The GMS1800b Laboratory Counter can be used with most common types of Geiger or Scintillation radiation detectors.

Measurement results are displayed on a large backlit LCD display. The Laboratory Counter also provides an audible indicator, which emits short clicks at lower count rates, and may also be used as an alarm indicator in rate meter mode.

The Laboratory Counter may also be used to count digital pulse signals from standard Alpha and Beta detector drawer units (such as the AEA Technology types ‘ADU’ and ‘BDU’, 0744, 0771 and 0772), or from other instruments providing digital pulse output signals. Two independent digital inputs are provided.

The GMS1800b Laboratory Counter is powered either by an internal rechargeable battery or externally by a mains supply unit, which recharges the battery at the same time. The instrument can also operate from a 12V DC source such as a vehicle battery, making it convenient for mobile field surveys.

  • Two digital inputs for AEA drawer units
  • Input for Scionix CdTe probe
  • Battery & mains power
  • Suitable for laboratory or field use
  • Output to computer or printer
  • User-selectable time interval
  • User-selectable count limit Dead-time correction
  • Variable HT voltage 300V-2000V
  • Ratemeter function with bar graph display and audible alarm
  • Probe set-up parameter library
  • Audible indicator & headphone output
  • Robust metal case
  • Auto plateau plotting
Item Data
Geiger & Photomultiplier detector (SHV connector and optional PET100 connector).
AEA Drawer Units ADU, BDU, 0744, 0771, 0772, 956012 (alpha), 956025 (beta) and compatible probes (9-pole D connector).
Digital Inputs - TTL and RS422
Scionix CdTe Probe (LEMO connector) Outputs
RS232 for logging results to a computer or PDA. All counting results are output via the RS232 port, and each result is assigned a unique identification number.
HT voltage 20V – 2000V 0.5mA.
Counting & Timing
Max count rate All inputs: 150kHz
Max Count 4,294,967,295 (232–1).
Duration Maximum (free running) count duration is 99,999s.
Repeat Automatic repeat counting operation up to 10 times, with count results retained for review, or up to 250 times, with count results logged via the RS232 port.
Dead-time Dead-time correction using user-selectable dead-time values, and background subtraction.
Alphanumeric Display 4 line 20 character LCD with LED backlight.
Power Indicator Yellow lamp is lit when the instrument is powered.
Counting Indicator Green lamp is lit while counting, flashes when the count is completed.
HT Indicator Red lamp is lit when HT voltage is on.
Configuration Control PIN-code access control on configuration settings.
Main Buttons Three control buttons used together with menu captions shown on the display.
Selector Switch Selects the counting time, or Count limit, or ratemeter time-constant, and also switches the instrument on.
A rotary control Adjusts HT voltage & other set-up values.
Battery Battery isolation switch on rear panel.
Power Supplies
Internal Maintenance-free lead acid battery.
External Mains operation: 240V AC or universal input (110-240V AC) options.
Vehicle 12V DC supply adapter for vehicle operation, 2.1mm DC power socket on rear panel.
Battery Operation
Life 6-10 hours battery operation depending on the type of detector in use.
Status Battery voltage is shown on display.
Rating IP 30
Temperature range 0ºC to +40ºC.
Physical Dimensions
Case Strong metal case made of aluminium sheet with cast front bezel. Two front feet can be extended for easy viewing.
Size H 100 mm (feet folded in), D 280 mm W 250 mm,
Weight 2.8 kg
Get in touch with The JCS team
Request JCS Certificates
Please let us know which certificates you need.