Ludlum Model 15 Survey Meter

  • End Window G-M Detector for Alpha Beta and Gamma
  • BF│ Proportional Detector with Moderator for Neutron
  • 4 Ranges
  • Total Counting Range from 0 - 500,000 cpm


INDICATED USE: Fast and thermal neutron, alpha, beta-gamma survey
DETECTORS: Controlled by selector switch
NEUTRON: Model 42-9 BF│ proportional detector with 3"(7.6 cm) diameter cadmium lined moderator for fast neutrons (remove detector from moderator for thermal neutrons)
ENERGY RESPONSE: Count response is not linear throughout energy spectrum (0.025 - 8 MeV)
SENSITIVITY: Typically 60 cpm/mrem/hr (AmBe fast neutrons)
GAMMA REJECTION: Less than 10 cpm through 10 R/hr
ALPHA BETA-GAMMA: Model 44-7 thin end window G-M detector (others available)
WINDOW: 1.7 plus or minus 0.3 mg/cm▓ mica
Active - 6.4 cm▓
Open - 5.2 cm▓
EFFICIENCY(2pi geometry): Typically 5% - 14C; 20% - 90Sr/90Y; 15% - 239Pu
SENSITIVITY: Typically 2100 cpm/mR/hr (137Cs gamma)
METER DIAL: 0 - 500 cpm, 0 - 2.5 kV, BAT TEST (others available)
MULTIPLIERS: X1, X10, X100, X1000
LINEARITY: Reading within plus or minus 10% of true value
AUDIO: Built in unimorph speaker with ON/OFF switch (greater than 60 dB at 2 feet)
CALIBRATION CONTROLS: Accessible from front of instrument (protective cover provided)
RESPONSE: Toggle switch for FAST (4 seconds) or SLOW (22 seconds) from 10% to 90% of final reading
RESET: Push-button to zero meter
POWER: 2 each "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)
METER: 2.5"(6.4cm) arc, 1 mA analog type
CONSTRUCTION: Cast and drawn aluminum with beige polyurethane enamel paint
TEMPERATURE RANGE: -4░ F(-20░ C) to 122░ F(50░ C)
May be certified for operation from -40░ F(-40░ C) to 150░ F(65░ C)
SIZE: 12.5"(31.8cm)H X 3.5"(8.9cm)W X 8.5"(21.6cm)L
WEIGHT: 8 lbs(3.7 kg) including batteries

Waterproof Pelican Cases Available

Common Meter Dial

0 -500 cpm



Replacement Parts

Check Source
Standard Carrying Case
Air and Water Tight Carrying Case

Meter Bezel
Meter Movement
Probe Clip

Detector Assembly



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