; unregulated supply; instrument common ground; alarm signal (current sink); pulse out; external background subtract; and recorder output.
RECORDER OUTPUT: Correlated to meter reading (adjustable to 1 volt at 1 mA)
CALIBRATION CONTROLS: Accessible from back of instrument (protective cover provided)
HIGH VOLTAGE: Adjustable from 200 - 2500 volts (can be read on meter)
THRESHOLD: Adjustable from 2 - 60 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: 95 - 135 VAC (178 - 240 VAC available), 50 - 60 Hz single phase (less than 100 mA), 6 volt sealed lead acid rechargeable battery (built in)
BATTERY LIFE: Typically 50 hours (battery condition can be checked on meter)
BATTERY CHARGER: Battery is continuously trickle charged when instrument is connected to line power and turned on (optional external fast charger is available)
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: 5" (12.7 cm) H X 8" (20.3 cm) W X 6" (15.2 cm) L
WEIGHT: 4.2 lbs (1.9 kg)

This Product is CE Certified

Compatible Radiation Detectors

Compatible radiation detectors are listed below and are not included with the survey meter price. An additional charge will be added for each detector ordered. 

*For Mylar window scintillators it is strongly suggested that the optional overload indicator be used on the Model 177-61 Radiation Alarm Ratemeter to better determine the presence of a light leak.

Meter Face

202-158 0 - 500 cpm; 0 - 2.5 kV

Options

• Check Source

• Overload Indicator

• Low Battery Light Indicator Option - Model L-4347-155

• 4-20 mA Output (Non-Isolated) - Model L-5173-351

• 4-20 mA Outout (Isolated) - Model L-5347-079

• Shelf (or Wall) Bracket - Model L-7173-078-02

• Alarm Set Cover - Model L-7328-021

Replacement Parts

• Cables

• Meter Assembly

• Meter Movement

• Battery

Technical Information

• Model 177-61 Manual

• Model 177-61 ANSI Test Results