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  • Ludlum model 2221 Scaler/Ratemeter SCA with Top loaded RS-232 adapter for GPS use-Like new

$4,400.00 $2,200.00

1 in stock

These portable Digital Scaler /Rate Meters are like new condition and all bench tested to assure working status.  Easy to switch settings for various probes.

These differ from the standard Model 2221 because they have the top face mounted RS-232 adapter option from Ludlum.  See the photos and the small coaxial connection under the handle.

●  Digital Radiation Ratemeter with Built-In Scaler

●  Dual Analog Meter and Digital LCD Presentation

●  Rich Array of Discrete Front Panel Controls with digital output of each reading

●  Single Channel Analyzer with threshold settings for alpha, beta, and gamma discrimination

●  Wide Range HV

●  Overload Protection

●  Supports GM, Proportional and Scintillation Detectors

Add a Counts.Pro for $499 to digitize your surveys and turn your meter into a digital scaler/ratemeter/cloud connected GPS datalogger!  Take your meter to the next level with Counts.Pro

– See full spec’s below.

The Ludlum Model 2221 is a general purpose radiation ratemeter and scaler that provides both an analog and digital display for optimally viewing the count rate and rate of change through all possible four decades of display. The digital LCD can present either the count rate data or be switched over to read the scaler counts. It has a 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/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. The instrument housing is cast aluminum with a separate battery compartment and accompanying metal handle. This design delivers industrial robustness, quality, capability, and versatility that is difficult to surpass anywhere.

These differ from the standard Model 2221 since they have the modification to allow datalogging with a GPS unit.  This is a Ludlum installed modification found on these meters.  See the small coaxial connection under the handle, and a photo of the actual board.

This meter is great for industrial use and with the Scaler function is a fantastic all around meter for performing all sorts of surveys and even counting samples.  We sell a lot of these with a 2X2 NaI detector which is the industry standard for performing walkover surveys.  We also supply these with our floor monitor carts.  

For civil defense, you can perform long term counts of samples to detect even trace levels of radioactivity. We sold a lot of these during the Fukushima incident with a 2×2 NaI to home users and Sushi importers and exporters!  Note that we have quite a few of these.  Some look better than others, but they are all fully functional.  We sell the best looking ones on a first come, first served basis.  If you want a photo of the actual unit you will buy, let us know and we will send you one.

We are near a Ludlum Measurements Lab and can drop these meters off to have an RS-232 connection applied to them at cost ($460.00 in Dec of 2015) by the Ludlum Lab.


APPLICATIONS: radiation field analysis

RATEMETER: provides a four-decade analog display that is operational any time the instrument is turned on, the ratemeter can also be presented on the accompanying LCD as a digital value when the LCD is switched to the “Dig. Rate” position
SCALER: range from 0-999999 counts
TIMER: switch selectable divisions of 0.1, 0.5, 1, 2, 5, 10 minutes or CONT (continuous) for manual timing
CONCURRENT USE: scaler or digital ratemeter is active when not selected, allowing for concurrent use

HIGH VOLTAGE: adjustable from 400-2400 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)

CONNECTOR: series “C” type (can switch to BNC or other for $30 extra).
METER FACE: 0–500 cpm, 50–500k cpm logarithmic scale (others available)
DIGITAL DISPLAY: 6-digit LCD display with 0.5 in. (1.3 cm) high digits
LCD BACKLIGHT: activated by LAMP switch

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

Power Switch: On/Off

Scale Selector Switch: x1, x10, x100, x1K, Log

Response Switch: toggles between FAST (4 s) or SLOW (22 s) from 10% to 90% of final reading

Meter Zero Pushbutton: to zero meter

Audio Volume Knob: adjusts volume of audio output
Audio Divide Switch: divides audio clicks by either 1, 10, or 100

Meter Lamp Switch: illuminates meter
Window Switch: for selecting between wide open window counts or a narrower setting for viewing a specific energy band

Scaler Count Time Selector Switch: 0.1, 0.2, 0.5, 1, 2, 5, or 10 minutes

Count Pushbutton: starts or resets scaler count
Count Hold Pushbutton: stops scaler count and leaves result in the display
Scaler/Digital Rate Switch: selects which mode is presented on the LCD
Test Buttons: battery, high voltage, threshold, window

Calibration Controls: recessed screwdriver adjustments with calibration cover

POWER: 4 each “D” cell batteries

BATTERY LIFE: typically 250 hours with alkaline batteries (battery check on meter)
SIZE: 9 x 4.3 x 10 in. (22.9 x 10.9 x 25.4 cm) (H x W x L) including handle
WEIGHT: 5.5 lb (2.5 kg) including batteries

Additional information

Weight 7 lbs