Model 193

microR Survey Meter

Part Number: 48-2959

Features

Used with External Scintillator Detectors
Special Algorithms for Finding Loose Sources
Alarms
Rugged

The Ludlum Model 193 Survey Meter is a portable gamma survey instrument with adjustable audio and visual alarms. The instrument is designed to be used with external scintillation detectors for optimum performance in locating and measuring low-level (near ˝background˝) gamma radiation.

The Model 193 offers two types of alarms for both experienced and inexperienced users:

A user adjustable meter-driven alarm for alarm indication above a particular set-point
A deviation beep alarm which gives indication to the rise of radiation above background levels

The unit features range multipliers of ×1, ×10, ×100, and ×1000, which provide an overall range of 0 to 5000 µR/hr when used in conjunction with a 0 to 5 µR/hr meter dial (others are available). Other features include a two-position meter response time switch, adjustable detector operating voltage (HV), and an audio ON/OFF switch. Multi-turn potentiometers are located under a removable front panel calibration cover (removed for clarity in image).

The instrument is capable of using either standard ˝D˝ cell batteries or nickel-cadmium rechargeable batteries. The two ˝D˝ cell batteries are located in an isolated compartment, easily accessible from the front panel.

Specifications

Application	Low-level (microR) gamma survey
Compatible Detectors	Scintillation
Linearity	Reading within 10% of true value
Meter Scale	0 to 5 µR/hr provides an overall range of 0 to 5000 µR/hr (other meter scales available)
Meter	1 mA, 6.4 cm (2.5 in.) scale, pivot-and-jewel suspension
Controls	Rotary Selector: Switches between instrument off, battery check, ranges: x1, x10, x100, x1000 Response Switch: Toggles between FAST (4 s) or SLOW (22 s) from 10% to 90% of final reading Reset Pushbutton: To zero meter, and also re-accumulate background data and recalculate the alarm point 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)
Alarm	The alarm is adjustable from 10% of full meter scale to greater than full meter scale. An alarm is manifested by an alarm lamp on the front panel and an audio signal.
Detector Failure	Indicated by a rapid audible beep and meter reading of zero, instrument waits for 8 s after initial power-up sequence before giving indication to a detector failure (no count) condition
Front-Panel Potentiometers	Located under a removable front panel (not shown): alarm set, discriminator, HV adjustment, range calibration adjustments (x1000, x100, x10, x1)
High Voltage	Externally adjustable and variable from 200 to 1500 Vdc
Audio Output	Built-in unimorph speaker, audible click-per-deviation; beeps for every 1/8 second interval that is 2 sigma above background level, enabled or disabled by the audio ON/OFF switch, corresponds to the ALARM lamp initiation
Power	Two standard alkaline ˝D˝ cell batteries, secured in an isolated compartment
Battery Life	600 hours
Construction	Cast and drawn aluminum with beige powder coat and silk-screened nomenclature
Size (H x W x L)	16.5 x 8.9 x 21.6 cm (6.5 x 3.5 x 8.5 in.) including instrument handle
Weight	1.6 kg (3.5 lbs.), including batteries

Options

Option	Description	Part Number
Overload Indicator Option	Adds Overload indicator with a light.	4464-130