Model 52-1-1

Radiation Portal Monitor

Portable

Model 52-1 control panel Model 52-1 side view Model 52-1 carrying case

Features

The Model 52-1, 52-5, and 52-6 Series Portable Portal Monitors are used for beta-gamma contamination monitoring on personnel and meet the FEMA standard for Emergency Response Portal Monitoring (FEMA-REP-21). They are designed to be disassembled for ease of transportation and storage, and can be set up in five minutes or less without any tools.

Each instrument’s non-volatile parameters are preset at the factory to detect a 1.0 μCi 137 Cs source in a 10 μR/hr background field. Microprocessor-based electronics provide ease of setup and reliability. Status LEDs indicate count-cycle status and audible signals accompany the LEDs for additional indication. Detector counts, background, and all parameters may be viewed on the instrument display. All setup is accomplished by way of pushbuttons located below the display.

These portal monitors can be operated in a walk-through mode with a quick scan occurring while a person is positioned within the portal. In this mode, checking is performed every 200 milliseconds while the portal is occupied, and 600 milliseconds before and 600 milliseconds after the portal is occupied. The portal monitor can also monitor in a stop-and-count mode, allowing for a more sensitive scan. In stop-and-count mode, the fixed count time may be set from 1 to 20 seconds.

These instruments have automatic background update and dynamic alarm setting capabilities. On startup, the instrument will take a background count and calculate alarm levels for each detector. Self-diagnostic routines check the background count and warn if the background becomes either too high or too low.

Alarms are calculated with a user-adjustable sigma parameter and the current background count. During setup, the user can also specify individual alarms only, sum alarm only, or both individual and sum alarm. The sum alarm groups upper detectors and lower detectors.

Included with each instrument are a wheeled transport case and a clear polypropylene sleeve to protect against wet weather conditions.

These instruments are able to operate from 85 to 250 Vac, 50/60 Hz without a voltage selector switch. They may also be powered from the supplied vehicle cigarette lighter adapter, or three or six “D” cell batteries.

Specifications

Application Personnel gamma radiation monitoring
Detectors 52-1 Series: Plastic scintillator, 4 ea. 2.75 L (168 in3) on sides; Total: 11 L (672 in3)
Sensitivity In walk-through mode, this instrument will detect a 1.0 μCi (37.5 kBq) 137Cs source in a 10 μR/hr (0.1 µSv/h) background field with a portal width of 91.4 cm (36 in.) or less.
Energy Response 30 keV to 3 MeV
Detector High Voltage 700 to 1200 V
Detector Threshold -4 mV
Display 2-line x 20-character LCD shows background rates from all detectors and sigma values above background, backlit when operated from AC power; daylight-visible LEDs show instrument status and radiation alarm location
Status Indicator LEDs
Enter/Checking: Green LED, indicates system is ready for use. Flashing LED indicates a count is in progress.
Incomplete/Updating: Amber LED, indicates user has vacated the portal before counting was completed or that an update is in progress.
Radiation Alarm: Red LED and user-adjustable audible signal (greater than 60 dB at 61 cm [24 in.])
Instrument Failure: Red LED, indicates a high or low background
Low Battery: Red LED, indicates batteries need to be replaced
Count Time Adjustable from 0 to 20 seconds (0 second setting for walk-through mode)
Infrared Sensor Senses portal occupancy
Output RS-232 and relay output connectors located on the bottom of the electronics chassis
Audio Alarm with an adjustable baffle indicates portal entry and incomplete count, continuous beeping indicates radiation alarm and instrument failure. Audio can be disabled in setup mode.
Parameters All parameters are stored in non-volatile memory
Temperature Range -20 to 50 °C (-4 to 122 °F)
Power Options

Construction Aluminum housing with beige powder-coat
Environmental IP 40
Transport Case High-density plastic with wheels and dual padded handles, 122 x 61 x 30.5 cm (48 x 24 x 12 in.) (H x W x D)
Size

Weight Approx. 32 kg (70 lb), 45 kg (100 lb) in case

Ludlum Model 52-1 manual

Manual