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Ludlum Model 26 GM Detector

Radiation detection for a safer world

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Frisking people and objects for alpha & beta contamination has always been a little awkward because manipulation of the cable, detector, and electronics required the use of both hands. The new cable-less Ludlum Model 26 consolidates the electronics and the detector into one ergonomic housing. This optimized configuration incorporates a standard 15 cm² GM pancake probe, loud audio “click” output, and large auto-ranging LCD display with automatic back lighting into one convenient package, making it easier than ever to detect contamination.

Operation is kept extremely simple through the use of just two buttons. A useful feature employed in the design is the MAX mode, which captures the highest or peak count rate. It is particularly convenient whenever the display is not directly visible. The scaler mode, with a preset count time, allows the user to take a discrete measurement. This system also incorporates low power circuitry, delivering hundreds of hours of use with just two standard “AA” size batteries. The calibrator can protect parameters (cps/cpm, response time, alarm points, & scaler time) or allow the user to adjust them.

Item Numbers
5250-0155 Ludlum Model 26 GM Detector

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  • Integrated, Lightweight Design Simplifies Frisking
  • Protective Rubber Covering Enhances Ruggedness, Water Resistance, and Non-Slip Comfort
  • Employs Standard 15 cm2 GM Pancake Detector
  • Ratemeter, Peak, and Scaler Operating Modes
  • Simple Two-Button Operation
  • Count Rate and Scaler Alarms

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  • DETECTOR: pancake GM (Geiger-Mueller) detector, stainless steel screen
  • WINDOW AREA: Active: 15 cm² ( 2.3 in²); Open: 12.2 cm² (1.9 in²)
  • EFFICIENCY (4 π): Alpha: 15% for 239Pu; Beta: 19% for 99Tc; 32% for 32P; Gamma: 3300 cpm/mR/hr or 5.5 cps/μSv/hr (137Cs)
  • ALARMS: count rate and scaler alarm setpoints adjustable over the display range
  • OVERLOAD: high count rate saturation protection prevents false display of lower count rates
  • ZERO PROTECTION: unit will flash a zero reading & audio alarm if no pulses from detector after 60 seconds
  • LCD DISPLAY: 3½ digit LCD with large 12.7 mm (0.5 in.) digits, (k)cps, (k) cpm, low-battery indicator, MAX, ALARM
  • RANGE: 0.1 cps to 1.99 kcps, or 1 cpm to 99.9 kcpm
  • BACKLIGHT: built-in ambient light sensor automatically activates low-power LED backlight
  • CONTROLS: two push buttons
  • ON/OFF/QUIET: press to turn ON, tap to alternate between ‘click’ audio and QUIET,
    hold for OFF
  • MODE: alternates between NORMAL (count rate) and MAX (captures peak rate), and
  • SCALER (user-selectable preset count time from 0 to 20 minutes)
  • RESPONSE TIME: user-selectable from 1 to 60 seconds, or Auto-Response Rate FAST or SLOW
  • CLICK AUDIO: greater than 60 dB at 0.6 m (2 ft)
  • POWER: two “AA” batteries
  • BATTERY LIFE: approximately 1000 hours of operations, 16-hour low battery warning
  • CONSTRUCTION: high-impact plastic with separate battery compartment
  • SIZE: 4.6 x 6.9 x 27.2 cm (1.8 x 2.7 x 10.7 in.) (H x W x L)
  • WEIGHT: 0.45 kg (1.0 lb)

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