The Ludlum Model 3 General Purpose Survey Meter is a portable radiation survey instrument with four linear ranges used in combination with exposure rate dials. The instrument features a regulated high-voltage power supply, unimorph speaker with audio ON/OFF capability, fast-slow meter response, meter reset button and 6-position switch for selecting battery check or scale multiples of X0.1, X1, X10 and X100. Each range multiplier has its own calibration potentiometer.
The Ludlum Model 44-2 Sodium Iodide (Nal) Gamma Scintillator Detector is primarily used for detecting low levels of gamma radiation (uR) in the range of 60 keV to 1.25 MeV. It consists of a 1-inch diameter x 1-inch thick Nal crystal coupled to a photomultiplier tube and is housed in a 0.062-inch thick aluminum housing. The Ludlum Model 44-9 G-M Pancake G-M Detector will detect alpha, beta and gamma radiation in mR. Its size and shape provide easy handling for surveying or personnel monitoring.
The detector is energy dependent, over responding by a factor of six in the 60 keV to 100 keV range when normalized to 137Cs. This combination meter and detectors ship with a carrying case and certificate of calibration. A specification sheet and operating manual are available upon request.
- Detector: Pancake-type halogen quenched G-M
- Window: 1.7 ± 0.3 mg/cm2 mica
- Window Area: Active — 15 cm2; Open — 12 cm2
- Efficiency (4 pi geometry): Typically 5% for 14C; 22% for 90Sr/90Y; 19% for 99Tc; 32% for 32P; 15% for 239Pu
- Sensitivity: Typical 3300 cpm per mR/hr (137Cs Gamma)
- Energy Response: Energy dependent
- Dead Time: Typically 80 µS