Models 3090-3

Area Alarm Monitor

Models 3090-3

The Model 3090-3 Area Alarm Monitor measures radiation field intensities from x-ray or gamma radiation sources in the range of 1mR/h to 100R/h. The internal detector will measure radiation in the immediate vicinity of the instrument while the remote probe can be used to measure radiation up to 300ft. from the instrument, including exterior and underwater monitoring locations. The internal and optional external detectors are Geiger-Mueller tubes. When the external detector is plugged into the readout, the internal detector is disabled. The detectors are energy compensated to obtain good energy responses. Four easily accessible calibration potentiometers are provided to accurately calibrate each instrument across their entire indicating range. The alarm setting can be observed, even in a radiation field, by pressing the "check" button on the front panel. The alarm "set" potentiometer is on the front panel also. Changes made in the "set" potentiometer can be observed using the "check" button. An alarm speaker volume control is available on the front panel for reducing the sound level in locations where it would be irritating or unwanted. A red flashing light on the readout is also used to indicate an alarm condition. All alarms are deactivated by pressing the alarm reset switch.

The accessories available for use with the area monitors include a remote readout and a door interlock kit. In addition, repair kits are available for the external probes.

FEATURES:
• Four plus decade logarithmic scale
• Alarm Check Pushbutton that permits the alarm trip point to

be viewed or set from the front panel
• Sound volume control and power on light also on front panel
• Calibration to within +20% across all decades of instrument
• Operates from internal detector or optional external probe
• External probe is waterproof to depths of 100 ft. and cable may

be up to 300 ft. in length
• Readout is small enough to sit on a shelf or may be wall

mounted with the included wall mounting brackets
• Flashing red light, speaker, and electrical output for

alarm indication
• Easily accessible calibration pots

Available with either Roentgen or SI unit scales

OPERATING CHARACTERISTICS

Units of Measure:

Roentgens (Model 3090-3) and Sieverts (Model 3090-3 Sv)

Range of Reading:

1.0 mR/h to 100 R/h (0.01 mSv/h to 1000 mSv/h)

Range of Alarm Setting:

2.0 mR/h to 100 R/h (0.02 mSv/h to 1000 mSv/h)

Readout:

Panel meter, d'arsonval movement, 250º span, 14 cm scale length (see front view of instrument for typical scale markings)

Speaker:

Sonalert >80 dBA at 2 ft. on front panel

Visual Indicators:

Power ON, LED on front panel, red alarm light on top of instrument

Controls:

Speaker volume control on front panel. Alarm "Set" potentiometer on front panel with locking nut to inhibit accidental change. Alarm "Check" pushbutton on front panel. Power switch "115/230" on side of instrument. Calibration potentiometers, four, internally mounted and accessible through covered port on top of instrument.

Power:
AC Power
DC Power

Operates from AC power and/or optional backup battery pack. Nominal 4 watts. Fused at 1/8 Amp.
115 VAC ±15%, 60 Hz or 230 VAC ±15%, 50 Hz
+ and - 9 volts connected to appropriate pins of auxiliary connector

Accuracy:

Within ±20% referred to CS137 from 2 mR/h too 100 R/h (0.02 mSv/h to 1000 mSv/h)

Response Time:

90% of final reading within 7 seconds

Exposure Rate Limit:

Remains above full scale for fields in excess of 500R/h

Warm up Time:

Warm up is less than 15 seconds

Operating Temperature Range:
Instrument:
External Probe:

-10º C to +50º C (+12º F to 122º F)
-40º C to +75º C (-40º F to 167º F)

Temperature Dependence:

Within ±20% over stated temperature ranges

Relative Humidity:

25% to 95% non-condensing

PHYSICAL CHARACTERISTICS

Connectors:
Jack #1
Jack #2
Jack #3

on left side of instrument, external probe connector, 5 pin
on left side of instrument, backup power supply and remote monitor connection, 6 pin
(Optional) on left side of instrument. This jack is added when door interlock option is purchased.

Mechanical:

Finish
Baked on enamel

Case
Material Aluminum

Dimensions
W: 3.5" (90mm)
L: 8" (210mm)
H: 4.25" (110mm)
AC line cord L: 7.5' (2.3m)

Net Weight
3.25 lbs.
(1500 gm)

Shipping Weight
5.25 lbs.
(2400 gm)

RADIATION CHARACTERISTICS

Radiation Detected:

X-Ray and Gamma

Energy Response:
Internal Detector
External Detector

±30% 80 keV to 1.33 MeV
±30% 80 keV to 1.33 MeV

Pulse Radiation Fields:

Generally not recommended for pulsed field measurement, particularly pulse widths of less than 100 mSec and duty cycles less than 10%. An evaluation unit can be provided for testing when there is a question concerning the proper operation of the area monitor.

Detector:
Internal
External

Energy Compensated, halogen quenched GM tube
Energy Compensated, halogen quenched GM tube

Detector Location:
Internal
External

Indicated by crosshairs on back, bottom, and side of instrument.
GM tube is mounted on central axis of probe with sensitive volume centered 7/8" from closed end of probe

Accumulated Dose:

GM tube life is approximately 10k Rads

Dead Time:

Approximately 15µSec, which is compensated by proper calibration of the instrument

ACCESSORIES

External Detectors:

Model 3094A-R External Probe, provided in cable lengths from 50 ft. - 200 ft.

Download PDF Operators Manual