GMS1800a | JCS Nuclear Solutions

The GMS1800a can be used with industry standard Alpha and Beta detector drawer units (such as the AEA Technology I Harwell Instruments types ‘ADU’ and ‘SDU’, 0744, 0771 and 0772), or with other instruments providing digital pulse output signals.

The Laboratory Counter is a microprocessor based unit which may be used to count digital pulse signals over a range of user selectable counting periods. It is a compact and robust unit suitable for laboratory or field use.

GMS1800a 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.

The unit provides two counting channel inputs and displays the accumulated counts in each channel over a user- selected counting period. The unit may alternatively display the count difference between the two input signals.

Features at a glance

Two independent counting inputs
Simple operation
Battery & mains power
Suitable for laboratory or field use
Output to computer or printer
User-selectable time interval
50kHz maximum counting rate
Deadtime correction
Maximum count > 4×10⁹
Robust metal case

Specifications

Item	Data
Inputs	‘ADU’ Alpha Drawer Unit & Type 0744, 956012
	‘BDU’ Beta Drawer Unit & Types 0771,0772, 956025
	TTL
Outputs	RS232 for connection to a computer or printer
Counting
Maximum Rate	50kHz on each input
Maximum Count	4,294,967,295 (232⁻¹)
Duration	Maximum (free running) count duration is 99,999 sec.
Repeat	Automatic repeat counting operation up to 10 times, with individual count results retained for review
Dead time	Provides dead time correction, using user defined dead time values
Indicators
Alphanumeric Display	4 line 16 character LCD with LED backlight
Power Indicator	Yellow lamp is lit when the instrument is powered
Counting Indicator	Counting Indicator - A green lamp is lit when the instrument is counting, and the lamp flashes when the count is completed.
Power Supplies
Internal	Maintenance-free lead acid battery
External	Mains operation, 240VAC or universal input (110~240VAC) options
Vehicle	12V DC supply adapter for vehicle operation 2.1 mm DC power socket on rear panel
Controls
Main Buttons	Two Control Buttons which are used together with menu captions shown on the display
Main Dial	A rotary control selects the count duration (10, 30, 60, 100, 300, 600, 1000, 1800, 3600 seconds and free running), and also switches the instrument on.
Battery	Battery isolation switch on rear panel
Battery
Life	>10 hours battery operation with two drawer units connected
Status	Battery voltage is shown on display
Environmental
Environmental Protection	IP 30
Temperature Range	Temperature range +5°C to +40°C
Case	Strong metal case made of aluminium sheet with cast front bezel, Two front feet can be extended for easy viewing
Size	H100 mm (feet folded in), D200 mm, W230 mm
Weight	2.2 kg