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Model 3-98
Ludlum's Model 3-98 is uniquely configured to optimize measurements for 125I and any alpha, beta, or gamma contamination. The dual detector design allows the user to select the detector for the task at hand. The internally-housed GM pancake detector can be used to measure gamma. This detector's face can be exposed via a slide located along the bottom of the instrument, thus making it sensitive to alpha and beta as well. The external NaI detector, Ludlum Model 44-3, is optimized for low-energy gamma from 125I.
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 long 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. Also included are a standard 1-meter (39 inch) cable with series "C" connector (others available), detector clip, and two "D" cell batteries.
Features
- Dual Purpose Detection
- 125I & Alpha-Beta-Gamma Contamination
- 4-Range Analog Ratemeter
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- Rugged Construction
- 0 to 500 kcpm
- User-Selectable Internal and External Detectors
Specifications
Indicated Use:
Alpha, beta, low-energy gamma survey
Internal Detector:
Type: Pancake-style GM detector with 1.7 ± 0.3 mg/cm² window; stainless steel protective screen (79% open)
Active Area: 15.51 cm2 (2.4 in2)
Open Area: 12.26 cm2 (1.9 in2)
Efficiency (4π): 14C: 5%, 90Sr/90Y: 23%, 99Tc: 19%, 32P: 33%, 239Pu: 15%
Sensitivity (137Cs gamma): Typically 3300 cpm per mR/hr
Alpha-Beta Shield: Retractable 211 mg/cm2 phenolic slide
External Detector:
Type: Model 44-3: 125I and low-energy gamma scintillator
Efficiency (4π): 125I: 33.5% (based on 129I efficiency of 18%)
Sensitivity (125I): 675 cpm per μR/hr
Energy Range: Recommended 5 keV to 60 keV
Background (10 µR/hr): < 350 cpm
Linearity:
Reading within ±10% of true value with detector connected
Meter Dial:
0 - 5 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: x0.1, x1, x10, x100
Response Switch: Toggle switch for FAST (4 s) or SLOW (22 s) from 10% to 90% of final reading
Reset Push-Button: Push-button to zero meter
Audio Switch: Built-in unimorph speaker with ON/OFF switch (greater than 60 dB at 0.61m [2 ft])
Calibration Controls: Accessible from front of instrument (protective cover provided)
Int/Ext Switch: Selects the internal GM detector or the external detector
High Voltage:
Adjustable from 400 to 1500 V
Threshold:
-30 mV ± 10 mV
Temperature Range:
-20 to 50 °C (-4 to 122 °F)
Power:
2 "D" cell batteries (housed in sealed compartment that is externally accessible)
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:
2.5 kg (5.6 lb) including batteries and detector
Related Products
Headphone Jack
This modification for survey meters adds a headphone jack to the instrument body so headphones can be used to monitor click-per-event audio and audio alarms. Headphones are helpful when the instrument is being used in areas with high ambient noise levels or in areas where the audio would be distracting to others, such as in a medical or office environment.
Shoulder Strap
This 1.8 m (6 ft) adjustable shoulder strap is a great way to keep your hands free while operating survey meters. The nylon strap with a wide rubber comfort pad can also be helpful for conveying some of the heavier instrument/detector combinations in the field.
Model 3-IS NORM Kit
- Ready-to-Go Kit in Rugged Case
- Intrinsically Safe Analog Survey Meter
- Measures Alpha, Beta, and Gamma Contamination
- Includes:
- Model 3-IS Intrinsically Safe Survey Meter
- Model 44-9 Alpha-Beta-Gamma Detector
- Model 44-2 High Energy Gamma Detector
- Check Source, Cable, Batteries, Transport & Storage Case
Model 14C-MERK
Medical Environment Response Kit
- Model 14C Survey Meter
- Model 44-2 Gamma Scintillator Detector
- Model 44-9 Alpha-Beta-Gamma GM Detector
- Model 25 Series Personal Radiation Monitor
- Check Source and Holder
- Rugged Case
Model 2241-3MERK
Medical Environment Response Kit
- Model 2241-3 Scaler-Ratemeter
- Model 44-2 Gamma Scintillator Detector
- Model 44-9 Alpha-Beta-Gamma GM Detector
- Model 44-142 Beta Scintillator Detector
- Model 25 Series Personal Radiation Monitor
- Check Source and Holder
- Rugged Case
Model 3001-MERK
Medical Environment Response Kit
- Model 3001 Survey Meter
- Model 44-2 Gamma Scintillator Detector
- Model 44-9 Alpha-Beta-Gamma GM Detector
- Model 44-142 Beta Scintillator Detector
- Model 25 Series Personal Radiation Monitor
- Check Source
- Rugged Case
Model 14C-RK
Emergency Response Kit
- Model 14C Survey Meter
- Model 44-2 Gamma Scintillator Detector
- Model 44-9 Alpha-Beta-Gamma GM Detector
- Check Source and Holder
- Rugged Case
Cables
Ludlum offers straight cables with either type C, BNC, SHV, MHV, or UHF connectors. Unless specified otherwise, Ludlum survey meters and detectors are shipped with “C” type connectors. When a meter and accompanying probe are ordered as a matched set, Ludlum automatically includes a 99 cm (39 in.) straight-type cable with “C” connectors at no additional charge. (Note: We no longer offer coiled cables.)
Model 3002/FM Series
Alpha-Beta Floor Monitor
- Alpha-Beta Scintillation Detectors
- Active Window Area: 400 or 1080 cm2 (62 or 167.4 in2)
- 22.4, 40.9, or 65.7 cm (8.8, 16.1, or 25.9 in.) Wide Detection Path
- Adjustable Detector Height
Model 42-38
WENDI-2 Wide Energy Neutron Detector
- Detector Type:
- 3He Tube
- Moderator: 22.9 cm (9 in.) dia.
- Sensitivity (241Am/Be): 450 cpm per mrem/hr
- Detection Range: Thermal to 5 GeV
Model 78-6
Stretch Scope Survey Meter
- Analog + Digital Meter
- Extends to 3.6 m (12 ft.)
- NaI(Tl) Scintillator Detector
- Range: 0.01 to 50 µSv/h (1 to 5000 µR/hr)
Model 79/2
Stretch Scope Survey Meter
- Digital Meter
- Extends to 4.5 m (14.75 ft.)
- Internal Energy-Compensated GM
- Range: 0.001 mSv/h to 0.04 Sv/h (0.1 mR/hr to 4 R/hr)
Model 79/1
Stretch Scope Survey Meter
- Digital Meter
- Extends to 4.5 m (14.75 ft.)
- CsI(Tl) Scintillator Detector
- Range: 0.01 µSv/h to 500 µSv/h (1 µR/hr to 50 mR/hr)
Model 79
Stretch Scope Survey Meter
- Digital Meter
- Extends to 4.5 m (14.75 ft.)
- Energy-Compensated GM Detector
- Range: 10 µSv/h to 10 Sv/h (1 mR/hr to 1000 R/hr)
