Model 3-97

Gamma Survey Meter

Part Number: 48-1410

Features

• Wide Range from μR/hr to 200 mR/hr
• High-Sensitivity Gamma
• Rugged
• 4-Range Analog Ratemeter

The Model 3-97 provides a great solution for locating potential contamination and then accurately measuring the exposure rate, or for simply measuring the ambient exposure levels over a wide range. The instrument is equipped with an internal 2.5 x 2.5 cm (1 x 1 in.) NaI detector that is highly sensitive to gamma, with readings in the μR range between 0 to 3000 μR/hr (0 to 3 mR/hr). The instrument is additionally equipped with an external Model 44-38 energy-compensated GM to extend the detection range up to 200 mR/hr. The ratemeter is Ludlum's venerable Model 3-series, which employs a robust cast aluminum instrument housing with a separate battery compartment for long-lasting protection and instrument life. The front-panel controls include a rotary switch for selecting the 4-decade range, instrument shut-off and battery test, audio on/off switch, fast/slow response switch, count reset button, and internal/external detector switch. The Model 3-97 is a complete turn-key system with the detector cable and two "D" cell batteries.

• Specifications
• Meter Faces
• Options
• Documents
• Replacement Parts

• Specifications
• Meter Faces
• Options
• Documents
• Replacement Parts

Specifications

Indicated Use	Beta-gamma survey
Internal Detector	Type: NaI(Tl) scintillator, 2.5 x 2.5 cm. (1 x 1 in.) Sensitivity: Typically 175 cpm per μR/hr ( 137Cs gamma) High Voltage: Adjustable from 200 to 1200 V
External Detector	Type: Model 44-38 energy compensated GM detector (others available) Sensitivity: Typically 1200 cpm per mR/hr (137Cs gamma) High Voltage: Factory set for 900 V, may be adjusted from 400 to 1500 V
Linearity	Reading within ± 10% of true value with detector connected
Meter Dial	0 - 2 mR/hr, 0 - 2.4 kcpm, BAT TEST (Meter Faces tab lists other available meter faces)
Meter	6.4 cm (2.5 in.) arc, 1 mA analog type
Controls	Rotary Selector Switch: Switches between: Off, Battery Check, Ranges: x0.1, x1, x10, x100 Response Switch: Toggle switch for FAST (4 seconds) or SLOW (22 seconds) from 10% to 90% of final reading Reset Push-Button: Push-button to zero meter Audio Switch: Audio On/Off switch, Built-in unimorph speaker (greater than 60 dB at 0.61 m [2 ft.]) Calibration Controls: Accessible from front of instrument (protective cover provided) Int/Ext Switch: Selects the internal scintillation detector or the external detector
Threshold	30 mV ± 10 mV
Temperature Range	-20 to 50 °C (-4 to 122 °F)
Power	2 "D" cell batteries (housed in externally accessible sealed compartment)
Battery Life	Typically 600 hours with alkaline batteries (battery condition can be checked on meter)
Construction	Cast and drawn aluminum with beige powder coating
Connector	Series "C" (others available)
Size (H x W x L)	24.1 x 8.9 x 21.6 cm (9.5 x 3.5 x 8.5 in.) with handle
Weight	2 kg (4.4 lb) including batteries and detector, 1.4 kg (3 lb) alone

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Meter Faces

This table lists the most commonly used meter faces. Others are available upon request.

 

Meter Face	Image (click to view larger)	Description	Detectors
202-350		0 - 2.4 kcpm 0 - 2 mR/hr 0 - 200 mR/hr BAT TEST	Model 44-38
202-728		0 - 50 µR/hr 0 - 8.5 kcpm BAT TEST	Any External
202-876		0 - 0.5 µSv/h 0 - 8 .5 kcpm BAT TEST	Any External
202-993		0 - 50 µR/hr 0 - 7.2 mR/hr BAT OK	Model 44-38
202-1101		0 - 50 µR/hr 0 - 8.5 kcpm BAT TEST	Any External
202-1114		0 - 140 cps 0 - 0.5 µSv/hr BAT OK	Model 44-9

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Options

Option	Description	Part Number
Portable Scaler Option	Adds scaler counting capability. Includes digital readout, count time selector switch, and count control button.	4464-114
Lighted Handle	Handle with LED to illuminate the instrument display.	4464-154
Shoulder Strap	Adjustable nylon shoulder strap.	4363-413
Headphone Jack	Adds headphone jack to instrument.	4464-464
Stereo/Mono Headphones	Adjustable stereo/mono headphones.	22-9313
Plastic Disk Check Sources	General purpose check sources used to check instrument response.	Depends on source material and activity.

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Documents

• Data Sheet
• Product Manual
• CE Certificate

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Replacement Parts

Description	Part Number
NaI(Tl) Scintillator glued to PMT, Non-Based with Voltage Divider	2004-033
NaI(Tl) Scintillator with PMT, Non-Based with Voltage Divider	40-5154
Detector Assembly (Includes 2004-033)	47-1574

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