Environmental Restoration Group

Ludlum Model 2221
Ludlum Product Description
Here's a general purpose ratemeter and scaler with just about every bell and whistle you'll ever need or want. This ultimate tool provides a customary analog display for optimally viewing the count rate and rate of change through all possible 6 decades of display. It is accompanied by a digital LCD which can present either the countrate data or be switched over to read the scaler counts. What makes this instrument so well liked by experts is its rich array of logically arranged discrete controls on the front panel that permit precise control of the desired measurement. Control functions available include, decade range selection, scaler count time, power on/off, response setting, LCD analog/digital switch, PHA window switch, lamp, audio divide by, audio volume, count zeroing, scaler start and halt. The wide range high voltage supply supports a wide variety of detectors with additional threshold and window settings that facilitate switching between gross counts and the energy band.


INDICATED USE: Field analysis
SUGGESTED DETECTORS: GM, proportional, scintillation
AUDIO: Built in unimorph speaker with volume control
AUDIO DIVIDE: Toggle switch for 1, 10, or 100 events-per-click
AUDIO JACK: For optional headset
METER DIAL: 0 - 500 cpm; 50 - 500k cpm logarithmic scale (others available)
MULTIPLIERS: X1, X10, X100, X1K, and LOG for logarithmic scale
DIGITAL DISPLAY: 6 digit LCD display with 0.5" (1.3 cm) high digits
LCD BACKLIGHT: Activated by LAMP switch
DIGITAL RATEMETER: Provides a digital display of count rate when selector switch is in Dig. Rate position
SCALER: Range from 0 - 999999 counts
NOTE: Scaler or digital ratemeter is active when not selected, allowing for concurrent use
TIMER: Switch selectable divisions of 0.1, 0.5, 1, 2, 5, 10 minutes or CONT (continuous) for manual timing
HIGH VOLTAGE: Adjustable from 200 - 2400 volts (can be checked on display)
THRESHOLD: Adjustable from 100 - 1000 (can be checked on display)
WINDOW: Adjustable from 0 - 1000 above threshold setting (can be turned on or off)
GAIN: Adjustable from 1.5 - 100 mV at a threshold setting of 100
OVERLOAD: Senses detector saturation. Indicated by on LCD display and meter going to full scale (adjustable depending on detector selected)
POWER: 4 each D cell batteries
BATTERY LIFE: Typically 250 hours with alkaline batteries (battery condition can be checked on digital display)
SIZE: 9" H x 4.3" W x 10" L (22.9 x 10.9 x 25 cm) including handle
WEIGHT: 5.5 lbs (2.5 kg) including batteries
RS-232 OUTPUT OPTION: Part No. 4261-148: This option facilitates exporting data to be read as output to a computer or serial printer from either the ratemeter or scaler reading. 
8809 Washington St. NE Suite 150
Albuquerque, NM 87113
Tel: (505) 298-4224
Fax: (505) 797-1404