Analog Survey meter with external pancake detector

SPECIFICATIONS(BODY)
COMPATIBLE DETECTORS: GM, proportional,
scintillation
HIGH VOLTAGE: adjustable from 400 to 1500 Vdc
THRESHOLD: fixed at 40 mV ± 10 mV
LINEARITY: within 10% of true value
CONTROLS:
• Rotary Selector Switch: off, battery check, range selections for x0.1, x1, x10, x100
• Reset: pushbutton to zero meter
• Response Switch: toggles between FAST (4 seconds) or SLOW (22 seconds) from 10% to 90% of final reading
• Audio Switch: on/off, built-in unimorph speaker, 60 dB at 61 cm (2 ft)
• Calibration Controls: accessible from front of instrument (protective cover provided)
CONSTRUCTION: cast and drawn aluminum with beige powder coating
METER DIAL: 0–2 mR/hr, or 0–500 kcpm, BAT TEST (others available)
DETECTOR CONNECTOR: type “C” series (others available)
TEMPERATURE RANGE: -20 to 50 °C (-4 to 122 °F)
May be certified for operation from -40 to 65 °C (-40 to 150 °F)
POWER: two each “D” cell batteries (housed in externally accessible sealed compartment)
BATTERY LIFE: typically greater than 2000 hours with alkaline batteries (battery
condition can be checked on meter)
SIZE: 16.5 x 8.9 x 21.6 cm (6.5 x 3.5 x 8.5 in.) (H x W x L)
WEIGHT: 1.6 kg (3.5 lb), including batteries
 
SPECIFICATIONS(Detector) 
       Model 44-9 GM pancake detector with a removeable energy compensation filter that flattens the energy response to facilitate measuring Ambient Equivalent Dose (Sieverts).  And also offers another filter for Exposure.   
         As most know, the venerable GM pancake has a significant over-response at lower energies between approximately 20 to 160 keV (see red line on graph below).  Any exposure or dose measurements taken with an unfiltered GM pancake detector would thus have unacceptable errors at these lower energies.     
          This  filter developed by flattens the response to within  ± 20% referenced to 137Cs (662 keV) over an energy range of 20 keV to 1.2 MeV . 
         This filter simply snaps on across the face of the Model 44-9 GM pancake probe whenever this type of measurements is desired.  The filter is then easily removed to continue on with measuring contamination (cpm or Bq).