Ludlum offers our Model 44-9 GM pancake detector with a removable energy compensation filter that flattens the energy response to facilitate measuring Ambient Equivalent Dose (Sieverts).
The venerable GM pancake detector has a significant over-response at lower energies between approximately 20 to 160 keV (see red line on graph below). Any dose measurements taken with an unfiltered GM pancake detector would thus have unacceptable errors at these lower energies. This filter developed by Ludlum 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 measurement is desired. The filter is then easily removed to measure contamination (cpm or Bq).
Note: This filter is designed to fit Model 44-9 Series of Radiation Detectors with serial number 97000 and higher. It will not fit the Model 44-9-13 or older units unless modified.
