MicroR Ratemeter - Model 193
CE Seal

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 avid and inexperienced users:
  1. A user adjustable meter-driven alarm for alarm indication above a particular set-point
  2. 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 microroentgens per hour (µR/hr) when used in conjunction with a 0 to 5µR/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.